Introduction

While the prior page was more about colonization motivation and methods, this page is more about good planets, hell-hole planets, scouting good planets, and changing hell-hole planets into good planets.

Galactic Neighborhood

First off, galactic empires tend to be spherical. This is because they generally start from a point (the homeworld) and expand in all directions like blowing up a balloon.

Which means they are subject to a sort of cube law. This means if the radius of an empire expands a teeny-tiny bit, the volume of the empire will expand lots and lots. Specifically if the radius doubles the volume will increase about eight times (23). This is because the equation for a volume of a sphere is 4/3 πr3, but the dramatic increase in volume is not obvious by just eye-balling the equation.


If you are mapping your empire, you will need to figure some sizes. If you decide upon the empire's radius and want to know how many stars and stars with Terran-type planets, use the rules of thumb:

Nstars = Rly^3 * 0.01

NhStars = Rly^3 * 0.0022

where

  • Rly = empire radius in light years
  • Nstars = number of stars
  • NhStars = number of stars with human habitable planets

If you decide upon the number of stars in the empire and want to know it's radius:

Rly = cubeRoot(Nstars * 97)

Rly = cubeRoot(NhStars * 464)

(If your calculator does not have a cube root button, you can use the "Xy" button instead. Type in the number, hit Xy, type in 0.333333333 then hit the equal button.)

Note: the above equations are based upon the work of Jill Tarter and Margaret Turnbull. They were not trying to figure out which stars could host a human habitable planet. They were trying to figure out which stars could host a planet that was not so hideously uninhabitable that no possible form of life could live there. In other words, many of these planets could host alien life forms but would quickly kill an unprotected human being. The equations were derived by me using an analysis of the Habcat database, and thus could be wildly inaccurate. If you can find better figures, use them, but these are better than no figures at all.

If my slide rule isn't lying to me, this works out to an average distance between adjacent stars of 9.2 light years, and an average distance of 15.4 light years between adjacent habitable stars.

Example

You have decided that the NeoRoman Star Empire will contain 10,000 habitable planets. How wide is it? cubeRoot(10,000 * 464) = cubeRoot(5,643,000) = 167 light years radius = 334 light years in diameter.

Example

In his Flandry of Terra novels, Poul Anderson specified that the Terran Empire was four hundred light years in diameter. How many stars will it probably have? A sphere 400 light years in diameter has a 200 light year radius. 200^3 * 0.01 = 8,000,000 * 0.01 = 80,000 stars. Anderson cites a figure of about four million stars, which means one of us is a bit off the mark (probably me).

OUTPOST OF EMPIRE

Why, I shall tell you what we are and these are, John Ridenour. We are one more-or-less intelligent species in a universe that produces sophonts as casually as it produces snowflakes. We are not a hair better than our great, greenskinned, gatortailed Merseian rivals, not even considering that they have no hair; we are simply different in looks and language, similar in imperial appetites. The galaxy—what tiny part of it we can ever control—cares not one quantum whether their youthful greed and boldness overcome our wearied satiety and caution. (Which is a thought born of an aging civilization, by the way).

Our existing domain is already too big for us. We don't comprehend it. We can't.

Never mind the estimated four million suns inside our borders (Terran Empire has diameter of 400 light-years, 200 light-year radius). Think just of the approximately one hundred thousand whose planets we do visit, occupy, order about, accept tribute from. Can you visualize the number? A hundred thousand; no more; you could count that high in about seven hours. But can you conjure up before you, in your mind, a wall with a hundred thousand bricks in it: and see all the bricks simultaneously?

Of course not. No human brain can go as high as ten.

Then consider a planet, a world, as big and diverse and old and mysterious as ever Terra was. Can you see the entire planet at once? Can you hope to understand the entire planet?

Next consider a hundred thousand of them.

No wonder Dietrich Steinhauer here is altogether ignorant about Freehold. I myself had never heard of the place before I was asked to take this job. And I am a specialist in worlds and the beings that inhabit them. I should be able to treat them lightly. Did I not, a few years ago, watch the total destruction of one?

Oh, no. Oh, no. The multiple millions of … of everything alive … bury the name Starkad, bury it forever. And yet it was a single living world that perished, a mere single world.

No wonder Imperial Terra let the facts about Freehold lie unheeded in the data banks. Freehold was nothing but an obscure frontier dominion, a unit in the statistics. As long as no complaint was registered worthy of the sector governor's attention, why inquire further? How could one inquire further? Something more urgent is always demanding attention elsewhere. The Navy, the intelligence services, the computers, the decision makers are stretched too ghastly thin across too many stars.

And today, when war ramps loose on Freehold and Imperial marines are dispatched to fight Merseia's Arulian cat's-paws—we still see nothing but a border action. It is most unlikely that anyone at His Majesty's court is more than vaguely aware of what is happening. Certainly our admiral's call for help took long to go through channels: "We're having worse and worse trouble with the hinterland savages. The city people are no use. They don't seem to know either what's going on. Please advise."

And the entire answer that can be given to this appeal thus far is me. One man. Not even a Naval officer—not even a specialist in human cultures—such cannot be gotten, except for tasks elsewhere that look more vital. One civilian xenologist, under contract to investigate, report, and recommend appropriate action. Which counsel may or may not be heeded.

From OUTPOST OF EMPIRE by Poul Anderson (1967)

Galactic Survey

This section has been moved here.

Colonizable Worlds

If your first-in scouts have given you the luxury of lots of human-habitable worlds to choose your colony sites from, naturally you will pick the ones closest to being paradise planets.

If all the planets range from miserable hell-holes to utterly uninhabitable you have roughly five options:

BEZOS AND MUSK ARE SHAPING THE WORLDVIEWS OF FUTURE SPACE SETTLEMENTS

The divergence of human exocivilizations both from terrestrial civilization and from each other will be in evidence to the careful observer early on in their development.

While living on Mars will not be easy, it will be far more planet-like than living in an entirely artificial habitat. We are the kind of beings that evolve on a planetary surface, i.e., our bodies and our minds both were shaped by our planetary endemism, and this homeworld effect is expressed in our characteristic modes of life and thought. Human instincts for planetary life will be seamlessly exapted for life on Mars, and, farther in the future, for life on other planets.

The Martian settlers would have a homeworld, albeit a homeworld other than Earth. Martian parents will indicate a point of light in the sky as Earth to their children, and these children may or may not be interested depending on their inclination to astronomy (for Earth would now be an object of astronomy), but their lives will be on Mars, i.e., Mars will be the site of the lived experience of planetary endemism, and the lived experience of planetary endemism is the homeworld effect.

One can imagine, whatever the comforts of a well-constructed artificial habitat, that the residents of O’Neill cylinders (as well as Stanford toruses and Bernal spheres, if such are built), if they are born on Earth, will continue to think of Earth as their homeworld, and this will result in the societies of artificial habitats being more tightly-coupled to terrestrial civilization than Martian societies. The viewpoint of residents of artificial habitats will more closely reflect terrestrial viewpoints than those of Martian settlers. The ever-present, palpable immediacy of the overview effect for those in artificial habitats in Earth’s vicinity will be a continual reminder of the connection to terrestrial civilization, reinforcing the tie.

If residents are born on the habitat, the tie to Earth is likely to be somewhat weakened, and they may feel the want of a homeworld, if only on a subconscious level. Perhaps they will evolve a distinctive sense of identity apart from planetary endemism, or they may go in search a of world to call home. These two possibilities suggest an eventual bifurcation of the population upon lines of inherent geocentrism, with this cognitive expression of individual variability becoming a source of social tension and eventually a selection pressure on the population.

Both experiences—those of Mars and those of artificial habitats—will be strongly selective, and they will select different traits, both of body and mind. The adaptive radiation of humanity in the cosmos will begin with these early spacefaring settlement efforts, but biological and cognitive adaptation to changed circumstances will still be in the far future when the first settlers are making themselves at home on Mars, and the first artificial habitats are being built and occupied. During the earliest stages in the development of spacefaring civilization, the adaptation will primarily be that of individual attitudes.

As spacefaring civilization continues to develop, artificial habitats are likely to be constructed at a distance from Earth beyond which the overview effect tapers off, and eventually where Earth is just another star in the sky, as on Mars. Here, the selection pressure either to evolve a distinctive conception of humanity in space, or to find a homeworld, would be magnified. If spacefaring civilization endures for biologically significant periods of time, and populations evolve under these selection pressures, the early attitudinal differences within populations will become the basis of speciation and adaptive radiation. One might call this the founder effect for spacefaring civilization.

Habitable Planets

HABITABLE

HABITABLE. Any PLANET that people (mainly EARTH HUMANS) can live on without having to wear a space suit or at least an oxygen supply. Habitable Planets fall mostly into two classes.

     1) Paradises. These are almost exactly like Earth — more precisely the Garden of Eden, or at least coastal California. Summers are baskingly warm, winters briskly cool, and the rain falls only at night. Landforms have dramatic variety, a typical planetscape resembling San Francisco Bay, only with the Sierras in place of the Oakland hills. These Planets teem with native life forms that we can eat (and tasty to boot; see FOOD), but none — either carnivores or microbes — who eat us. It is easy to understand why COLONIZATION happened on these Planets. Who wouldn't want to live on one, if you could?

     2) Hells. These nominally Habitable Planets pose greater challenges for interstellar real estate promoters. The entire Planet usually has only one climatic zone, and it isn't mediterranean. Desert Planets seem to be most common, followed by ice-age Planets, steaming jungle Planets, and howling windswept steppe Planets. The local life is mostly inedible, but it can eat us with no problem, and does so whenever it can catch us. It is difficult to understand why Colonization happened on these Planets. Perhaps they produce something valuable in TRADE, but if so the Colonists never seem to benefit, since they are mostly poor. If even limited TERRAFORMING is available, you would think that someone would give these Planets a bit of touch-up.

 

From HABITABLE by Rick Robinson
GARDEN WORLDS, PARK WORLDS

In the old days, interstellar colonization was pretty simple and straightforward (once you had a starship handy). Heinlein, naturally, provided the real estate pitch:

"Imagine a place like Earth, but sweeter than Terra ever was … forests aching to be cut, game that practically jumps into the stew pot. If you don't like settlements, you move on until you've got no neighbors, poke a seed in the ground, then jump back before it sprouts. No obnoxious insects. Practically no terrestrial diseases and no native diseases that like the flavor of our breed." (Starman Jones, Ballantine pback, p. 68.)

Nova Terra, to be sure, was the pick of the lot. In the same book Heinlein alludes to harsh colony worlds – and later on, an Eden planet turns out to have non-prelapsarian locals already in possession, who intend to stay that way. But given a sky full of stars and a ship to get you there, why settle for the also-rans? Heinlein also supplied a host of secondary tropes, such as the utility of horses that can fuel themselves from a handy pasture and (given a stallion and a mare) manufacture their own replacements.

Unfortunately, as commenter Ian M. noted a couple of months back (in comments spinning off a post about the Moon), it is desperately unlikely to work out that way. Suppose a planet with complex life, and enough of it to have built up an oxygen-rich atmosphere. It may look like Paradise, or at any rate Earth. Convergent evolution might well produce para-forests and para-grasslands, just as dolphins have a similar configuration to fish. But dophins aren't fish, and alien life almost certainly will not be like us. Hydrocarbon life anywhere will be built out of the same basic building blocks, but with differing architectural details – and our digestive keys will not fit its nutritional locks.

The good news is that the local tigers and local germs won't find us tasty and nutritious. But by the same token we can't eat the local venison or berries, and chances are only slightly better that our cattle can graze on the grass. Plants have a far less demanding diet, and might well grow nicely in any soil that has nitrogen fixed in it. In fact they might grow too well, at least the ones that don't rely on bees or other terrestrial creatures as their dating service.

Terrestrial plants, devoid of natural enemies, might crowd the native stuff out of any remotely suitable environment – wrecking entire ecosystems. But this too could go both ways. To local para-algae we could be walking Petri dishes: warm, moist, and fertile. Our bodies' defenses, if any, are likely to take the form of allergic reactions, not terribly helpful to us.

In short, any garden worlds out there are probably not for us. Those valleys with forested slopes above babbling streams filled with flashing para-trout are the ultimate nature preserves, to be appreciated but not subdivided for housing tracts. Yes, theoretically we might simply wipe out the native life, then recolonize with a terrestrial ecosystem including ourselves. I don't think you have to be a Jain to find something repulsive about this.

Which leaves the option of terraforming. For every nature-park world we will probably find dozens that didn't quite make it. We do not yet know whether life arises wherever there is liquid water to be had – we may begin to find out on Mars and Europa. But if a planet has oceans but no life it is a candidate for terraforming, and only the ecopoetic or gardening stage is required – no need to sling comets from the outer system to provide water, or hoover up 90 bars of CO2 out of the atmosphere. Worlds with limited 'primitive' life may even allow a sort of biological nonaggression pact, the native forms going quietly on in their own local ecosystems. There are still ethical questions (we're precluding or at least greatly altering their evolutionary prospects), but not like the ethics of sterilizing a rich, living world.

Yet even interstellar colonization is not as simple as it used to be.


Ian M:

In Lois McMaster Bujold's Vorkosigan books, the world Barrayar seems to have been a particularly bad choice in real estate. Humans are allergic to practically every plant on the planet, and terraform by slash-and-burn agriculture and bulk dumping of fertilizer. It's one of the few SF settings I've seen that touch on the biochemical issues of colonization.

If your planning horizon is short enough (Say, because you're transplanting undesirables to a new world) the prospect of a planetary triple toe loop probably doesn't bother you. On the other hand, any culture that practices terraforming obviously does think in the long term and I think the idea of transporting prisoners to other worlds is unlikely even with FTL. Why dump the prisoners on Ceti Alpha V when it's cheaper to dump them on Antarctica?

Using Earth as a baseline, the prime real estate would probably be any world that has not yet hit it's equivalent of the Devonian era. So long as complex life is confined largely to the seas, terraforming the land is remarkably straightforward. It's a lot of hard work, but it's not hard work that fights back and evolves to destroy your work. And the presence of marine ecosystems means you don't have to terraform the oceans (Or only have to introduce species like salmon, eels, or tortoises, that return nutrients to the land from the ocean). I did some calculations for terraforming ocean volumes comparable to the Earth's, and was quickly reminded that humans are just a thin biofilm confined to a narrow portion of the habitable world.

Completely lifeless worlds are your next best bet. But you should probably check out the local neighborhood and find out why the place is lifeless...

In his novel Nemesis Isaac Asimov included a fictional life-signs scanner that worked by detecting complex repetitive electromagnetic events. Something like that wouldn't spot anything without a rudimentary nervous system, but it was an interesting idea. Throw in spectrographic analysis, telescopic studies, and automated surveys, and any colonists should have a good idea of what they're getting into even if they are the first humans to set foot on the planet.

Daniel:

" To local para-algae we could be walking Petri dishes: warm, moist, and fertile. Our bodies' defenses, if any, are likely to take the form of allergic reactions, not terribly helpful to us."

I find this to be a highly questionable assertion. Without even going into far afield things like amino acid chirality, most earth-born bacteria and virii do a poor job jumping across species. It can't recall the last time I caught a cold from a tree. :)

But beyond that I think you vastly underestimate the sheer hostility of the environment that is the human body. While you may be right about our response being an allergic reaction, our bodies aren't the only factor. Those foreign bacteria will be trying to compete with the fauna you already carry around with you. Fauna that has been selected for ruthless survival in that environment over uncountable generations.

Think like this — a gang wants to move into the city to do their business. You are talking about how they would do against the cops, but completely ignoring the fact that Don Corleone is going to have some very pointed ideas about them moving in on his territory.

From GARDEN WORLDS, PARK WORLDS by Rick Robinson (2009)
STARSHIP TROOPERS

I never have learned the co-ordinates of Sanctuary, nor the name or catalogue number of the star it orbits — because what you don't know, you can't spill; the location is ultra-top-secret, known only to ships' captains, piloting officers, and such . . . and, I understand, with each of them under orders and hypnotic compulsion to suicide if necessary to avoid capture. So I don't want to know. With the possibility that Luna Base might be taken and Terra herself occupied, the Federation kept as much of its beef as possible at Sanctuary, so that a disaster back home would not necessarily mean capitulation.

But I can tell you what sort of a planet it is. Like Earth, but retarded.

Literally retarded, like a kid who takes ten years to learn to wave bye-bye and never does manage to master patty-cake. It is a planet as near like Earth as two planets can be, same age according to the planetologists and its star is the same age as the Sun and the same type, so say the astrophysicists. It has plenty of flora and fauna, the same atmosphere as Earth, near enough, and much the same weather; it even has a good-sized moon and Earth's exceptional tides.

With all these advantages it barely got away from the starting gate. You see, it's short on mutations; it does not enjoy Earth's high level of natural radiation.

Its typical and most highly developed plant life is a very primitive giant fern; its top animal life is a proto-insect which hasn't even developed colonies. I am not speaking of transplanted Terran flora and fauna — our stuff moves in and brushes the native stuff aside.

With its evolutionary progress held down almost to zero by lack of radiation and a consequent most unhealthily low mutation rate, native life forms on Sanctuary just haven't had a decent chance to evolve and aren't fit to compete. Their gene patterns remain fixed for a relatively long time; they aren't adaptable — like being forced to play the same bridge hand over and over again, for eons, with no hope of getting a better one.

As long as they just competed with each other, this didn't matter too much — morons among morons, so to speak. But when types that had evolved on a planet enjoying high radiation and fierce competition were introduced, the native stuff was outclassed.

Now all the above is perfectly obvious from high school biology . . . but the high forehead from the research station there who was telling me about this brought up a point I would never have thought of.

What about the human beings who have colonized Sanctuary?

Not transients like me, but the colonists who live there, many of whom were born there, and whose descendants will live there, even into the umpteenth generation — what about those descendants? It doesn't do a person any harm not to be radiated; in fact it's a bit safer — leukemia and some types of cancer are almost unknown there. Besides that, the economic situation is at present all in their favor; when they plant a field of (Terran) wheat, they don't even have to clear out the weeds. Terran wheat displaces anything native.

But the descendants of those colonists won't evolve. Not much, anyhow. This chap told me that they could improve a little through mutation from other causes, from new blood added by immigration, and from natural selection among the gene patterns they already own — but that is all very minor compared with the evolutionary rate on Terra and on any usual planet. So what happens? Do they stay frozen at their present level while the rest of the human race moves on past them, until they are living fossils, as out of place as a pithecanthropus in a spaceship?

Or will they worry about the fate of their descendants and dose themselves regularly with X-rays or maybe set off lots of dirty-type nuclear explosions each year to build up a fallout reservoir in their atmosphere? (Accepting, of course, the immediate dangers of radiation to themselves in order to provide a proper genetic heritage of mutation for the benefit of their descendants.)

This bloke predicted that they would not do anything. He claims that the human race is too individualistic, too self-centered, to worry that much about future generations. He says that the genetic impoverishment of distant generations through lack of radiation is something most people are simply incapable of worrying about. And of course it is a far-distant threat; evolution works so slowly, even on Terra, that the development of a new species is a matter of many, many thousands of years.

From STARSHIP TROOPERS by Robert Heinlein (1959)

Hostile Planets

If one is dealing with near-future colonization of the non-shirtsleeve planets of the solar system using weak chemical rockets, the difficulties are overwhelming. It is vastly easier to colonize hypothetical human-habitable garden worlds around other stars using handwaving faster than light starships (because the author said so).

The sad fact of the matter is that it is about a thousand times cheaper to colonize Antarctica than it is to colonize Mars. Antarctica has plentiful water and breathable air, Mars does not. True, the temperature of Mars does occasionally grow warmer than Antarctica, but at its coldest Mars can get 50° C colder than Antarctica. In comparison to Mars, Antarctica is a garden spot.

Yet there is no Antarctican land-rush. One would suspect that there is no Martian land-rush either, except among a few who find the concept to be romantic.

I'll believe in people settling Mars at about the same time I see people setting the Gobi Desert. The Gobi Desert is about a thousand times as hospitable as Mars and five hundred times cheaper and easier to reach. Nobody ever writes "Gobi Desert Opera" because, well, it's just kind of plonkingly obvious that there's no good reason to go there and live. It's ugly, it's inhospitable and there's no way to make it pay. Mars is just the same, really. We just romanticize it because it's so hard to reach.

On the other hand, there might really be some way to make living in the Gobi Desert pay. And if that were the case, and you really had communities making a nice cheerful go of daily life on arid, freezing, barren rock and sand, then a cultural transfer to Mars might make a certain sense.

If there were a society with enough technical power to terraform Mars, they would certainly do it. On the other hand. by the time they got around to messing with Mars, they would have been using all that power to transform themselves. So by the time they got there and started rebuilding the Martian atmosphere wholesale, they wouldn't look or act a whole lot like Hollywood extras.

THE SANDS OF MARS

“I won’t jump the gun,” he said, “and I can’t tell you what’s happening now. But here’s a little story that may amuse you. Any resemblance to — ah — real persons and places is quite coincidental.”

“I understand,” grinned Gibson. “Go on.”

“Let’s suppose that in the first rush of interplanetary enthusiasm world A has set up a colony on world B. After some years it finds that this is costing a lot more than it expected, and has given no tangible returns for the money spent. Two factions then arise on the mother world.

One, the conservative group, wants to close the project down — to cut its losses and get out. The other group, the progressives, wants to continue the experiment because they believe that in the long run Man has got to explore and master the material universe, or else he’ll simply stagnate on his own world. But this sort of argument is no use with the taxpayers, and the conservatives are beginning to get the upper hand.

“All this, of course, is rather unsettling to the colonists, who are getting more and more independently minded and don’t like the idea of being regarded as poor relations living on charity. Still, they don’t see any way out until one day a revolutionary scientific discovery is made. (I should have explained at the beginning that planet B has been attracting the finest brains of A, which is another reason why A is getting annoyed.) This discovery opens up almost unlimited prospects for the future of B, but to apply it involves certain risks, as well as the diversion of a good deal of B’s limited resources. Still, the plan is put forward — and is promptly turned down by A. There is a protracted tug-of-war behind the scenes, but the home planet is adamant.

“The colonists are then faced with two alternatives. They can force the issue out into the open, and appeal to the public on world A. Obviously they’ll be at a great disadvantage, as the men on the spot can shout them down.

The other choice is to carry on with the plan without informing Earth — I mean, planet A — and this is what they finally decided to do.

“Of course, there were a lot of other factors involved political and personal, as well as scientific. It so happened that the leader of the colonists was a man of unusual determination who wasn’t scared of anything or anyone, on either of the planets. He had a team of first-class scientists behind him, and they backed him up. So the plan went ahead; but no one knows yet if it will be successful. I’m sorry I can’t tell you the end of the story; you know how these serials always break off at the most exciting place.”

From THE SANDS OF MARS by Sir Arthur C. Clarke (1951)

Dome Colony

As a general rule colonists like places with breathable atmospheres, so they don't immediately die upon stepping out of the transport spacecraft. Unfortunately, if there are no starships, the only naturally occurring place like that in the solar system is Terra. Everywhere else is a non-shirtsleeve environment, the colonists will have to build and maintain a large pressurized volume to live in.

This might be a purpose-build operation that is part of a grand plan to colonize the place. Or it might be unplanned, usually by some organization establishing some kind of base; then as other bases and boomtowns spring up nearby, the entire establishment morphs into a colony. As previously mentioned: the main difference between a base and a colony is that the members of a colony do not expect to ever leave.


Functionally a colony on an airless world is a space habitat that is sited on the ground instead of floating in orbit. Structurally they will be different. A ground based colony will have access to lots of local resources that a space colony will have to import. In other words: a space colony will probably be constructed out of metal shipped in, while a ground colony will be a series of underground tunnels.

Why? Because radiation from galactic cosmic rays (GCR) and solar proton storms is not healthy for children and other living things. It heinously expensive to ship radiation shielding to a space habitat under construction, but planet-based naturally-occurring lava tubes are practically free.

Planets with no atmospheres will need to build underground for radiation protection. Not counting Terra, Venus and the Gas Giants, the only planets with appreciable atmospheres are Mars and Titan. The Mars Radiation Environment Experiment discovered that the pathetic Martian atmosphere would let through enough radiation to expose the colonists to 73 milliGrays per year (mGy/a, where "a" {per annum} = 8760 hours = 365 days). On Terra people suffer about 0.4 mGy/a from GCR, and close to zero from proton storms. Translation: the Martian atmosphere is not going to do diddly-squat to protect the colonists from deadly radiation sleeting from the sky, so you'd best build the colony underground anyway. Or pile lots of Martian dirt on top of the buildings. Titan got lucky, it actually has a denser atmosphere than Terra.

Old illustrations of lunar colonies liked to depict them under transparent domes, because the artist did not know about the radiation hazard.


Since all the living spaces have to be pressurized and otherwise equipped with life support, they will be limited and the colony will feel cramped. Cubicles will be minuscule, and the connecting corridors will be narrow. Much the same as any underground building or rabbit burrow. Privacy will be very hard to come by.


EARTHLIGHT

(ed note: the novel mostly takes place in various Lunar habitats. "Central City" is the main residential section.)

     The colonization of the Moon had been a slow, painful, sometimes tragic and always fabulously expensive enterprise. Two centuries after the first landings, much of Earth's giant satellite was still unexplored. Every detail had, of course, been mapped from space, but more than half that craggy globe had never been examined at close quarters.
     Central City and the other bases that had been established with such labor were islands of life in an immense wilderness, oases in a silent desert of blazing light or inky darkness...
     ...Slowly, with countless heartbreaking setbacks, man had discovered how to exist, then to live, and at last to flourish on the Moon. He had invented whole new techniques of vacuum engineering, of low-gravity architecture, of air and temperature control. He had defeated the twin demons of the lunar day and the lunar night, though always he must be on the watch against their depredations. The burning heat could expand his domes and crack his buildings; the fierce cold could tear apart any metal structure not designed to guard against contractions never encountered on Earth. But all these problems had, at last, been overcome...
     ...Such was the strange world which was now home to some thousands of human beings. For all its harshness, they loved it and would not return to Earth, where life was easy and therefore offered little scope for enterprise or initiative. Indeed, the lunar colony, bound though it was to Earth by economic ties, had more in common with the planets of the Federation. On Mars, Venus, Mercury and the satellites of Jupiter and Saturn, men were fighting a frontier war against Nature, very like that which had won the Moon. Mars was already completely conquered; it was the only world outside Earth where a man could walk in the open without the use of artificial aids. On Venus, victory was in sight, and a land surface three times as great as Earth's would be the prize. Elsewhere, only outposts existed: burning Mercury and the frozen outer worlds were a challenge for future centuries...

(ed note: the novel was written in 1955, years before the Mariner 2 mission in 1962 revealed just what a hell-hole Venus actually was)

     The cluster of great domes began to hump themselves over horizon. A beacon light burned on the summit of each, but otherwise they were darkened and gave no sign of life. Some, Sadler knew, could be made transparent when desired. All were opaque now, conserving their heat against the lunar night.
     The monocab entered a long tunnel at the base of one of the domes. Sadler had a glimpse of great doors closing behind them — then another set, and yet another. They're taking no chances, he thought to himself, and heartily approved of such caution. Then there was the unmistakable sound of air surging around them, a final door opened ahead, and the vehicle rolled to a halt beside a platform that might have been in any station back Earth. It gave Sadler quite a shock to look through the windy and see people walking around outside without spacesuits...
     ...He walked out of the station and found himself at the top of a large ramp, sloping down into the compact little city. The main level was twenty meters below him. He had not realized that the whole dome was countersunk this far into the lunar plain, thus reducing the amount of roof structure necessary. By the side of the ramp a wide conveyor belt was carrying freight and luggage into the station at a leisurely rate. The nearest buildings were obviously industrial, and though well kept had the slightly seedy appearance which inevitably overtakes anything in the neighborhood of stations or docks.
     It was not until Sadler was halfway down the ramp that he realized there was a blue sky overhead, that the sun was shining just behind him, and that there were high cirrus clouds floating far above.
     The illusion was so perfect that he had taken it completely for granted, and had forgotten for a moment that this was midnight on the Moon. He stared for a long time into the dizzy depths of that synthetic sky, and could see no flaw in its perfection. Now he understood why the lunar cities insisted upon their expensive domes, when they could just as well have burrowed underground like the Observatory.
     There was no risk of getting lost in Central City. With one exception each of the seven interconnected domes was laid out in the same pattern of radiating avenues and concentric ring roads. The exception was Dome Five, the main industrial and production center, which was virtually one vast factory and which Sadler decided to leave alone.
     He wandered at random for some time, going where his stray impulses took him. He wanted to get the "feel" of the place, for he realized it was completely impossible to know the city properly in the short time at his disposal. There was one thing about Central City that struck him at once — it had a personality, a character of its own. No one can say why this is true of some cities and not of others, and Sadler felt a little surprised that it should be of such an artificial environment as this. Then he remembered that all cities, whether on Earth or on the Moon, were equally artificial.
     The roads were narrow, the only vehicles small, three-wheeled open cars that cruised along at less than thirty kilometers an hour and appeared to be used exclusively for freight rather than pasengers. It was some time before Sadler discovered the automatic subway that linked the outer six domes in a great ring, passing under the center of each. It was really a glorified conveyor belt, and moved in a counterclockwise direction only. If you were unlucky, you might have to go right round the city to get to the adjacent dome, but as the circular tour took only about five minutes, this was no great hardship.
     The shopping center, and main repository of lunar chic, was in Dome One. Here also lived the senior executives and technicians — the most senior of all in houses of their own. Most of the residential buildings had roof gardens, where plants imported from Earth ascended to improbable heights in this low gravity...
     ...The clear, bell-like note, thrice repeated, caught him unaware. He looked around him, but could not locate its source. At first it seemed that no one was taking any notice of the signal, whatever it might mean. Then he observed that the streets were slowly clearing — and that the sky was getting darker.
     Clouds had come up over the sun. They were black and ragged, their edges flame-fringed as the sunlight spilled past them. Once again, Sadler marveled at the skill with which these images — for they could be nothing else — were projected on the dome. No actual thunderstorm could have seemed more realistic, and when the first rumble rolled round the sky he did not hesitate to look for shelter. Even if the streets had not already emptied themselves, he would have guessed that the organizer of this storm were going to omit none of the details. The little sidewalk café was crowded with the other refugees when the initial drops came down, and the first fiery tongue of lightening licked across the heavens. Sadler could never see lightng without counting the seconds before the thunder peal. It me when he had got to "Six," making it two kilometers away. That, of course, would put it well outside the dome, in the soundless vacuum of space. Oh well, one had to allow some artistic license, and it wasn't fair to quibble over points like this. Thicker and heavier came the rain, more and more continuous the flashes. The roads were running with water, and for the first time Sadler became aware of the shallow gutters which, if he had seen them before, he had dismissed without a second thought. It was not safe to take anything for granted here; you had to keep stopping and asking yourself "What function does this serve — What's it doing here on the Moon? Is it even what I think it is?" Certainly, now he came to consider the matter, a gutter was as unexpected a thing to see in Central City as a ox plow. But perhaps even that — Sadler turned to his closest neighbor, who was watching the storm with obvious admiration.
     "Excuse me," he said, "but how often does this sort of thing happen?"
     'About twice a day — lunar day, that is," came the reply. "It's always announced a few hours in advance, so that it won't interfere with business."
     "I don't want to be too inquisitive," continued Sadler, fearing that was just what he was, "but I'm surprised at the trouble you've gone to. Surely all this realism isn't necessary?"
     "Perhaps not, but we like it. We've got to have some rain, remember, to keep the place clean and deal with the dust. So we try to do it properly."
     If Sadler had any doubts on that score, they were dispelled when the glorious double rainbow arched out of the clouds. The last drops spattered on the sidewalk; the thunder dwindled away an angry, distant mutter. The show was over, and the glisten, g streets of Central City began to fill with life once more...
     ...The food, somewhat to his surprise, was excellent. Every bit must have been synthesized or grown in the yeast and chlorella tanks, but it had been blended and processed with great skill. The trouble with Earth. Sadler mused, was that it could take food for granted, and seldom gave the matter the attention it deserved. Here, on the other hand, food was not something that a bountiful Nature, with a little prompting, could be relied upon to provide. It had to be designed and produced from scratch, and since the job had to be done, someone had seen that it was done properly. Like the weather, in fact...
     ... All human communities, wherever they may be in space, follow the same pattern. People were getting born, being cremated (with careful conservation of phosphorus and nitrates), rushing in and out of marriage, moving out of town, suing their neighbors, having parties, holding protest meetings, getting involved in astonishing accidents, writing Letters to the Editor, changing jobs; yes, it was just like Earth. That was a somewhat depressing thought. Why had Man ever bothered to leave his own world if all his travels and experiences had made so little difference to his fundamental nature? He might just as well have stayed at home, instead of exporting himself and his foibles, at great expense, to another world.
     Your job's making you cynical, Sadler told himself. Let's see what Central City has in the way of entertainment.
     He'd just missed a tennis tournament in Dome Four, which should have been worth watching. It was played, so someone had told him, with a ball of normal size and mass. But the ball was honeycombed with holes, which increased its air-resistance so much that ranges were no greater than on earth. Without some such subterfuge, a good drive would easily span one of the domes. However the trajectories followed by these doctored balls were most peculiar, and enough to induce a swift nervous breakdown in anyone who had learned to play under normal gravity.
     There was a cyclorama in Dome Three, promising a tour of the Amazon Basin (mosquito bites optional), starting at every alternate hour. Having just come from Earth, Sadler felt no desire to return so promptly. Besides, he felt he had already seen an excellent cyclorama display in the thunderstorm that had now passed out of sight. Presumably it had been produced in the same manner, by batteries of wide-angle projectors...

     ...CENTRAL CITY, thought Sadler, had grown since he was here thirty years ago. Any one of these domes could cover the whole seven they had back in the old days. How long would it be, at this rate, before the whole Moon was covered up? He rather hoped it would not be in his time...
     ...There were far more vehicles in the streets; Central City was too big to operate on a pedestrian basis now. But one thing had not changed. Overhead was the blue, cloud-flecked sky of Earth, and Sadler did not doubt that the rain still came on schedule...
     ...So they had a lake here now, complete with islands and swans. He had read about the swans; their wings had to be carefully dipped to prevent their flying away and smashing into the "sky."...
     ...Because the illusion of sky was so well contrived, it was not easy to tell when you were about to leave one dome and enter another, but Sadler knew where he was when the vehicle went past the great metal doors at the lowest part of the tube. These doors, so he had been told, could smash shut in less than two seconds, and would do so automatically if there was a pressure drop on either side. Did such thoughts as these, he wondered, ever give sleepless nights to the inhabitants of Central City? He very much doubted it; a considerable fraction of the human race had spent its life in the shadow of volcanoes, dams and dykes, without developing any signs of nervous tension. Only once had one of the domes of Central City been evacuated — in both senses of the word — and that was due to a slow leak that had taken hours to be effective.
     The cab rose out of the tunnel into the residential area, and Sadler was faced with a complete change of scenery. This was no dome encasing a small city; this was a single giant building in itself, with moving corridors instead of streets...
     ...There was a large bulletin board a few meters away, displaying a three-dimensional map of the building. The whole place reminded Sadler of a type of beehive used many centuries ago, which he had once seen illustrated in an old encyclopedia. No doubt it was absurdly easy to find your way around when you'd got used to it, but for the moment he was quite baffled by Floors, Corridors. Zones and Sectors...
     ...The ramp ahead ended abruptly in a broad, slowly moving roller-road. This carried them forward a few meters, then decanted them on to a high-speed section. After sweeping at least a kilometer past the entrances to countless corridors, they were switched back on to a slow section and carried to a huge, hexagonal concourse. It was crowded with people, coming and going from one roadway to another, and pausing to make purchases at little kiosks. Rising through the center of the busy scene were two spiral ramps, one carrying the up and the other the down traffic. They stepped on to the "Up" spiral and let the moving surface lift them half a dozen floors. Standing at the edge of the ramp, Sadler could see that the building extended downward for an immense distance. A very long way below was something that looked like a large net. He did some mental calculations, then decided that it would, after all, be adequate to break the fall of anyone foolish enough to go over the edge. The architects of lunar buildings had a light-hearted approach to gravity which would lead to instant disaster on Earth.

From EARTHLIGHT by Sir Arthur C. Clarke (1955)
THE MENACE FROM EARTH

     I was born right here in Luna City, which seems to surprise Earthside types. Actually, I’m third generation; my grandparents pioneered in Site One, where the Memorial is. I live with my parents in Artemis Apartments, the new co — op in Pressure Five, eight hundred feet down near City Hall. But I’m not there much; I’m too busy...
     ...“All city guides are girls,” Mr. Dorcas explained. “Holly is very competent.”
     “Oh, I’m sure,” she answered quickly and went into tourist routine number one: surprise that a guide was needed just to find her hotel, amazement at no taxicabs, same for no porters, and raised eyebrows at the prospect of two girls walking alone through “an underground city.”
     Mr. Dorcas was patient, ending with: “Miss Brentwood, Luna City is the only metropolis in the Solar System where a woman is really safe — no dark alleys, no deserted neighborhoods, no criminal element.”...
     We were in the tunnel outside and me with a foot on the slidebelt when she stopped. “I forgot! I want a city map.”
     “None available.”
     “Really?”
     “There’s only one. That’s why you need a guide.”
     “But why don’t they supply them? Or would that throw you guides out of work?”
     See? “You think guiding is makework? Miss Brentwood, labor is so scarce they’d hire monkeys if they could.”
     “Then why not print maps?”
     “Because Luna City isn’t flat like — ” I almost said, “ — groundhog cities,” but I caught myself.
     “ — like Earthside cities,” I went on. “All you saw from space was the meteor shield. Underneath it spreads out and goes down for miles in a dozen pressure zones.”
     “Yes, I know, but why not a map for each level?”
     Groundhogs always say, “Yes, I know, but — ”
     “I can show you the one city map. It’s a stereo tank twenty feet high and even so all you see clearly are big things like the Hall of the Mountain King and hydroponics farms and the Bats’ Cave.”...

From THE MENACE FROM EARTH by Robert Heinlein (1957)
The Alaskan Town Living Under One Roof

(ed note: Whittier is a real town in Alaska. But the situation is probably very similar to a small colony on an airless planet. Much like a standard railroad town, including season-based workers and a stranded permanent population. Unsurprisingly they also have a plumbing school. Tip of the hat to Markus Glanzer for bringing this article to my attention.)

     An impossibly long, single-lane tunnel is your only way into Whittier, and your only way out. Make it to the other end of those dimly lit miles, and you'll find all the ingredients of a city. Except instead of a sprawling, urban center, this town has been scaled to fit almost entirely into one lonely Alaskan tower.
     The two-and-a-half mile-long tunnel leading into Whittier is never that crowded — it physically can't be. At about 16 feet wide, it can only accommodate traffic flowing in one direction at a time. What it empties out into is a smattering of buildings, few of which still serve their original purpose.
     The two largest of those are the Buckner Building and the Begich Towers. Both were constructed in the wake of World War II along with the railroad leading in, a combined $55 million build that gave the military a home base at the very farthest Cold War frontier. Buckner was abandoned just seven years after its completion; the military realized quickly that it didn't have much use for such a far-flung outpost. Today, it exists as little more than ruin porn.
     Begich Towers (or BTI as it's more commonly known) held on, though. More than that; it essentially became Whittier, housing 75 percent of the town's 200 residents and providing nearly all of its municipal essentials. The first floor alone provides most of your basic city functions. The police department behind one door, the post office behind another. Walk a bit further down the hall and you'll find the city offices as well as the Kozy Korner, your local, neighborhood grocery store.
     A handful of other buildings dot the landscape. A large, military gymnasium now acts as boat storage. There's an inn or two doubling (quadrupling?) as laundromat, bar, and restaurant. But the big, brightly colored fortress below is Whittier's centerpiece, because almost the entirety of Whittier calls it home.
     To get a sense of daily Whittier life, we spoke with Jen Kinney, a writer and photographer who lived in Whittier for several years and became fascinated by a town whose peculiar physical structures have had such a profound effect on its social structures as well.
     "This really was the most community-centered place I had ever lived in my life," Kinney explained over the phone. "But at the same time, because you're so close to everyone, sometimes you feel really claustrophobic. Other times you feel enormously grateful that they're there. And still, other times, even when you're surrounded by all your neighbors, you can feel completely and utterly isolated."...

     ...That sparseness of infrastructure and general isolation is part of what drew Jen Kinney to the mountain-lined inlet years ago...
     ..."Everybody has to play a role. The town just wouldn't function if at least half of the people weren't willing to step in and be an EMT or even just cook for your neighbors when they're sick — everybody functions as part of a larger organism."
     In a town of Whittier's size, it really does take everyone to keep the town functioning. A few residents work on the railroad, some monitor the tunnel, but for the most part, people are employed by the City of Whittier itself. Whether it's snow clearance, building maintenance, city functions, or the school, for those who stay year-round, Whittier itself is their livelihood.
     Because the town is so small, everyone has to play a vital role to keep this self-contained organism alive. Without the the high school teacher, without the volunteer EMTs, — even without the guys sitting at the bar, drinking from 9am to closing — Whittier's social and physical infrastructure just wouldn't quite work.

     The tourists, and seasonal workers who visit Whittier in the summer to work on the dock and at the cannery make sense. They're there for work or just passing through. But what about those who claim Whittier as their sole, year-round residence? According to Kinney, the longer she stayed amongst the town's relatively few walls, the more difficult it became to make any generalizations about what it was that drew her neighbors to Whittier in the first place.
     "For one person," Kinney explained, "living in Whittier was idyllic because they were really social and were constantly able to be around people. And for others, it was really idyllic because they were able to be completely isolated all the time. But as for why people are there and how they ended up there, the range of stories was really staggering."
     For the majority of people, though, Whittier is a transitional town. They'll come, stay for a year, and never live in Whittier again. Or they'll come as a tourist on a summertime cruise. Or to traverse the abandoned Buckner building. But it's the ones who stay the winter that make up its core.
     Kinney recounted to us how one woman found herself in Whittier because her mother, a one-time heavy drinker and partier, traveled to Alaska in the 70s, found a job in there, fell in love, and turned her life around. After mending her relationship with her daughter, the daughter came to visit for two months that eventually turned into 35 years and four generations, all in Whittier.
     Another resident sought out Whittier explicitly as a safe haven from her abusive ex-husband. There, she was able to tell the train conductors not to let him through the tunnel. For her, Whittier meant a safer life.
     What makes Whittier so fascinating to the outside isn't just that this wildly diverse group of people happened upon Whittier, but that they happened upon Whittier together.
     "You have this sort of forced camaraderie where, superficially, these people might not necessarily have anything in common," Kinney elaborated. "In the summer, we would have these bonfires, and everybody would come. The age range might be between 17 and 55, because you can't have much social distinction in a place with so few people....
     ..."I'd lived in New York City, so I was used to being totally surrounded by people all the time; that wasn't what phased me. What was so weird was knowing the person on the other side of every wall. In most cases, I knew exactly who lived next door on my left, on my right, above, and below."...

From The Alaskan Town Living Under One Roof by Ashley Feinberg (2015)

Terraforming

Terraforming is using planetary engineering to make a planet's environment more like a prime vacation spot, or a least one where an unprotected human being won't instantly die.

It generally takes hundreds to thousands of years for the process to be complete. It also requires access to incredibly large amounts of advanced technology, planetary-sized stocks of raw materials, and an energy budget comparable to all of Terra combined.

Martyn J. Fogg wrote the definitive book on the topic, sadly out of print. His web page has lots of terraforming information.

Terraforming a world inhabited by sentient beings is considered to be attempted genocide, or at the least to be very rude. Extreme moralists go to the point of only allowing terraforming on planets that are totally lifeless. Examples include Sir Arthur C. Clarke's The Songs of Distant Earth, Star Trek: The Wrath of Khan, and sort of in Roger Zelazny's "The Keys to December".

Terraforming Ganymede with Robert Heinlein

HOW THE SOLAR SYSTEM WAS WON

THEY SAID, OF COURSE, that it was impossible. They always do.

Even after the human race had moved into the near-Earth orbits, scattering their spindly factories and cylinder-cities and rock-hopping entrepreneurs, the human race was dominated by nay-saying stay-at-homes. Sure, they said, space worked. Slinging airtight homes into orbit at about one astronomical unit’s distance from the Sun was–in retrospect–an obvious step. After all, there was a convenient Moon nearby to provide mass and resources. But Earth, they said, was a benign neighborhood. You could resupply most outposts within a few days. Except for the occasional solar storm, when winds of high-energy particles lashed out, the radiation levels were low. There was plenty of sunshine to focus with mirrors, capture in great sheets of conversion wafers, and turn into bountiful, high-quality energy.

But Jupiter? Why go there? Scientific teams had already touched down on the big moons and dipped into the thick atmosphere. By counting craters and taking core samples, they deduced what they could about how the solar system evolved. After that brief era of quick-payoff visits, nobody had gone back. One big reason, everyone was quick to point out, was the death rate for those expeditions: half never saw Earth again, except as a distant blue-white dot.

Scientists don’t tame new worlds; pioneers do. And except for bands of religious or political refugee-fanatics, pioneers don’t do it for nothing. To understand why mankind undertook the most dangerous development project in its history (so far), you have to ask the eternal question: Who stood to get rich from it?

By the year 2124, humans had already begun to spread out of the near-Earth zone. The bait was the asteroids–big tumbling lodes of metal and rock, rich in heavy elements. These flying mountains could be steered slowly from their looping orbits and brought to near-Earth rendezvous with refineries. The delta V wasn’t all that large.

There, smelters melted them down and fed the factories steady streams of precious raw materials: manganese, platinum, cadmium, chromium, molybdenum, tellurium, vanadium, tungsten, and all the rare metals. Earth was running out of these, or else was unwilling to further pollute its biosphere to scratch the last fraction out of the crust. Processing metals is messy and dangerous. The space factories could throw their waste into the solar wind, letting the gentle push of protons blow it out to the stars.

Early in the space-manufacturing venture, people realized that it was cheaper in energy to tug small asteroids in from the orbits between Mars and Jupiter than to lift them with mighty rocket engines from Earth. Asteroid prospecting became the Gold Rush of the late twenty-first century. Corporations grubstaked loners who went out in pressurized tin cans, sniffing with their spectrometers at the myriad chunks. Most of them were duds, but a rich lode of vanadium, say, could make a haggard, antisocial rockrat into a wealthy man. Living in zero-gravity craft wasn’t particularly healthy, of course. You had to scramble if a solar storm blew in and crouch behind an asteroid for shelter. Most rock-hoppers disdained the heavy shielding that would ward off cosmic rays, figuring that their stay would be short and lucky, so the radiation damage wouldn’t be fatal. Many lost that bet. One thing they could not do without, though, was food and air. That proved to be the pivot-point that drove humanity still further out.

Life runs on the simplest chemicals. A closed artificial biosphere is basically a series of smoldering fires: hydrogen burns (that is, combines with oxygen) to give water; carbon burns into carbon dioxide, which plants eat; nitrogen combines in the soil so the plants can make proteins, enabling humans to be smart enough to arrange all this artificially.

The colonies that swam in near-Earth orbits had run into this problem early. They needed a steady flow of organic matter and liquids to keep their biospheres balanced. Supply from Earth was expensive. A better solution was to search out the few asteroids which had significant carbonaceous chondrites–rocks rich in light elements: hydrogen, oxygen, carbon, nitrogen. There were surprisingly few. Most were pushed painfully back to Earth orbit and gobbled up by the colonies. By the time the rock-hoppers needed light elements, the asteroid belt had been picked clean. Besides, bare rock is unforgiving stuff. Getting blood from a stone was possible in the energy-rich cylinder-cities. The loose, thinly-spread coalition of prospectors couldn’t pay the stiff bills needed for a big-style conversion plant.

From Ceres, the largest asteroid, Jupiter looms like a candy-striped beacon, far larger than Earth. The rockrats lived in the broad band between two and three astronomical units out from the Sun–they were used to a wan, diminished sunshine and had already been tutored in the awful cold. For them it was no great leap to Jove, hanging there 5.2 times farther from the Sun than Earth.

They went for the liquids. Three of the big moons–Europa, Ganymede, and Callisto–were immense iceballs. True, they circled endlessly the most massive planet of all, three hundred and eighteen times the mass of Earth. That put them deep down in a gravitational well. Still it was far cheaper to send a robot ship coasting out to Jupiter, looping into orbit around Ganymede, than it was to haul water from the oceans of Earth. The first stations set up on Ganymede were semiautomatic–meaning a few unlucky souls had to tend the machinery.

If they could survive at all. A man in a normal pressure suit could live about an hour on Ganymede. The unending sleet of high-energy protons would fry him, ripping through the delicate cells and spreading red destruction. This was a natural side effect of Jupiter’s hugeness – its compressed core of metallic hydrogen spins rapidly, generating powerful magnetic fields that are whipped around every ten hours. These fields are like a rubbery cage, snagging and trapping particles (mostly protons) spat out by the sun. Io, the innermost large moon, belches ions of sulfur and sodium into the magnetic traps, adding to the protons. All this rains down on the inner moons, spattering the ice.

It was not feasible to burrow under the ice to escape –the crew had to work outside, supervising robot ice-diggers. The first inhabitants of Ganymede instead used the newest technology to fend off the proton hail: superconducting suits. Discovery of a way to make superconducting threads made it possible to weave them into pressure suits. The currents running in the threads made a magnetic field outside the suit, where it brushed away incoming protons. Inside, by the laws of magnetostatics, there was no field at all to disturb instrumentation. Once started, the currents flowed forever, virtually without electrical resistance.

Those first men and women worked in an eerie dim sunlight. Over half of Ganymede’s mass was water ice, with liberal dollops of frozen carbon dioxide, ammonia and methane, and minor traces of other frozen-out gases. Its small rocky core was buried under a thousand-kilometer-deep ocean of water and slush. The surface was a thin seventy-kilometer-deep frozen crust, liberally sprinkled over billions of years by infalling meteors. These meteorites peppered the surface and eventually became a major facet of the landscape. On top of Ganymede’s weak ice crust, hills of metal and rock gave the only relief from a flat, barren plain.

This frigid moon had been tugged by Jupiter’s tides for so long that it was locked, like Luna, with one face always peering at the banded, ruddy planet. One complete day-night cycle was slightly more than an Earth-week long. Adjusting to this rhythm would have been difficult if the Sun had provided clear punctuation to the three-and-a-half-day nights. But even without an atmosphere, the Sun from Ganymede was a dim twenty-seventh as bright as at Earth’s orbit. Sometimes you hardly noticed it, compared to the light of Jove’s nearby moons.

Sunrise was legislated to begin at Saturday midnight. That made the week symmetric, and scientists love symmetry. Around late afternoon of Monday, Jupiter eclipsed the Sun, seeming to clasp the hard point of white light in a reddish glow, then swallowing it completely. Europa’s white, cracked crescent was then the major light in the sky for three and a half hours. Jupiter’s shrouded mass flickered with orange lightning strokes between the rolling somber clouds. Suddenly, a rosy halo washed around the rim of the oblate atmosphere as sunlight refracted through the transparent outer layers. In a moment the Sun’s fierce dot broke free and cast sharp shadows on the Ganymede ice.

By Wednesday noon it had set, bringing a night that was dominated by Jupiter’s steady glow as it hung unmoving in the sky. This slow rotation was still enough to churn Ganymede’s inner ocean, exerting a torque on the ice sheets above. A slow-motion kind of tectonics had operated for billions of years, rubbing slabs against each other, grooving and terracing terrain, erasing craters in some areas.

In the light gravity–one-seventh of Earth’s–carving out immense blocks of ice was easy. Boosting them into orbit with tug rockets was the most expensive part of the long journey. From there, electromagnetic-thruster robot ships lugged the ice to the asteroids, taking years to coast along their minimum-energy spirals.


AGRIBUSINESS IN THE SKY

“Ice might be nice, but wheat you can eat.”

So began one of the songs of that era, when the asteroids were filling up with prospectors, then miners, then traders. Then came settlers, who found the cylinder-cities too crowded, too restrictive, or simply too boring. They founded the Belt-Free State, with internal divisions along cultural and even family lines. (Susan McKenzie, the first Belt Chairwoman and a proud native of the Outermost Hebrides, was three generations removed from her nearest Earth-born Scot relative. Not that Belters stopped to think about Earth that much anymore.)

By then, the near-Earth orbital zone was as comfortable as a suburb, and as demanding. The few iceteroids available in the asteroid belt had already been used up, but ice from Ganymede, originally hauled to the asteroids, could be revectored and sent to the rich artificial colonies. As the colonies developed a taste for luxury, increasingly that meant food. No environment can be completely closed, so human settlements throughout the solar system steadily lost vapors and organic matter to the void. No inventory ever came up 100 percent complete. (Consider your own body, and try to keep track of a day’s output: feces, urine, exhaled gas, perspiration, flatus, sheddings. Draw the flow chart.) The relatively rich inner-solar-system colonies soon grew tired of skimpy menus and of the endless cycle in which goat and rabbit and chicken were the prized meats.

Inevitably, someone noticed that it would be cheap to grow crops on Ganymede. Water was plentiful, and mirrors could warm greenhouses, enhancing the wan sunlight. Since Ganymede was going to ship light elements to the asteroids and beyond anyway, why not send them in the form of grains or vegetables?

Thus began the Settlements. At first they were big, domed greenhouses, lush with moist vegetables or grain. The farmers lived below in the sheltering ice. Within two generations, humans had spread over a third of the moon’s purplish, grooved fields. In the face of constant radiation hazard, something in the human psyche said mate!–and the population expanded exponentially.

Robot freight haulers were getting cheaper and cheaper, since the introduction of auto-producers in the Belt. These were the first cumbersome self-reproducing machines, sniffing out lodes of iron and nickel, and working them into duplicates of themselves. An auto-producer would make two replicas of itself and then, following directives, manufacture a robot ion rocket. This took at least ten years, but it was free of costly human labor, and the auto-producers could work in lonely orbits, attached to bleak gray rocks where humans would never last. The ion rocket dutifully launched itself for Ganymede, to take up grain-hauling chores. Every year there were more of them to carry the cash crops sunward.

Working all day in a skinsuit is not comfortable. Day-to-day routines performed under ten meters of ice tend to pall. Fear of radiation and cold wears anyone down. For the first generation Ganymede was an adventure, for the next a challenge, and for the third, a grind. One of the first novels written in Jovian space opens with:

Maybe I should start off with a big, gaudy description. You know–Jupiter’s churning pinks and browns, the swirling white ammonia clouds like giant hurricanes, the spinning red spots. That kind of touristy stuff.

Except I don’t feel like writing that kind of flowery crap. I’m practical, not poetic. When you’re swinging around Jupiter, living meters away from lethal radiation, you stick to facts. You get so vectors and grease seals and hydraulic fittings are more important than pretty views or poetry or maybe even people.

The psychological profile of the entire colony took a steep downward slope. Even the kids in the ice warren streets knew something had to be done.

In the long run, no large colony could live healthily with the death-dealing threats to be found on any of the Jovian moons. Therefore, erase the dangers.

All sorts of remedies were suggested. One serious design was done for an immense ring of particles to orbit around Ganymede, cutting out most of the incoming high-energy protons. Someone suggested moving Ganymede itself outward, to escape the particle flux. (This wasn’t crazy, only premature. A century later it would be feasible, though still expensive.) The idea that finally won looked just as bizarre as the rest, but it had an ace up its sleeve.

The Ganymede Atmosphere Project started with a lone beetlelike machine crawling painfully around the equator of the world. Mechanical teeth ground up ice and sucked it inside, where an immense fusion reactor waited. The reactor burned the small fraction of heavy water in the ice and rudely rejected the rest as steam. From its tail jetted billowing clouds that in seconds condensed into an ammonia-rich creek.

This fusion plant crept forward on caterpillar treads, making a top speed of a hundred meters an hour. Its computer programs sought the surest footing over the black-rock outcroppings. It burned off toxic gases and left a mixture of water vapor, ammonia, oxygen, and nitrogen, with plenty of irritating trace gases. The greatest danger to it was melting itself down into a self-made lake. A bright orange balloon was tethered to the top. If the crawler drowned itself, the balloon would inflate and float the plant to the surface, to be fished out by a rescue team.

The trick was that the fusion-crawler wasn’t made with valuable human labor, but rather by other machines: the auto-producers. Decades before, the auto-producers had begun multiplying like the legendary rabbits who overran Australia. Now there were hundreds of them in the Belt, duplicating themselves and making robot freighters. The Belters were beginning to get irritated at the foraging machines; two had been blown to fragments for trespassing on Belters’ mines. Simple reprogramming stopped their ferocious reproduction and set them to making fusion-crawlers.

Freighters hauled the crawlers out to Ganymede, following safe, cheap, low-energy trajectories. The crawlers swarmed out from the equator, weaving through wrinkled valleys of tumbled stone and pink snowdrifts, throwing out gouts of gas and churning streams. The warm water carried heat into neighboring areas, melting them as well. A thin gas began to form over the tropics. At first it condensed out in the Ganymede night, but then it began to hold, to spread, to take a sure grip on the glinting icelands below.

The natives saw these stolid machines as a faint orange aura over the horizon. Crawlers stayed away from the Settlements, to avoid accidents and flooding. Their rising mists diffused the fusion torches’ light, so that a second sun often glowed beyond the hills, creeping northward, its soft halo contrasting with the blue-green shadows of the ice fields.

TO BE CONTINUED...

From Terraforming Ganymede with Robert A. Heinlein by Gregory Benford (2011)
Terraforming Ganymede with Robert Heinlein part 2

Why Go?

Both Heinlein and those who followed knew that inevitably, as humanity opened the Solar System to exploration and commerce, it would be cheaper in energy to tug small asteroids in from the orbits between Mars and Jupiter than to lift them with mighty rocket engines from Earth. So I began constructing a future history that led to Farmer in the Sky and beyond. I’ll present it here, as in Part 1, as a popular historian would. There we left our colonists with some crunched gravel and grit, but had not really introduced biology. Heinlein didn’t use biotech either—this was around the 1950s, and DNA had barely been discovered. But I have the advantage of sixty years of progress, and have even started some biotech companies myself (Genescient, LifeCode). So I envision how we’ll use that to make a new world…


HELP WANTED: MUTANTS

Any atmosphere can blunt the energy of incoming protons and screen against the still-dangerous Sun’s ultraviolet, but to be breathable, it has to be engineered. Once a tiny fraction of the ice plains were melted into vapor, a greenhouse effect began to take hold. Sunlight striking the ice no longer reflected uselessly back into space; instead, the atmosphere stopped the infrared portion, trapping the heat. Once this began, the fusion-crawlers were a secondary element in the whole big equation.

The fresh ammonia streams and methane-laced vapors were deadly to Earth-based life. A decade after the first fusion-crawler lumbered through a grooved valley, hundreds of them scooped and roared toward Ganymede’s poles, having scraped off a full hundred meters of the ice crust. They had made an atmosphere worth reckoning with. Ice tectonics adjusted to the shifting weight, forcing up mountains of sharp shards, uncovering lodes of meteorites, which in turn provided fresh manufacturing ore for yet more fusion-crawlers.

The first rains fell. A slight mist of virulent ammonia descended on the Zamyatin Settlement. It collected in a dip on the main dome, dissolving the tenuous film on it. After some hours, the acid ate through. A whoosh of lost pressure alerted the agriworkers. They got out in time, scared but unshaken. These were farsighted people: they knew one accident wasn’t reason to kill the project that gave them so much hope.

The only solution was to change the atmosphere as it was made. Further rains underlined the point – it became harder to work outside because the vapors would attack the monolayer skinsuits. The fusion plants were no help. They were hopelessly crude engines, chemically speaking, limited to regurgitating vapors that had been laid down three billion years before, when the moon formed. They could not edit their output. As they burrowed deeper into the ice fields, the situation worsened.

Io, the pizza planet, had once enjoyed a more active stage. Its volcanoes had belched forth plumes of sulfur that had escaped the moon’s gravity, forming a torus around Jupiter that included all the moons. On Ganymede, this era was represented by a layer of sulfur that now occasionally found its way into the deep-dug crawlers’ yawning scoops. The result was a harshly acidic vapor plume, condensing to fierce yellow rains that seared whatever they touched. Fifty-seven men and women died in the torrents before something was done.

The fusion-crawlers had been a fast and cheap solution because they were self-reproducing machines. The answer to bioengineering of the atmosphere lay in a tried-and-true method: self-reproducing animals. But these creatures were unlike anything seen on Earth.

The central authority on Ganymede, Hiruko Station, introduced a whole catalog of high-biotech beings that could survive in the wilds of near-vacuum and savage chemicals. Hiruko Station’s method was to take perfectly ordinary genes of Earthside animals and splice them together. This began as a program in controlled mutation but rapidly moved far beyond that. Tangling the DNA instructions together yielded beings able to survive extreme conditions. The interactions of those genes were decidedly nonlinear: when you add a pig to an eel, flavor with arachnid, and season with walrus, do not expect anything cuddly or even recognizable.

There were bulky gravel gobblers, who chewed on rocky ices heavy with rusted iron. They in turn excreted a green, oxygen-rich gas. The scooters came soon after, slurping at ammonia-laden ice. These were pale yellow, flat shapes, awkward and blind on their three malformed legs. They shat steady acrid streams of oxy-available mush. Hiruko Station said the first plant forms could live in the bile-colored scooter stools. Eventually, plants did grow there, but they weren’t the sort of thing that quickens the appetite.

Both gravel-gobblers and scooters were ugly and dumb, hooting aimlessly, waddling across the fractured ice with no grace or dignity, untouched by evolution’s smoothing hand. They roved in flocks, responding to genes that knew only two imperatives: eat and mate. They did both with a furious, single-minded energy, spreading over the ice, which was for them an endless banquet.

Hiruko Station liked the results, and introduced a new form – rockjaws – that consumed nearly anything, breathing in the ammonia-rich atmosphere, and exhaling it back as oxygen and nitrogen. Rockjaws could scavenge far more efficiently than the gravel gobbler, and even bite through meteorites. Metallic jaws were the key. The high-biotech labs had turned up a method of condensing metal in living tissues, making harder bones possible.

Rockjaws were smart enough to stay away from the Settlements (unlike the others, who constantly wandered into greenhouses or tried to eat them). At this point the long-chain DNA-tinkering of Hiruko Station ran afoul of its own hubris. The rockjaws were too smart. They were genetically programmed to think the loathsome methane ices were scrumptious, but they also saw moving around nearby even more interesting delicacies: gravel-gobblers. And they were smart enough to hunt these unforeseen prizes.

Hiruko Station later excused this miscalculation as an unfortunate side effect of the constant proton sleet, which caused fast genetic drift and unpredictable changes. Hiruko Station pointed to the big inflamed warts the creatures grew and the strange mating rituals they began to invent – none of this in the original coding. The scooter flocks were showing deformities, too. Some seemed demented (though it was hard to tell) and took to living off the excretion of the gravel-gobblers, like pigs rooting in cow manure.

First Hiruko Station tried introducing a new bioengineered animal into the equation. It was a vicious-looking thing, a spider with tiny black eyes and incisors as big as your finger. It stood three meters high and was forever hungry, fine-tuned to salivate at the sight of any mutation of the normals. This genetically ordained menu was quite specific and complexly coded, so it was the first thing to go wrong with the ugly beast. Pretty soon it would hunt down and eat anything that moved – even humans – and Hiruko Station had to get rid of it.

That led to a surprising solution to other rising societal stresses. The only way to exterminate the spiders was by hunting them down. Many men and women in the Settlements volunteered for the duty. After some grisly incidents, they had grudges to settle, and anyway it gave them a reason to get out of the domed regularity of their hothouse gardens and manicured fields. Thus was revived a subculture long missing from Earth: the Hunt, with its close bonding and reckless raw life in the alien wilderness.

These disorderly bands exterminated the spiders within a year. Hiruko Station found it was cheaper to pay the hunters a bounty to track down and destroy aberrant scooters, rockjaws and gravel-gobblers, than it was to try for a biotech fix. It was also healthier for the psyche of Ganymede’s settlers. The Settlements were tradition-steeped societies – internal discipline is essential when an open valve or clogged feed line can kill a whole community. The Hunt provided an outlet for deeply atavistic human urges and pressures, long pent and fiercer for their confinement.


A LARGER CANVAS

The atmosphere thickened. Hiruko Station added more mutant strains of quick-breeding animals to the mix, driving the chemical conversion still faster. The biotechnicians found ways to implant microprocessors into the animals, so that they wouldn’t get out of control. That was expensive, though, so hunting continued, echoing the heritage of mankind that came down from the plains of Africa. Bounty hunters were hard to fit into the labor scheme, and the socioplanners kept trying to phase them out, largely from sheer embarrassment. But Earthside 3D programs lapped up tales of the rough ‘n’ ready bountymen and –women of the Hunt, giving what the planners felt was a “false image” of the Settlements. Mutation of the released gene-engineered animals was rapid, however, and the biosphere was never truly stabilized. The hunters became an institution. To this day, they are an unruly crew who don’t fit into planners' orderly diagrams.

Rain lost its sulfuric tang. Steam rose at morning from the canyons, casting rosy light over the Settlements. The moon’s first rivers cut fresh ravines and snaked across ice plains.

All this hung in delicate balance. Huge sodium-coated mirrors were spread in orbit nearby, to reflect unceasing light on the paths ahead of the fusion-crawlers. This speeded evaporation and was used also to hasten crops to ripeness. But Ganymede was, after all, an ice world. Too much heating and a catastrophic melting of the crust would begin. If the crust broke or even shifted, moonquakes would destroy the Settlements.

Thus it was a careful hand that started up the first Ganymede weather cycle. Solar heating at the equator made billowing, moist clouds rise. They moved toward the poles as colder air flowed below, filling spaces the warm air left. As they moved, masses of warm clouds dropped sheets of rain. This meant there was only one circulation cell per hemisphere, an easier system to predict than the several-cell scale of Earth. Rainfall and seasons were predictable; weather was boring. As many on Luna and in the asteroids had learned long before, low gravity and a breathable atmospheric pressure gave a sensational bonus: flying. Though Ganymede would always be cold and icy, people could soar over the ice ecology on wings of aluminum. Compared to the molelike existence of only a few generations before, this was freedom divine.

There came at last the moment when the air thickened enough to absorb the virulent radiation flux. Years later, a foolhardy kid stepped outside an airlock five hours before the official ceremony was to begin, and sucked in a thin, piercingly cold breath. She got back inside only moments before oxygen deprivation would have knocked her out, but she did earn the title she wanted: first to breathe the free air of Ganymede. Molecules locked up for billions of years in the ice now filled the lungs of a human. Her family was fined a month’s labor credit by her Settlement.

By this time Europa’s cracked and cratered face was also alive with the tiny ruby dots of fusion-crawlers, chewing away at that moon as well. They crept along the cracks that wrapped the entire moon, melting the wall away, hoping to open the old channels below the cracks. In spots the churning slush below burst forth, spreading stains of rich mineral wealth. Jove itself, hanging eternally at the center of the sky, was now the only face unmarked in some way by mankind.

Not to be outdone, the Republic of Ganymede hastened the heating of their air. They laid a monolayer over the top of the atmosphere, spinning it down from orbit and layering it in place, letting it fall until the pressure supported it. All the while, weaving sheets stitched themselves together and automatically locked as the smart-layers stretched. This gossamer film stopped the lighter molecules from escaping into space, feeding the chemical reactions balanced in the atmosphere and hastening the greenhouse effect. Chlorfluorocarbons, especially, did their complex work. The designers of the atmospheric cap left holes large enough to let orbital tugs slip through. With control modules fitted to the boundaries of these openings, they could be closed at will. From the Ganymede surface, Callisto, Europa and Io swam in the sky, lambent with halos of gauzy, scattered light.

Rain hammered the plains of Ganymede and evaporated within hours. But the gas density rose and water did its ancient trick of passing through phase transitions at the change of a degree or two. The first lake on Ganymede formed in a basin of dirty meteorite rock eight kilometers wide. This created a ready source of fresh water and soon elaborate homes were carved into the spongy rock overlooking the view. In insulated suits people could sail and even swim. Mirrors hung in orbit, focusing sunlight on fields that slowly turned an odd blue-green, patches spreading wherever water trickled.

Space continued to yield up mineral riches. Near-Jovian space held many useful nuggets the size of cities, both the Trojan asteroids, locked in stable resonance at Jupiter’s Lagrange points, and the wide-wandering Transjovians. At first, ready access to manufacturers made producing metal-rich products much cheaper on Ganymede, where the skilled workers and robot factories already were. This briefly cut into the asteroid commerce from the outer planets, but there were other commodities flowing both ways along that same slow route.

Interplanetary trade increased. Stations around distant Saturn drew food and other perishable supplies from Ganymede to support their key energy industries. Saturn, Uranus and Neptune were fast becoming "the Persian Gulf of the Solar System" – a phrase referring to an era centuries past, when fossil fuels in a single Earthside zone provided the major energy sources. Now the outer planets were the largest sources of deuterium and helium-3 to drive the fusion economy. Saturn was the most valuable of the three, because of its relative proximity, low radiation, and excellent system of moons. The largest of these--gloomy, ruddy Titan--was now explored and its resources identified. Some tried to make a go of it at the bottom of that chilly bowl of primordial soup. Few stayed – something in the human psyche cried out to see the skies. Robots busily labored on, untouched by such biological considerations, in murk where only people with acute claustrophila could be happy.

There were many other moons, though, some ripe for development and colonization, some just icy rocks with a number, not a name. A portion of these were set aside as preserves, where scientists and selected tourists could see how the ice worlds had once been. Some never felt the explorer’s boot, held for far-future technologies to understand. Humanity had learned from the Age of Appetite to preserve bleak wastes and allow them to become future frontiers.

As always, economics called the tune. Moons just now boiling off their ices had to find innovative ways to compete with long-established Ganymede. They quickly realized that not capping their atmospheres would make it simple to profit from the new business of slinging asteroids, using atmospheric braking effects to dissipate incoming energies.

Simple chunks — nickel, iron, differentiated silicates rich in rare ores, the usual—came arcing in on long slow ellipses. Deftly dropping their momentum with a brush through uncapped atmosphere simplified and shortened their delivery orbits. Vast fortunes were made and lost with bewildering speed in the early days of the Second Asteroid Rush. Demand continued to escalate, as the off-Earth populations increased in numbers and affluence, but transport was the key to supply. The Jovestar Conglomerate crashed when their monopoly market faltered. Their legal crews, moving quickly, had locked up mineral rights of the obvious first million Trojan asteroids, and their grip on those could not be broken. But the Transjovians were still out there for the plundering, if only they could be cheaply moved to near-Ganymede orbit. The siren song of fabulous wealth ensured that it happened sooner rather than later.

The Europa entrepreneurs jumped into the fray, taking advantage of every last commercial possibility. Since their atmosphere was open to space, they had long sent asteroids zooming through it, en route to easy orbits in Ganymede’s neighborhood. The incoming asteroids, linked to guiding tugs, also heated up Europa’s air, and properly marketed, provided a valuable tourist attraction, with their well-choreographed displays of burnt gold, electric blue, and ruby amber. As the trajectories of these rockships became more graceful and regularly scheduled, they began to carry passengers. Later, atmosphere-grazing in protected fallsuits became popular. In the freewheeling ethical climate of the time, bookings were permitted for those who signed on as suicides. Indeed, the rates were even lowered, contingent on use of long-obsolete suits. The in-fall failure of century-old systems sealed the decision for some with second thoughts.

Some time later, a large Earthside foundation proposed capping the Callisto atmosphere. They intended the largest work of art possible – a gaudy, beribboned design of loops and swirls that could be seen (properly magnified) throughout the Solar System. The glorious monolayer film would have changeable polarization and colors, so that later generations of artists could express themselves through it.

This idea was opposed by a rare coalition of environmentalists – Keep Callisto Clean – and business interests, who wanted to horn in on Europa’s atmospheric deceleration franchise. The foundation lost its zoning permit. Undeterred, they set about plans to move Pluto into a long, looping orbit, which passed through the inner Solar System. Suitably decorated, they said, Pluto would make a magnificent touring art gallery.

Ganymede, oldest and wealthiest of the Jovian colonies, was becoming relatively luxurious. A shining complex of high-end hotels and shops went up, surrounding a sybaritic waterpark that took full advantage of low gravity. Reservations to surfglide at the wave pool became the most hotly sought date in the Settlements. The songs of The Beach Boys, fallen into obscurity as Earth’s rising oceans made crashing waves a source of societal terror, became wildly popular again. Surf culture was resurrected, albeit in forms no twen-cen California Girl could have foreseen.

Soon there was talk of starting a power-generating plant on Io. Not one using the volcanoes there – those had already been tapped. This plan proposed hooking directly into the currents that ran between Io and Jupiter itself – six million amperes of electricity just waiting to be used. Work began. Soon they would harness the energy that drove the aurora.

The forward vector of humanity had by now passed beyond the Jovian moons. Near Earth, the first manned starship was abuilding, soon to depart for Alpha Centauri. Given the engineering abilities of humanity, the matter of whether an Earthlike planet circled there seemed beside the point. (As it turned out, there was no such world within 18 light years.) Humans could survive anywhere. Better, they would prevail, and learn to enjoy just about anything. Any place where sunlight and mass accumulated, mankind would find a way to form a roiling, catch-as-catch-can society – and probably make a profit doing it.

Of course, there was Jupiter itself. It and the other gas giant planets had formed the backdrop for all this drama, but that was all. Many a Ganymede native, perhaps as he lounged beside a lake in a heated skinsuit or banked and swooped through gossamer clouds, peered up at the swollen giant and idly wondered. Jupiter occupies two hundred and fifty times as much of the sky as Luna does from Earth; it was never far from the minds of the millions who lived nearby.

So it was probably inevitable. A physicist on Luna had developed a new theory of Jove’s interior, accounting for all the latest data on pressure and temperature and chemical composition. She found that there had to be stratified bands of pure hydrogen metal near the surface of Jupiter. Such hydrogen metal might be close to the outer layers of rock, shallow enough to mine.

Her theory suggested that once compressed into being by Jupiter’s huge gravitational pressure, metallic hydrogen would be a stable form. At great expense, laboratory tests synthesized a few grams of the stuff. It was incredibly strong, light and durable. It could even survive a slow transition up to low pressure. If you could go down there and mine it...

The pressures deep in that thick Jovian atmosphere were immense. Where they had even been measured at all, the conditions were brutal. The technology for handling the mines was completely undeveloped. It was an insane idea.

They said, of course, that it was impossible. They always do.

How Do We Terraform Ceres?

In the Solar System’s Main Asteroid Belt, there are literally millions of celestial bodies to be found. And while the majority of these range in size from tiny rocks to planetesimals, there are also a handful of bodies that contain a significant percentage of the mass of the entire Asteroid Belt. Of these, the dwarf planet Ceres is the largest, constituting of about a third of the mass of the belt and being the sixth-largest body in the inner Solar System by mass and volume.

In addition to its size, Ceres is the only body in the Asteroid Belt that has achieved hydrostatic equilibrium – a state where an object becomes rounded by the force of its own gravity. On top of all that, it is believed that this dwarf planet has an interior ocean, one which contains about one-tenth of all the water found in the Earth’s oceans. For this reason, the idea of colonizing Ceres someday has some appeal, as well as terraforming.

Ceres also has the distinction of being the only dwarf planet located within the orbit of Neptune. This is especially interesting considering the fact that in terms of size and composition, Ceres is quite similar to several Trans-Neptunian Objects (TNOs) – such as Pluto, Eris, Haumea, Makemake, and several other TNOs that are considered to be potential candidates for dwarf planets status.

The Dwarf Planet Ceres:

Current estimates place Ceres’ mean radius at 473 km, and its mass at roughly 9.39 × 1020 kg (the equivalent of 0.00015 Earths or 0.0128 Moons). With this mass, Ceres comprises approximately a third of the estimated total mass of the Asteroid Belt (between 2.8 × 1021 and 3.2 × 1021 kg), which in turn is approximately 4% of the mass of the Moon.

The next largest objects are Vesta, Pallas and Hygiea, which have mean diameters of more than 400 km and masses of 2.6 x 1020 kg, 2.11 x 1020 kg, and 8.6 ×1019 kg respectively. The mass of Ceres is large enough to give it a nearly spherical shape, which makes it unique amongst objects and minor planets in the Asteroid Belt.

Ceres follows a slightly inclined and moderately eccentric orbit, ranging from 2.5577 AU (382.6 million km) from the Sun at perihelion and 2.9773 AU (445.4 million km) at aphelion. It has an orbital period of 1,680 Earth days (4.6 years) and takes 0.3781 Earth days (9 hours and 4 minutes) to complete a single rotation on its axis.

Based on its size and density (2.16 g/cm³), Ceres is believed to be differentiated between a rocky core and an icy mantle. Based on evidence provided by the Keck telescope in 2002, the mantle is estimated to be 100 km-thick, and contains up to 200 million cubic km of water, which is equivalent to about 10% of what is in Earth’s oceans, and more water than all the freshwater on Earth.

What’s more, infrared data on the surface also suggests that Ceres may have an ocean beneath its icy mantle. If true, it is possible that this ocean could harbor microbial extraterrestrial life, similar to what has been proposed about Mars, Titan, Europa and Enceladus. It has further been hypothesized that ejecta from Ceres could have sent microbes to Earth in the past.

Other possible surface constituents include iron-rich clay minerals (cronstedtite) and carbonate minerals (dolomite and siderite), which are common minerals in carbonaceous chondrite meteorites. The surface of Ceres is relatively warm, with the maximum temperature estimated to reach approximately 235 K (-38 °C, -36 °F) when the Sun is overhead.

Assuming the presence of sufficient antifreeze (such as ammonia), the water ice would become unstable at this temperature. Therefore, it is possible that Ceres may have a tenuous atmosphere caused by outgassing from water ice on the surface. The detection of significant amounts of hydroxide ions near Ceres’ north pole, which is a product of water vapor dissociation by ultraviolet solar radiation, is another indication of this.

However, it was not until early 2014 that several localized mid-latitude sources of water vapor were detected on Ceres. Possible mechanisms for the vapor release include sublimation from exposed surface ice (as with comets), cryovolcanic eruptions resulting from internal heat, and subsurface pressurization. The limited amount of data thus far suggests that the vaporization is more likely caused by sublimation from exposure to the Sun.


Possible Methods:

As with the moons of Jupiter and Saturn, terraforming Ceres would first require that the surface temperature be raised in order to sublimate its icy outer layer. This could be done by using orbital mirrors to focus sunlight onto the surface, by detonating thermonuclear devices on the surface, or colliding small asteroids harvested from the Main Belt onto the surface.

This would result in Ceres’ crust thawing and turning into a dense, water vapor-rich atmosphere. The orbital mirrors would once again come into play here, where they would be used to trigger photolysis and transform the water vapor into hydrogen and oxygen gas. While the hydrogen gas would be lost to space, the oxygen would remain closer to the surface.

Ammonia could also be harvested locally, since Ceres is believed to have plentiful deposits of ammonia-rich clay soils. With the introduction of specific strains of bacteria into the newly created atmospheres – such as the Nitrosomonas, Pseudomonas and Clostridium species – the sublimated ammonia could be converted into nitrites (NO²-) and then nitrogen gas. The end result would be an ocean world with seas that are 100 km in depth.

Another option would be to employ a process known as “paraterraforming” – where a world is enclosed (in whole or in part) in an artificial shell in order to transform its environment. In the case of Ceres moons, this could involve building large “Shell Worlds” to encase it, keeping the newly-created atmospheres inside long enough to effect long-term changes. Within this shell, Ceres temperature could be increased, UV lights would convert water vapor to oxygen gas, ammonia could be converted to nitrogen, and other elements could be added as needed.

In the same vein, a dome could be built over one or more of Ceres’ craters – particularly the Occator, Kerwan and Yalode craters – where the surface temperature could slowly be raised, and silicates and organic molecules could be introduced to create a terrestrial-like environment. Using water harvested from the surface, this land could be irrigated, oxygen gas could be processed, and nitrogen could be pumped in to act as a buffer gas.


Potential Benefits:

The benefits of colonizing and (para)terraforming Ceres are numerous. For instance, it would take comparatively less energy to sublimate the surface than with the moons of Jupiter or Saturn. Under normal conditions, Ceres’ surface is warm enough (and it is likely there is sufficient ammonia) that its ices are unstable.

Also, Ceres appears from all accounts to be rich in resources, which include water ices and ammonia, and has a surface that is equivalent in total land area to Argentina. Also, the surface receives an estimated 150 W/m2 of solar irradiance at aphelion, one ninth that of Earth. This level of energy is high enough that solar-power facilities could run on its surface.

And being the largest body in the asteroid belt, Ceres could become the main base and transport hub for future asteroid mining infrastructure, allowing mineral resources to be transported to Mars, the Moon, and Earth. Its small escape velocity, combined with large amounts of water ice, means that it also could process rocket fuel, water and oxygen gas on site for ships going through and beyond the Asteroid Belt.


Potential Challenges:

Despite the benefits of a colonized or transformed Ceres, there are also numerous challenges that would need to be addressed first. As always, they can be broken down into the following categories – Distance, Resources and Infrastructure, Hazards and Sustainability. For starters, Ceres and Earth are (on average) approximately 264,411,977 km apart, which is 1.7675 times the distance between the Earth and the Sun (and twice that between Earth and Mars).

Hence, any crewed mission to Ceres – which would involve the transport of both colonists, construction materials, and robotic workers – would take a considerable amount of time and involve a large expenditure in fuel. To put it in perspective, missions to Mars have taken anywhere from 150 to over 300 days, depending on how much fuel was expended. Since Ceres is roughly twice that distance, we can safely say that it would take a minimum of a year for a spacecraft to get there.

However, since these spacecraft would likely be several orders of magnitude heavier than anything previously flown to Mars – i.e. large enough to carry crews, supplies and heavy equipment – they would either need tremendous amounts of thrust to make the journey in the same amount of time, would have to spend much longer in transit, or would need more advanced propulsion systems altogether.

And while NASA currently has plans on the table to build laser-sail spacecraft that could make it Mars in three days times, these plans are not practical as far as colonization or terraforming are concerned. More than likely, advanced drive systems such as Nuclear-Thermal Propulsion (NTP) or a Fusion-drive system would be needed. And while certainly feasible, no such drive systems exist at this time.

Second, the process of building colonies on Ceres’ surface and/or orbital mirrors in orbit would require a huge commitment in material and financial resources. These could be harvested from the Asteroid Belt, but the process would be time-consuming, expensive, and require a large fleet of haulers and robotic miners. There would also need to be a string of bases between Earth and the Asteroid Belt in order to refuel and resupply these missions – i.e. a Lunar base, a permanent base on Mars, and most likely bases in the Asteroid Belt as well.

In terms of hazards, Ceres is not known to have a magnetic field, and would therefore not be shielded from cosmic rays or other forms of radiation. This would necessitate that any colonies on the surface either have significant radiation shielding, or that an orbital shield be put in place to deflect a significant amount of the radiation the planet receives. This latter idea further illustrates the problem of resource expenditure.

The extensive system of craters on Ceres attests to the fact that impactors would be a problem, requiring that they be monitored and redirected away from the planet. The surface gravity on Ceres is also quite low, being roughly 2.8% that on Earth (0.27 m/s2 vs. 9.8 m/s2). This would raise the issue of the long-term effects of near-weightlessness on the human body, which (like exposure to zero-g environments) would most likely involve loss of muscle mass, bone density, and damage to vital organs.

In terms of sustainability, terraforming Ceres presents a major problem. If the dwarf planet’s surface ice were to be sublimated, the result would be an ocean planet with depths of around 100 km. With a mean radius of less than 500 km, this means that about 21% of the planet’s diameter would consist of water. It is unlikely that such a planet (especially one with gravity as low as Ceres’) would be able to retain its oceans for long, and a significant amount of the water would likely be lost to space.


Conclusions:

Under the circumstances, it seems like it would make more sense to colonize or paraterraform Ceres than to subject it to full terraforming. However, any such venture would have to wait upon the creation of a Lunar base, a settlement on Mars, and the development of more advanced propulsion technology. It was also require the creation of a fleet of deep-space ships and an army of construction and mining robots.

However, if and when such a colony were created, the resources of the Asteroid Belt would be at our disposal. Humanity would effectively enter an age of post-scarcity, and would be in a position to mount missions deeper into the Solar System (which could include colonizing the Jovian and Cronian systems, and maybe even the Trans-Neptunian region).

From How Do We Terraform Ceres? by Matt Williams (2016)
TERRAFORMING 59 VIRGINIS III

PHYSICAL ENVIRONMENT

Genesis, third planet of the star system 59 Virgo, can be found 43.5 light years from Earth. 59 Virgo, a smallish type F8V star, is hotter and younger than Earth's sun. Although it's expected to have a shorter life-span than Earth's sun, it still has several billion years to go.

No large moon like Earth's orbits Genesis, but it possesses an asteroid-like belt of more than 250 moonlets orbiting between ten and twenty thousand kilometers from its surface. Most of these satellites have an irregular shape and tumble slowly in their orbits. From the planet's surface, the naked eye can plainly see more than 100 of them forming a beautiful night time display. The largest measures about twenty-eight kilometers long, but it lies so far out that it appears only slightly larger than a star when viewed from the ground. Composition of the moonlets varies from nearly pure iron to siliceous rock. No one knows if the moons ever formed part of one larger moon, or if they are the captured remnants of a prehistoric meteor shower. The moon belt exerts negligible tidal forces on the oceans, since the moons are distributed evenly around the planet. Principal tidal action is due to the pull of the sun, 59 Virgo.

Genesis is barely larger than Earth, with a diameter less than one percent greater and a gravitational attraction at the surface only one percent higher. Land covers 21 percent of its surface. The bulk of it is divided into four continents: Harvestland, Virginis, Barrenland, and Maiden Spring. Three continents have less area than Earth's average continent, but one, Harvestland, has more surface than Earth's Eurasian land mass. The continents take a more closed form than continents on Earth and are separated by larger ex- panses of open ocean.

Genesis orbits 59 Virgo once every 347 days in nearly circular orbit. Its day clocks iust over 12 hours, the shortest among the present colonies. Genesis inclines 27° degree toward its ecliptic plane, making its arctic regions larger than Earth's and its seasonal temperature variations more extreme. Its short day lessens extreme daily temperature variations, however. The planet's atmospheric pressure at mean sea level gauges just 55 percent of Earth's, but since the atmosphere contains 31 percent oxygen, Humans can breath it. The lower atmospheric density reduces the heat transferred from the poles to the equator by atmospheric convection, causing somewhat greater temperature variations with latitude than Earth's. Lower density also reduces the effective wind pressure, so even though wind velocities average somewhat higher than Earth's, their destructive and wave-generating forces are lower.

Genesis is believed to be much younger than the Earth, perhaps by as much as 1.5 billion years. The planet appears to contain more residual heat than Earth and exhibits much greater volcanic activity. Flying over the surface, one rarely loses sight of active volcanoes.

LIFE FORMS

Except for its blue sky and white clouds, the natural surface of Genesis looks more like Earth's moon or Mars than a habitable planet. Not one tree or one blade of grass breaks the monotonous expanse of cold grey rock, stony rubble and sand. No native animals, not even the smallest insect-like creatures, scurry across the empty waste. There is no food, no soil, no single living thing!

If ancient space travellers had landed on Earth half a billion years ago, they would have viewed a similar scene. Life on all habitable planets began in the sea. Genesis is such a world in its earliest stage of development; so its only life exists in the oceans. Because life evolves from the simple to the complex, most life on this young planet seems elementary when compared with the other colony worlds.

MARINE LIFE

Sea life consists mainly of microorganisms. These tiny monocellular species fill all the functions in the life cycle from tiny one-celled photosynthetic plants, resembling Earth's diatoms, to tiny bacteria-like creatures that consume the dead remains of plants and animals. Larger plants take the forms of simple seaweed while still other small plants containing only a few thousand cells float freely in the water. Animals range in structure from tiny multicellular free-floaters and larger free-floaters resembling iellyfish to numerous species of tiny animals with external skeletons. The latter creatures look like the trilobites which dominated Earth's seas in the Cambrian period, 500 million years ago. Earth's phylum of arthropods, which today includes lobsters, insects, and spiders, traces its ancestry to the trilobites. All animals on Genesis exhibit extremely simple behavior patterns; they have few instincts apart from the desire to eat and avoid being eaten. Complex adaptations like the spider's web, the hermit crab's borrowed shell, and the symbiosis between ants and aphids have not even begun to emerge.

A BRIEF HISTORY

The discovery of Genesis by Captain Ben Alan and the crew of the Aurora in 2240 adtc, did not bring universal jubilation on Earth. No statement illustrates the anguish this planet caused the pioneering movement than the following passage from Ben Alan's personal log.

“Our excitement reached frenzied levels as we made final preparations to land on the planet's surface! The beautiful, blue sphere below us possessed breathable atmosphere, warm temperatures, no radiological hazards, and no evidence of intelligent life. As the landing craft began its descent, we stared intently at the main screen which amplified the view below. We broke beneath a layer of clouds and glimpsed our first clear view of the grey landscape.

“Just our luck! We came down in a desert! Thinking that surely it couldn't go on forever, we pressed forward, travelling at 1200 kilometers per hour, 7000 meters above the surface. Four hours later upon reaching the seacoast, hydrocarbon scanners had not revealed the slightest chemical traces of life. Even Earth's most barren wastes would not have produced such readings. We continued parallel to the shore for fourteen hours more, circumnavigating the entire continent without sensing a living thing on the land. Yet carbon readings in the sea revealed some life there and proved our sensors were functioning. ln desperation we touched down and still clad in our biosuits, stepped from the shuttle into an awful landscape littered with ugly black rocks and totally devoid of any life. We took microspopic samples from many places, but even stagnant pools of water in the rocks didn't reveal a single living cell.

“Fatigued and feeling uneasy, we returned to the ship. The next day and for fourteen days after, I dispatched landing parties to the surface. At last the awful reality dawned on us. This planet is a desert. True, some elementary life exists in the sea which probably accounts for the oxygen atmosphere, but how could Humankind survive on those dreadful rock plains below?”

Aurora remained on Genesis for four months, studying what native life there was. When it returned to Earth, Alan's report classified Genesis uninhabitable, but he appended the following comment to his recommendation.

“Despite the planet's inhospitable environ- ment, l believe that someday Humans will live on it. The planet contains the fundamental conditions necessary to support our form of life. When our technology advances enough to allow us to transport much larger payloads across the interstellar space, then we will be able to bring enough equipment and enough supporting life forms from our mother planet to permit life as we know it to thrive there."

He went on to exercise his preogative as captain and named the planet, an unprecedented custom for a world considered uninhabitable.

For 20 years no planetologist challenged Alan's conclusion. The problems of colonizing his barren planet seemed insurmountable. The elementary shellfish of Genesis’ seas could have provided some minimal sustenance to a Human population, but nothing approaching a normal Human diet could be cultivated on its barren continents. Humans need more than food too. Few would voluntarily agree to spend their lives in a desolate wasteland. Grass, trees, and other living animals may not seem like necessities of life, but early in the history of space travel, scientists learned how important they could be. After more than two years on the first permanent Martian base, the total bleakness of that planet's landscape began to have serious psychological effects upon the trained and experienced travellers that staffed them. No large and inexperienced group of pioneers could have coped with Genesis indefinitely.

Yet even before the discovery of Genesis, events were under way that eventually made its colonization possible. Contact with the Ardotians in 2217 adtc created a tremendous increase in the level of both Human and Ardot knowledge. Within a few years, the formulation of the Comprehensive Unified Field Theory led to the development of highly efficient matter-antimatter reactors. These reactors allowed people to transport far greater cargoes across interstellar space at a fraction of the cost.

Both Humans and Ardotians soon became interested in Ben Alan's barren planet again. They reasoned that Genesis provided a rare opportunity for an advanced civilization to create a biologically perfect world, a world without disease, pests, vermin, even weeds! lt would provide the ultimate test of intelligent life's ability to shape and control its environment. Because of their scientific interest in Genesis, the Ardotians offered to supply engines for the largest starship ever built, if the people of Earth would undertake the planet’s development and provide the life-support modules, equipment, and supplies for the vessel. All the Ardotians asked in return for their contribution were detailed reports about the progress of the experiment.

Earth's lnternational Council for Space Exploration began planning for the first colony on Genesis soon after receiving the Ardotian offer; yet another 20 years passed before the launching of the first “Noah's Ark.” The magnitude of the project seemed overwhelming. ln the space of a few years, Humankind would attempt to leap half a billion years of evolution. Techniques for creating living soil from barren rock had to be developed. The proper mix of desirable Earth species had to be selected, and safeguards to insure that Genesis would not become contaminated by pests and diseases from Earth had to be refined. Finally, a large-scale evacuation plan had to be drawn up, should the entire proiect fail catastrophically. No detail escaped scrutiny. As a final check, Ardotian computers analyzed the entire plan, independently assessed its probable outcome and made several important recommendations.

Planners chose the southernmost tip of Harvestland for the first settlement, which pioneers named Malthus. Situated at the edge of the southern tropic zone, the climate is warm and the ocean is protected from violent storms. The colony organization followed the lines of a socialist de mocracy, similar in concept to the highly successful kibbutz used in the 20th century redevelopment of Israel.

The first 3000 pioneers brought food for five years, although the starship made the round trip to Earth annually, bringing still more food, equipment and new colonists. Pioneers lived in temporary housing constructed from parts of the ship that brought them, early precursors to the residential spires of today's pioneering vessels. ln the early years, most efforts focussecl on cultivation of Earth's native life forms. lt took two years to prepare the soil for planting the first crops. At the same time, the pioneers began to develop aquaculture of both native and imported species to hedge against possible failure of the primary food supply. The first pioneers had no resources for manufacturing or processing industrial goods. Most of them were biologists or farming technicians, with a smattering of the mechanics, programmers, and comtechs needed to keep their equipment functioning.

Life's foothold on the planet was assured as food production became self-sustaining at the end of the fourth year. After that the slow process of building basic industries began, first with the importation of mineral recovery equipment, followed by critical manufacturing processes. Development of Genesis has proceeded steadily, if more slowly than on worlds more bountifully endowed by nature. Today, 92 years later, it boasts a modern, industrial society with many of the luxuries and conveniences of Earth.


After six months, soil preparation crews an equipment began to work. Giant combination soil preparation machines, larger than any previous built, performed the task. (See figure 3.13.) In one operation, these mechanical monsters broke rock into coarse chunks using laser drills, then ground fine with ultrasonic grinders and mixed it with nutrients and mulch from giant hoppers they dragged behind them. In past proiects, the pulverization depth reached about a meter below the surface, but the depth to which these large trees’ roots would grow dictated that rock be broken up three meters deep and pulverized to a depth of 1.5 meters.

Earth's natural soil is very fine-grained, but organic mulch within it inhibits its natural tendency to compact and congeal into a solid mass. On Genesis, soil technicians must add a synthetic mulch prepared from seaweed. Since the mass of the synthetic humus cannot equal the mass of natural humus, special chemical treatments must augment it. The addition of fixed nitrogen and other necessary plant minerals follows the mulch, and the soil is chemically balanced. As a final step, technicians seed the new soil with a hardy grass, specially bred from Earth grasses, called “prep grass.” After two years the prep grass is plowed under to provide further mulch and natural nutrients to the soil. The addition of bacteria and worms of appropriate species complete the formation of synthetic soil.

While the prep grass grew we began sprouting seedling trees in the mature soil of the developed area not far from my home. Since no natural barriers existed to blunt the ferocious gales that blew off the south Genesean Ocean, protecting the young trees from wind damage became our most pressing problem. Solid shelter of any kind would have been prohibitively expensive, but fortunately a wind-breaking field had been developed a few years earlier. The field employed a special configuration of the g-field to slow inrushing air to a standstill in the space of two decimeters. Unfortunately, the field would kill anyone who accidently walked through it, so its perimeter had to be guarded by sensors, coupled to visual, sound, and telepathic alarms to warn stray children or absent-minded scientists who might not heed posted warnings.

After two years huge transplanting machines began to move the seedlings from the nursery beds to the forest site. The machines passed over the seedling beds, picking up the young trees together with their roots and a clump of soil, then travelled out to the newly plowed forest and deposited the seedlings in holes dug by the machine itself. Each machine carried about 1000 seedlings and planted at the rate of two per minute.

The machines planted the trees in a predesigned pattern that allowed for optimum tree growth and insured that mature trees would someday provide natural shelter for future seedlings, thus avoiding the need to raise the young trees in a sheltered nursery. A major conflict arose among the forest planning staff over the pattern in which the trees would be planted. Some wanted to plant the trees in regular rows resembling a European garden, while others wanted an irregular, pseudo-random pattern that would resemble a natural forest. The regular pattern made the trees easier to care for and would have cost less, but fortunately the “naturalists” won out. The forest, now quite mature, is one of my favorite vacation spots on Genesis. It gives me great satisfaction to walk among the towering trees and feel that I helped place them there. Despite the fact I aligned with the ordered pattern camp, I am glad that the trees now grow in a naturalistic pattern, for I have come to appreciate the marvelous “order” in nature's randomness.

From HANDBOOK FOR SPACE PIONEERS by L. Stephen Wolfe and Roy L. Wysack (1977)
Transplant Ecosystem

Colonists are going to want to grow local food they can eat, the native plants and animals can be unsuitable as food in so very many ways. Since plants and animals depend upon a circle of life, terraformers will have to transplant a minimal but viable Terran ecosystem that is self-sustaining. And try to avoid importing anything that is a threat to said ecosystem, such as potato blight.

And of course also import useful things that are not food, such as Bamboo.

There are some science fiction novels where aliens invade not by full-blown terraforming but simply by introducing alien hyper-invasive species to alienoform the Terran ecosystem (the functional equivalent of introducing xenomorph-bunnyrabbits to Australia). Examples include David Gerrold's The War Against the Chtorr series and Philip E. High's No Truce With Terra

CHANGING THE AIR

(ed note: In the novel, our hero was cryogenically frozen and was awakened many centuries in the future. He is forced to become a Bussard Ramjet pilot, delivering Biological Package Probes to a series of planets around nearby stars.)

     He came awake suddenly, already up on one elbow, groping for some elusive thought.
     Ah.
     Why haven’t I been wondering about the biological package probes?
     A moment later he did wonder.
     What are the biological package probes?
     But the wonder was that he had never wondered.
     He knew what and where they were: heavy fat cylinders arranged around the waist of the starship’s hull. Ten of these, each weighing almost as much as Corbell’s own life-support system. He knew their mass distribution. He knew the clamp system that held them to the hull and he could operate and repair the clamps under various extremes of damage. He almost knew where the probes went when released; it was just on the tip of his tongue… which meant that he had had the RNA shot but had not yet seen the instructions.
     But he didn’t know what the probes were for...
     ...He looked up during study period the next day and found Pierce watching him. He blinked, fighting free of a mass of data on the attitude jet system that bled plasma from the inboard fusion plant that was also the emergency electrical power source, and asked, “Pierce, what’s a biological package probe?”
     “I would have thought they would teach you that. You know what to do with the probes, don’t you?”
     “The teaching widget gave me the procedures two days ago. Slow up for certain systems, kill the fields, turn a probe loose and speed up again.”
     “You don’t have to aim them?”
     “No. I gather they aim themselves. But I have to get them down below a certain velocity or they’ll fall right through the system.”
     “Amazing. They must do all the rest of it themselves.” Pierce shook his head. “I wouldn’t have believed it. Well, Corbell, the probes steer for an otherwise terrestrial world with a reducing atmosphere. They outnumber oxygen-nitrogen worlds about three-to-one in this region of the galaxy and probably everywhere else too—as you may know, if your age got that far.”
     “But what do the probes do?”
     “They’re biological packages. A dozen different strains of algae. The idea is to turn a reducing atmosphere into an oxygen atmosphere, just the way photosynthetic life forms did for Earth, something like fifteen-times-ten-to-the-eighth years ago.” The checker smiled, barely. His small narrow mouth wasn’t built to express any great emotion. “You’re part of a big project.”
     “Good Lord. How long does it take?”
     “We think about fifty thousand years. Obviously we’ve never had the chance to measure it.”

From RAMMER by Larry Niven (1971)
SEEDING LIFE

...he watched the cover panels roll back from the probe airlocks. Cold vapor flashed out, danced and gleamed and vanished from sight. The spray of compressed air pushed out thick-bodied probes (biovats) studded with antennae and lmobs. A mile beneath Pegasus they flashed as small thrusters locked in their proper attitudes relative to the planet below. Now Seavers looked down, saw the probes reflecting golden sun, in the distance watched the onrush of the glowing terminator line heralding nightfall.

All this was still unfolding as his mind raced ahead, at first only minutes into the future as the biovats within the probes came to life, poised, waiting for their moment. Then the timers counted through and small wasplike rocket engines screamed, only for seconds but enough to break the balance that poised the probes so delicately between gravity and outward spiraling force. The probes now yielded to gravity and fell Earthward on a long slanting descent. A panel opened in the lead probe and a thick package ejected. Seconds later another, and then another and another and still more. Each probe clicked and shuddered and hissed and released panels and springs, and the thick packages fell blunt-nosed into atmosphere. At five miles every second the probes soon glowed red with frictional heat and then spattered chunks of blazing ablation material from the thick nose cones. The heat dissipated rapidly, never reaching the precious payload behind the shield. Finally the speed fell to something sensible, friction was far behind, and more relays clicked in each probe.

The first probe began to tumble. Small tubes extended and a thin spray whipped away by centrifugal force from each tube. For two hundred miles the probe tumbled, ever lower, ever slower, still spraying its cargo of superseeds, genetically altered seeds for grass, wheat, alfalfa, corn, hay, all manner of plants, all mutated for swift growth under the most hostile of environments.

All along the flight path of Pegasus the larger probes fell away and spat flame and fell, the thick packages ejected and began their entry into the high atmosphere of Earth. The Tumblers kept spraying across an area of Earth fifty-nine degrees north and south of the equator. Much of their payload would fall into the sea. Just as much would fall to ground in a gentling rain of life.

Beneath the Floaters, the ablation heatshields fell away to lighten the load. Springs snapped out stiffly, blowing away door panels, ejecting long ribbons of nylon. Parachutes slowed down descent, valves opened, and helium gushed from containers into flyweight plastic. The balloons filled and halted descent and now the Floaters went to work, riding the high atmosphere, easing their precious cargo into the thicker, lower atmosphere in a long-lasting trickle to cover the greatest area. Eggs, billions of eggs of spiders, honeybees, beetles, butterflies, earthworms rained gently to the largely barren land below.

The Tumblers and Floaters separated. The Tumblers, their containers finally empty, continued their madcap descent all the way to impact against the ground or disappeared forever in some faceless body of water. Not yet the Floaters. They would drift for days and then for weeks, releasing their spore at timed intervals until, at last, the helium would seep through the balloon plastic and lift would decay. Those still aloft, having escaped storms and lightning and cold, would then descend silently, also to be absorbed by earth or water and disappear: unseen, unnoticed, unheard, but with an impact that could not be measured.

Marc Seavers knew thaf after their swooping curve about the Earth when they came back into direct observation of what remained of Hestia on the moon, no sign would be visible of the biovats that had left Pegasus. When again they fell down the farside of the planet in relation to the moon, Noah would send forth the flowers and plants and insects of the future.

From EXIT EARTH by Martin Caidin (1987)
THE FORGOTTEN PLANET

      The Survey-Ship Tethys made the first landing on the planet, which had no name. It was an admirable planet in many ways. It had an ample atmosphere and many seas, which the nearby sun warmed so lavishly that a perpetual cloudbank hid them and most of the solid ground from view. It had mountains and continents and islands and high plateaus. It had day and night and wind and rain, and its mean temperature was within the range to which human beings could readily accommodate. It was rather on the tropic side, but not unpleasant.
     But there was no life on it.
     No animals roamed its continents. No vegetation grew from its rocks. Not even bacteria struggled with its stones to turn them into soil. So there was no soil. Rock and stones and gravel and even sand—yes. But no soil in which any vegetation could grow. No living thing, however small, swam in its oceans, so there was not even mud on its ocean bottoms. It was one of that disappointing vast majority of worlds which turned up when the Galaxy was first explored. People couldn't live on it because nothing had lived there before.
     Its water was fresh and its oceans were harmless. Its air was germ-free and breathable (in reality, no-life = no-oxygen-atmosphere). But it was of no use whatever for men. The only possible purpose it could serve would have been as a biological laboratory for experiments involving things growing in a germ-free environment. But there were too many planets like that already. When men first traveled to the stars they made the journey because it was starkly necessary to find new worlds for men to live on. Earth was over-crowded—terribly so. So men looked for new worlds to move to. They found plenty of new worlds, but presently they were searching desperately for new worlds where life had preceded them. It didn't matter whether the life was meek and harmless, or ferocious and deadly. If life of any sort were present, human beings could move in. But highly organized beings like men could not live where there was no other life.

     So the Survey-Ship Tethys made sure that the world had no life upon it. Then it made routine measurements of the gravitational constant and the magnetic field and the temperature gradient; it took samples of the air and water. But that was all. The rocks were familiar enough. No novelties there! But the planet was simply useless. The survey-ship recorded its findings and went hastily on in search of something better. The ship did not even open one of its ports while on the planet. There were no consequences of the Tethys' visit except that record. None whatever.
     No other ship came near the planet for eight hundred years.

     Nearly a millennium later, however, the Seed-Ship Orana arrived. By that time humanity had spread very widely and very far. There were colonies not less than a quarter of the way to the Galaxy's rim, and Earth was no longer overcrowded. There was still emigration, but it was now a trickle instead of the swarming flood of centuries before. Some of the first colonized worlds had emigrants now. Mankind did not want to crowd itself together again! Men now considered that there was no excuse for such monstrous slums as overcrowding produced.
     Now, too, the star-ships were faster. A hundred light-years was a short journey. A thousand was not impractical. Explorers had gone many times farther, and reported worlds still waiting for mankind on beyond. But still the great majority of discovered planets did not contain life. Whole solar systems floated in space with no single living cell on any of their members.
     So the Seed-Ships came into being. Theirs was not a glamorous service. They merely methodically contaminated the sterile worlds with life. The Seed-Ship Orana landed on this planet—which still had no name. It carefully infected it. It circled endlessly above the clouds, dribbling out a fine dust—the spores of every conceivable microorganism which could break down rock to powder, and turn that dust to soil. It was also a seeding of molds and fungi and lichens, and everything which could turn powdery primitive soil into stuff on which higher forms of life could grow. The Orana polluted the seas with plankton. Then it, too, went away.

     More centuries passed. Human ships again improved. A thousand light-years became a short journey. Explorers reached the Galaxy's very edge, and looked estimatingly across the emptiness toward other island universes. There were colonies in the Milky Way. There were freight-lines between star-clusters, and the commercial center of human affairs shifted some hundreds of parsecs toward the Rim. There were many worlds where the schools painstakingly taught the children what Earth was, and where, and that all other worlds had been populated from it. And the schools repeated, too, the one lesson that humankind seemed genuinely to have learned. That the secret of peace is freedom, and the secret of freedom is to be able to move away from people with whom you do not agree. There were no crowded worlds any more. But human beings love children, and they have them. And children grow up and need room. So more worlds had to be looked out for. They weren't urgently needed yet, but they would be.

     Therefore, nearly a thousand years after the Orana, the Ecology-Ship Ludred swam to the planet from space and landed on it. It was a gigantic ship of highly improbable purpose. First of all, it checked on the consequences of the Orana's visit.
     They were highly satisfactory, from a technical point of view. Now there was soil which swarmed with minute living things. There were fungi which throve monstrously. The seas stank of minuscule life-forms. There were even some novelties, developed by the strictly local conditions. There were, for example, paramecia as big as grapes, and yeasts had increased in size until they bore flowers visible to the naked eye. The life on the planet was not aboriginal, though. All of it was descended and adapted and modified from the microorganisms planted by the seed-ship whose hulk was long since rust, and whose crew were merely names in genealogies—if that.
     The Ludred stayed on the planet a considerably longer time than either of the ships that had visited it before. It dropped the seeds of plants. It broadcast innumerable varieties of things which should take root and grow. In some places it deliberately seeded the stinking soil. It put marine plants in the oceans. It put alpine plants on the high ground. And when all its stable varieties were set out it added plants which were genetically unstable. For generations to come they would throw sports, some of which should be especially suited to this planetary environment.
     Before it left, the Ludred dumped finny fish into the seas. At first they would live on the plankton which made the oceans almost broth. There were many varieties of fish. Some would multiply swiftly while small; others would grow and feed on the smaller varieties. And as a last activity, the Ludred set up refrigeration-units loaded with insect eggs. Some would release their contents as soon as plants had grown enough to furnish them with food. Others would allow their contents to hatch only after certain other varieties had multiplied to be their food-supply.
     When the Ecology-Ship left, it had done a very painstaking job. It had treated the planet to a sort of Russell's Mixture of life-forms. The real Russell's Mixture is that blend of the simple elements in the proportions found in suns. This was a blend of life-forms in which some should survive by consuming the now-habituated flora, others by preying on the former. The planet was stocked, in effect, with everything that it could be hoped would live there.
     But only certain things could have that hope. Nothing which needed parental care had any chance of survival. The creatures seeded at this time had to be those which could care for themselves from the instant they burst their eggs. So there were no birds or mammals. Trees and plants of many kinds, fish and crustaceans and tadpoles, and all kinds of insects could be planted. But nothing else.
     The Ludred swam away through emptiness.

     There should have been another planting centuries later. There should have been a ship from the Zoological Branch of the Ecological Service. It should have landed birds and beasts and reptiles. It should have added pelagic mammals to the seas. There should have been herbivorous animals to live on the grasses and plants which would have thriven, and carnivorous animals to live on them in turn. There should have been careful stocking of the planet with animal life, and repeated visits at intervals of a century or so to make sure that a true ecological balance had been established. And then when the balance was fixed men would come and destroy it for their own benefit.
     But there was an accident.
     Ships had improved again. Even small private spacecraft now journeyed tens of light-years on holiday journeys. Personal cruisers traveled hundreds. Liners ran matter-of-factly on ship-lines tens of thousands of light-years long. An exploring-ship was on its way to a second island universe. (It did not come back.) The inhabited planets were all members of a tenuous organization which limited itself to affairs of space, without attempting to interfere in surface matters. That tenuous organization moved the Ecological Preparation Service to Algol IV as a matter of convenience. In the moving, one of the Ecological Service's records was destroyed.

     So the planet which had no name was forgotten. No other ship came to prepare it for ultimate human occupancy. It circled its sun, unheeded and unthought-of. Cloudbanks covered it from pole to pole. There were hazy markings in some places, where high plateaus penetrated its clouds. But that was all. From space the planet was essentially featureless. Seen from afar it was merely a round white ball—white from its cloudbanks—and nothing else.
     But on its surface, on its lowlands, it was pure nightmare. But this fact did not matter for a very long time.

     Ultimately, it mattered a great deal—to the crew of the space-liner Icarus. The Icarus was a splendid ship of its time. It bore passengers headed for one of the Galaxy's spiral arms, and it cut across the normal lanes and headed through charted but unvisited parts of the Galaxy toward its destination. And it had one of the very, very, very few accidents known to happen to space-craft licensed for travel off the normal space-lanes. It suffered shipwreck in space, and its passengers and crew were forced to take to the lifecraft.
     The lifeboats' range was limited. They landed on the planet that the Tethys had first examined, that the Orana and the Ludred had seeded, and of which there was no longer any record in the Ecological Service. Their fuel was exhausted. They could not leave. They could not signal for help. They had to stay there. And the planet was a place of nightmares.
     After a time the few people—some few thousands—who knew that there was a space-liner named Icarus, gave it up for lost. They forgot about it. Everybody forgot. Even the passengers and crew of the ship forgot it. Not immediately, of course. For the first few generations their descendants cherished hopes of rescue. But the planet which had no name—the forgotten planet—did not encourage the cherishing of hope.
     After forty-odd generations, nobody remembered the Icarus anywhere. The wreckage of the lifeboats was long since hidden under the seething, furiously striving fungi of the soil. The human beings had forgotten not only their ancestors' ship, but very nearly everything their ancestors had brought to this world: the use of metals, the existence of fire, and even the fact that there was such a thing as sunshine. They lived in the lowlands, deep under the cloudbank, amid surroundings which were riotous, swarming, frenzied horror. They had become savages.

     They were less than savages, because they had forgotten their destiny as men.

(ed note: The planet had become a hideous place covered in fungus and infested with gigantic man-eating insects.)

From THE FORGOTTEN PLANET by Murray Leinster (1954)
FOREST SUCCESSION

Thick, weedy grass and flowers covered much of the land of the campus (of the L5 space colony). At first J.D. could not figure out why it looked so familiar to her, until she realized that the ecosystem of Starfarer, planned as a natural succession, reproduced the first growth in a forest after a big fire. Of course the campus lacked the black tumble of half-burned trees, snags, uprooted trunks.

From STARFARERS by Vonda McIntyre (1989)
ECOLOGICAL SUCCESSION

(ed note: the idea is that interstellar colonists or space colony builders trying to establish a plant ecosystem will find themselves mimicking Mother Nature's natural process of succession. Because both are trying to establish an ecosystem in an alien or barren environment.)

Ecological succession is the process of change in the species structure of an ecological community over time. The time scale can be decades (for example, after a wildfire), or even millions of years after a mass extinction.

The community begins with relatively few pioneering plants and animals and develops through increasing complexity until it becomes stable or self-perpetuating as a climax community. The ʺengineʺ of succession, the cause of ecosystem change, is the impact of established species upon their own environments. A consequence of living is the sometimes subtle and sometimes overt alteration of one's own environment.

It is a phenomenon or process by which an ecological community undergoes more or less orderly and predictable changes following a disturbance or the initial colonization of a new habitat. Succession may be initiated either by formation of new, unoccupied habitat, such as from a lava flow or a severe landslide, or by some form of disturbance of a community, such as from a fire, severe windthrow, or logging. Succession that begins in new habitats, uninfluenced by pre-existing communities is called primary succession, whereas succession that follows disruption of a pre-existing community is called secondary succession.

From ECOLOGICAL SUCCESSION entry in Wikipedia
PRIMARY SUCCESSION

(ed note: Primary succession is establishing an ecosystem on sterile ground. You see this in nature on a newly formed volcanic island rising from the sea, where there isn't even any soil to start with. In rocketpunk this would be done inside a newly constructed space colony, seeding the sterile ground.)

Primary succession is one of two types of biological and ecological succession of plant life, occurring in an environment in which new substrate devoid of vegetation and other organisms usually lacking soil, such as a lava flow or area left from retreated glacier, is deposited. In other words, it is the gradual growth of an ecosystem over a longer period.

In contrast, secondary succession occurs on substrate that previously supported vegetation before an ecological disturbance from smaller things like floods, hurricanes, tornadoes, and fires which destroyed the plant life.

Occurrence

In primary succession pioneer species like lichen, algae and fungi as well as other abiotic factors like wind and water start to "normalize" the habitat. Primary succession begins on rock formations, such as volcanoes or mountains, or in a place with no organisms or soil. This creates conditions nearer optimum for vascular plant growth; pedogenesis or the formation of soil is the most momentous process.

These pioneer plants are then dominated and often replaced by plants better adapted to less harsh conditions, these plants include vascular plants like grasses and some shrubs that are able to live in thin soils that are often mineral based.

For example, spores of lichen or fungus, being the pioneer species, are spread onto a land of rocks. Then, the rocks are broken down into smaller pieces and organic matter gradually accumulates, favouring the growth of larger plants like grasses, ferns and herbs. These plants further improve the habitat and help the adaptation of larger vascular plants like shrubs, or even medium- or mountainous-sized trees. More beasts are then attracted to the place and finally a climax community is reached.

Example

A good example of primary succession takes place after a volcano has erupted. The lava flows into the ocean and hardens into new land. The resulting barren land is first colonized by pioneer plants which pave the way for later, less hardy plants, such as hardwood trees, by facilitating pedogenesis, especially through the biotic acceleration of weathering and the addition of organic debris to the surface regolith. An example of primary succession is the island of Surtsey, which is an island formed in 1963 after a volcanic eruption from beneath the sea. Surtsey is off the South coast of Iceland and is being monitored to observe primary succession in progress. About thirty species of plant had become established by 2008 and more species continue to arrive, at a typical rate of roughly 2–5 new species per year./p>

From PRIMARY SUCCESSION entry in Wikipedia
SECONDARY SUCCESSION

(ed note: Secondary succession is when an ecosystem is diminished to a smaller population of species and it is doing its darnedest to expand. You see this in a forest burnt to the ground by a forest fire. In rocketpunk this would be done in an interstellar colony on an alien planet, trying to remove the alien ecosystem locally and replacing it with a Terran ecosystem that can be used to do things like, you know, grow food to eat.)

Secondary succession is one of the two types of ecological succession of plant life. As opposed to the first, primary succession, secondary succession is a process started by an event (e.g. forest fire, harvesting, hurricane) that reduces an already established ecosystem (e.g. a forest or a wheat field) to a smaller population of species, and as such secondary succession occurs on preexisting soil whereas primary succession usually occurs in a place lacking soil.

Simply put, secondary succession is the ecological succession that occurs after the initial succession has been disrupted and some plants and animals still exist. It is usually faster than primary succession as:

  1. Soil is already present, so there is no need for pioneer species;
  2. Seeds, roots and underground vegetative organs of plants may still survive in the soil.

Mechanism

Many mechanisms can trigger succession of the second including facilitation such as trophic interaction, initial composition, and competition-colonization trade-offs. The factors that control the increase in abundance of a species during succession may be determined mainly by seed production and dispersal, micro climate; landscape structure (habitat patch size and distance to outside seed sources); Bulk density, pH, soil texture (sand and clay).

Vegetation

Imperata grasslands are caused by human activities such as logging, forest clearing for shifting cultivation, agriculture and grazing, and also by frequent fires. The latter is a frequent result of human interference. However, when not maintained by frequent fires and human disturbances, they regenerate naturally and speedily to secondary young forest. The time of succession in Imperata grassland (for example in Samboja Lestari area), Imperata cylindrica has the highest coverage but it becomes less dominant from the fourth year onwards. While Imperata decreases, the percentage of shrubs and young trees clearly increases with time. In the burned plots, Melastoma malabathricum, Eupatorium inulaefolium, Ficus sp., and Vitex pinnata. strongly increase with the age of regeneration, but these species are commonly found in the secondary forest.

Soil

Soil properties change during secondary succession in Imperata grassland area. The effects of secondary succession on soil are strongest in the A-horizon (0–10 cm), where an increase in carbon stock, N, and C/N ratio, and a decrease in bulk density and pH are observed. Soil carbon stocks also increase upon secondary succession from Imperata grassland to secondary forest.

Post-fire succession

For more details on this topic, see Fire ecology.

Soil

Generation of carbonates from burnt plant material following fire disturbance causes an initial increase in soil pH that can affect the rate of secondary succession, as well as what types of organisms will be able to thrive. Soil composition prior to fire disturbance also influences secondary succession, both in rate and type of dominant species growth. For example, high sand concentration was found to increase the chances of primary Pteridium over Imperata growth in Imperata grassland. The byproducts of combustion have been shown to affect secondary succession by soil microorganisms. For example, certain fungal species such as Trichoderma polysporum and Penicillium janthinellum have a significantly decreased success rate in spore germination within fire-affected areas, reducing their ability to recolonize.

Vegetation

Vegetation structure is affected by fire. In some types of ecosystems this creates a process of renewal. Following a fire, early successional species disperse and establish first. This is then followed by late successional species. Species that are fire intolerant are those that are more flammable and are desolated by fire. More tolerant species are able to survive or disperse in the event of fire. The occurrence of fire leads to the establishment of deadwood and snags in forests. This creates habitat and resources for a variety of species. Fire can act as a seed dispersing stimulant. Many species require fire events to reproduce, disperse, and establish. For example, the knobcone pine ("Pinus attenuata") has closed cones that open for dispersal when exposed to heat caused by forest fires. This particular conifer grows in clusters because of this limited method of seed dispersal. A tough fire resistant outer bark and lack of low branches help the knobcone pine survive fire with minimal damage.

From SECONDARY SUCCESSION entry in Wikipedia
ECOSYSTEM TO BRING

(ed note: Our heroes and heroines are building a space ark to fly a few survivors to the planet Bronson Beta, before the planet Bronson Alpha splatters Terra like a bug on an automobile windshield)

"In the early days on this world, the great majority of plants did not reproduce by seeds, but by the far more resistant spores, which have survived as the method of reproduction of many varieties. So we will count upon a native flora which, undoubtedly, will appear very strange to us. Of course, as you know, we are taking across with us our own seeds and our own spores."

"I know," said Tony, "and even our own insects too."

"An amazing list—isn't it, Tony?—our necessities for existence. We take so much for granted, don't we? You do not realize what has been supplied you by nature on this world of ours—until you come to count up what you must take along with you, if you hope to survive."

"Yes," said Tony, "ants and angleworms—and mayflies."

"Exactly. You've been talking with Keppler, I see. I put that problem entirely up to Keppler.

"Our first and most necessary unit for self-preservation proved to be the common honey bee, to secure pollination of flowering plants, trees and so on. Keppler says that of some twenty thousand nectar insects, this one species pollinates more than all the rest put together. The honey bee would take care of practically of this work, as his range is tremendous. There are a few plants—Keppler tells me—such as red clover, which he cannot work on; but his cousin the bumblebee, with his longer proboscis, could attend to them. So, first and foremost among living things, we bring bees.

"We also take ants, especially the common little brown variety, to ventilate, drain and work the soil; and, as you have observed, angleworms also.

"Since we are going to take with us fish eggs to hatch into fish over there, we have to take mayflies. Their larvas, in addition to providing food for the fish, are necessary to keep the inland waters from becoming choked with algæ and the lower water plants.

"In the whole of the Lepidoptera there is not, Keppler says, one necessary or even useful species; but for sheer beauty's sake—and because they take small space—we will take six butterflies and at least the Luna moth.

"And we must take one of the reputed scourges of the earth."

"What?" said Tony.

"The grasshopper—the locust. Such an insect will be vitally necessary to keep the greenery from choking our new earth; and the one best suited for this job is, paradoxically enough, one of mankind's oldest scourges, the grasshopper. He is an omnivorous feeder and would keep the greenery in check— after he got his start. Our first problem may be that he will not multiply fast enough; and then that he multiply too fast. So to keep him in check, and also the butterfly and the moth, we will take parasitic flies. We will have to have these—two or three of the dozen common Tachinidæ have been chosen.

"These will be the essential insects. Here on earth, with a balanced and bewilderingly intricate economy already established, a tremendously longer list would be vital to provide the proper checks and balances; but starting anew, on Bronson Beta, we can begin, at least, with the few insects we have chosen. Unquestionably, differentiation and evolution will swiftly set in, and they will find new forms.

"We are bringing along vials of mushroom and other fungi spores. Otherwise vegetation would fall down, never disintegrate, and pile up till everything was choked. A vial the size of your thumb holds several billion spores of assorted fungi— in case the spores of the fungi of Bronson Beta have not survived. They are absolutely essential.

"Also, besides our own water supply for the voyage, we are taking bottles of stagnant pond-water and another of sea-water containing our microorganisms such as diatoms, plankton, unicellular plants and animals which form the basis for our biotic economy and would supplement, or replace, such life on the other globe.

"About animals—" He halted.

"Yes, about animals," Tony urged.

"There is, naturally, still discussion. Our space is so limited, and there is most tremendous competition. Birds offer a somewhat simpler problem; but possibly you have heard some of the arguments over them."

"I have," said Tony, "and joined in them. I confess I argued for warblers—yellow warblers. I like them; I have always liked them; and meadow larks."

"The matter of dogs and cats is the most difficult," Hendron said, closing the subject.

From WHEN WORLDS COLLIDE by Philip Wylie and Edwin Balmer (1932)
STARSHIP TROOPERS

I never have learned the co-ordinates of Sanctuary, nor the name or catalogue number of the star it orbits — because what you don't know, you can't spill; the location is ultra-top-secret, known only to ships' captains, piloting officers, and such . . . and, I understand, with each of them under orders and hypnotic compulsion to suicide if necessary to avoid capture. So I don't want to know. With the possibility that Luna Base might be taken and Terra herself occupied, the Federation kept as much of its beef as possible at Sanctuary, so that a disaster back home would not necessarily mean capitulation.

But I can tell you what sort of a planet it is. Like Earth, but retarded.

Literally retarded, like a kid who takes ten years to learn to wave bye-bye and never does manage to master patty-cake. It is a planet as near like Earth as two planets can be, same age according to the planetologists and its star is the same age as the Sun and the same type, so say the astrophysicists. It has plenty of flora and fauna, the same atmosphere as Earth, near enough, and much the same weather; it even has a good-sized moon and Earth's exceptional tides.

With all these advantages it barely got away from the starting gate. You see, it's short on mutations; it does not enjoy Earth's high level of natural radiation.

Its typical and most highly developed plant life is a very primitive giant fern; its top animal life is a proto-insect which hasn't even developed colonies. I am not speaking of transplanted Terran flora and fauna — our stuff moves in and brushes the native stuff aside.

With its evolutionary progress held down almost to zero by lack of radiation and a consequent most unhealthily low mutation rate, native life forms on Sanctuary just haven't had a decent chance to evolve and aren't fit to compete. Their gene patterns remain fixed for a relatively long time; they aren't adaptable — like being forced to play the same bridge hand over and over again, for eons, with no hope of getting a better one.

As long as they just competed with each other, this didn't matter too much — morons among morons, so to speak. But when types that had evolved on a planet enjoying high radiation and fierce competition were introduced, the native stuff was outclassed.

From STARSHIP TROOPERS by Robert Heinlein (1959)
CLASH OF ECOSYSTEMS

(ed note: on the planet Thalassa, a human colony has been established. Of course they plant Terra vegetation.)

     By Terran standards, the waterfall was not very impressive — perhaps one hundred metres high and twenty across. A small metal bridge glistening with spray spanned the pool of boiling foam in which it ended.
     To Loren’s relief, Mirissa dismounted and looked at him rather mischievously.
     ‘Do you notice anything… peculiar?’ she asked, waving towards the scene ahead.
     ‘In what way?’ Loren answered, fishing for clues. All he saw was an unbroken vista of trees and vegetation, with the road winding away through it on the other side of the fall.
     ‘The trees — the trees!’
     ‘What about them? I’m not a — botanist.’
     ‘Nor am I, but it should be obvious. Just look at them.’
     He looked, still puzzled. And presently he understood, because a tree is a piece of natural engineering — and he was an engineer.
     A different designer had been at work on the other side of the waterfall. Although he could not name any of the trees among which he was standing, they were vaguely familiar, and he was sure that they came from Earth … yes, that was certainly an oak, and somewhere, long ago, he had seen the beautiful yellow flowers on that low bush.
     Beyond the bridge, it was a different world. The trees — were they really trees? — seemed crude and unfinished. Some had short, barrel-shaped trunks from which a few prickly branches extended; others resembled huge ferns; others looked like giant, skeletal fingers, with bristly haloes at the joints. And there were no flowers …
     ‘Now I understand. Thalassa’s own vegetation.’
     ‘Yes — only a few million years out of the sea. We call this the Great Divide. But it’s more like a battlefront between two armies, and no one knows which side will win. Neither, if we can help it! The vegetation from Earth is more advanced; but the natives are better adapted to the chemistry. From time to time one side invades the other — and we move in with shovels before it can get a foothold.’
     How strange, Loren thought as they pushed their bicycles across the slender bridge. For the first time since landing on Thalassa, I feel that I am indeed on an alien world …
     These clumsy trees and crude ferns could have been the raw material of the coal beds that had powered the Industrial Revolution — barely in time to save the human race. He could easily believe that a dinosaur might come charging out of the undergrowth at any moment; then he recalled that the terrible lizards had still been a hundred million years in the future when such plants had flourished on Earth …

From THE SONGS OF DISTANT EARTH by Sir Arthur C. Clarke (1985)
ONLY TERRAFORM DEAD PLANETS

(ed note: The starship Magellan is visiting the Terran colony on the planet Thalassa. Their destination is the planet Sagan 2, to found a new colony there. The starship crew gives a seminar for some Thalassan scientists.)

‘Here it is,’ she began. ‘I’m sure you’ve all seen this map of Sagan — the best reconstruction possible from fly-bys and radioholograms. The detail’s very poor, of course — ten kilometres at the best — but it’s enough to give us the basic facts.

‘Diameter — fifteen thousand kilometres, a little larger than Earth. A dense atmosphere — almost entirely nitrogen. And no oxygen — fortunately.’

That ‘fortunately’ was always an attention-getter; it made the audience sit up with a jolt.

‘I understand your surprise; most human beings have a prejudice in favour of breathing. But in the decades before the Exodus, many things happened to change our outlook on the Universe.

‘The absence of other living creatures — past or present — in the solar system and the failure of the SETI programs despite sixteen centuries of effort convinced virtually everyone that life must be very rare elsewhere in the universe, and therefore very precious.

‘Hence it followed that all life forms were worthy of respect and should be cherished. Some argued that even virulent pathogens and disease vectors should not be exterminated, but should be preserved under strict safeguards. “Reverence for life” became a very popular phrase during the Last Days and few applied it exclusively to human life.

‘Once the principle of biological noninterference was accepted, certain practical consequences followed. It had long been agreed that we should not attempt any settlement on a planet with intelligent life-forms; the human race had a bad enough record on its home world. Fortunately — or unfortunately! — this situation has never arisen.

‘But the argument was taken further. Suppose we found a planet on which animal life had just begun. Should we stand aside and let evolution take its course on the chance that megayears hence intelligence might arise?

‘Going still further back — suppose there was only plant life? Only single-cell microbes?

‘You may find it surprising that, when the very existence of the human race was at stake, men bothered to debate such abstract moral and philosophical questions. But Death focuses the mind on the things that really matter: why are we here, and what should we do?

‘The concept of “Metalaw” — I’m sure you’ve all heard the term — became very popular. Was it possible to develop legal and moral codes applicable to all intelligent creatures, and not merely to the bipedal, air-breathing mammals who had briefly dominated Planet Earth?

‘Dr Kaldor, incidentally, was one of the leaders of the debate. It made him quite unpopular with those who argued that since H. sapiens was the only intelligent species known, its survival took precedence over all other considerations. Someone coined the effective slogan: “If it’s Man or Slime Moulds, I vote for Man!”

‘Fortunately, there’s never been a direct confrontation — as far as we know. It may be centuries before we get reports from all the seedships that went out. And if some remain silent — well, the slime moulds may have won…

‘In 3505, during the final session of the World Parliament, certain guidelines — the famous Geneva Directive — were laid down for future planetary colonization. Many thought that they were too idealistic, and there was certainly no way in which they could ever be enforced. But they were an expression of intent — a final gesture of goodwill towards a Universe which might never be able to appreciate it.

‘Only one of the directive’s guidelines concern us here — but it was the most celebrated and aroused intense controversy, since it ruled out some of the most promising targets.

‘The presence of more than a few percent oxygen in a planet’s atmosphere is definite proof that life exists there. The element is far too reactive to occur in the free state unless it is continually replenished by plants — or their equivalent. Of course, oxygen doesn’t necessarily mean animal life, but it sets the stage for it. And even if animal life only rarely leads to intelligence, no other plausible route to it has ever been theorized.

‘So, according to the principles of Metalaw, oxygen-bearing planets were placed out of bounds. Frankly, I doubt so drastic a decision would have been made if the quantum drive hadn’t given us essentially unlimited range — and power.

‘Now let me tell you our plan of operation, when we have reached Sagan 2. As you will see by the map, more than fifty per cent of the surface is ice-covered, to an estimated average depth of three kilometres. All the oxygen we shall ever need!

‘When it’s established its final orbit, Magellan will use the quantum drive, at a small fraction of full-power, to act as a torch. It will burn off the ice and simultaneously crack the steam into oxygen and hydrogen. The hydrogen will quickly leak away into space; we may help it with tuned lasers, if necessary.

‘In only twenty years, Sagan 2 will have a ten per cent O2 atmosphere, though it will be too full of nitrogen oxides and other poisons to be breathable. About that time we’ll start dumping specially developed bacteria, and even plants, to accelerate the process. But the planet will still be far too cold; even allowing for the heat we’ve pumped into it, the temperature will be below freezing everywhere except for a few hours near noon at the Equator.

‘So that’s where we use the quantum drive, probably for the last time. Magellan, which has spent its entire existence in space, will finally descend to the surface of a planet.

‘And then, for about fifteen minutes every day at the appropriate time, the drive will be switched on at the maximum power the structure of the ship — and the bedrock on which it is resting — can withstand. We won’t know how long the operation will take until we have made the first tests; it may be necessary to move the ship again if the initial site is geologically unstable.

‘At a first approximation, it appears that we’ll need to operate the drive for thirty years, to slow the planet until it drops sunward far enough to give it a temperate climate. And we’ll have to run the drive for another twenty-five years to circularize the orbit. But for much of that time Sagan 2 will be quite livable — though the winters will be fierce until final orbit is achieved.

‘So then we will have a virgin planet, larger than Earth, with about forty percent ocean and a mean temperature of twenty-five degrees. The atmosphere will have an oxygen content seventy percent of Earth’s — but still rising. It will be time to awaken the nine hundred thousand sleepers still in hibernation, and present them with a new world.

From THE SONGS OF DISTANT EARTH by Sir Arthur C. Clarke (1985)
WRATH OF KHAN

(ed note: Chekov and Captain Terrell are looking for a totally lifeless planet to test Dr. Carol Marcus' "Genesis Device." Since the device will instanly kill any life forms already on the planet Dr. Marcus is quite firm that "lifeless" means LIFELESS.)

CAROL: Now let me get this straight. Something you can transplant?
CHEKOV: Yes, Doctor.
CAROL: Something you can transplant? I don't know.
TERRELL: It might only be a particle of preanimate matter.
CAROL: Then again it may not. You boys have to be clear on this. There can't be so much as a microbe or the show's off. Why don't you have a look? But if it is something that can be moved I want...
TERRELL: You bet, Doctor. We're on our way!
From movie STAR TREK: THE WRATH OF KHAN (1982)

Pantropy

If changing an entire planet to suit human colonists is out of the question, the next best thing is changing the colonists to fit the planet (much cheaper as well). This is done by extreme genetic engineering, James Blish coined the term "pantropy". This can go beyond humans engineered to handle slightly hotter or colder temperatures: it can theoretically lead to engineering "people" with totally different biochemistries, breathing methane and having bones composed of water ice.

This appears in James Blish's Pantropy series, Roger Zelazny's "The Keys to December ", Charles Sheffield's Proteus in the Underworld and Olaf Stapedon's Last and First Men.

Understand this is not taking a person and giving them a treatment to transform their bodies into something that can breath methane and survive sub-sub-zero cold. This is about genetically engineering their as yet unborn children. You take a person's germ cells into the lab, and genetically engineering the living daylights of the the cells so they will grow into a child that can breath methane and survive sub-sub-zero cold. Maybe someday Mommy and Daddy can wear a space suit and visit their offspring, happily walking around in their shirt-sleeves on a planet that would instantly kill an unprotected standard human being.


There are a few older science fiction story about transforming a standard human into something else for purposes of colonizing an inhospitable world, but nowadays that seems far fetched. In The Impossible World they have the miracle drug "adaptene". In Farthest Star they have teleportation by duplication. But the duplicate can be "edited" e.g., a water breather can be transformed into a air breather. And in Enchanted Village I guess the astronaut can adapt into a life form suitable for the Martian villiage because the village is, well, enchanted.

A TIME TO SURVIVE

The facts were simple and implacable. Sweeney was an Adapted Man — adapted, in this instance, to the bitter cold, the light gravity, and the thin stink of atmosphere which prevailed on Ganymede. The blood that ran in his veins, and the sol substrate of his every cell, was nine-tenths liquid ammonia; his bones were Ice IV; his respiration was a complex hydrogen-to-methane cycle based not upon catalysis by an iron-bearing pigment, but upon the locking and unlocking of a double sulfur bond; and he could survive for weeks, if he had to, upon a diet of rock dust.

He had always been this way. What had made him so had happened to him literally before he had been conceived: the application, to the germ cells which had later united to form him, of an elaborate constellation of techniques — selective mitotic poisoning, pinpoint X-irradiation, tectogenetic micro-surgery, competitive metabolic inhibition, and perhaps fifty more whose names he had never even heard — which collectively had been christened “pantropy.” The word, freely re-translated, meant “changing everything” and it fitted.


Even the ultimate germ cells were the emergents of a hundred previous generations, bred one from another before they had passed the zygote stage like one-celled animals, each one biassed a little farther toward the cyanide and ice and everything nice that little boys like Sweeney were made of.


Item: the Authorities. Long before space travel, big cities in the United States had fallen so far behind any possibility of controlling their own traffic problems as to make purely political solutions chimerical. No city administration could spend the amount of money needed for a radical cure, without being ousted in the next elections by the enraged drivers and pedestrians who most needed the help.

Increasingly, the traffic problems were turned over, with gratitude and many privileges, to semi-public Port, Bridge and Highway Authorities: huge capital-investment ventures modelled upon the Port of New York Authority, which had shown its ability to build and/or run such huge operations as the Holland and Lincoln Tunnels, the George Washington Bridge, Teterboro, LaGuardia, Idlewild and Newark airports, and many lesser facilities. By 1960 it was possible to travel from the tip of Florida to the border of Maine entirely over Authority-owned territory, if one could pay the appropriate tolls (and didn’t mind being shot at in the Poconos by embattled land-owners who were still resisting the gigantic Incadel project).

Item: the Tolls. The Authorities were creations of the states, usually acting in pairs, and as such enjoyed legal protections not available to other private firms engaged in interstate commerce. Among these protections, in the typical enabling act, was a provision that “the two said states will not … diminish or impair the power of the Authority to establish, levy and collect tolls and other charges …” The federal government helped; although the Federal Bridge Act of 1946 required that the collection of tolls must cease with the payment of amortization, Congress almost never invoked the Act against any Authority. Consequently, the tolls never dropped; by 1953 the Port of New York Authority was reporting a profit of over twenty million dollars a year, and annual collections were increasing at the rate of ten per cent a year.

Some of the take went into the development of new facilitiesm, most of them so placed as to increase the take, rather than solve the traffic problem. Again the Port of New York Authority led the way; it built, against all sense, a third tube for the Lincoln Tunnel, thus pouring eight and a half million more cars per year into Manhattan’s mid-town area, where the city was already strangling for want of any adequate ducts to take away the then-current traffic.

Item: the Port cops. The Authorities had been authorized from the beginning to police their own premises. As the Authorities got bigger, so did the private police forces.

By the time space travel arrived, the Authorities owned it.

They had taken pains to see that it fell to them; they had learned from their airport operations — which, almost alone among their projects, always showed a loss — that nothing less than total control is good enough. And characteristically, they never took any interest in any form of space-travel which did not involve enormous expenditures; otherwise they could take no profits from sub-contracting, no profits from fast amortization of loans, no profits from the laws allowing them fast tax writeoffs for new construction, no profits from the indefinitely protracted collection of tolls and fees after the initial cost and the upkeep had been recovered.

At the world’s first commercial spaceport, Port Earth, it cost ship owners $5000 each and every time their ships touched the ground. Landing fees had been outlawed in private atmosphere flying for years, but the Greater Earth Port Authority operated under its own set of precedents; it made landing fees for spacecraft routine. And it maintained the first Port police force which was bigger than the armed forces of the nation which had given it its franchise; after a while, the distinction was wiped out, and the Port cops were the armed forces of the United States. It was not difficult to do, since the Greater Earth Port authority was actually a holding company embracing every other Authority in the country, including Port Earth.

And when people, soon after spaceflight, began to ask each other, “How shall we colonize the planets?,” the Greater Earth Port Authority had its answer ready.

Item: Terraforming.

Terraforming — remaking the planets into near-images of the Earth, so that Earth-normal people could live on them.

Port Earth was prepared to start small. Port Earth wanted to move Mars out of its orbit to a point somewhat closer to the sun, and make the minor adjustments needed in the orbits of the other planets; to transport to Mars about enough water to empty the Indian Ocean — only a pittance to Earth, after all, and not 10 per cent of what would be needed later to terraform Venus; to carry to the little planet top-soil about equal in area to the state of Iowa, in order to get started at growing plants which would slowly change the atmosphere of Mars; and so on. The whole thing, Port Earth pointed out reasonably, was perfectly feasible from the point of view of the available supplies and energy resources, and it would cost less than thirty-three billion dollars. The Greater Earth Port Authority was prepared to recover that sum at no cost in taxes in less thap a century, through such items as $50 rocket-mail stamps, $10,000 Mars landing fees, $1,000 one-way strap-down tickets, 100-per-desert-acre land titles, and so on.

Of course the fees would continue after the cost was re-covered — for maintenance.

Alternative? Nothing but domes. The Greater Earth Port Authority hated domes. They cost too little to begin with, and the volume of traffic to and from them would always be miniscule.

Experience on the Moon had made that painfully clear. And the public hated domes, too; it had already shown a mass reluctance to live under them.

As for the governments, other than that of the United States, that the Authority still tolerated, none of them had any love for domes, or for the kind of limited colonization that the domes stood for. They needed to get rid of their populating masses by the bucket-full, not by the eye-dropper-full.

If the Authority knew that emigration increases the home population rather than cuts it, the Authority carefully reframed from saying so to the governments involved; they could rediscover Franklin’s Law for themselves. Domes were out; terraforming was in.

Then came pantropy.

If this third alternative to the problem of colonizing the planets had come as a surprise to the Authority, and to Port Earth, they had nobody to blame for it but themselves.

There had been plenty of harbingers. The notion of modifying the human stock genetically to live on the planets as they were found, rather than changing the planets to accommodate the people, had been old with Olaf Stapledon; it had been touched upon by many later writers; it went back, in essence, as far as Proteus, and as deep into the human mind as the werewolf, the vampire, the fairy changeling, the transmigrated soul.

But suddenly it was possible; and, not very long afterwards, it was a fact.

The Authority hated it. Pantropy involved a high initial investment to produce the first colonists, but it was a method which with refinement would become cheaper and cheaper.

Once the colonists were planted, it required no investment at all; the colonists were comfortable on their adopted world, and could produce new colonists without outside help. Pantropy, furthermore, was at its most expensive less than half as costly as the setting-up of the smallest and least difficult dome.

Compared to the cost of terraforming even so favorable a planet as Mars, it cost nothing at all, from the Authority’s point of view.

And there was no way to collect tolls against even the initial expense. It was too cheap to bother with.

(ed note: example of propaganda from The Authority. They had to kill pantropy dead; or bye-bye graft, kick-backs, and lucrative fees.)

WILL YOUR CHILD BE A MONSTER?

If a number of influential scientists have their way, some child or grandchild of yours may eke out his life in the frozen wastes of Pluto, where even the sun is only a spark in the sky — and will be unable to return to Earth until after he dies, if then!

Yes, even now there are plans afoot to change innocent unborn children into alien creatures who would die terribly the moment that they set foot upon the green planet of their ancestors. Impatient with the slow but steady pace of man’s conquest of Mars, prominent ivory-tower thinkers are working out ways to produce all kinds of travesties upon the human form — travesties which will be able to survive, somehow, in the bitterest and most untamed of planetary infernos.

The process which may produce these pitiful freaks at enormous expense is called “pantropy.” It is already in imperfect and dangerous existence. Chief among its prophets is white-haired, dreamy-eyed Dr. Jacob Rullman, who…

From A TIME TO SURVIVE by James Blish (1956)
PROTEUS IN THE UNDERWORLD

(ed note: In Sheffield's Proteus novels he postulates a breakthrough technology called Purposive Form Change. It is an advanced form of biofeedback that allows a person to program a form-change tank with the desired change, get in, and let the tank guide them in making drastic changes to their bodies. Congenital defects and injuries can be fixed, lost limbs re-grown, eyesight corrected, hormonal imbalances remedied. Doctors are obsolete.

But more to the point the person can also drastically alter their appearance, capabilities, and even their biochemistries.

In other words it is a kind of Pantropy that can adapt a given person to live on another planet, instead of only being able to adapt a person's offspring.

Obviously organizations with a vested interest in terraforming will have a problem with this.)


(ed note: Trudy has Bey on Mars, showing him the asteroid-fall. This is part of the terraforming of Mars.)

      "Other way." Trudy placed gloved hands on his shoulder and spun him around, just in time to see one to the south. A ball of fire came flaming across the southern sky from west to east. It vanished from sight in twenty seconds. One minute later a brighter flash of crimson light lit the south-eastern horizon. The sky in that direction already glowed with incandescent streaks and plumes.
     "Now the other." She had Bey's arm and was turning him again, this time toward the north. "Get ready for the quakes, they come every few minutes."
     A second fireball ripped the northern sky, again traveling from west to east. Before it could pass out of sight the shock of an earlier impact was arriving. A surface wave came rippling in from the south and shifted the ground beneath Bey's feet in a double up-and-down that had him swaying and sent die rubble-strewn desert into new patterns of cracks and small fissures.
     Bey hardly followed the trajectory of the second object. The ground beneath your feet was not supposed to move like that. He felt much less safe.
     "That was a big one." Trudy still had her hand on his arm, steadying him. "Close to maximum size, at a guess."
     Which meant it was about a hundred meters in diameter; a rough-edged chunk of water ice, dirtied throughout with smears of ammonia ice, silicate rock and metallic ore, had smashed into the surface and vaporized on impact.
     "What's the energy release?" Bey felt a second, smaller ripple of movement.
     "About a thousand megatons, for one that size."

     Like a really big volcanic explosion back on Earth. Bey was watching events that were equal in energy to several Krakatoa eruptions — except that these were happening every few minutes rather than every few decades. It was the hail-storm of the Gods, with hailstones the size of Melford Castle hitting the ground at forty kilometers a second; and mortal humans, not gods, were responsible for it.
     The chunks of ice had been on their way for a long time. Even with a strong initial boost the journey in from the middle of the Oort Cloud, a quarter of a light-year out, took a comet fragment at least thirty years. And even with the most precise direction by the Cloudlanders during the first phase of the trajectory, a fragment's fusion motor usually needed a small corrective burn as it came closer to Mars. The specification was a tight one: tangential impact along a due west-to-east line of travel, striking between latitudes twenty and twenty-five degrees north or south of the equator. The thin atmosphere of Mars ablated a little from the bolide, but most of it would make it all the way to the surface and strike at over forty kilometers a second.
     Space-based lasers in orbit high above Mars watched for correction rocket malfunction. At the first sign of a guidance problem the fragment would be disintegrated in space, long before it could become a danger to dwellers on the planet.

     The rain of comets had begun a century ago and continued ever since. It was slow work. Even with a hundred years of added volatiles from orbit and the help of bespoke ground-based organisms to split oxygen from iron oxide, it took a Martian eye to see much difference in the planet's atmosphere. The water vapor was up to only a thirtieth that of Earth, the oxygen content one fortieth.
     The contribution of the comet fragments to changing the Martian day was even harder to appreciate. Arriving tangentially at forty-two kilometers a second, every one made an addition to the planets angular momentum. Mars was gradually being spun up like a gigantic top, whipped by in falling chunks of frozen volatiles; but a century of impacts had shortened the period by less than a second. If anyone hoped to see a time when the Mars day of twenty-four hours and thirty-nine minutes was reduced to exactly equal that of Earth, they would have to be prepared to live a long, long time.

(ed note: Bey has been taken to meet the Old Mars Policy Council. They are devoted to the terraforming of Mars.)

     The glass doors swung open, to reveal a lobby beyond, escalators, and a bank of elevators. Fermiel went in, but he remained right by the entrance. A great cube of grey stone stood there, as tall as a human. He pointed to one face of it, where a plate of hardened transparent plastic had been set into the rock.
     "The original." Rafael Fermiel tried to sound casual, but the reverence showed through. "There have been millions of copies, but this is the original."
     Bey stepped closer. Behind the impermeable plastic sheet stood an oblong piece of yellowed paper. He could see the printing and the couple of dozen signatures scrawled at the bottom, but the words were almost too faded to make out.
     "Be it known by all who follow … " he read aloud.

     And then he knew. "The Declaration! I thought it was lost — a century ago."
     "It was. It was buried when the Ladnier Cavern collapsed. We found it last year during a secondary excavation. Are you amazed now, Behrooz Wolf?"
     "More than amazed. I am overwhelmed." Bey leaned close. Of the original Mars colony, three men and three women had died during the first few days. The remaining twenty-four signatories were all here, immortalized by far more than a crumbling piece of paper a century and a half old. Their names were engraved on the memory of every child born on Mars.

     (The leader of the Council said) Let us get right down to business. That" — he pointed to the engraving on the far wall — "was not placed in this room by accident. The Declaration guides and motivates all the council's work. We begin and end each of our meetings with its words. I now ask that we do so again, familiar as it may already be to most of us." Be it known by all who follow …
     The Mars Declaration was indeed familiar to Bey, and to the whole solar system — as a unique historical document. But no one else, in Bey's experience, treated the words with anything like the reverence accorded them here.
Be it known by all who follow that Mars is now a home for humans. We, the surviving crew of the exploration ship Terra Nova, pledge never to leave this world. We will not obey any order to return to Earth, no matter how or by whom delivered. We will venture no more into space. We will remain here to live, to labor, and to die.

Since we will not survive to see the end of our work, we give our dream to those who come after. This we believe:

That Mars, before our arrival, was barren of life.

That Mars will never after this be without the life forms of Earth.

That Mars is destined to be one day fertile and blooming, as a second Earth.

That human children will breathe the air of this New Earth, and sit at ease beside its flowing rivers…

     Its flowing rivers. Bey was sure that the crew of the Terra Nova had known nothing of the deep caves of Mars, had never imagined a Mars Underworld of simulated Earths like the ones that he had just seen.
     Their vision had been of the surface. Its flowing rivers. Bey saw again in his mind's eye the old, dried-out watercourses and jagged, rusty rocks, the desolate wilderness beneath a thin, dry atmosphere and a diminished sun. But on that frigid red desert, without life-support equipment, stood a handful of long-legged bipeds. How did Mars appear to them, the new forms that Trudy Melford had shown him?
     Bey tried to make the mental shift of viewpoint, to look on Mars through other eyes. He was still struggling when he became aware that everyone else at the long table was sitting patiently waiting. And he was less than a third of the way through reading the text of the Declaration.

     "We know what you must be thinking, Mr. Wolf." Rafael Fermiel spoke softly and sympathetically. "You have seen our work, creating the ecosystems for New Earth within Mars. On your last trip you visited the surface, and saw our progress in the Mars conversion process. Day-to-day changes are too small to notice, but the atmosphere constantly thickens and every year holds a little more water vapor. Had you gone farther north, you would have seen temporary pools of surface water near the cometary fragment impact points. The goals of the Declaration are being realized. Full terraforming will one day be completed. But there are complications."
     "The new surface forms?" (form-changed humans adapted to live in the current Martian surface conditions covertly created by an unknown organization) Bey had made no promise of secrecy to Trudy Melford.
     "Exactly. Not so much their existence and present numbers as their implications. There are powerful groups on Mars who insist that the new forms point the direction of the future. 'It is far easier to change humans,' they tell us, 'than planets. Why not do as the Cloudlanders and Colonies do, and adapt form to setting?' We know and reject those arguments. We also believe that the most powerful voice in those dissenting groups is the newest one, and the one with most to gain from the use of form-change."

(ed note: Bey is talking to Georgia Kruskals, the creator and leader of the form-changed Martian surface forms)

     (Bey said) "One more question, then it will be your turn. You say you are known and hated in Old Mars. Why?"
     "You can answer that for yourself, Behrooz Wolf, if you think for a second."
     "I think I know, but I want to confirm it. Old Mars is afraid of you. They see you as interfering with their plans."
     "Interfering, and worse." The broad mouth widened. It was a smile, toothless and tongueless. Bey guessed that both those features lay far back, out of sight within the long snout. "Isn't it obvious that Old Mars sees us as a major enemy? The policy council is committed to terraforming Mars, making it into a world in Earth's image. They take the Mars Declaration and they misunderstand it. The first colonists wanted Mars to be a world where humans can live. The policy council read that statement, and think terraform. But our existence proves that more change is unnecessary. If the comets ceased to arrive and Mars remained as it is today, humans can be quite at home on its surface. We prove that fact daily. Our version of the Mars Declaration would recognize a simple truth: It is easier to change a human than to change a planet."

(ed note: The Greater Earth Port Authority liked terraforming and hated pantropy because it got in the way of their profits. The Old Mars Policy Council has different reasons, but they too favor terraforming and feel threatened by form-change.)


(ed note: Bey is talking to Robert Capman, an old friend who has form-changed into a Logian. As such he is hyper-intelligent and very long-lived. Bey discovers that the Logians are bankrolling the Old Mars Policy Council's Mars terraforming operation. But why?)

     (Bey said) "So it seemed to me that the means were there. The thing missing was motive. Logians can't survive on either Mars or Earth. Why would they choose to help Old Mars in its efforts to terraform the planet?
     "I couldn't answer that question. But it suggested another idea: If the Logians were favoring the Mars terraforming efforts, that action opposed Georgia Kruskals desire to keep the surface just the way that it is. She can live there without a suit, in today's conditions — provided that she has continuing access to form-change equipment. And that led me to one more thought: the people of every inhabited world in the system make use of form-change, but usually they do not depend on it. Everywhere, on every major body from Europa to Cloudland, the natural environment of each world is being changed so that humans can live there in their original form, without dependence on form-change. People in Cloudland choose to adopt a different shape, but that's for convenience, not necessity. I have been to Cloudland, just as I am, and managed very well. But I couldn't survive on the surface of Mars for five minutes. Unless it is terraformed, any human living there will depend on the use of form-change every day, just to remain alive."
     Bey paused, as though he had arrived at some profound and significant conclusion. Sondra, listening closely, could not begin to guess what it might be. And yet watching the body language of Bey Wolf and Robert Capman, it was clear to her that a crucial moment had been reached. The style of their interaction had changed. Bey was leaning forward expectantly, while Capman was nodding slowly in a gesture not at all like the bobbing motion of the Logian smile.

     And when he finally spoke, it sounded like a total change of subject. "Behrooz Wolf." The deep voice was slow and sad. "You have known me for many, many years. How would you describe my work, and its relationship to the science of purposive form-change?"
     If the question surprised Bey, he did not show it. He replied at once. "You have contributed more than anyone in the whole field since the original work of Ergan Melford, two hundred and fifty years ago. Until you adopted the Logian form and moved to Saturn, your whole life's work revolved around the theory and practice of purposive form-change."
     "Very well. And your work?"
     "I won't try to estimate the value of what I've done. Someone else should make that assessment. But I can honestly say that for more than half a century I have worked constantly on form-change problems; and nothing else in my life has been as important to me as that effort."
     "We seem to be in total agreement. We have each devoted most of our lives to the same single end: the advancement of purposive form-change techniques. We have each — despite your modesty — made deep and far-reaching contributions to the subject, more than any other living persons." Capman's massive head lifted, and he stared straight at Bey. "So you, Behrooz Wolf, will find it as disturbing as I did, when I realized that purposive form-change, in widespread, necessary, and universal use, poses a great and terrible threat to the future of humanity. Does that answer your question?"

     The gasp came from Sondra, not from Bey. He sat totally silent and still as Old Mars Policy Council continued: "I should add that my interest in form-change work and its effects did not cease when I assumed the Logian form. We Logians are not human in appearance, and we sometimes appear to have superhuman powers; but in our concerns we remain all human. And we operate with a very long time-frame."
     "You say it's a threat." Bey spoke in a low voice and his face had become paler than usual. "I don't see why. Form-change has done more good for more people than any other discovery in history. I'm not talking about trivial nonsense like cosmetic change, I mean the important things like birth defect correction and medical treatment and healthy old age."
     "All hugely important, and all hugely valuable. But not the whole story." Capman swung to face Sondra.

     "Miss Dearborn, you visited the Fugate Colony. Do you think you could mate with a Fugate?"
     "Never." Sondra recalled the lumbering seventy-foot tall figures. "I mean, I didn't actually see their sex organs, but if they're anything like in proportion … Anyway, they were repulsive. I wouldn't want to mate with one of them, even if I could."
     "Which is perhaps of far greater practical importance." Capman turned back to Bey. "You have heard the modern dictum, echoed throughout the solar system: Easier to change people than planets. With today's form-change methods that is certainly true. As Georgia Kruskal is demonstrating, forms can be created that thrive in extreme natural environments. But the idea of matching people to settings neglects a profound problem. The celestial bodies of the solar system display an amazing diversity, in atmosphere, gravity, composition, temperature, and size. If humans seek to adapt to each situation, the inhabitants of each world will diverge from every other.
     "The long-term effect of such a divergence has been known since the time of Darwin and Wallace. It is termed speciation. Today, humans constitute a single species. At some time in the far future there could be many; different in size and form and function, fragmented in purpose, unable and unwilling to interbreed. And all thanks to the use of purposive form-change. If such a future is to be avoided, currently accepted thinking must change. It must become: Better to change planets than people. Terraform Mars and Europa, as is happening today. Terraform Venus, terraform Titan, terraform Oberon, terraform Triton, terraform the worldlets of the Kuiper Belt and Cloudland. Modify environments. And by doing so, allow humanity to continue as a single species."

From PROTEUS IN THE UNDERWORLD by Charles Sheffield (1995)
KEYS TO DECEMBER

Born of man and woman, in accordance with Catform Y7 requirements, Coldworld Class (modified per Alyonal), 3.2-E, G.M.I. option, Jarry Dark was not suited for existence anywhere in the universe which had guaranteed him a niche. This was either a blessing or a curse, depending on how you looked at it.

So look at it however you would, here is the story:

It is likely that his parents could have afforded the temperature control unit, but not much more than that. (Jarry required a temperature of at least -50 C. to be comfortable.)

It is unlikely that his parents could have provided for the air pressure control and gas mixture equipment required to maintain his life.

Nothing could be done in the way of 3.2-E grav-simulation, so daily medication and physiotherapy were required. It is unlikely that his parents could have provided for this.

The much-maligned option took care of him, however. It safe-guarded his health. It provided for his education. It assured his economic welfare and physical well-being.

It might be argued that Jarry Dark would not have been a homeless Coldworld Catform (modified per Alyonal) had it not been for General Mining, Incorporated, which had held the option. But then it must be borne in mind that no one could have foreseen the nova which destroyed Alyonal.

When his parents had presented themselves at the Public Health Planned Parenthood Center and requested advice and medication pending offspring, they had been informed as to the available worlds and the bodyform requirements for them. They had selected Alyonal, which had recently been purchased by General Mining for purposes of mineral exploitation. Wisely, they had elected the option; that is to say, they had signed a contract on behalf of their anticipated offspring, who would be eminently qualified to inhabit that world, agreeing that he would work as an employee of General Mining until he achieved his majority, at which time he would be free to depart and seek employment wherever he might choose (though his choices would admittedly be limited). In return for this guarantee, General Mining agreed to assure his health, education and continuing welfare for so long as he remained in their employ.

When Alyonal caught fire and went away, those Coldworld Catforms covered by the option who were scattered about the crowded galaxy were, by virtue of the agreement, wards of General Mining.

From "KEYS TO DECEMBER" by Roger Zelazny (1966)
THE IMPOSSIBLE WORLD

(ed note: again, something like Adaptene is more handwavium than it is unobtainium)

The builders of the New York World's Fair of 1939 had called it the "World of Tomorrow." They would have been utterly amazed, however. to see what reared on those some grounds a century later.

To the eye, it was simply a group of giant windowless buildings: the conditioning chambers of ETBI—Extra-Terra Bio-Institute. But within them, in sealed cubicles. were a hundred varieties of temperature, pressure, lighting, and the other strange conditions of extra-terrestrial environments. It was a large-scale biological project that had meant much in Earth colonization of the planets.

One building was devoted solely to Martian conditioning. Men and women emerged from there with bodies whose metabolism was suited perfectly to Martian environment, with its utterly dry, wispy air, freezing climate, and light gravity. They were taken to Mars in specially conditioned space ships, a steady stream of them.

Mars had been the first to be colonized. Already the resident population of Earth people on the Red Planet was over five million. A dozen industries thrived there. Beautiful ceramics from Martian clay were much in demand on Earth. And the exquisitely fine cloths from Martian spider webs.

Another building conditioned colonists to withstand the torrid dampness of Venus, ten times as trying to humans as the hottest jungles of Africa or South America. These people reaped tremendous harvests of the Cloudy Planet's boundless fertility. Crops ripened in a short month in the hot, steamy plains that stretched endlessly under veiled skies. Imported grains from Earth grew in riotous abundance. More than half of Earth's staple food supplies came from the rich farms of Venus.

All this would have been impossible to normal, unconditioned Earth people. They would have had to labor in sealed suits against adverse environment, with all the insurmountable handicaps of such methods. But with people whose metabolism had been altered to fit the new conditions, they lived and breathed as freely as though born on those planets.

But how had human metabolism. the stabilized result of millions of years of evolution on Earth, been changed? In the final analysis, it all centered about the use of one remarkable product of biological science, developed twenty-five years before.

It was called, for the press and public, just “adaptene," but only the most trusted officials of the Institute knew what it was by formula. By its very nature, it had to be shrouded in secrecy and kept from the hands of unscrupulous individuals. The Earth Union Government controlled exclusively the manufacture and use of adaptene.

Adaptene was the parent substance of all hormones in the living body. It controlled all metabolism, and therefore all the body processes to the last one.

Most remarkable of the applications of this near-miraculous substance had been the conquest of Jupiter's inimical environment. It so seemed impossible at first. At Jupiter's surface was a crushing gravity, almost three times that of Earth, that made human bones and muscles crack in a few hours.

A moisture-choked heat, from the Titanic layers of pressing gases, promised constantly parched throats and slowly boiling skin. Worst of all, the atmosphere itself was laden with gases besides oxygen, never meant for earthly lungs—methane, ammonia, and even traces of searing bromine that exuded from volcanic sources and gave the whole atmosphere its brownish tinge.

The natural life-forms of Jupiter's wild environment were adapted by millions of years of evolution. How could Earthmen, nurtured in a gentler climate, meet that terrible challenge?

It was tried. A series of conditioning rooms had been prepared, with successively greater air pressure, heat and foreign gases. In a way, it was like the Twentieth Century compression chambers, which had been used to prepare divers for the great pressures under the sea. Three Earthmen, given strong doses of adaptene, had gone from chamber to chamber. Leaden suits were prepared for them and weight added day by day. Their metabolism had faithfully undergone the necessary changes!

At the end of three months, they had reached the final conditioning room, which practically duplicated Jupiter's conditions. Their skins had become tough and heat-resisting. Their lungs filtered out methane, ammonia and bromine automatically, retaining only the necessary oxygen. Their muscles, motivated by superactive adrenalin, easily supported five hundred pounds of weight without tiring. All this through the magic touch of adaptene, working in its mysterious way throughout every cell and vein.

The men had been sent to Jupiter. One of them succumbed to the continued harshness of life there, but the other two survived. With this proof of success, other men were bio-conditioned, and soon a settlement was founded and work begun to extract the chemical riches of Jupiter's soil.

Now, in 2050 A.D., bio-conditioned Earthmen were to be found on ten different worlds of the Solar System—Mercury, Venus. Mars, Jupiter, Io, Europa, Ganymede, Callisto, Saturn and Titan. Adaptene had burst the former bonds of the narrow range of condition under which the human body could survive.

It did not matter whether the atmosphere was thin or thick, whether life-supporting oxygen was scarce or overabundant, whether frigid cold or suffocating heat existed, whether the force of gravity was weak or bruisingly powerful—adaptene made metabolic corrections for all variations.

They were still humans, these made-over colonists on other worlds. Science had changed their bodies some-what, but not their minds. They lived and loved and worked in alien surroundings with as much of the measure of well being and happiness as came to Earth-living humans. Their children were easily bio-conditioned from birth onward by adaptene. It was only the start, but colonization was rapidly gaining momentum toward a great empire in which Earth people lived on all the worlds of the Solar System—by the virtue of adaptene.

ETBI, where the bio-conditioning was carried on, was a separate branch of the Earth Union Government, along with the Space Navy, Interplanetary Exploration and Planetary Survey Bureaus. The exploitation of space was a highly organized process.

First the ships of the exploration service mapped and explored, on any new world. Then the Planetary Survey experts tabulated all raw resources, mineral and otherwise. The Space Navy stepped in next, to establish outposts and fueling stations. Finally ETBI sent its tailored, permanent colonists to dig in and develop the planet. And a new world had been added to man’s growing roster!

From THE IMPOSSIBLE WORLD by Otto Binder (1939)
BATTLEFIELDS OF SILENCE

(ed note: The protagonists are going to visit a space colony around Saturn populated by a space nation called the Istini.)

"And the Isinti?"

"They haven't isolated themselves. They've been isolated by an almost superstitious fear of the unknown. They're the first people to live entirely in a gravity-free environment. And you know what's been said about that."

Moore had heard the conjecture. The human body had been designed by eons of evolution to function within a gravitational field. Regardless of what had become of the Isinti, it was generally accepted that no Isinti would ever again function within, or even survive within, a gravitational field. The Isinti, unlike the rest of humanity living in space, had utterly and irrevocably cut their bonds with man's biological heritage. For the remaining span of their existence, they would survive only by their skills in providing an artificial environment in the hard vacuum of space.


(ed note: Upon arrival at the colony, the protagonists find themselves in a room. A large video display lights up and they hear the voice of their Istini host.)

The screen before them danced with white snow on a dark-blue background. Suddenly, the screen came to life. A white line drawing of a naked male figure on a dark background appeared.

"The form of the human body evolved to function in the Earth environment. The Isinti live within the psyche of Homo sapiens, but our bodies live in new environments. Consciousness must expand to fill previously unconscious roles.

"Many changes are necessary for a human body to function in a zero-gravity field and utilize inherent advantages fully, most involving body chemistry, internal structure, and functioning of the organs, especially the cardiovascular system. Certain structural modifications were deemed advantageous. First, a smaller overall size."

The line drawing shrank to half its former size, but the head remained the same, giving the line drawing a childlike appearance with the facial features occupying the lower third of the skull.

"Next, the elimination of body rigidity and excess muscular development."

The body thinned down considerably, the arms long and curved with an apparently flexible bone structure, but with proportionately oversized hands and long, slender fingers.

"The legs, designed primarily for support and locomotion upon a two-dimensional plane within a gravity field, can be entirely reconfigured."

The drawing changed again. Now, the legs extended perpendicular from the torso, parallel to outstretched arms, the entire pelvis changed. The feet became another pair of hands complete with five long and slender fingers.

"These changes are on a genetic level. We give live birth to children like ourselves. You have requested to speak with me in person. You are curious and fascinated, but shocked and uncomfortable as well. We seem to have destroyed our natural beauty and denied our human heritage. A deep level of your mind protests the sacrilege that which we have committed upon ourselves, a biological prejudice that cannot be countered by intellectual rationalization. You do not wish to meet me in person. I would not appear to be human to you."

From BATTLEFIELDS OF SILENCE by William Tedford (2007)
SURFACE TENSION

(ed note: A pantropy ship of the Colonization Council crashes on the planet Hydrot around Tau Ceti. They decide to create colonists for the planet even though the colonists will be unaware of their origins. Ordinarily the ship crew would educate the colonists, but the crew will be dead in a month, the FTL radio is broken, and the Colonization Council has no idea they are there.

Since the ship lost its germ cell banks, they will have to use germ cells from the crew. This means that some of the created colonists will look like and have the same personalities as the crew. Dr. Chatvieux will have a corresponding colonist named "Shar", pilot la Ventura will be "Lavon", communication officer Strasvogel will be "Stravol".

The fun part is there is no suitable place for colonization except for the tiny ponds. So the colonists will be microscopic. In the story they interact with the local equivalent of parameciums, diatoms, and the dreaded rotifers. The colonist call the latter "Eaters" because they prey on men.

After conquering their pond, the colonists build a "spaceship." This is a huge (2 inch long) wooden tracked vehicle, driven by diadoms harnessed to a wooden gear transmission. It holds water so the crew can breath in the waterless space between ponds, and can downshift gears to have the power to penetrate the surface tension of the pond roof.

In the next pond they find other colonists who are dying out because they cannot cope with the rotifers. However the spaceship crew is armed with underwater crossbows and quickly give the rotifers what for.

This would be fun background in a role-playing game, in the spirit of Bunnies & Burrows. For one thing, you can use an elementary school textbook about protozoan of pond water as the Monster Manual.

The story was selected in 1970 by the Science Fiction Writers of America as one of the best science fiction short stories published before the creation of the Nebula Awards. It can be found in many collections. But don't get the one in The Science Fiction Hall of Fame, Volume One, that version is abridged.)


     “This place isn’t dead,” Chatvieux said. “There’s life in the sea and in the fresh water, both. On the animal side of the ledger, evolution seems to have stopped with the Crustacea; the most advanced form I’ve found is a tiny crayfish, from one of the local rivulets, and it doesn’t seem to be well distributed. The ponds and puddles are well-stocked with small metazoans of lower orders, right up to the rotifers—including a castle-building genus like Earth’s Floscularidae. In addition, there’s a wonderfully variegated protozoan population, with a dominant ciliate type much like Paramoecium, plus various Sarcodines, the usual spread of phyto-flagellates, and even a phosphorescent species I wouldn’t have expected to see anywhere but in salt water. As for the plants, they run from simple blue-green algae to quite advanced thallus-producing types—though none of them, of course, can live out of the water.”

     “The sea is about the same,” Eunice said. “I’ve found some of the larger simple metazoans—jellyfish and so on—and some crayfish almost as big as lobsters. But it’s normal to find salt-water species running larger than fresh-water. Ana there’s the usual plankton and nannoplankton population.”…
     …Chatvieux turned to Saltonstall, “Martin, what would you think of our taking to the sea? We came out of it once, long ago; maybe we could come out of it again on Hydrot.”
     “No good,” Saltonstall said immediately. “I like the idea, but I don’t think this planet ever heard of Swinburne, or Homer, either. Looking at it as a colonization problem alone, as if we weren’t involved in it ourselves, I wouldn’t give you an Oc dollar for epi oinopa ponton. The evolutionary pressure there is too high, the competition from other species is prohibitive; seeding the sea should be the last thing we attempt, not the first. The colonists wouldn’t have a chance to learn a thing before they’d be gobbled up.”
     “Why?” la Ventura said. Once more, the death in his stomach was becoming hard to placate.
     “Eunice, do your sea-going Coelenterates include anything like the Portuguese man-of-war?”
     The ecologist nodded.
     “There’s your answer, Paul,” Saltonstall said. “The sea is out. It’s got to be fresh water, where the competing creatures are less formidable and there are more places to hide.”
     “We can’t compete with a jellyfish?” la Ventura asked, swallowing.
     “No, Paul,” Chatvieux said. “Not with one that dangerous. The pantropes make adaptations, not gods. They take human germ-cells—in this case, our own, since our bank was wiped out in the crash—and modify them genetically toward those of creatures who can live in any reasonable environment. The result will be manlike, and intelligent. It usually shows the donors’ personality patterns, too, since the modifications are usually made mostly in the morphology, not so much in the mind, of the resulting individual.
     “But we can’t transmit memory. The adapted man is worse than a child in the new environment. He has no history, no techniques, no precedents, not even a language. In the usual colonization project, like the Tellura affair, the seeding teams more or less take him through elementary school before they leave the planet to him, but we won’t survive long enough to give such instruction. We’ll have to design our colonists with plenty of built-in protections and locate them in the most favorable environment possible, so that at least some of them will survive learning by experience alone.”…

     …“Saltonstall, what would you recommend as a form?”
     The pantropist pulled reflectively at his nose. “Webbed extremities, of course, with thumbs and big toes heavy and thorn-like for defense until the creature has had a chance to learn. Smaller external ears, and the eardrum larger and closer to the outer end of the ear-canal. We’re going to have to reorganize the water-conservation system, I think; the glomerular kidney is perfectly suitable for living in fresh water, but the business of living immersed, inside and out, for a creature with a salty inside means that the osmotic pressure inside is going to be higher than outside, so that the kidneys are going to have to be pumping virtually all the time. Under the circumstances we’d best step up production of urine, and that means the antidiuretic function of the pituitary gland is going to have to be abrogated, for all practical purposes.”
     “What about respiration?”
     “Hm,” Saltonstall said. “I suppose book-lungs (trigger warning: spiders), like some of the arachnids have. They can be supplied by intercostal spiracles. They’re gradually adaptable to atmosphere-breathing, if our colonist ever decides to come out of the water. Just to provide for that possibility. I’d suggest that the nose be retained, maintaining the nasal cavity as a part of the otological system, but cutting off the cavity from the larynx with a membrane of cells that are supplied with oxygen by direct irrigation, rather than by the circulatory system. Such a membrane wouldn’t survive for many generations, once the creature took to living out of the water even for part of its life-time; it’d go through two or three generations as an amphibian, and then one day it’d suddenly find itself breathing through its larynx again.”
     “Also, Dr. Chatvieux, I’d suggest that we have it adopt sporulation. As an aquatic animal, our colonist is going to have an indefinite life-span, but we’ll have to give it a breeding cycle of about six weeks to keep up its numbers during the learning period; so there’ll have to be a definite break of some duration in its active year. Otherwise it’ll hit the population problem before it’s learned enough to cope with it.”
     “And it’d be better if our colonists could winter over inside a good, hard shell,” Eunice Wagner added in agreement.


     “So sporulation’s the obvious answer. Many other microscopic creatures have it.”
     “Microscopic?” Phil said incredulously.
     “Certainly,” Chatvieux said, amused. “We can’t very well crowd a six-foot man into a two-foot puddle. But that raises a question. We’ll have tough competition from the rotifers, and some of them aren’t strictly microscopic; for that matter even some of the protozoa can be seen with the naked eye, just barely, with dark-field illumination. I don’t think your average colonist should run much under 250 microns (0.25 millimeters), Saltonstall. Give them a chance to slug it out.” (in the movie Fantastic Voyage, the crew was miniaturized to the size of 0.4 microns)
     “I was thinking of making them twice that big.”
     “Then they’d be the biggest animals in their environment,” Eunice Wagner pointed out, “and won’t ever develop any skills. Besides, if you make them about rotifer size, it will give them an incentive for pushing out the castle-building rotifers, and occupying the castles themselves, as dwellings.
     Chatvieux nodded. “All right, let’s get started. While the pantropes are being calibrated, the rest of us can put our heads together on leaving a record for these people. We’ll micro-engrave the record on a set of corrosion-proof metal leaves, of a size our colonists can handle conveniently. We can tell them, very simply, what happened, and plant a few suggestions that there’s more to the universe than what they find in their puddles. Some day they may puzzle it out.”

(ed note: The colonists are created by pantropy and seeded in the ponds. The crew dies. In one of the ponds, over several generations, the colonists use cooperation and tactics to eventually rid their pond of the rotifer menace. A colonist name Lavon tries to explore "space" by crawling up a plant stalk which pierces the surface tension. The experience almost kills him because in Air nobody can hear your liquid scream. He recovers by creating an out-of-season spore. Then he talks with the "scientist" Shar.)


     “You have answered me,” Shar said, even more gently than before. “Come, my friend; join me at my table. We will plan our journey to the stars.”…
     Shar XVI had, as a matter of fact, discovered certain rudimentary rules of inquiry which, as he explained it to Lavon, he had recognized as tools of enormous power. He had become more interested in passing these on to future workers than in the seductions of any specific experiment, the journey to the stars perhaps excepted. The Than, Tanol and Stravol of his generation were having scientific method pounded into their heads, a procedure they maintained was sometimes more painful than heaving a thousand rocks.
     That they were the first of Lavon’s people to be taxed with the problem of constructing a spaceship was, therefore, inevitable. The results lay on the table: three models, made of diatom-glass, strands of algae, flexible bits of cellulose, flakes of stonewort, slivers of wood, and organic glues collected from the secretions of a score of different plants and animals.

     Lavon picked up the nearest one, a fragile spherical construction inside which little beads of dark-brown lava—actually bricks of rotifer-spittle painfully chipped free from the wall of an unused castle—moved freely back and forth in a kind of ball-bearing race. “Now whose is this one?” he said, turning the sphere curiously to and fro.
     “That’s mine,” Tanol said. “Frankly, I don’t think it comes anywhere near meeting all the requirements. It’s just the only design I could arrive at that I think we could build with the materials and knowledge we have to hand now.”
     “But how does it work?”
     “Hand it here a moment, Lavon. This bladder you see inside at the center, with the hollow spirogyra straws leading out from it to the skin of the ship, is a buoyancy tank. The idea is that we trap ourselves a big gas-bubble as it rises from the Bottom and install it in the tank. Probably we’ll have to do that piecemeal. Then the ship rises to the sky on the buoyancy of the bubble. The little paddles, here along these two bands on the outside, rotate when the crew—that’s these bricks you hear shaking around inside—walks a treadmill that runs around the inside of the hull; they paddle us over to the edge of the sky. I stole that trick from the way Didin gets about. Then we pull the paddles in—they fold over into slots, like this—and, still by weight-transfer from the inside, we roll ourselves up the slope until we’re out in space. When we hit another world and enter the water again, we let the gas out of the tank gradually through the exhaust tubes represented by these straws, and sink down to a landing at a controlled rate.”
     “Very ingenious,” Shar said thoughtfully. “But I can foresee some difficulties. For one thing, the design lacks stability.”
     “Yes, it does,” Tanol agreed. “And keeping it in motion is going to require a lot of footwork. But if we were to sling a freely-moving weight from the center of gravity of the machine, we could stabilize it at least partly. And the biggest expenditure of energy involved in the whole trip is going to be getting the machine up to the sky in the first place, and with this design that’s taken care of—as a matter of fact, once the bubble’s installed, we’ll have to keep the ship tied down until we’re ready to take off.”
     “How about letting the gas out?” Lavon said. “Will it go out through those little tubes when we want it to? Won’t it just cling to the walls of the tubes instead? The skin between water and gas is pretty difficult to deform—to that I can testify.”
     Tanol frowned. “That I don’t know. Don’t forget that the tubes will be large in the real ship, not just straws as they are in the model.”
     “Bigger than a man’s body?” Than said.
     “No, hardly. Maybe as big through as a man’s head, at the most.”
     “Won’t work,” Than said tersely. “I tried it. You can’t lead a bubble through a pipe that small. As Lavon says, it clings to the inside of the tube and won’t be budged unless you put pressure behind it—lots of pressure. If we build this ship, we’ll just have to abandon it once we hit our new world; we won’t be able to set it down anywhere.”
     “That’s out of the question,” Lavon said at once. “Putting aside for the moment the waste involved, we may have to use the ship again in a hurry. Who knows what the new world will be like? We’re going to have to be able to leave it again if it turns out to be impossible to live in.”

     “Which is your model, Than?” Shar said.
     “This one. With this design, we do the trip the hard way—crawl along the Bottom until it meets the sky, crawl until we hit the next world, and crawl wherever we’re going when we get there. No aquabatics. She’s treadmill-powered, like Tanol’s, but not necessarily man-powered; I’ve been thinking a bit about using motile diatoms. She steers by varying the power on one side or the other. For fine steering we can also hitch a pair of thongs to opposite ends of the rear axle and swivel her that way.”
     Shar looked closely at the tube-shaped model and pushed it experimentally along the table a little way. “I like that,” he said presently. “It sits still when you want it to. With Than’s spherical ship, we’d be at the mercy of any stray current at home or in the new world—and for all I know there may be currents of some sort in space, too, gas currents perhaps.
     Lavon, what do you think?”
     “How would we build it?” Lavon said. “It’s round in cross-section. That’s all very well for a model, but how do you make a really big tube of that shape that won’t fall in on itself?”
     “Look inside, through the front window,” Than said. “You’ll see beams that cross at the center, at right angles to the long axis. They hold the walls braced.”
     “That consumes a lot of space,” Stravol objected. By far the quietest and most introspective of the three assistants, he had not spoken until now since the beginning of the conference. “You’ve got to have free passage back and forth inside the ship. How are we going to keep everything operating if we have to be crawling around beams all the time?”

     “All right, come up with something better,” Than said, shrugging.
     “That’s easy. We bend hoops.”
     “Hoops!” Tanol said. “On that scale? You’d have to soak your wood in mud for a year before it would be flexible enough, and then it wouldn’t have the strength you’d need.”
     “No, you wouldn’t,” Stravol said. “I didn’t build a ship model, I just made drawings, and my ship isn’t as good as Than’s by a long distance. But my design for the ship is also tubular, so I did build a model of a hoop-bending machine—that’s it on the table. You lock one end of your beam down in a heavy vise, like so, leaving the butt striking out on the other side. Then you tie up the other end with a heavy line, around this notch. Then you run your line around a windlass, and five or six men wind up the windlass, like so. That pulls the free end of the beam down until the notch engages with this key-slot, which you’ve pre-cut at the other end. Then you un-lock the vise, and there’s your hoop; for safety you might drive a peg through the joint to keep the thing from springing open unexpectedly.”
     “Wouldn’t the beam you were using break after it had bent a certain distance?” Lavon asked.
     “Stock timber certainly would,” Stravol said. “But for this trick you use green wood, not seasoned. Otherwise you’d have to soften your beam to uselessness, as Tanol says. But live wood will flex enough to make a good, strong, single-unit hoop—or if it doesn’t, Shar, the little rituals with numbers that you’ve been teaching us don’t mean anything after all”
     Shar smiled. “You can easily make a mistake in using numbers,” he said.
     “I checked everything.”
     “I’m sure of it. And I think it’s well worth a trial. Anything else to offer?”
     “Well,” Stravol said, “I’ve got a kind of live ventilating system I think should be useful. Otherwise, as I said, Than’s ship strikes me as the type we should build; my own’s hopelessly cumbersome.”

     “I’ve got a question,” Stravol said quietly.
     “All right, let’s hear it.”
     “Where are we going?”
     There was quite a long silence. Finally Shar said: “Stravol, I can’t answer that yet. I could say that we’re going to the stars, but since we still have no idea what a star is, that answer wouldn’t do you much good. We’re going to make this trip because we’ve found that some of the fantastic things that the history plate says are really so. We know now that the sky can be passed, and that beyond the sky there’s a region where there’s no water to breathe,, the region our ancients called ‘space.’ Both of these ideas always seemed to be against common sense, but nevertheless we’ve found that they’re true.

     Yet despite the bleeding away of the years, the spaceship was still only a hulk. It lay upon a platform built above the tumbled boulders of the sandbar which stretched out from one wall of the world. It was an immense hull of pegged wood, broken by regularly spaced gaps through which the raw beams of its skeleton could be seen.
     For that matter, part of the vehicle’s apparent incompleteness was an illusion. About a third of its fittings were to consist of living creatures, which could not be expected to install themselves in the vessel much before the actual takeoff.

     Lavon turned from the arrangement of speaking-tube megaphones which was his control board and looked at Para.…
     …Lavon shifted to another megaphone. He took a deep breath. Already the water seemed stifling, although the ship hadn’t moved. “Ready with one-quarter power… . One, two, three, go.”
     The whole ship jerked and settled back into place again.
     The raphe diatoms along the under hull settled into their niches, their jelly treads turning against broad endless belts of crude caddis-worm leather. Wooden gears creaked, stepping up the slow power of the creatures, transmitting it to the sixteen axles of the ship’s wheels.…
     …The slapping of the endless belts and the squeaking and groaning of the gears and axles grew louder as the slope steepened. The ship continued to climb, lurching. Around it, squadrons of men and Protos dipped and wheeled, escorting it toward the sky.
     Gradually the sky lowered and pressed down toward the top of the ship.
     “A little more work from your diatoms, Tanol,” Lavon said. “Boulder ahead.” The ship swung ponderously. “All right, slow them up again. Give us a shove from your side, Tolno, that’s too muchthere, that’s it. Back to normal; you’re still turning us I Tanol, give us one burst to line us up again. Good. All right, steady drive on all sides. It shouldn’t be long now.”…
     …The sand bar began to level out and the going became a little easier. Up here, the sky was so close that the lumbering motion of the huge ship disturbed it. Shadows of wavelets ran across the sand. Silently, the thick-barreled bands of blue-green algae drank in the light and converted it to oxygen, writhing in their slow mindless dance just under the long mica skylight which ran along the spine of the ship. In the hold, beneath the latticed corridor and cabin floors, whirring Vortae kept the ship’s water in motion, fueling themselves upon drifting organic particles.…
     …Now the sky was nothing but a thin, resistant skin of water coating the top of the ship. The vessel slowed, and when Lavon called for more power, it began to dig itself in among the sandgrains and boulders.
     “That’s not going to work,” Shar said tensely. “I think we’d better step down the gear-ratio (increase spin force at the expense of spin velocity), Lavon, so you can apply stress more slowly.”
     “All right,” Lavon agreed. “Full stop, everybody. Shar, will you supervise gear-changing, please?”
     Insane brilliance of empty space looked Lavon full in the face just beyond his big mica bull’s-eye.…
     …Surely, he thought, there must be a better way to change gear-ratios than the traditional one, which involved dismantling almost the entire gear-box. Why couldn’t a number of gears of different sizes be carried on the same shaft, not necessarily all in action at once, but awaiting use simply by shoving the axle back and forth longitudinally in its sockets? It would still be clumsy, but it could be worked on orders from the bridge and would not involve shutting down the entire machine—and throwing the new pilot into a blue-green funk.
     Shar came lunging up through the trap and swam himself to a stop. “All set,” he said. “The big reduction gears aren’t taking the strain too well, though.”
     “Splintering?”
     “Yes. I’d go it slow at first.”
     Lavon nodded mutely. Without allowing himself to stop, even for a moment, to consider the consequences of his words, he called: “Half power.”
     The ship hunched itself down again and began to move, very slowly indeed, but more smoothly than before. Overhead, the sky thinned to complete transparency. The great light came blasting in. Behind Lavon there was an uneasy stir. The whiteness grew at the front ports.
     Again the ship slowed, straining against the blinding barrier. Lavon swallowed and called for more power. The ship groaned like something about to die. It was now almost at a standstill.
     “More power,” Lavon ground out.
     Once more, with infinite slowness, the ship began to move. Gently, it tilted upward. Then it lunged forward and every board and beam in it began to squall.
     “Lavon! Lavon!”
     Lavon started sharply at the shout. The voice was coming at him from one of the megaphones, the one marked for the port at the rear of the ship.
     “Lavon!”
     “What is it? Stop your damn yelling.”
     “I can see the top of the sky! From the other side, from the top side! It’s like a big flat sheet of metal. We’re going away from. it. We’re above the sky, Lavon, we’re above the sky!”
     Another violent start swung Lavon around toward the forward port. On the outside of the mica, the water was evaporating with shocking swiftness, taking with it strange distortions and patterns made of rainbows.
     Lavon saw space.

     It was at first like a deserted and cruelly dry version of the Bottom. There were enormous boulders, great cliffs, tumbled, split, riven, jagged rocks going up and away in all directions, as if scattered at random by some giant.
     But it had a sky of its own—a deep blue dome so far away that he could not believe in, let alone estimate, what its distance might be. And in this dome was a ball of reddish-white fire that seared his eyeballs.
     The wilderness of rock was still a long way away from the ship, which now seemed to be resting upon a level, glistening plain. Beneath the surface-shine, the plain seemed to be made of sand, nothing but familiar sand, the same substance which had heaped up to form a bar in Lavon’s universe, the bar along which the ship had climbed. But the glassy, colorful skin over it—
     Suddenly Lavon became conscious of another shout from the megaphone banks. He shook his head savagely and said, “What is it now?”
     “Lavon, this is Tol. What have you gotten us into? The belts are locked. The diatoms can’t move them. They aren’t faking, either; we’ve rapped them hard enough to make them think we were trying to break their shells, but they still can’t give us more power.”
     “Leave them alone,” Lavon snapped. “They can’t fake; they haven’t enough intelligence. If they say they can’t give you more power, they can’t.”
     “Well, then, you get us out of it.”
     Shar came forward to Lavon’s elbow. “We’re on a space-water interface, where the surface tension is very high,” he said softly. “If you order the wheels pulled up now, I think we’ll make better progress for a while on the belly tread.”
     “Good enough,” Lavon said with relief. “Hello below—haul up the wheels.”
     “For a long while,” Shar said, “I couldn’t understand the reference of the history plate to ‘retractable landing gear,’ but it finally occurred to me that the tension along a space-mud interface would hold any large object pretty tightly. That’s why I insisted on our building the ship so that we could lift the wheels.”
     “Evidently the ancients knew their business after all, Shar.”
     Quite a few minutes later—for shifting power to the belly treads involved another setting of the gear box—the ship was crawling along the shore toward the tumbled rock. Anxiously, Lavon scanned the jagged, threatening wall for a break. There was a sort of rivulet off toward the teft which might offer a route, though a dubious one, to the next world. After some thought, Lavon ordered his ship turned toward it.
     “Do you suppose that thing in the sky is a ‘star’?” he asked. “But there were supposed to be lots of them. Only one is up there—and one’s plenty for my taste.”…
     …“Well, if you’re right, it means that all we have to do is crawl along here for a while, until we hit the top of the sky’ of another world,” Lavon said. “Then we dive in. Somehow it seems too simple, after all our preparations.”
     Shar chuckled, but the sound did not suggest that he had discovered anything funny. “Simple? Have you noticed the temperature yet?”
     Lavon had noticed it, just beneath the surface of awareness, but at Shar’s remark he realized that he was gradually being stifled. The oxygen content of the water, luckily, had not dropped, but the temperature suggested the shallows in the last and worst part of autumn. It was like trying to breathe soup.
     “Than, give us more action from the Vortae,” Lavon said. “This is going to be unbearable unless we get more circulation.”
     There was a reply from Than, but it came to Lavon’s ears only as a mumble. It was all he could do now to keep his attention on the business of steering the ship.
     The cut or defile in the scattered razor-edged rocks was a little closer, but there still seemed to be many miles of rough desert to cross. After a while, the ship settled into a steady, painfully slow crawling, with less pitching and jerking than before, but also with less progress. Under it, there was now a sliding, grinding sound, rasping against the hull of the ship itself, as if it were treadmilling over some coarse lubricant the particles of which were each as big as a man’s head (about 30 microns. Smallest grain of sand is 2,000 microns, grain of silt is 62 to 4 microns).
     Finally Shar said, “Lavon, we’ll have to stop again. The sand this far up is dry, and we’re wasting energy using the tread.”
     “Are you sure we can take it?” Lavon asked, gasping for breath. “At least we are moving. If we stop to lower the wheels and change gears again, we’ll boil.”
     “We’ll boil if we don’t,” Shar said calmly. “Some of our algae are dead already and the rest are withering. That’s a pretty good sign that we can’t take much more. I don’t think we’ll make it into the shadows, unless we do change over and put on some speed.”
     There was a gulping sound from one of the mechanics. “We ought to turn back,” he said raggedly. “We were never meant to be outhere in the first place. We were made for the water, not for this hell.”
     “We’ll stop,” Lavon said, “but we’re not turning back. That’s final.”…
     …There was a wooden clashing from below, and then Shar’s voice came tinnily from one of the megaphones. “Lavon, go aheadi The diatoms are dying, too, and then we’ll be without power. Make it as quickly and directly as you can.”…
     …He rasped into the banked megaphones. Once more, the ship began to move, a little faster now, but seemingly still at a crawl. The thirty-two wheels rumbled. It got hotter.
     Steadily, with a perceptible motion, the “star” sank in Lavon’s face. Suddenly a new terror struck him. Suppose it should continue to go down until it Was gone entirely? Blasting though it was now, it was the only source of heat. Would not space become bitter cold on the instant—and the ship an expanding, bursting block of ice?
     The shadows lengthened menacingly, stretching across the desert toward the forward-rolling vessel. There was no talking in the cabin, just the sound of ragged breathing and the creaking of the machinery.
     Then the jagged horizon seemed to rush upon them. Stony teeth cut into the lower rim of the ball of fire, devoured it swiftly. It was gone.
     They were in the lee of the cliffs. Lavon ordered the ship turned to parallel the rock-line; it responded heavily, sluggishly. Far above, the sky deepened steadily, from blue to indigo.
     Shar came silently up through the trap and stood beside Lavon, studying that deepening color and the lengthening of the shadows down the beach toward their own world. He said nothing, but Lavon was sure that the same chilling thought was in his mind.
     “Lavon.”
     Lavon jumped. Shar’s voice had iron in it. “Yes?”
     “We’ll have to keep moving. We must make the next world, wherever it is, very shortly.”
     “How can we dare move when we can’t see where we’re going? Why not sleep it over—if the cold will let us?”
     “It will let us,” Shar said. “It can’t get dangerously cold up here. If it did, the sky—or what we used to think of as the sky—would have frozen over every night, even in summer. But what I’m thinking about is the water. The plants will go to sleep now. In our world that wouldn’t matter; the supply of oxygen there is enough to last through the night. But in this confined space, with so many creatures in it and no supply of fresh water, we will probably smother.”
     Shar seemed hardly to be involved at all, but spoke rather with the voice of implacable physical laws.
     “Furthermore,” he said, staring unseeingly out at the raw landscape, “the diatoms are plants, too. In other words, we must stay on the move for as long as we have oxygen and power—and pray that we make it.”
     “Shar, we had quite a few Protos on board this ship once. And Para there isn’t quite dead yet. If he were, the cabin would be intolerable. “The ship is nearly sterile of bacteria, because all the protos have been eating them as a matter of course and there’s no outside supply of them, either. But still and all there would have been some decay.”
     Shar bent and tested the pellicle of the motionless Para with a probing finger. “You’re right, he’s still alive. What does that prove?”
     “The Vortae are also alive; I can feel the water circulating. Which proves that it wasn’t the heat that hurt Para. It was the light. Remember how badly my skin was affected after I climbed beyond the sky? Undiluted starlight is deadly. We should add that to the information from the plate.”
     “I still don’t get the point.”
     “It’s this: We’ve got three or four Noc down below. They were shielded from the light, and so must be still alive. If we concentrate them in the diatom galleys, the dumb diatoms will think it’s still daylight and will go on working. Or we can concentrate them up along the spine of the ship, and keep the algae putting out oxygen. So the question is: Which do we need more, oxygen or power? Or can we split the difference?”
     Shar actually grinned. “A brilliant piece of thinking. We may make a Shar out of you some day, Lavon. No, I’d say that we can’t split the difference. Noc’s light isn’t intense enough to keep the plants making oxygen; I tried it once, and the oxygen production was too tiny to matter. Evidently the plants use the light for energy. So we’ll have to settle for the diatoms for motive power.”
     Lavon brought the vessel away from the rocky lee of the cliff, out onto the smoother sand. All trace of direct light was now gone, although there was still a soft, general glow on the sky. , “Now then,” Shar said thoughtfully, “I would guess that there’s water over there in the canyon, if we can reach it. I’ll go below again and arrange”
     Lavon gasped.
     “What’s the matter?”
     Silently, Lavon pointed, his heart pounding.
     The entire dome of indigo above them was spangled with tiny, incredibly brilliant lights. There were hundreds of them, and more and more were becoming visible as the darkness deepened. And far away, over the ultimate edge of the rocks, was a dim red globe, crescented with ghostly silver. Near the zenith was another such body, much smaller, and silvered all over…
     Under the two moons of Hydrot, and under the eternal stars, the two-inch wooden spaceship and its microscopic cargo toiled down the slope toward the drying little rivulet.

(ed note: my slide rule says if the colonists are 0.25mm long, and the 2 inch ship is 50.8mm long, then the ship is about 203 man-lengths long. So if you were 1.77 meters tall, the equivalent ship would be 1.77×203 = 359 meters long, a quarter of a mile or a bit more than 3 NFL football fields long.

As a retcon, I personally think a 2 centimeter ship is less outrageous. That would only be 141 meters long, about one and a third NFL football fields.)


     The ship rested on the Bottom of the canyon for the rest of the night. The great square doors were unsealed and thrown open to admit the raw, irradiated, life-giving water from outside—and the wriggling bacteria which were fresh food. No other creatures approached them, either out of curiosity or for hunting, while they slept, although Lavon had posted guards at the doors just in case. Evidently, even up here on the very floor of space, highly organized creatures were quiescent at night.
     But when the first flush of light filtered through the water, trouble threatened.
     First of all, there was the bug-eyed monster. The thing was green and had two snapping claws, either one of which could have broken the ship in two like a spirogyra strand. Its eyes were black and globular, on the ends of short columns, and its long feelers were thicker through than a plant bole. It passed in a kicking fury of motion, however, never noticing the ship at all.
     “Is that—a sample of the kind of life they have here?” Lavon whispered. “Does it all run as big as that?” Nobody answered, for the very good reason that nobody knew.
     After a while, Lavon risked moving the ship forward against the current, which was slow but heavy. Enormous writhing worms whipped past them. One struck the hull a heavy blow, then thrashed on obliviously.
     “They don’t notice us,” Shar said. “We’re too small. Lavon, the ancients warned us of the immensity of space, but even when you see it, it’s impossible to grasp. And all those stars—can they mean what I think they mean? It’s beyond thought, beyond belief!”
     “The Bottom’s sloping,” Lavon said, looking ahead intently.“The walls of the canyon are retreating, and the water’s becoming rather silty. Let the stars wait, Shar; we’re coming toward the entrance of our new world.”

     Now the Bottom was tilting upward again. Lavon had no experience with delta-formation, for no rivulets left his own world, and the phenomenon worried him. But his worries were swept away in wonder as the ship topped the rise and nosed over.
     Ahead, the Bottom sloped away again, indefinitely, into glimmering depths. A proper sky was over them once more, and Lavon could see small rafts of plankton floating placidly beneath it. Almost at once, too, he saw several of the smaller kinds of Protos, a few of which were already approaching the ship—
     Then the girl came darting out of the depths, her features blurred and distorted with distance and terror. At first she did not seem to see the ship at all. She came twisting and turning lithely through the water, obviously hoping only to throw herself over the mound of the delta and into the savage streamlet beyond.
     Lavon was stunned. Not that there were men here—he had hoped for that, had even known somehow that men were everywhere in the universe—but at the girl’s single-minded flight toward suicide. “What—”
     Then a dim buzzing began to grow in his ears, and he understood. “Sharl Than! Stravoll” he bawled. “Break out crossbows and spears! Knock out all the windows!” He lifted a foot and kicked through the port in front of him. Someone thrust a crossbow into his hand.
     “What?” Shar blurted. “What’s the matter? What’s happening?”
     “Eaters!”
     The cry went through the ship like a galvanic shock. The rotifers back in Lavon’s own world were virtually extinct, but everyone knew thoroughly the grim history of the long battle man and Proto had waged against them.
     The girl spotted the ship suddenly and paused, obviously stricken with despair at the sight of this new monster. She drifted with her own momentum, her eyes alternately fixed upon the ship and jerking back over her shoulder, toward where the buzzing snarled louder and louder in the dimness.
     “Don’t stop!” Lavon shouted. “This way, this way! We’re friends! We’ll help!”
     Three great semi-transparent trumpets of smooth flesh bored over the rise, the many thick cilia of their coronas whirring greedily. Dicrans, arrogant in their flexible armor, quarreling thickly among themselves as they moved, with the few blurred, pre-symbolic noises which made up their own language.
     Carefully, Lavon wound the crossbow, brought it to his shoulder, and fired. The bolt sang away through the water. It lost momentum rapidly, and was caught by a stray current which brought it closer to the girl than to the Eater at which Lavon had aimed.
     He bit his lip, lowered the weapon, wound it up again. It did not pay to underestimate the range; he would have to wait.
     Another bolt, cutting through the water from a side port, made him issue orders to cease firing “until,” he added, “you can see their eyespots.”
     The irruption of the rotifers decided the girl. The motionless wooden monster was of course strange to her, but it had not yet menaced her—and she must have known what it would be like to have three Dicrans over her, each trying to grab from the others the largest share. She threw herself towards the bull’s-eye port. The three Eaters screamed with fury and greed and bored in after her.
     She probably would not have made it, had not the dull vision of the lead Dicran made out the wooden shape of the ship at the last instant. The Dicran backed off, buzzing, and the other two sheered away to avoid colliding with her. After that they had another argument, though they could hardly have formulated what it was that they were fighting about; they were incapable of exchanging any thought much more complicated than the equivalent of “Yaah,” “Drop dead,” and “You’re another.”
     While they were still snarling at each other, Lavon pierced the nearest one all the way through with an arbalest bolt. The surviving two were at once involved in a lethal battle over the remains.
     “Than, take a party out and spear me those two Eaters while they’re still fighting,” Lavon ordered. “Don’t forget to destroy their eggs, too. I can see that this world needs a little taming.”

     The girl shot through the port and brought up against the far wall of the cabin, flailing in terror. Lavon tried to approach her, but from somewhere she produced a flake of stonewort chipped to a nasty point. Since she was naked, it was hard to tell where she had been hiding it, but she obviously knew how to use it, and meant to. Lavon retreated and sat down on the stool before his control board, waiting while she took in the cabin, Lavon, Shar, the other pilots, the senescent Para.
     At last she said: “Are—you—the gods—from beyond the sky?”
     “We’re from beyond the sky, all right,” Lavon said. “But we’re not gods. We’re human beings, just like you. Are there many humans here?”
     The girl seemed to assess the situation very rapidly, savage though she was.
     She tucked the knife back into her bright, matted hair—aha, Lavon thought confusedly, there’s a trick I may need to remember—and shook her head.
     “We are few. The Eaters are everywhere. Soon they will have the last of us.”
     Her fatalism was so complete that she actually did not seem to care.
     “And you’ve never cooperated against them? Or asked the Protos to help?”
     “The Protos?” She shrugged. “They are as helpless as we are against the Eaters, most of them. We have no weapons that kill at a distance, like yours. And it’s too late now for such weapons to do any good. We are too few, the Eaters too many.”
     Lavon shook his head emphatically. “You’ve had one weapon that counts, all along. Against it, numbers mean nothing. We’ll show you how we’ve used it. You may be able to use it even better than we did, once you’ve given it a try.”
     The girl shrugged again. “We dreamed of such a weapon, but never found it Are you telling the truth? What is the weapon?”
     “Brains, of course,” Lavon said. “Not just one brain, but a lot of them. Working together. Cooperation.”

From SURFACE TENSION by James Blish (1952)
SPACE RATING

      “Well, there’s one thing about that last place, Riggs,” Hawley observed, “it had enough of an atmosphere to look a little like Earth.” He swung a leg nonchalantly over the arm of his seat.
     “Yes, sir,” Riggs got out, “but I’ve never seen quite so vicious a cloudburst as the one we landed in.”
     Hawley laughed. “That’s one of the places where a live observer would go mad in three months, right?"

     “You bet,” Riggs replied, drawn into conversation in spite of himself. “Makes you fed kind of queer, do you know it,” he went on, “to go from planet to planet, and never see a sign of intelligent life ? Why, take a look at this system here. At least four of these nine planets could be inhabited, especially if the settlers were willing to do a little selective breeding. They all have oxygen atmospheres, their gravities are close to Earth’s, and temperatures and pressure aren’t impossible at all. You’d think they’d be inhabited.”

     Hawley shook his head. “There’s too much prejudice against it. They’ll have to develop a new race. Those planets won’t be colonized from Earth, but as soon as the few colonies that are in existence now get going, they’ll start colonizing all over the Galaxy. They’ll have a heritage of pioneering behind them, not so much attachment to the place they live in. That’s what’s the matter with Earth. Population groups stagnated for so many thousands of years that the attractions of staying home are too great. You really can’t blame them.”

From SPACE RATING by John Berryman (1939)

Space Colony

The thought occured to some people (most notably Gerard O'Neill) that if the delta-V cost for traveling up and down a planet's gravity well is so expensive, the expense can be avoided if you simply live in space inside a titanic space station. The classic "L5 Colony" was about 32 km long, and held 10,000 inhabitants. Such a colony could earn its keep by harvesting solar energy or with other more shady revenue streams. A quick Google search on "L5 Colony" will reveal a wealth of details.

And if you stick an engine on the end, you have a Generation Starship

It sounds very utopian, and it is.

Now, in a Rocketpunk future, when space stations are dotted over the entire solar system (or even the entire galaxy), they might start out as being just a tiny habitat functioning as a Transport Nexus. Yes, they may start as glorified airplane terminals, but they can become more than that. Space stations near research sites can become college towns, ones near mining sites can become mining towns. Then along will come people willing to import and sell things to the inhabitants, and suddenly you've got a city. Think about the TV show Babylon 5, about a space station at the intersection of interstellar transport routes between several star nations. Started as an outer space bus terminal, but grew to become a center of trade and diplomacy.

If the space city has its own revenue stream, it can go even further, and become an independent city state or station-republic. At some point they will be growing fast enough to justify investing in the construction of a full sized L5 colony.

But remember what Thucydides said above about devolution. If the space city's revenue stream dries up, the city becomes a slum, or even a ghost town. Especially if the space city is a boomtown, there to supply a fine selection of expensive vices to the local asteroid gold strike or Spaceguard military base. If the strike dries up or the base is relocated, the space city will die and become a ghost town.

Space habitats appear in science fiction in the Mobile Suit Gundam Wing animes, C. J. Cherryh's Alliance-Union novels, Alexis Gilliland's Rosinante trilogy, George Zebrowski's Macrolife, John Varley's Gaea Trilogy, Sir Arthur C. Clarke's Rendezvous with Rama, and the tv series Babylon 5.

One problem is that you cannot make a small O'Neill cylinder as a pilot project to gain the expertise to build a full size one, due to the nausea caused by the Coriolis effect. Your first one has to be full sized.

A space colony is a particularly pure example of a hydralic state because Air Is Not Free. If citizens make angry the powers-that-be (defined as "the people who control life support), said citizens will suddenly find themselves trying to breath vacuum. Obey or die. The way to avoid this is with massively redundant life support infrastructure, in an attempt to decentralize control. Of course this only means you do not have to obey the space colony boss, just obey the boss of the segment you live in.

In C.J. Cherryh's Alliance-Union universe, none of the interstellar colonies are actually on an extrasolar planet. Instead they are space habitats in orbit around various lifeless planets (with the exception of Pell). The glaring unanswered question is if you are not going to be using the extrasolar planets, why did you go to the insane expense of using slower-than-light technology to create space habitats in other stellar systems? It would have been about a million times cheaper to just build the habitats somewhere in our own solar system.

If one is colonizing other stellar systems with slower-than-light starships, mass is at a premium. The expense of delta-Ving every microgram up to insterstellar velocities then braking to a halt means you won't be able to carry much of anything. It requires much lower mass to carry the needs for a colony on a human-habitable planet as compared to carrying the industrial machinery required to construct kilometer-long L5 colonies. In fact, such a colony ship might not even carry full grown colonists.

Naturally if you postulate FTL starships, all bets are off. Then it simply becomes a matter of transport costs.

This may or may not boil down to Space Habitats initially being unique to Terra's solar system.

If the space colony is larger than your average planet it is called a Megastructure. This includes things like Ringworlds and Dyson Swarms.

ECLIPSE PHASE

A QUICK PRIMER ON TRANSHUMAN HABITATS

  • Aerostats are massive cities floating in the upper cloud layers of Venus.
  • Beehives are tunnel warrens inside asteroids and moons.
  • Clusters are microgravity habitats consisting of interconnected modules.
  • Cole bubble habitats are hollowed-out asteroids, terraformed on the inside, and also spun for gravity.
  • Dome habitats are massive domes built on the surface of moons, asteroids, or Mars.
  • Hamilton cylinders are self-building advanced nano-tech habitats designs.
  • O'Neill cylinder habitats are like large soda cans, only huge, over a kilometer wide and several kilometers long. The interior is terraformed and the entire cylinder is spun for light gravity. O'Neill cylinders are sometimes paired together, end to end.
  • Reagan cylinders are an inefficient type of O'Neill cylinder, built by hollowing a cylinder within a spinning asteroid, and used in the Jovian Republic.
  • Tin can habitats are small, cramped, cheap, modular boxes, typically used in early space colonization.
  • Torus habitats are big donuts or wheels, spun so that the outer rim has gravity. The interior spokes are zero-G.

LIFE IN SPACE

Transhumanity is not just a spacefaring race, it is also largely space-dwelling. While a substantial portion of transhumanity inhabits planetary bodies like Mars, Luna, Venus, and the moons of the gas giants, the balance live in a variety of space habitats, ranging from the old-fashioned O'Neill cylinders of the inner system to the Cole bubbles of the outer system.

Space Habitats

Space habitats come in many sizes and configurations, from survivalist outposts designed to support ten or fewer people to miniature worlds in resource-rich areas housing as many as ten million people. In heavily settled regions of space, such as Martian orbit, habitats may be integrated into local infrastructure, relying to some extent on supply shipments from other orbital installations.

More commonly, especially in the outer system, habitats are independent entities. This usually means that in addition to the main space station, the habitat is attended by a host of support structures, including zero-g factories, gas and volatiles refineries, foundries, defense satellites, and mining bases.

Habitats—especially large ones—sometimes have visitors, as well. Majors habitats are crossroads in space. In addition to scheduled bulk freighter stops, they may have hangers-on such as scum barges, prospectors, or out-of-work autonomous bot swarms.

Many habitats have some form of transportation network. This is most common in large cylindrical habitats with centrifugal gravity. Common solutions for public transit include monorail trains, trams, and dirigible skybuses. Common personal transit options included bicycles, scooters, motorcycles, and micro-light aircraft, with larger vehicles being uncommon and usually reserved for official use.

Most habitats with large interior spaces also use augmented reality overlays to create consensual hallucinations of a sky and clouds, to which most residents keep their AR channels tuned. One would think that in space, talking about the weather would have disappeared from transhumanity's repertoire of small talk, but the habit persists—only the weather discussed is usually virtual (if it's not real "weather"—solar flare activity and the like).


Cluster Colony

Clusters are the most common form of microgravity habitat. Clusters consist of networks of spherical or rectangular modules made of light materials and connected by floatways. Typically business and residential modules are clustered around arterial floatways and infrastructure modules such as farms, power, and waste recycling. Limited artificial gravity areas may exists, frequently parks or other public places and specialized modules like resleeving facilities (morphs often keep better when stored in gravity). Arterial floatways in large clusters may have "fast lanes" where a constantly moving conveyor of grab-loops speeds people along.

Clusters are most commonly found in volatile-rich environments like the Trojans and the ring systems of the gas giants (particularly Saturn). Clusters are rare in the Jovian system because shielding a cluster of individual modules rather than one large station from Jupiter's intense magnetosphere is hideously inefficient.

Cluster colonies can have anywhere from 50 to 250,000 inhabitants.


Cole Bubbles

Cole bubbles (or "bubbleworlds") are found mostly in the main asteroid belt, where the large nickel-iron asteroids used to construct them are abundant. Bubbleworlds are less common in the Trojans and Greeks, where crusty ice asteroids predominate. A Cole bubble is similar in many respects to an O'Neill cylinder, but there are no longitudinal windows. Sunlight instead enters through axial mirror arrays. The bubbleworld is also constructed very differently, using a large solar array to heat a pocket of water inside of a metal asteroid so that the metal expands. Rotating the asteroid causes the malleable material to form a cylinder, which is then capped off and the water drained. The inside can then be pressurized, built out, and planted. Cole bubbles can also be spun for gravity, according to the whims of the inhabitants, though the gravity lowers as you near the poles of the bubble, with zero gravity at the axis of rotation.

Cole bubbles are among the largest structures transhumanity has created in space. The largest Cole habitat, Extropia, has a population of 10 million.


Hamilton Cylinders

Hamilton cylinders are a new technology. There are only two fully operational Hamilton cylinders in the system, but the design shows great promise and is likely to be widely adopted over the coming period. Hamilton cylinders are grown using a complex genomic algorithm that orchestrates nanoscale building machines. These nanobots build the habitat slowly over time, a process more like growing than construction.

Similar to O'Neill cylinders and Cole bubbles, a Hamilton cylinder is a cylindrical habitat rotating on its long axis to provide gravity. Both known Hamilton cylinders orbit Saturn in positions skimming the rings near the Cassini division. From this position, they can graze on silicates and volatiles using harvester ships.

Neither of the currently-operating Hamilton cylinders have grown to full size yet, but estimates say they could each house up to 3 million people.


O'Neill Cylinders

Found mostly in the orbits of Earth, Luna, Venus, and Mars, O'Neill cylinders were among transhumanity's first large space habitat designs. O'Neill cylinders are no longer built, having been replaced by more efficient designs, but are still home to tens of millions of transhumans. O'Neill cylinders were constructed from metals mined on Luna or Mercury, Lunar volatiles (including Lunar polar ice), and asteroidal silicates.

A typical O'Neill habitat is thirty-five kilometers long, eight kilometers in diameter, and rotates around its long axis at a speed sufficient for centrifugal force to create one Earth gravity on the inner wall of the cylinder. Smaller cylinders exist, though these usually feature lower gravity (typically Mars standard). Cylinders are sometimes joined together, end-to-end, for extra long habitats. A spaceport is situated at one end on the rotational axis of the cylinder (where there is no gravity). Arrivals by space use a lift or microlight launch pad to get down to the habitat floor.

The inside of an O'Neill cylinder has six alternating strips of ground and window running from one cap of the cylinder to the other. One narrow end of an O'Neill cylinder points toward the sun. The opposite end is the mooring point for three immense reflectors angled to reflect sunlight into the windows. Smart materials coating the windows and reflectors prevent fluctuations in solar activity from delivering too much heat. The air inside the cylinder and its metal superstructure provide radiation shielding.

The land in most O'Neill cylinders is one-third agricultural (a combination of food vats and high-yield photosynthetic crops), one-third park land, and one-third mixed use residential and business. O'Neill habitats have a day and night cycle regulated by the position of the external mirrors. The business and residential sections of the cylinder usually alternate with the park land over two of the strips of land; cropland usually takes up the third. Bridges cross the windows every kilometer or so, linking the land strips. The interior climate, the architectural style of the structures, and the types of vegetation and fauna present vary with the tastes of the habitats' designers.

Depending upon size, O'Neill cylinders can house from 25,000 to 2 million people.


Tin Cans

Antique research stations and survivalist prospector outposts often fit this description. Tin can habitats are only a few notches up from the early 21st-century International Space Station. Tin cans usually consist of one or more modules connected to solar panels and other utilities by an open truss. Deluxe models feature actual floatways or crawlways between modules, while barebones setups require a vacsuit or vac-resistant morph to go from room to room. Food growing capacity is severely limited and there may be no farcasters, but fabricators are available, as well as mooring for shuttles and perhaps prospecting craft. Tin cans rarely house more than 50 people.


Toruses

Interchangeably called toruses, toroids, donuts, and wheels, these circular space habitats were a cheap alternative to the O'Neill cylinder used for smaller installations. Like O'Neill cylinders, toruses are seldom constructed anymore, but many are still encountered in the inner system, particularly in Earth and Lunar orbit.

A toroidal habitat looks like a donut 1 kilometer in diameter, rotating on great spokes. There is a zero-g spaceport at the wheel's hub. Visitors take a lift down one of the spokes to the level of the donut, where rotation creates one Earth gravity.

The plan of toroidal habitats varies greatly, as many were designed for specific scientific or military purposes and only later taken over as habitats by entrepreneurs or squatters. Many have a succession of decks in the donut. Most of those designed for long-term self-sufficient habitation have smart material-covered glass windows for growing plants along much of the inside surface of the torus. Toroidal habitats equipped for farming normally face the sun in a direction perpendicular to their rotational axis, but then use a slow processional wobble of that axis to create a day/night cycle.

Toruses were usually built to accommodate small crews of 500 or fewer people, though some larger ones exist, able to house 50,000. A few rare double-toruses also exist, like two large wheels spinning in opposite directions, joined at the axis.

Mos Eisley Space Station 1

Byron:

The problem with a space station as Mos Eisley is simple. Who's providing the air? A lawless space station sounds good, but it's going to run into an extreme form of the "Three Generations Rule" from Attack Vector: Tactical. Either air will be ignored and everyone dies, or it will be the major point of conflict. No space station can survive without a single controlling power that runs the life support. The same applies to any other form of space habitat.


Neon Sequitur:

The 'Mos Eisley' concept may not work for an entire functional space station, but it makes a bit more sense if all or part of a station is considered 'written off'. Babylon 5 had a slum sector, which the station management considered not worth cleaning up. This conveniently allowed the writer(s) to have both a strong central authority on B5 as well as part of the station which resembled Mos Eisley.

In Transhuman Space, the Three Generations Rule rule might be considered a blessing when it comes to squatters in abandoned habitats. It saves the Powers That Be the expense of evicting them, or even deciding who's responsible for doing so. It's a given the life support will fail eventually. Until that happens, however, it's sort of a temporary 'tent city' version of Mos Eisley. (And that sounds like yet another pile of story ideas....)


jollyreaper:

There's no reason that this can't be worked into the plot. Our own human nations are not immortal. Our corporations can be consumed or die of incompetence. Just because Rome was not eternal did not mean it could not exist for the span it did. The vast majority of seeds do not become trees but that does not mean a forest cannot be.

Any properly vast station would have hundreds of sectors with redundant life support and power generation systems. If we imagine the station as an island in space, consider Hispaniola. On one side we have a functioning states, the Dominican Republic. On the other side we have Haiti, a dysfunctional mess. Same island, same resources, different results.

I could imagine a very interesting setting on a vast station that is suffering from the collapse of unified control. Some sectors are properly maintained and society is functioning as it should. Other sectors are in poor maintenance. Some of the common areas are completely out of maintenance, possibly open to hard vacuum. Perhaps the functioning side lacks the resources to fix the broken areas, maybe lack the manpower.

You have a story of resource depletion and civil war on Easter Island. A relatively advanced primitive society tore itself apart, likely over religion and politics. Imagine if you had a dozen islands within sight of each other, some of them maintaining social order while others descend into cannibalism and anarchy.

So as far as your Mos Eisley station example, a small one would be operated by one pirate king, the same way pirate settlements in the Carribean were founded by notable individuals. His house, his rules. Visitors pay rent. He provides the power, air, and food. For larger pirate settlements, each faction would maintain their own area. You wouldn't see chaotic evil pirates running these places, they'd be pragmatic amoral. These would be the guys you could trust in the sense that you know they are rational and have reputations to maintain in the community. You might get knifed in the back if no one is to be the wiser but they're not going to cheat you openly in a way that would harm their reputations. Get known as a cheat and no other pirate will risk doing business, savvy?

The rationale for a pirate haven like this is fairly obvious. Pirates can't get their ships worked on in legitimate yards. They need a place to handle repairs too big for the hands onboard. They need a place for R&R, can't exactly stretch your legs in places where the cops are. Ships can refit and recrew here. And there's also the need to fence stolen goods. Here pirate cargo gets traded to "honest" merchantmen and can get back on the open market.

Now any number of things can happen to jeopardize the viability of such a pirate haven and that's where the stories get interesting.


Byron:

In our hypothetical space station, however, why would people who are keeping their sections in good shape provide for those who don't. Any earth analogy can only be taken so far, as we can managed to get all we need to live pretty much on our own here. The same is not true of a station, and if a sector is in chaos, the life support is going to get neglected, and that's going to lead to a crash very quickly. Atomic rockets points out that a space colony very much resembles a hydraulic empire. It simply can't be anarchy. There might be some parts that are seedy, but I doubt an entire station will be a lawless area, or even most of it. The pirate lord described is plausible, however.


jollyreaper:

Ah, good question. That's just it — it wouldn't be a hydraulic empire. For a large station, I'm imagining it being more like a condo. Stations have sections and sections are controlled by some form of polity, a faction. All the equipment necessary for survival is contained within that section. Each section beyond that is also self-supporting, just like owners in a condo -- the owner pays the note on his mortgage and nobody else in the community needs to help him on that. Of course, condos have areas of common responsibility and expense. When the organization becomes dysfunctional, that sort of stuff deteriorates. And then you can end up with the situation of individual units held onto by owners as the rest of the neighborhood deteriorates.

Now you may ask "Why would a station be built with so much redundancy in the first place?" And that would be precisely to avoid the situation of a hydraulic empire as you state. Say three factions come together to build a trading station in neutral territory. The expense is greater than any individual power can afford so they split the cost. The station is constructed. Each faction has territory on the station that they own in the clear. Furthermore, those sections are self-supporting for all essentials because they wish to avoid the chance of anyone cutting them off from the station's grid. But because there are common needs of the station, all three pay towards the maintenance of the structure and what elements cannot be easily triplicated. On paper this operations company may be considered independent and neutral with personnel drawn from all three factions or maybe from third parties. But you can well imagine how things on such a station could become dysfunctional in time.

From comments to Transport Nexus
Mos Eisley Space Station 2

“Charges in place? Conduits sealed? Okay, go ahead and open it up.”

The heavy wrench descending, clangingly, on the sealed emergency hatch once, twice, three times before the seal broke, a wave of fouled air rushing out past the linobir enforcer and hsis men. Beyond, the milling crowd, faces pale and dark and congested with nerves, eyed them uneasily and decided not to make a break for it.

“All right, which of you self-f*****’ dock-rats claims t’be in charge of this section?” hse bellowed. “He’s got some things to ‘splain and so have I. Speak out, if breathin’ this crud hasn’t rotted your brains too much to parse plain Trade.”

Hser eye fell on a pair of scruffy deshnik arguing with one of his men, brandishing a smart-paper token.

“She’s got a pass? Any of the rest of you recognize this one?”

“Sure, boss, up on Thirty with the Torashanika clan.”

“Then get out of here — Just you, kid. He ain’t got a pass… No arguin’. You got three choices. You can stay here and kiss space with the rest of ‘em when their time comes, or you can run back to your clan-group and try an’ talk ‘em into buying out his life-debt.” Not that there was much chance of even a desperate clan-group doing that for a casteless deshnika flesh-peddler. “Or you can try and get past me an’ I’ll paint the deckhead with your brains. Estrev always gets his cut; no exceptions.”

“Listen up, the rest of you clut-grubbers! I speak for the drift-estrev, and the drift-estrev is not happy. You’re breathin’ his air and burnin’ his bunkerage, and what’s he getting back from you? Nothin’ but dioxide, taint, and an infestation of this pink s***.”

The linobir kicked at a squirming tendril of the ubiquitous hab-slime with a mid-limb.

“Now the estrev says you’ve got two cycles to pay off your life-debts and figure out how to make him value your worthless selves, or else I get to take the four pounds of trinol packed into these joints and blow your s***-house sewerslum right off station-end. Tell whoever’s hidin’ back there and breathe deep while y’can.”

“Close it up, boys. Message delivered.”

O'Neill Cylinder

    The Ahk designated as FT-0101 was an Espatier.  It’s Ka was the pruned fork of Sergeant 5Djeffries Muh.  It’s Ba was a mechanical monster.
    The interior of the vast O’Neill cylinder that was now part of 3Gleise’s territory was patrolled by Cerberus fighters modified for use as squad transports.  Eight hulking brutes, clipped to the exterior of each war rocket, were launched from the destroyers escorting the space station to secure the inside.  It had taken days to go through the vast habitat, comparment by compartment, capturing and removing the thousands of workers found within.  Most were Gleise citizens, now repatriated.  The remainder, AdStar overseers, were captured and sent for interrogation.
    FT-0101 lead the first squad of the first platoon of DesCon 3’s Expeditionary Force.  It had been online for eight-seven hours now, leading its squad in what was essentially a massive boarding action.  It was the certainly the right Ahk or the job.  FT-0101 had faught on planets, with and without atmosphere, asteroids, moons, and habitats of all sizes.  It had fought on starships ranging from corvettes to to titanic battlers. It was the best of the best.
    It had never seen anything like this before.
    “UNKNOWN TERRAIN.  DATA UPLINK ACTIVE.”
    “Roger that, FT-0101.  Get video on all frequencies.”  
    The Espatier Ahk began recording what it saw, in thermal, visible, ultraviolet and x-ray.  The O’Neill was small, as these things go; only eight kilometers long with a radius of a thousand meters.  Despite this, the interior cavity should have been at least five hundred meters wide.  Espatiers on the ground recorded an internal space only two hundred meters wide, divided into compartments every half kilometer.
    “This is downright claustrophobic.”
    “ROGER THAT.  OBSERVE.”
    FT-0101 focused on an area of the interior skin that hadn’t been completed.  A vast cenote in the artificial ground gaped open, exposing layers upon layers of water bags and aerogel bricks under the surface.  Through the middle of the hole was a what looked like a tall ridge made of carbon that was spun in long ropes of self-supporting latticework.
    “It looks almost like buttressing.”
   FT-0101 continued moving forward.  There was no soil on the decking — just layers of woven carbon fiber plates.  Here and there were other Espatiers examining the odd modifiactions to the habitat.  The central hub, for example, was ribbed by additional buttressing that curved outward toward the compartmenting wall dividing the entire open space of the cylinder a few hundred meters ahead.  The curving buttresses from the column gradually arched over the dividing wall to meet the even larger and wider ridges in the rimward walls.
   “STURCTURAL DESIGN UNUSUAL.”
   “That’s one way of putting it.  Looks familiar, though.  Keep panning around, please.”
   FT-0101 anchored its bulk to the deck and began rotating its main cameras around a hundred and eighty degrees, missing nothing.  There were veins of raised tubing standing out upon the partition like spiderwebs of renforcement.  The curving arches made a graceful symmetry.
   “Wait a moment!  Right there!”
   FT-0101 froze, as only a robotic Ba could.
  “Oh, oh Netjer.  I know what this is!
  “ELABORATE.”
  “Those dividing walls, they’re rib vaults.”
  “ELABORATE.”
  “They’re oriented to support the cylinder’s mass along the long axis. Against accelleration.”
  “ELABORATE.”
  “The outer walls are filled with enough insulation to absorb a full laser barrage.”
  “UNDERSTOOD.” This was the closest FT-0101 ever got to an exclamation. “THIS IS NOT A HABITAT CYLINDER.”
  “Not anymore.  Its a capital ship.”  

From O'Neill Cylinder by Ray McVay (2016)
Space Monasteries

(ed note: "Earthplanet" is Terra. It had a world government. It has since balkanized due to several civil wars. "Earthsystem" is the solar system space colonies. Politically they have little or no contact with Terra.)

     McNulty shut off the tapeviewer. “During the past two ship days,” he remarked, “I have recorded news reports of forty-two of these so-called miniwars on the planet. Several others evidently are impending. Is that normal?”
     “Actually it sounds like a fairly quiet period,” Hiskey said. “But we might liven it up!” He pulled out a chair, sat down. “Of course I haven’t been near Earthsystem for around eight years, and I haven’t paid too much attention to what’s been going on here. But on the planet it’s obviously the same old stuff. It’s been almost a century since the world government fizzled out; and the city states, the rural territories, the sea cities, the domes, the subterranes and what-not have been batting each other around ever since. They’ll go on doing it for quite a while. Don’t worry about that.”
     “I am not worrying,” McNulty said. “The employment possibilities here appear almost unlimited, as you assured us they would be."

     Hiskey grinned. “There’s a little more to it than that. Did your tapes tell you anything about Earthsystem’s asteroid estates?
     “Yes. They were mentioned briefly twice,” McNulty said. “I gathered their inhabitants retain only tenuous connections with the planetary culture and do not engage in belligerent projects. I concluded that they were of no interest to us.”
     “Well, start getting interested,” Hiskey told him. “Each of those asteroids is a little world to itself. They’re completely independent of both Earthplanet and Earthsystem. They got an arrangement with Earthsystem which guarantees their independent status as long as they meet certain conditions. From what Gage’s sister told him, the asteroid she’s on is a kind of deluxe spacegoing ranch. It belongs to a Professor Alston . . . a handful of people, some fancy livestock, plenty of supplies.”

     “A private asteroid—any private asteroid—is expected to go out of communication from time to time. They’re one of Solar U’s science projects. They seal their force field locks, shut off their transmitters; and when they open up again is entirely up to them. I’ve heard some have stayed incommunicado for up to ten years, and the minimum shutoff period’s supposed to be not less than one month out of every year."

     Professor Derek Alston’s asteroid also remained something of an enigma. In Mars Underground, and in the SP Academy’s navigation school, the private asteroids had been regarded much as they were on Earthplanet, as individually owned pleasure resorts of the very rich which maintained no more contact with the rest of humanity than was necessary. Evidently they preferred to have that reputation. Elisabeth had told him it wasn’t until she’d been a Solar U student for a few years that she’d learned gradually that the asteroids performed some of the functions of monasteries and castles in Earth’s Middle Ages, built to preserve life, knowledge, and culture through the turbulence of wars and other disasters. They were storehouses of what had become, or was becoming, now lost on Earth, and their defenses made them very secure citadels. The plants and animals of the surface levels were living museums. Below the surface was a great deal more than that. In many respects they acted as individual extensions of Solar U, though they remained independent of it.


     Elsewhere were the storerooms; and here Elisabeth loved to browse, and Harold browsed with her, though treasures of art and literature and the like were of less interest to him. Beautiful things perhaps, but dead.


     And then the projects—Step into a capsule, a raindrop-shaped shell, glide through a system of curving tunnels, checking here and there to be fed through automatic locks; and you came to a project. Two or three or at most four people would be conducting it; they already knew who you were, but you were introduced, and they showed you politely around. Elisabeth’s interest in what they had to show was moderate. Harold’s kept growing.

     “You’re running some rather dangerous experiments here,” he remarked eventually to Derek Alston.
     Derek shook his head. “I don’t run them,” he said. “They’re Solar U and SP projects. The asteroid merely provides facilities.”
     “Why do you let them set themselves up here?”
     Derek Alston shrugged. “They have to be set up somewhere. If there should be some disastrous miscalculation, our defensive system will contain the damage and reduce the probable loss in human lives.”

     And the asteroid had, to be sure, a remarkable defensive system. For any ordinary purpose it seemed almost excessive. Harold had studied it and wondered again.

     “In Eleven,” he said, “they’re working around with something on the order of a solar cannon. If they slip up on that one, you might find your defensive system strained.”
     Derek looked over at him. “I believe you weren’t supposed to know the purpose of that device,” he said idly.
     “They were a little misleading about that, as a matter of fact,” said Harold. “But I came across something similar in the outsystems once.”
     “Yes, I imagine you’ve learned a great deal more there than they ever taught in navigation school.” Derek scratched his head and looked owlish. “If you were to make a guess, what would you say was the real purpose of maintaining such projects on our asteroid? After all, I have to admit that the System Police and Solar U are capable of providing equally suitable protective settings for them.”
     “The impression I’ve had,” Harold told him, “is that they’re being kept a secret from somebody. They’re not the sort of thing likely to be associated with a private asteroid.”
     “No, not at all. Your guess is a good one. There are men, and there is mankind. Not quite the same thing. Mankind lost a major round on Earthplanet in this century and exists there only in fragments. And though men go to the outsystems, mankind hasn’t reached them yet.”
     “You think it’s here?”
     “Here in Solar U, in the System Police, in major centers like Mars Underground. And on the private asteroids. Various shapes of the same thing. Yes, mankind is here, what’s left of it at the moment. It has regrouped in Earthsystem and is building up.”
     Harold considered that. “Why make it a conspiracy?” he asked then. “Why not be open about it?”
     “Because it’s dangerous to frighten men. Earthplanet regards Earthsystem as an irritation. But it looks at our lack of obvious organization and purpose, our relatively small number, and it doesn’t take alarm. It knows it would take disproportionate effort, tremendous unified effort, to wipe us out, and we don’t seem worth it. So Earth’s men continue with their grinding struggles and maneuverings which eventually are to give somebody control of the planet. By that time Earthsystem’s mankind should not be very much concerned about Earthplanet’s intentions towards it.
     “The projects you’ve seen are minor ones. We move farther ahead of them every year, and our population grows steadily. Even now I doubt that the planet’s full resources would be sufficient to interfere seriously with that process. But for the present we must conceal the strength we have and the strength we are obtaining. We want no trouble with Earth. Men will have their way there for a time, and then, whatever their designs, mankind will begin to evolve from them again, as it always does. It is a hardy thing. We can wait. . . .”

     “Where’s the asteroid going on interstellar drives?”
     “I told you mankind hadn’t got to the outsystems yet,” Derek said. “But it’s ready to move there. We’ve been preparing for it. The outsystems won’t know for a while that we’re around—not till we’re ready to let them know it.”
     “This asteroid is moving to the outsystems?”
From "THE CUSTODIANS" by James H. Schmitz (1968) Collected in Agent of Vega

For twelve years, at a point where three major shipping routes of the Federation of the Hub crossed within a few hours' flight of one another, the Seventh Star Hotel had floated in space, a great golden sphere, gleaming softly in the void through its translucent shells of battle plastic. The Star had been designed to be much more than a convenient transfer station for travelers and freight; for some years after it was opened to the public, it retained a high rating among the more exotic pleasure resorts of the Hub. The Seventh Star Hotel was the place to have been that season, and the celebrities and fat cats converged on it with their pals and hangers-on. The Star blazed with life, excitement, interstellar scandals, tinkled with streams of credits dancing in from a thousand worlds. In short, it had started out as a paying proposition.

But gradually things changed. The Star's entertainment remained as delightfully outrageous as ever; the cuisine as excellent; the accommodations and service were still above reproach. The fleecing, in general, became no less expertly painless. But one had been there. By its eighth year, the Star was dated. Now, in its twelfth, it lived soberly off the liner and freighter trade, four fifths of the guest suites shut down, the remainder irregularly occupied between ship departures.

And in another seven hours, if the plans of certain men went through, the Seventh Star Hotel would abruptly wink out of existence.

From LION LOOSE by James H. Schmitz (1961) Collected in Trigger and Friends
Asteroid Athens 1

(ed note: in this essay, Asimov uses the term "g people" to mean the people living on Terra, and "null-g people" to mean those living in space habitats and asteroid colonies)

Second, the nature of the null-g environment will make it certain that they will far outstrip us in variability and versatility. The g people will exist as one large glob (earth's population) with small offshoots on Mars, the moon, and elsewhere, but the null-g's will be divided among a thousand or more worlds.

The situation will resemble that which once contrasted the Roman civilization with the Greek. The Romans wrought tremendous feats in law and government, in architecture and engineering, in military offense and defense. There was, however, something large, heavy, and inflexible about Roman civilization; it was Rome, wherever it was.

The Greeks, on the other hand, reaching far lesser material heights, had a life and verve in their culture that attracts us even today, across a time lapse of 2,500 years. No other culture ever had the spark of that of the Greeks, and part of the reason was that there was no Greece, really, only a thousand Greek city-states, each with its own government, its own customs, its own form of living, loving, worshiping, and dying. As we look back on the days of Greece, the brilliance of Athens tends to drown out the rest, but each town had something of its own to contribute. The endless variety that resulted gave Greece a glory that nothing before or since has been able to match; certainly not our own civilization of humanity-en-masse.

The null-g's may be the Greeks all over again. A thousand worlds, all with a common history and background, and each with its own way of developing and expressing that history and background. The richness of life represented by all the different null-g worlds may far surpass what is developed, by that time, on an earth rendered smaller and more uniform than ever by technological advance.

(ed note: though Asimov also pointed out that Greek City States had other problems.)

From SPOMELIFE: THE UNIVERSE AND THE FUTURE by Isaac Asimov (1965)
Asteroid Athens 2

It's not crazy dreams. It's not even Far Out. It's only basic engineering, and some economics, and a bit of hope. I may even have been too conservative. It probably won't take a hundred years.

Given the basic space civilization I've described, we'll have accomplished one goal: no single accident, no war, no one insane action will finish us off. We won't have to have outgrown our damn foolishness to insure survival of the race. Perhaps we'll all be adults, mature, satisfied with what we have, long past wars and conflicts and the like; but I doubt it. At least, though, there will be no way to exterminate mankind, even if we manage to make the Earth uninhabitable; and it's unlikely that any group, nation, or ideology can enslave everyone. That's Worth Something.

One suspects, too, that there will be an enormous diversity of cultures. Travel times between various city-states-asteroid, Martian, Lunar, O'Neill colony, Saturnian forward base, Jovian Trojan Point—will be weeks to months to years with presently foreseeable technology. That's likely to change, but by the time the faster travel systems are in widespread use the cultural diversities will be established. Meanwhile, communication among all the various parts of the solar system will be simple and relatively cheap, so that there will have been that unifying influence; cultures will become different because people want to be different, not because they don't know any better.

OK. In 100 years we'll have built a space civilization. We'll no longer have really grinding poverty, although there will undoubtedly be people who consider themselves poor, just as we have today people who live better than the aristocrats of 1776, but who think themselves in terrible straits. We'll have insured against any man-made disaster wiping out the race.

From THAT BUCK ROGERS STUFF by Jerry Pournelle (1976)
Greek Republic

The Ganapati was a new habitat founded by an alliance of two of the Common­wealth's oldest patrician families. It was of standard construction, a basaltic asteroid cored by a gigawatt X-ray laser and spun up by vented rock vapor to give 0.2 gee on the inner surface of its hollowed interior, factories and big reaction motors dug into the stern. With its AIs rented out for information crunching and its refineries synthesizing exotic plastics from cane sugar biomass and gengeneered oilseed rape precursors, the new habitat had enough income to maintain the interest on its construction loan from the Commonwealth Bourse, but not enough to attract new citizens and workers. It was still not completely fitted out, had less than a third of its optimal population.

Its Star Chamber, young and cocky and eager to win independence from their families, had taken a big gamble.


The (gamble) might have failed almost as soon as it begun, but potentially it might win the Ganapati platinum-rated credit on the Bourse. Margaret and the rest of the science crews would, of course, receive only their fees and bonuses, less deductions for air and food and water taxes, and anything they bought with scrip in the habitat's stores; the indentured workers would not even get that. Like every habitat in the Commonwealth, the Ganapati was structured like an ancient Greek Republic, ruled by share-holding citizens who lived in the landscaped parklands of the inner surface, and run by indentured and contract workers who were housed in the undercroft of malls and barracks tunnelled into the Ganapati's rocky skin.

On the long voyage out, the science crews had been on minimal pay, far lower than that of the unskilled techs who worked the farms and refineries, and the servants who maintained the citizens' households. There were food shortages because so much biomass was being used to make exportable biochemicals; any foodstuffs other than basic rations were expensive, and prices were carefully manipulated by the habitat's Star Chamber. When the Ganapati reached Enki and the contracts of the science crews were activated, food prices had increased accordingly. Techs and household servants suddenly found themselves unable to afford anything other than dole yeast. Resentment bubbled over into skirmishes and knife-fights, and a small riot the White Mice, the undercroft's police, subdued with gas. Margaret had to take time off to bail out several of her crew, had given them an angry lecture about threatening everyone's bonuses.

From REEF by Paul McAuley (2000)
Thalassocracy 1

In fact, it’s so difficult and expensive that, once you’re in space, it might make more sense to just stay there.

Landing on alien planets might not be worth doing unless you plan to settle there permanently. Instead, you could wander through space, harvesting all the resources you need from asteroids and comets and perhaps smaller planetoids like the Moon.

That brings us to the world of ancient thalassocracies. Thalassocracies are empires of the sea, as opposed to traditional land empires. The word is Greek for “rule of the seas.”

Well known examples include the Phoenicians, Athenians, and Carthaginians. The British Empire might also be described as a thalassocracy, except the British controlled a lot of land in addition to most of the world’s waterways.

Traditional thalassocracies possessed enormous navies. They rarely bothered waging war on land, preferring instead to exert their military power through piracy, naval blockades, and near unrivaled dominance of maritime trade routes.

I’m guessing that space-faring societies will end up behaving more like ancient thalassocracies than modern nation-states. This might be especially true for space-faring civilizations still early in their development and still struggling with the high costs of takeoffs and landings.

(ed note: I'm thinking this would also apply to mobile asteroid bubble space habitats who threw their weight around. They would have an advantage over planet-based civilizations since the thalassocrats are at the top of the gravity gauge. Thalassocracies can be examples of hydraulic states if they control access to spaceflight and interstellar trade.)

From Sciency Words: Thalassocracy by James Pailly (2015)
Thalassocracy 2

(ed note: discussion of Bussard ramjets omitted. The ramjets would be mounted on space habitats to make generation starships. He does believe in the now discredited idea that the magnetic field of a Bussard Ramjet can instantly kill all life on Terra.)

Now that we have the ships let us deal with the warriors and their society. If we assume one system trying to rule another, we have to have some reason for the society to send its sons across many light years (and more real years) to overcome the people of another. Aliens will have their own, alien reasons for doing this. As for humans, idealism, power-lust, need for resources, flight from disaster, or the desire to keep the status quo may cause interstellar invasions.

For instance, the citizens of nearby inhabitable stars hear that the residents of Sol System are going to erect a Dyson Sphere around their system to trap as much energy as possible. This troubles the nearby colonists, who fear that the power produced may go into a blackmailing gamma-ray laser which could reach across interstellar distances to nova suns. An armada is gathered...

The inhabitants of these systems would have some trouble manning their fleets, however. For while relativity would keep the voyager younger than his compatriots back home, you're still spending decades away from home. Hopefully there will be enough Idealists, Militarists, Patriots, and Tourists to man the fleet.

As for an occupation army, you could manage it as long as it was as much a colonization effort as an army. The settler/soldiers, in the midst of an unfriendly land, would tend to be more loyal to the homeland than to the conquered system, but matters would not remain so forever. Eventually they'd feel themselves to be members of the conquered system, and their loyalty would shift to themselves.

The situation may be helped by doubling or tripling the human life span, and thus encouraging a slowly-progressing society at home which could be left for thirty years and still be easily acclimatized to on return.

Nevertheless, an interstellar empire of any size using these methods will not be large, if only due to time lag. If a successful revolt occurred on a colony planet 10 light years away from the fuling system, it would take the rulers 10 years to hear about it and 10 years to send a punitive expedition. This gives the revolting system 20 years at the least to prepare for the counter attack.

Even if systemic rule is difficult or impossible, it may be that rule by a starship people may not be so difficult. Robert Silverberg and Poul Anderson have both written of a people who live out their lives in their ships, carrying the interstellar trade, and seeing many civilizations rise and fall as relativity slows their aging. Such a people could control interstellar trade and, if they wished, even the immediate space around the system.

If they controlled interplanetary space they'd control the planets within it, for shooting up against the pull of gravity is much more difficult than shooting down. Even a planet with no big cities to nuke is vulnerable. All the ship people have to do is turn on their ramfield, and every animal (living on the planet that is more highly evoloved than a) paramecium dies.

(ed note: it is no longer thought that Bussard ramjet fields can kill a planet. But being at the top of the gravity gauge is still quite the decisive military advantage.)

Using the resources of one system a ship people can build another fleet of their tribe, and send it out to conquer another system.

Their deployment in a system would have a star-ship and several systemic spaceships orbiting every inhabited planet, several military starships and systemic spaceships farther out as safeguards in case a revolt should destroy the guard ships, and, yet further out, the home ships of the tribe with escorts. If a successful revolt should occur, these would head for friendlier territory controlled by relatives or allies. As one successful revolt could spark others, they'd probably send forces.

The rule of a star tribe would necessarily be light, as cultural differences and the difficulty of maintaining a garrison on those dirty, disease-ridden, overgravitied planets would work against tight rule. They'd encourage the development of spatial resources and interstellar trade, which they would control the transportation for. Some systems could maintain a precarious independence, but on the whole I see little to stop the star tribes from expanding over the Galaxy. Each ship-family and each little tribe would have a very stable culture (as in Heinlein's "Citizen of the Galaxy") so that a trading voyage by a family will not doom it to the difficulties of culture lag. Eventually all human space (and beyond) would be ruled by many tribes of one people who would certainly have to cooperate with each other against the Flatlanders, the Fraki (Heinlein's Citizens of the Galaxy), the Groundhogs who would certainly attempt in places to overthrow their hold.

From INTERSTELLAR WAR by Scott Rusch, The Space Game issue #5 (1976)
Habitat Lasers And Military Adventurism

(ed note: the Munditos are L5 colonies set in the asteroid belt (paired spinning habitats about 50 kilometers long, set inside conical mirrors). They are owned by their founding nation and must pay taxes. They are protected by military ships from their founding nation. Mundito Rosinante becomes independent, and decides to build a huge laser, energized by sunlight from the mirrors. Later they use the laser to power a large high-deltaV laser thermal rocket.)

“Suppose we are preparing to defend against a future missile attack, like the one just past. Have you any ideas? I mean it's a little late to be brainstorming once the missile is on its way."

"We might build a big laser,” he said at last. “I mean a really big laser, Governor, say 50 meters by 10,000 meters, or even 20,000. Nothing ultra-hot like the Navy uses, but continuous, you know? Pump it with the big mirrors."

"Navy weapons doctrine calls for a power source to generate light, the hotter the better. We have the big arrays of mirrors for light. No need to use a middleman, as it were. We just build a cool, continuous gas laser, but very, very big. It ought to have an effective range of maybe 200,000 kilometers, and it could pick off a missile like nothing, don't you know?"


"What about your idea to maximize the light density by using only one of the three colors of light our mirrors reflect?"

"We've worked out the system for the green light best,” said Ilgen, running his hand over his crew cut. “We have that stack of mirrors—the red and blue mirrors left over from the quality-control work on making the big array—could we use them? How many do we have?"

"The red and blue combined? Maybe 60 or 70 hectares,” said Skaskash. “That would give us a working length of maybe 16 kilometers. I think we really need 21 or 22."

"Yes, 22 would take all the green light from one of the frustrums on the Don Q array-if we patched it up. But what about the cooling?"

“Hey! Skaskash! If we built a pressurized jacket, oh, say one kilometer in diameter, the laser would be air-cooled except for the face, which would be silica! Then we could run a higher light-density and 16 kilometers would be enough! Hell! We could do it with 10!"


"After the event, I ordered high-resolution pictures taken from Laputa."

"This is the double frustum of Don Quixote during the cleanup,” she said, turning the print over. “This is almost the same view taken on January 20, showing the construction in the right-hand frustum in the interim. The technicians call it the Purple Shaft. Notice the support system, which can rotate the shaft in two planes. I imagine that if it was aimed at an object on the other side of the mirror array, a few of the mirrors could be removed."

"This is an enlarged view of the same scene. It shows the Purple Shaft very clearly. We estimate that it is 1020 meters in diameter, 17,230 meters long. The outer surface is made of salvaged purlin tile mounted in salvaged purlin frames. The faint diamond pattern shows quite clearly."

"It doesn't look purple at all,” said Hulvey. “Why do they call it the Purple Shaft?"

"This is the device in operation,” she said. “A very short exposure time shows the inner structure vividly. It is a tube twelve or thirteen meters in diameter running the length of the structure. It is evidently covered with red and blue layered mirrors, so that it reflects purple light and passes green light into the gas mixture which the inner tube contains. In effect, you are looking at a huge gas laser pumped by an array of mirrors having an area of thousands of square kilometers."

"The radiation data is consistent with methyl isopropyl mercury and carbon dioxide,” she replied, “but we don't know.”

"Is it using the full power of the mirror array?” Hulvey asked.

"No, on that shot they were using 30 percent,” she said. “We took a picture of the mirror, and had the computer calculate the angle of each mirror in the array. It gave us a false-color developed picture.” She pulled a print out of the pile. “Yellow is aimed at the laser, the red and red-purple are not. The little green rectangle was probably being used for something else."

"Could they use the full power of the array to pump the laser?” asked Admiral Vong.

"They've had it as high as 80 percent,” she said. “That is, we've seen them take it as high as 80 percent. It is a formidable weapon."


"Rosinante has honored their agreement,” said Shinaka. “We have received their technical data for building the heat ray.

"This heat ray,” said Shinaka, gesturing with his chopsticks, “it is a most troublesome thing. Why couldn't we have invented it ourselves so we could have suppressed it?"

"It is implicit in the design of the Dragon Scale Mirror,” said Kogo. “I expect the reason we didn't invent it was because we consciously decided not to.” He ate a piece of tuna.

"I was with the Dragon Scale Mirror project as a senior team manager back in ‘23 when it was getting started,” Kogo went on, “and the feature that most troubled the Admiralty at that time was the capability to use the mirror array as a defense against docking ships."

"A short-range defense only,” said Shinaka. “Why were they troubled?"

"A city wall is a short-range defense,” replied Kogo, wishing he could light up a cigar, “but when a city builds such a wall it may suddenly become more adventuresome in its foreign policy. The Admiralty feared the drift away from the Central Government. The habitats lend themselves to autarky very naturally. If they also become defensible, like castles, how will we be able to collect our taxes? The big laser was considered in that context, and we never went ahead with it because the Admiralty was afraid that such a powerful weapon in the hands of the habitat managers would make them impossible to control. That is what bothers you now, isn't it?"

"Yes,” said Shinaka, eating a piece of octopus. “It diminishes our warships, also. Perhaps that bothers me even more."

"It does not matter,” said Kogo, “the heat ray is there. Either we use it to advantage or we do not, but we cannot make it disappear. Consider that to use it one must have the Dragon Scale Mirror—which is standard on Japanese habitats, while only a small number of non-Japanese habitats have them. If we use it, we will have a significant military advantage for a significant length of time.” He smiled, showing his lower teeth. “I say build it!"

"It is true,” conceded Shinaka, taking a fresh slice, “we would achieve a transient advantage with the device. What did you have in mind?"

"Use it to free our Navy from defending fixed and scattered points,” said Kogo, “so that we can concentrate our forces for a decisive victory!"

"The last time we did that was when we developed the Zero fighter plane at the beginning of World War II,” said Shinaka. “What happens afterward?"


"Right now I am concerned that the Japanese are building big laser prototypes at (Japanese asteroid colonies) Eije-Ito and Tanaka-Masada."

"Defensive weapons, pure and simple,” Lady Dark said. “How can you worry about them?"

"Up till now it was the Japanese Navy that provided the de facto protection,” said Corporate Susan. “Being released from that detail, they are now free to roll around the Solar System like loose cannon. I wouldn't be surprised to find (our home) Rosinante in their path."


"Perhaps you do not know, Captain. Please do not take offense, but Premier Ito felt that civilian control of the Imperial Japanese Navy would be weakened by building the big lasers. So in pursuit of this policy, what was done? The hijacking of the Foxy Lady was arranged, to prevent the completion of the Dragon Scale Mirror at NAU-Ceres I. Why? The NAU might build a big laser there, and then Japan would also have to build big lasers.” The image of Corporate Hulvey smoothed its slate-blue kimono. “Perfectly logical. If we did, then you must. You might call it prophylactic piracy. Why do you suppose that the NAU might want the big lasers at NAU-Ceres I?"

"To protect their gold shipments against piracy,” No-rigawa said, sipping his tea. “I, myself, have taken over two million ounces. In time, we would have taken the mines."

"Quite so,” the computer said. “Premier Ito was already unable to control his navy. And to execute his policy, a policy designed to avoid losing still more control, on whom must he rely? That same navy, of course. It has taken time, but I have learned that the order to hijack the Foxy Lady came from the office of Admiral Hideoshi Kogo. Would jt surprise you to learn that Admiral Kogo is the leading proponent of building big lasers on Japanese space stations?"

From LONG SHOT FOR ROSINANTE by Alexis Gilliland

Station Station Problems

Air Is Not Free

Habitable planets are great! Inhabitants have quaint expressions such as "Free as Air!"

In space, there ain't no free breathing mix. Any breathable air you consume is either brought along or is manufacturing out of local resources. Neither of which is free, or even inexpensive. Air costs money. If you want to breathe, you have to pay.

With interplanetary tourists, the "air tax" is included in the fee for their tour package. People living in a space station have to pay their periodic air tax or suffer the consequences. This is why a space habitat is a particularly pure example of a hydralic state. Obey the people who control life support, or you'll find yourself suddenly trying to learn how to breath vacuum.

MANNA

"Yes, the wording is such that the boycott will affect all space commerce activities carried on by the Commonwealth and its registered space facilities," Trip Sinclair observed, "even the League of Free Traders, Kevin."

"How about our Lagrangian operations?" Ursila Peri's video image wanted to know. "How can they boycott trade operations off-planet?"

"Is your air bill current, Ursila?" Trip asked her.

"Yes, but even if it wasn't, nobody out here would cut off another person's life support. If the credit line got over-extended too much for too long, we'd put the debtor on a ship home. We work together because there's a lot of nothing waiting for everybody beyond the bulkhead," she said. "They're going to have trouble enforcing tariff arrangements and trade boycotts out here, that agreement sounds exactly like something written up by a bunch of people who always have pressure around them and gravity to keep their feet on the floor. Earthworms!" She made it sound like an insult.


"Sandy, this is Jeri Hospah. Don't let his attempts at humor put you off; sometimes he means what he says. Jeri, find a sack for Sandy and issue him some chits. Then fake up some paperwork that will keep the Ell-Five people happy," Ali instructed us...

...Uncountable hours later, I awoke in the wan sleeping light of the personal compartment and was momentarily confused until I remembered where I was. I felt physically refreshed but still mentally fatigued. That's a dangerous condition in space because little things can kill a careless person.

Somebody had left a flight suit and a Remain-Over-Night kit. Jeri Hospah was either thoughtful or had a well-trained station crew. I took a sponge bath, put on the flight suit and slippers, and decided I might live if I could find breakfast.

The RON kit had a pack of chits—air, meal, water, airlock cycles—as well as an L-5 facilities directory and a visitor's card for the Free Traders' Lounge.

A note was in the kit. "Call me at 96-69-54 and I'll chit you breakfast—Jeri."

From MANNA by Lee Correy (G. Harry Stine) (1983)
BIRTH OF FIRE

(ed note: the superintendent explains the facts of life to the new voluntary exiles to Mars. Keep in mind that on Mars, the air you breath is NOT free, it has to be manufactured and you have to pay for it.)

     "Hear and believe," Farr said. "Okay, chums, let me give you the facts of life. Number one. Don't try to escape. There's no place to go. If you make it outside, you'll live about fifteen seconds. There's no air out there, and your blood will boil away in your veins. It's not a pretty way to go, and I'm told it's painful as hell.
     "Number two. Don't try to escape. You may think you're smart and see a way to get a p-suit. You may even be able to operate it. And then what? You can't make air, and you can't carry enough to get anywhere worth going. Running out of air's not a lot better than going out without a suit.
     "Number three. Don't try to escape. Sure there's a town here, and sure there are a lot of people in it. But you'll pay for everything, and I do mean everything."
     He lifted an orange disk that hung from a chain around his neck. I'd noticed that everyone except us newcomers wore one, but they weren't all the same color. "Air-tax receipt," Farr said. "Mine's orange because I'm due to have it recharged. If it turns red, that's it. Pay up or go outside. You'll need air medals, because God help you if anybody catches you in town without one."
     "Why? What happens?" someone demanded.
     "Outside," Farr said. "Not even a chance to pay up. Just out."
     "And who's to put me out?" Kelso demanded.
     Farr grinned. "Every man jack who's paid his taxes, that's who. Might take several for you, but they'll do it."


At Central Processing they charged our air tags to bright green, forty days' worth. They gave us a hundred Mars dollars, worth about half that in Federation credits. We changed our coveralls for new ones, with a choice of blue or orange.


I found a tunnel end to sleep in. They'd been digging out to expand the city, but this project was halted for lack of a labor force. Nobody bothered me. I figured I had nothing worth stealing, anyway. That turned out to be stupid: I had a charged air tag, and that would be worth my life if there was anybody around desperate enough to cut my throat for it. Nobody was, just then.


I'd been there ten days and my air tag was turning from green to yellow, It was getting time to move on. I figured another couple of days would do it.

From Birth of Fire (collected in Fires of Freedom) by Jerry Pournelle (1976)
LEVIATHAN WAKES

     "Okay, "Miller said. "What's my contract?"
     "Find Julie Mao, detain her, and ship her home."
     "A kidnap job, then," he said.
     "Yes."
     Miller stared down at his hand terminal, flicking the files open without particularly looking at them. A strange knot had tied itself in his guts. He'd been working Ceres security for thirty years, and he hadn't started with many illusions in place. The joke was that Ceres didn't have laws—it had police. His hands weren't any cleaner than Captain Shaddid's. Sometimes people fell out airlocks. Sometimes evidence vanished from the lockers. It wasn't so much that it was right or wrong as that it was justified. You spent your life in a stone bubble with your food, your water, your air shipped in from places so distant you could barely find them with a telescope, and a certain moral flexibility was necessary. But he'd never had to take a kidnap job before.
     "Problem, Detective?" Captain Shaddid asked.
     "No, sir," he said. "I'll take care of it."
     "Don't spend too much time on it," she said.


     "Okay," Havelock said. "I'm sorry, but I'm missing something here."
     "What?" Miller said. He meant What are you yammering about? Havelock took it as What are you missing?
     "A water hauler millions of klicks from here got vaporized. Why are we going to full alert? Our cisterns will last months without even going on rationing. There are a lot of other haulers out there. Why is this a crisis?"
     Miller turned and looked at his partner straight on. The small, stocky build. The thick bones from a childhood in full g. Just like the (Earther) a-hole in the transmission. They didn't understand. If Havelock had been in this James Holden's place, he might have done the same stupid, irresponsible, idiotic bullsh*t. For the space of a breath, they weren't security anymore. They weren't partners. They were a Belter and an Earther. Miller looked away before Havelock could see the change in his eyes.
     "That ***** Holden? The one in the broadcast?" Miller said. "He just declared war on Mars for us (nation of Ceres)."
     The cart swerved and bobbed, its internal computer adjusting for some virtual hiccup in the traffic flow half a kilometer ahead. Havelock shifted, grabbing for the support strut. They hit a ramp up to the next level, civilians on foot making a path for them.
     "You grew up where the water's maybe dirty, but it falls out of the sky for you," Miller said. "The air's filthy, but it's not going away if your door seals fail. It's not like that out here."
     "But we're not on the hauler. We don't need the ice. We aren't under threat,"
     Miller sighed, rubbing his eyes with thumb and knuckle until ghosts of false color bloomed.
     "When I was homicide," Miller said, "there was this guy. Property management specialist working a contract out of Luna. Someone burned half his skin off and dropped him out an airlock. Turned out he was responsible for maintenance on sixty holes up on level thirty. Lousy neighborhood. He'd been cutting corners. Hadn't replaced the air filters in three months. There was mold growing in three of the units. And you know what we (the police) found after that?"
     "What?" Havelock asked.
     "Not a goddamn thing, because we stopped looking. Some people need to die, and he was one. And the next guy that took the job cleaned the ducting and swapped the filters on schedule. That's what it's like in the Belt. Anyone who came out here and didn't put environmental systems above everything else died young. All us still out here are the ones that cared."
     "Selective effect?" Havelock said. "You're seriously arguing in favor of selective effect? I never thought I'd hear that sh*t coming out of you."
     "What's that?"
     "Racist propaganda bullsh*t," Havelock said. "It's the one that says the difference in environment has changed the Belters so much that instead of just being a bunch of skinny obsessive-compulsives, they aren't really human anymore."
     "I'm not saying that," Miller said, suspecting that it was exactly what he was saying. "It's just that Belters don't take the long view when you screw with basic resources. That water was future air, propellant mass, and potables for us. We have no sense of humor about that sh*t."


From LEVIATHAN WAKES by "James S.A. Corey" (Daniel Abraham and Ty Franck) 2011.
First novel of The Expanse
Lurkers

"Lurker" is a homeless destitute person living on a space station, especially a space colony. The person figures there are opportunities on the colony, they spend most of their money traveling to it, when they can find no jobs the money runs out, so they have no money for a space flight ticket to somewhere else. They then move to anyplace they can find in the station, much like terrestrial homeless live under bridges. The space colony administrators cannot afford to ship the lurkers elsewhere (there are so many of them), so the problem grows. Of course the lurkers are also preyed upon by the criminal underworld.

Michael Hutson pointed out to me that this actually happens in places like Hawaii, which require lots of money to leave. The destitute tend to accumulate in Hawaii since they cannot afford the air fair to leave and go somewhere else. And the Hawaiian government certainly cannot afford to give them free plane tickets.

Roger MacBride Allen has a simple solution, assuming the station controls all transport to the station.


The term was invented by J. Michael Straczynski for his TV series Babylon 5, more accurately he adapted an existing term. In internet forums "lurkers" are people who read the forums but do not make posts or otherwise draw attention to themselves. Straczynski noticed this phenomenon when he was discussion the proposed TV show on GEnie, Compuserve, and Usenet back in the early 1990's. He thought the invisible forum lurkers were a good metaphor for the invisible homeless people on the Babylon 5 space station.

IQ TOO LOW TO GET A JOB 1

Immigration should do something

     “Spare change, brother?”
     “Get a job!”
     “That’s quite impossible.”
     “Eh?”
     “Impossible: adj.: not possible; unable to be, exist, happen, etc.”
     “A wise guy, eh?”
     “Yeah. Everybody out here has an IQ over 110. ‘Cept you, ‘parently.”
     “Why, I never!”
     [sighs] “We’re all descended from Earth, one way or another, but the smartest all moved out to space. So us second- and third-gen folks are all the sons and daughters of the upper-bracket erudite–including a fair measure of genius. The funny thing about IQ is that 100 is always average, so the average Earther is 80-something and the average Belter is 120.”
     “I take grave exception to–”
     “Oh can it already. Where are you going anyway?”
     [testily] “… Bureau of Careers. Just shipped in with my last dime.”
     [sarcastically] “And may lady fortune herself light your path to employment.”
     “I will too!”
     “Nope. Yer too dumb. If I can’t get a job, then you sure as hell can’t get a job. And you’re in the same boat as I–without any cash, you can’t buy your way off this rock. Might as well take a seat next to me. Yer gettin’ no job, brother.”

From SPACE BUMS by Ian Mallett (2016)
IQ TOO LOW TO GET A JOB 2

(Journalist Cooper travels to the Lunar colony to do some investigative reporting, attempting to discover the secret that the scientists won't talk about. Spoilers for the story follow.)

Then Cooper whispered: "My God— you've found a way of prolonging life!"

"No," retorted Hastings. "We've not found it. The Moon has given it to us ... as we might have expected, if we'd looked in front of our noses." He seemed to have gained control over his emotions—as if he was once more the pure scientist, fascinated by a discovery for its own sake and heedless of its implications.

"On Earth," he said, "we spend our whole lives fighting gravity. It wears down our muscles, pulls our stomachs out of shape. In seventy years, how many tons of blood does the heart lift through how many miles? And all that work, all that strain is reduced to a sixth here on the Moon, where a one-hundred-and-eighty-pound human weighs only thirty pounds."

"I see," said Cooper slowly. "Ten years for a hamster—and how long for a man?"

"It's not a simple law," answered Hastings. "It varies with the size and the species. Even a month ago, we weren't certain. But now we're quite sure of this: on the Moon, the span of human life will be at least two hundred years."

"And you've been trying to keep it secret!"

"You fool! Don't you understand?"

"Take it easy, Doctor—take it easy," said Chandra softly.

With an obvious effort of will, Hastings got control of himself again. He began to speak with such icy calm that his words sank like freezing raindrops into Cooper's mind. "Think of them up there," he said, pointing to the roof, to the invisible Earth, whose looming presence no one on the Moon could ever forget. "Six billion of them, packing all the continents to the edges—and now crowding over into the sea beds. And here—" he pointed to the ground—"only a hundred thousand of us, on an almost empty world. But a world where we need miracles of technology and engineering merely to exist, where a man with an I.Q. of only a hundred and fifty can't even get a job.

"And now we find that we can live for two hundred years. Imagine how they're going to react to that news! This is your problem now, Mister Journalist; you've asked for it, and you've got it. Tell me this, please—I'd really be interested to know—just how are you going to break it to them?"

He waited, and waited. Cooper opened his mouth, then closed it again, unable to think of anything to say. In the far corner of the room, a baby monkey started to cry.

From THE SECRET by Sir Arthur C. Clarke (1963)
PREVENTING LURKERS VIA ROUND-TRIP TICKETS

(ed note: Garrison and Ben are at the Lunar Central colony, and have to travel to the remote isolated Farside station. Tickets for roller (Lunar tractors) transport to Farside are outrageously expensive. Ben has a better idea, buy their own second-had roller.)

“First off, two round-trip tickets overland to Farside cost nearly a third of what a used roller costs. There’s a glut on the market for some reason. Second, the prices for cargo shipment are even more ridiculous. Then I checked on the price of temporary accommodation out there at Farside. Insane. If we spent a month in a rented room out there then we’d have paid for the other two-thirds of the roller. But if we live in the roller until we find a permanent place to live, we’ll save plenty.”

“If the seals on the roller don’t give out and vent our air,” Garrison agreed. Something occurred to him. “Why did you check on the price of round-trip tickets, anyway? One-way is all we need.”

“And round-trip is all they sell. The story is that it's a limited-resource area, whatever the hell that means, and they can’t afford to clutter up the stations life-support system with poor slobs who spend their last buck getting out there and strand themselves. In real life, of course, they make more money selling return tickets. So I spend a roller instead and they don’t get any money at all.”

(ed note: Yes I know this is for Lunar tractors, but the principle can be applied to spacecraft tickets to a space station. Obviously this assumes that the space station can force the spacecraft passenger liners to cooperate.)

From FARSIDE CANNON by Roger MacBride Allen (1988)
LURKER

A lurker is a term used for the homeless on Babylon 5.

Lurkers are mostly human although others have been seen. They began settling on the station as soon as it was opened, beginning simply as people searching for new lives and opportunities. When they did not succeed, they often don't have the money to go back home so they end up moving into the undeveloped parts of Downbelow. There are also those that are destitute because they are on the run from something or someone, like the Psi Corps. Lurkers have hard lives to say the least and as if being poor and homeless wasn't bad enough, they often become victims of the criminal underworld that robs and steals from them. However, there have been situations where they are hired by smugglers etc. to handle illegal cargo.

In 2261 during Babylon 5's state of independence from Earth, Captain Sheridan instituted work programs so that they could earn money.

From THE BABYLON PROJECT entry for "LURKER"
DOWNBELOW

Downbelow refers to the various undeveloped areas of Babylon 5, mostly in the lower levels of Brown Sector near the outer hull. Very few ever go there, as it consists of the corridors and chambers around the waste recycling system, the air compressors, and the water reclamation facility.

History

Downbelow came about as a result of budgetary cutbacks and a rush to finish when construction was nearing completion, leaving many areas of the station unfinished, especially in the Brown and Grey sectors. Being the first station of the much-touted Babylon Project to open for public residency, people flocked to the station in search of a better life. However, many who came to the station didn't find their better life, soon ran out of money, and were reduced to squatting and living in the abandoned corridors of those unfinished levels, scrounging through the refuse of the hurried construction process for anything they could eat, wear, or sell. Due to this style of living, they became known as Lurkers.

In 2258 Dr. Stephen Franklin set up a free clinic in Downbelow to help treat those in need that couldn't afford to go to Medlab and to secretly sort runaway telepaths and get them out through the Underground Railroad.

Crime

Downbelow is a hotbed of crime and accounts for as much as 90% of the station's crime rate, mostly because it's the only place for many people to go when they come to the station looking for a new life, but run out of money, unable to buy passage home, effectively becoming the station's homeless. The very worst parts of Downbelow are located in Brown Sector, which is a less than pleasant locale at the best of times. Downbelow is often divided up between an ever changing roster of various criminal factions, small-time thugs and gangsters. Most are little more than violent bullies that have learnt to survive by stealing, intimidation, protection rackets and extortion. Even the secretive Thieves Guild have a presence in this area.

From THE BABYLON PROJECT entry for "DOWNBELOW"
Society Rules

The rules and societal norms on a space habitat are going to be different than here on Terra.

In the Albedo Anthropomorphics universe of Steve Gallacci, one has a cluster of planets colonized by slower-than-light starships (yes, the colonists are furry anthropomorphic animals, but that is beside the point). The planetary cultures that were founded as a consequence have a "shipboard discipline mentality."

Consider, on a spacecraft, if a civilian saw something like an air leak in the hull, and didn't report it to anybody, they would be endangering not only their own life but also the lives of everybody on the colony ship. So that is a crime.

In the United States on the other hand, if a person sees somebody lying injured on the side of the road, and they try to help the injured one, more often than not they wind up being sued by the injured person. Hands off, do not get involved, it is not your problem.

In the Albedo universe, with the shipboard discipline mentality, it is a crime not to try and help somebody who is injured, and there are "Good Samaritan" laws to protect the helpers.

Naturally such a shipboard discipline mentality will rule a society living inside a space habitat, since such a habitat is pretty much a huge spaceship. Even more so, a civilian not bothering to report an air leak on a habitat is endangering many more people than on a spaceship. By several orders of magnitude.

The closest thing to social tradition available to the people of ALBEDO is shipboard discipline, and this is strongly ingrained in all levels of society. Simply stated, the individual member of society is not quite as "free" (in one sense of the word) as a 20th century western man, because the individual is strongly constrained by a set of expectations and responsibilities. The individual is expected to be an active citizen, and is conceived of as having both civil liberties and responsibilities. The fragile ecological and social environment on board colonisation ships has lead to the development of societies where the individual is expected to take his social role very seriously, and to contribute to the working of things around him. The individual is expected to behave in an intelligent, responsible manner, and to be aware of the implications of his or her actions. Citizens are expected to be aware of the long running consequences of their actions, and to act accordingly.

Thus in most cultures, if a person is injured, it is the civil duty of passers-by to assist that person however possible. If a passer-by refuses to aid the injured party, or pretends to ignore them, then the passer-by is held to be partly responsible for the subsequent condition of the injured man, and will be charged under law accordingly. Regional attitudes do vary, however. For instance, to the inhabitants of the Dornthant system, the tools of an ordered and peaceful society are its security measures, and the co-operation of the common citizen is an expected duty. To a Dornthantii, running away from or obstructing the authorities is a clear admission of guilt.

The practical upshot of the social attitudes prevalent in most cultures in ALBEDO is the creation of societies which are very politically and ecologically aware. The average citizens feel that they have a vested interest in the running of their government, their society and their planetary environment. Albedo is set in an age of REASON, where forethought and responsibility are highly valued faculties. In the context of the culture of known space, "honour" will usually equate as social responsibility.

From Albedo RPG Player's Manual by Craig Hilton and Paul Kidd
Three Generation Rule
RocketCat sez

The Three-Gen rule just says that Space Colonies Die Because People Are Lazy. Unlike the rest of this website, it ain't rocket science. You disagree? Oh, and I suppose you never ever put off scooping the cat's litterbox "for later?"

As you rapidly discover when thrown out an airlock in your underwear; space has zippo breathable oxygen, atmospheric pressure, lack of broiling heat, and other incidentals you need or you'll die. A Ground-gripper living on a planet take these things for granted, but they ain't in space. Not unless you bring them along.

Which means lots of complicated delicate high-tech life-support equipment. All of which had better get regular maintenance or it breaks down. Which will kill everybody.

Commercial and military space station life-support will get that maintenance, since the owners don't want their expensive investments going kablooey. Well unless there is some serious corruption or mismanagement goin' on, but I digress.

Space colonies on the other paw are full of lazy people who figure they can put off fixing the leaky oxygen generator until next Monday. Keep up that attitude for a few decades and you can bet your last rocket it's just a matter of time before a catastrophic breakdown forces mass evacuation or death. This is much the same mindset you see in cities that keep putting off fixing aging bridges and water supply plumbing.

Three-Generation Rule was codified by Ken Burnside's. It suggests that space habitats (space stations where people live and raise new generations of children, not commerical or military bases) have an average lifespan of three generations before everbody dies or is forced to evacuate.

You see, unlike living on a habitable planet, there is no air in space. Likewise other life-support requirements that can only be provided by lots of technology. Which must be regularly maintained or it breaks down.

Commercial and military space stations (controlled by exterior corporation or military forces) are much better at keeping up the maintenance than are space habitats (controlled successive generations of lazy people who just live there).

THE 3 GENERATION RULE

Three Generations Rule, The – Human habitats in hostile environments are fragile, and human nature tends towards short term, rather than long-term thinking. Because of this, most hostile environment colonies last for three to five generations, once they cease to be outposts of planetary governments. The second generation tends to make choices based on the here and now, and the third generation pays for them. Strongly autocratic societies tend to last longer, but have a lifespan matched primarily by that of their leader.


Visionaries paint futures of humanity living in space. History has not proven kind to them.

From the disasters in the Mars colonies of the late 21st century to the present, human nature has set a clock on human habitation in a hostile environment. While planets have multiple redundant environmental failure modes, artificial habitats in hostile environments lack them. Worse, human beings are frequently forgetful, lazy, criminally negligent, or outright hostile.

So long as an outside government or agency is continually putting funds into a station, or it’s run as a benevolent dictatorship, these problems can be minimized. When the stations gain a measure of autonomy, and the citizens relax bothersome rules as “unnecessary”, the seeds of tragedy are sown.

The first generation keeps things in good working order, remembering enough of the procedures that they are followed, even when they’re boring, or aggravating, or expensive in the short term. The decline begins when the first children are born: any parent can tell you that a 2 year old is 14 kilos of self-animated entropy and destruction, fully equipped with a curious mind, opposable thumbs and no regard for the consequences of actions.

As the second generation comes into power on its own, the “pioneer” ethic dwindles. Children view many of the choices of their parents in a different light. Long-term needs are postponed for shorter-term gains. Budgets aren’t increased as parts wear out, and attitudes of “You were able to do it last year with this amount, I’m sure you can think of something...” enter decision making processes. Elections accelerate this process because politicians play on the short-term concerns of their constituents. The second generation has children of their own, who teach the same entropic lessons their parents did... often with a few tragic accidents to boot.

The third generation reaps the whirlwind sown by the second generation’s decisions. It has to maintain 50 year old equipment that has seen constant use in a high radiation, oxidizing environment. Rust accumulates in awkward places, plants mutate. Machinery works by cannibalization, duct tape and prayers, while the budget for overhaul shrinks due to taxpayer demand. All the problems previously ignored or partially solved come to a head. Crisis follows crisis follows short-term fix. As soon as the environment becomes uncomfortable, those who can afford to emigrate do so, destroying the tax base for future repairs, and accelerating the process. Eventually, the system collapses: everyone departs, or dies in a catastrophic failure. (Example: in the Corinth station in Epsilon Eridani system, with air and water recycling systems nearly failing, the sanitation workers went on strike. Out of 7,324 inhabitants of Corinth Station, 13 were alive when a rescue freighter arrived.)

The greater the degree of personal autonomy, the faster this cycle runs. The few habitats to defeat this rulehave had a cultlike devotion to a leading cadre or code of behavior, with extensive brainwashing and forced learning, beginning with toddlers, with social codes that make the Bedouins of Earth look sybaritic.

From ATTACK VECTOR TACTICAL SETTINGS BOOK by Ken Burnside (2004)
BASIC 3 GENERATION RULE

Ken can make authoritative correction of this, but the premise of the 3-gen rule is that the degree of social discipline needed for a space habitat to survive indefinitely is beyond the capability of "normal" human societies. The human tendency to favor short-term expediency will, over time, make the habitat ecosystem more and more precarious.

Putting it loosely, people tend to put off patching the leak in the roof till its raining.

In the Ten Worlds setting, this means that space habs tend to run down, and fail catastrophically in 1-5 generations from when they were established. The average is 3 generations, hence 3-gen rule. The one society in the 10W setting that has beaten this rule is the Library of Man, by adopting a social system that makes it seem very strange and almost "inhuman" to others.

Proviso: This applies only to habs that are socially independent, i.e., the major decisions are made locally, thus subject to local political expediency, etc. It does not apply to bases and such that are ultimately under some outside authority — the outside authority can order the leaks fixed, even if it means everyone has to work double shifts.

Rick Robinson
3 IS THE MEDIAN

Alistair “Cerebrate” Young

     Been contemplating the Three Generation Rule, worldbuilding-wise, since reading through the Attack Vector: Tactical Setting Book.
     I'm not a particular fan of the Humans Are Morons trope — I prefer my universes without anyone holding the Idiot Ball, even if it wasn't purely hypothetical — assuming rather that humanity is hovering somewhere around about galactic average for smart.
     But, yeah, those special talents of ours for failing to grasp our enlightened self-interest and having abysmally short planning horizons probably would discourage Our Protagonists from handing us serious long-term projects, yeah.

Ken Burnside

     Even in the Ten Worlds setting (the one described in the AV:T Settings Book), the Three Generations Rule is a median in a range. It's really closer to being a "two-to-six" generations rule, with the primary determinant on longer durations being a VASTLY more communitarian society than is the norm.
     This can be from adaptive societal structures like some varieties of Mennonite faiths all the way over to extensive brainprinting of attitudes along with education to keep things running.
     The Library of Man uses the latter... (An organization dedicated to brokering and selling information throughout the Ten Worlds, they are more like fanatical monks or a cult than they are a colony)

Alistair “Cerebrate” Young

     nod
     I figured it would work out something like that in practice, and indeed, I can totally believe it where Mark 1 Humans are concerned.
     (But having spent a bunch of time marinating my brain in the inhuman psychology of my main protagonist species — as rampaging a bunch of rabid individualists as ever sat around disagreeing with each other about where, when, and how to rampage — I've got a bunch of characters in my head making snarky remarks about how odd it is that a species that isn't, by nature, nearly so predisposed to libertist fanaticism nevertheless manages to suck so much at cooperating long-term without being indoctrinated to first...
     ...don't mind me, writer syndrome.)

Ken Burnside

     One of the little notes that didn't make it in the setting book is that the frothing Libertarians in the setting tended to be disasters at running contained environment systems...

Alistair “Cerebrate” Young

     Heh. Even as someone with a lot of libertarian inclinations, I can see exactly that. (Mostly because I know too many of the unfortunately dim kind of libertarian.) I imagine quite a few similar things happened at various times and places in my setting, too, for that matter.
     The space libertarians mentioned above, contrariwise, when such a thing happens, have a standard response which amounts to rolling their eyes and world-wearily pointing out that "if you want to have a free and consensual society, you have to be at least an order of magnitude better at managing cooperation and obligation and quote public goods unquote than any of those buggers with governments that can brute-force their way out of the situation; and anyone who thinks that taking away the whips and jackboots abolishes all those things too is obviously Doing It Wrong. Idiot atomists had it coming."
     Then they cut a check to the Ellfive Habitat Systems Management Group and call the Life Support Tech-Adhoc to confirm their required-by-volume-lease 10 am atmosphere-sensor checking appointment, 'cause Mama Versine didn't raise no vacuum-sucking dummy, no sir.

Ken Burnside

     I have never seen any arguments more rancorous than zoning arguments at city council planning meetings.
     The fundamental logical fallacy of a lot of libertarianism is that they can find solutions that won't leave some faction desperately unhappy; the knock-on effect of that is that the people left unhappy tend to carry grudges the next time some dispute needs mediation.
     Government serves a purpose in that it acts as a remove on that animus being personal.

From a comment thread in Google Plus (2014)
DETROIT AND ENTROPY

Brian Renninger

     Well, IMO, 3-gen rule is more like the Pirate's Code — a guideline. There are ways around it, or at least to extend it. Or, not worry about it. 3-gens is certainly enough time to begin something new. Those in a failing colony will certainly have some incentive to move to greener pastures or make a greener pasture.

Ken Burnside

     If you can sidestep the 3-gen rule on an enclosed habitat, you can sidestep it on a planet, and you won't be moving enough people into space to impede humanity's impact on a planet.
     3 generations is the median, and you can see a 3-gen rule scenario playing out now in Detroit. ("now" meaning "2013")

Brian Renninger

     Ken Burnside, Concur with the idea that if you can avoid it in an enclosed habitat you can avoid it on a planet, thus negating any gains made by making habitats. My comment was more on the rule itself rather than the idea that space habitats are a way of avoiding impacts on Earth.
     I think several of Heinlein's novels touch on this with characters having these particular hopes dashed.

Ken Burnside

     It's largely an historical observation about human nature, political corruption, and the fact that infrastructure maintenance tends to result in fewer jobs than infrastructure construction or renewal.
     On a planet, letting your infrastructure rot results in places like Detroit: The population shrinks over the course of 20 years because everyone moves away.
     On a space station, there's no "away" to move to, and the failure modes tend to be more catastrophic.
     My supposition is that different cultures will have different spots on this curve; I suspect a strongly neo-Confucian culture that taught conformity would be both very alien to modern Westerners, and might be able to make this last longer — but even then, there's going to be a tendency to cut corners, put off fixing things until the next budget cycle, and then some. It largely takes a military organization to, say, keep an aircraft carrier running, and that's only because the people in charge of the aircraft carrier aren't living on it....and if you've read readiness reports for Soviet Navy stuff (or seen the Russians try to get their Navy back into functional status...) you'll see that corruption and graft are even worse there than they are in our Navy.
     The best way to solve this problem is to get rid of people. :)

Mad Fabe

     Ken Burnside, the way around that may be to have drones that go out and fix things before they break.

Ken Burnside

     And who fixes the drones? :) Entropy wins in the end, and (at least at our current understanding of the macrocosmic all), human societies have to allocate resources.
     The record for human beings making sensible long-term allocation of resources for society as a whole isn't great.

Mad Fabe

     Ken Burnside, you are making the case for a computer run society. Kind of like the one in Colossus the Forbin Project.

Ken Burnside

     Both the Bedouin and Inuit live in very simple societies without a lot of amenities or social complexity.
     When presented with complex luxuries, they tend to be even worse at taking care of them than "conventional Westerners."
     Talk to anyone who's had to deal with typical Arab/Bedouin maintenance of vehicles, modern firearms and electronics, they'll back this assertion up.
     Three generations is a long span, and space habitats are fragile, and certain types of maintenance really are more easily done by refurbishing the entire system with it's uninhabited.
     Or, let me put to to you like this:
     Have you ever put off cleaning the toilet or doing the dishes? Can you imagine a society where nobody ever puts things off because they're messy, smelly or unpleasant?

From a comment thread in Google Plus (2013)

4) Political priorities — life path problems. Kinda getting back to the idea that each colony will need to come up with their own character, colonies would start with an archetype (not sure how to do this, but it'd be a function of looking at the initial reason for building the colony, money input and world climate/world traits) and then within that framework have random events that could happen based on planet and who colonized it. This would generate a set of planetary traits, such as idealism, pragmatism, greed, environmentalism et al that would effect the options available to the government when problems turned up. For example, a Three Generations Rule problem might be very easy for a highly pragmatic colony to deal with, while one that was high in idealism might run into problems. Yes, in a sense this is trying to ascribe in a half dozen variables a political/social culture...maybe impossible.

(UNDER) 1 GENERATION RULE

I’ll start by saying that the “Three Generation Rule” is more of a general statement and SF plot device, not an absolute.

We live in a kind and gentle biosphere which forgives many (individual and widespread) forms of self-delusion deception and overt ignorance including corruption, laziness, and just plain cost-cutting substandard work.

Might I suggest the (Under) 1 Generation Rule.

In regards to critical maintenance: the life support systems maintenance contractor (and however many of his crew as deemed necessary) who skimps on the work by not changing out filters, aggressively removing mold in air ducts, and swapping out seals on airlocks as usage and maintenance cycles demand will be shortly hauled up on formal charges, yes, of course, by the local authorities, or perhaps simply, and quietly, find themselves chucked out the airlock. If it’s the local authorities at fault, shrugs, well politicians don’t tread vacuum more successfully than crooked contractors, as a rule. Wash rinse repeat enough times and soon space stations and/or even large habitats will arrive at individuals who perform the work to spec.

Populations of entire Habitats who just shrug away such maintenance, well, they will just be the poor (dead) slobs who taught the lesson to everyone else.

Societies do change over time. Social tolerances and attitudes are not fixed, but mutate over time. I am not convinced that any particular aspect of human attitude or behavior can be said to be immutable.

As example. Fifty years ago (speaking largely in regards to American culture) racial, gender, cultural, and sexual-lifestyle intolerance was the norm, and tolerance was a small growing movement of social awareness, viewed in large swaths of American culture with, at best, suspicion. These attitudes have been changing and increasingly those who express overt intolerance are viewed as the misfits, outliers, and oddballs. While there are still notable exceptions, bigotry in general is in decline, which is to say it is not universally socially accepted (not that it has gone away).

From William Black (2015)
REFUTING THE 3 GENERATION RULE

Isaac Kuo

     The three generation rule is just idiotic nonsense contrived for purposes of...a misguided attachment to planetary chauvinism.
     Actual historical reality shows us that a city like New York manages to exist for an indefinite number of generations without people magically forgetting how to run essential infrastructure.

William Black

     Isaac Kuo, while I wouldn't necessarily presume to know with absolute certainty, much less judge, the intention of thought behind the rule, I do agree that the three generation rule is a contrivance.
     The "rule" simply doesn't match the real world in any way. Here is my rebuttal to the three generation rule:
  1. It fails to account for the long term viability of cities over historical spans of time.

  2. It presumes a complete lack of self-interest and will to survive.

  3. It presumes a universal and abject lack of critical thinking, and presents an unexplained inability to perceive consequences of inaction. It presumes but does not explain an absence of rational decision making affecting entire city-sized populations. While you might find individual cases of any of the above in any population, it is an over generalization to assume universality of these deficits in cognition for entire populations.

Lilith Dawn

     Isaac Kuo, forget? What about "ignore"? Flint stands out in my mind.

William Black

     Lilith Dawn, granted, however people in the community perceived there was a problem and acted, in a persistent and on-going manner to determine the nature of the problem and raise the alarm. 

John Reiher

     Well, Nieuw Amsterdam New York is bad example. It always has had a constant influx of new people moving in and others moving out. New York City has resources from outside to help it sustain it's growth and infrastructure.
     The 3rd Gen rule assumes no influx of new blood into the colony. That all the resources are internal and no new resources are added to the colony.
     Just changing these two assumptions and the colony becomes much more long term. But... the colonists won't be grounders. They live in a much more precarious environment and there's a certain amount of discipline a resident must have over a grounder living in a city on a planet.
     If a grounder sees a rusty fire hydrant, they shrug and say "The city will fix it."
     If a colonist sees that a fire suppression device shows excess wear, they will report it as it's their responsibility as a citizen of the colony to help keep it up.

Isaac Kuo

     John Reiher I don't see any reason why a constant flux of people and resources wouldn't equally apply to space colonies. In order to create a space colony in the first place, there must be a practical logical chain to bring materiel and people. Whatever that was...the most plausible thing is that they will keep on using it.
     To me, this is the same sort of complaint as those who deride terraforming because lesser gravity will cause the atmosphere to go away in mere millions of years. Okay...but whatever practical mechanism was used to create the human usable atmosphere must surely have taken place over mere hundreds or perhaps thousands of years. Why not just keep on using it to keep the atmosphere topped off?
     (There are plenty of other problems with terraforming, but this one is silly, IMO.)

Alistair “Cerebrate” Young

     Well, that's true to a certain extent, and I generally agree with you as a rule —
     But there are a lot of bits of that history (and live-action examples in any major company's cost-center support departments, like IT) that also demonstrate the tendency of people to skimp on any maintenance that isn't absolutely necessary until the last minute, or to make unwarranted assumptions that the thing that's always been there always will be, or that the low-probability emergency condition will obviously never happen because it never has yet.
     ...it's just that the Northeast Blackout of 2003 (and its cascading effects), or the Flint Water Crisis, or assorted lengthy emergency-maintenance London Underground closures, et al. ad naus., were uncomfortably survivable (for most people) because the absolute essentials for life didn't depend on that infrastructure.
     So, y'know, I don't believe in the Three Generations Rule as a general principle. It's quite avoidable by a combination of competence, proper incentives, and cultural support.
     On the other hand, I do expect it to happen all the time if habitat systems management is delegated to the presently incumbent Earthside infrastructure-management firm of Chumpy McTimeserver and Representative Weaselface.

John Reiher

     Isaac Kuo I was just pointing out the base assumption of the 3rd Gen rule is that it's a closed system. As soon as you have a new influx of resources, people, or both, you never get that third generation. Everyone is second generation in that situation.
     New York if full of 2nd Gen New Yorkers. An active and realistic space colony should also be a 2nd Gen place to live.
     Of course, this assumes that the colony is in a civilized system. If you're the first one to a new star system and the only way to get there is by slow ship. It may take multiple generations for any new blood to show up. In that situation the only thing the colony has going for it is resources.
     However, I would say that a proper colony would have a colonial attitude, and the subsequent generations would also have that attitude. So the idea that complacency that would affect the "3rd Gen" situation, isn't a factor. Everyday is a new day and new challenge to overcome. Only when the colony is fully established would you have to worry about 3rd Gen issues arising. 

William Black

     John Reiher If the three generation rule assumes no influx of new blood into the colony. That all the resources are internal and no new resources are added to the colony ... well it seems even more of a contrivance.
     I have no idea why anyone would think this is a reasonable set of assumptions in the first place.
     Once you are on orbit, well you are half-way to everywhere, as a relatively well known author somewhat famously observed.
     Civilization is built on trade. Go as far back in human history as you care, trade is the universal activity of human populations.
     By the time anyone is constructing large scale space habitats there will be widespread ISRU and extensive industry involved in resource extraction, this is the only way such habitats could ever be built.

John Reiher

     William Black that's my point. The 3rd Gen rule assumes that there are no new additions to the colony, no new blood. It also assumes that the parents do not instill a proper respect of the environment the colony is in. It assumes that bunch of Millennial slackers are the 3rd generation, not the children of a viable and prosperous colony.
     And as Alistair Young pointed out, the colony isn't run as a for profit venture, with quality of life management and maintenance done by the lowest bidder.
     The second you get new people on the colony, the dynamic changes and everyone is always 2nd Gen and you never run into the problems of the 3rd Gen.
     It sounds like we're all talking past each other here and we are all in agreement that the 3rd Gen Rule doesn't make much sense. It's more a plot contrivance than an actual rule. 

Alistair “Cerebrate” Young

     John Reiher Well, I wouldn't necessarily say that. After all, the only things I generally see done worse than things done for profit are things done not for profit. Especially by monopolies — for myself, I'd like to see at least two competing life support providers...
     (Another approach worth considering might be the give-the-life-support-department-etc.-medical-officer-privileges approach, in which the CELSS Engineer gets to tell the station commander to shut up, sit down, and replace the gorram auxiliary scrubbers NOW, whatever it means for the rest of his budget.)

From a comment thread in Google Plus (2016)
RAPID TURNOVER IN SPACE HABITATS

(ed note: in John Varley's Gaea Trilogy, there are some corporations that wait for the 3-gen rule to kill a habitat. Then they swoop in, take possession, vent it to vacuum to sterilize it, and then sell it to some other idealistic group as a unique fixer-upper opportunity.)

They built the Coven there. It was a cylinder seven kilometers long with a radius of two kilometers. Artificial gravity was provided by spin; night, by closing the windows.

But the days of isolation were over almost before they began. The Coven was one of the first nongovernmental groups to move into space in a big way, but they were not the last. Soon the techniques of space colonization were refined, cheapened, standardized. Construction companies began to turn them out the way Henry Ford had turned out Model T’s. They ranged in size from the merely gigantic to the Brobdingnagian.

The neighborhood began to look like Levittown, and the neighbors were odd. Just about any sizable lunatic fringe, band of separatists, or shouting society could now afford to homestead in the LaGrangians. L2 became known as Sargasso Point to the pilots who carefully avoided it; those who had to travel through it called it the Pinball Machine, and they didn’t smile.

Some of the groups couldn’t be bothered with the care and feeding of complex machinery. They expected to exist in pure pastoral squalor inside what was really just a big hollow coffee can. The developers were often happy to accommodate them, reasoning that all that expensive hardware, if installed, would only be abused. Every few years one of these colonies would come apart and fling itself and its inhabitants across the sky. More often, something would go wrong with the ecology and people would starve or suffocate. There was always someone willing to take one of the resulting hulks, sterilize it with free vacuum, and move in at a bargain price. The Earth never ran short of the alienated and the dissatisfied. The United Nations was happy to get rid of them and did not ask too many questions. It was a time of speculation-of instant fortunes and shoddy practices. Deals were made that would have shocked a Florida real estate developer.

From WIZARD by John Varley (1980)
THIRTY YEARS OF DEFERRED MAINTENANCE

(ed note: the asteroid L5 colony of Rosinante is offered a contract to refurbish the NAU-Ceres I L5 colony. To their horror they discover an early onset case of the Three Generation Rule)

NAU-Ceres I, officially the Senator J. Walter Deegnan III Class II Naval Logistics Support Facility at Ceres, was completed in 2008 by the State of the Art Space Construction Company, the only responsive bidder on the contract issued by NAUGA-Navy, two and one-half years after the deadline and many, many megabucks over cost.


"This place is in ba-ad shape, Charlie,” Rubenstein replied. “The window bays have a biological fouling problem you wouldn't believe. It rains in here, Charlie, from clouds. The windows get rained on, too, okay? They were designed to drain off—when the cylinder was pulling a cee of 500 to 520 cm/sec/sec. They had to reinforce the mirrors to keep them from flexing, okay? And then they were so heavy that they had to cut the rotation speed to keep the hinges from failing."

"So you have algae growing on the windows?” Cantrell asked.

"Charlie, you got duckweed growing on the windows!” Rubenstein replied. “On window bay number two, there is a two-hundred-fifty-hectare lake a meter deep in some places. I saw water lilies and frogs and snails and a turtle—must have been somebody's pet—that was a foot long. Guess what else? Don't guess, I'll tell you. Charlie, the gasket material is rotten."

"That's impossible,” said Cantrell. “We've had silicone rubber formulations that would last forever since ... since ... hell, since before space flight."

"And the Navy specified the right stuff,” Rubenstein agreed, “but this place was built on low bid, remember? The Navy inspector must have missed it.” He grinned and pulled his nose. “Shave two to three cents a pound off a quarter million tons, Charlie, it's a tidy piece of change. Of course, the mylar/aluminum mirror is reflecting ultraviolet, and the whole thing is cycling wet and dry—that doesn't help either."

"The gaskets have to be replaced?” Marian asked.

"From the books, it looks like this dump is leaking a ton of oxygen a day,” said Rubenstein, “and it's getting worse. Myself, I would sooner rebuild from scratch. But what would you use for money?"

"What else is wrong with NAU-Ceres I?” Cantrell asked.

"Thirty years of deferred maintenance. It wasn't built right to begin with, and if they couldn't fix it on the cheap, it didn't get fixed at all. The elevators don't work right, the pipes—steam, sewer, potable water, you name it—they all leak. The ductwork is in need of a major overhaul. The wiring, Charlie, it would make you weep. The wiring has no relation to any of the wiring diagrams on file, the youngest of which, by the way, is dated March 1, 2019."

"Oh, Christ. I think I have the picture, Mordecai.” Cantrell slumped back in the telecon chair and laced his fingers across his chest. “So all right. We'll have to work out the details, but figure I want a sound structure at NAU-Ceres I. Whether we do an extensive overhaul or rebuild from scratch—either way, the first thing we need to do is get an estimate on the cost. We can use the Japanese at Yamamoto and Nakajima as well as the locals and our people from Rosinante."

"You want a write-up, Charlie, I'll do you one,” Rubenstein said at last, “but, Charlie, it'll be guesswork. How much will it cost to build a machine to replace rotten gaskets in the window bays? Multiply that by a few hundred or a few thousand...” He shrugged. “The whole thing will be guesswork, Charlie.” Cantrell sat biting his thumbnail. “And then what you wind up with isn't all that great. Talk about industrial slum—"

"I understand,” Cantrell said. “What's the bottom line?"

"Basically, Charlie, you can spend as much money as you want on this slowly spinning sack of s**t. There just ain't no limit. There really ain't."

From THE PIRATES OF ROSINANTE by Alexis Gilliland (1982)
FLASH FICTION: THREE-GENERATIONS RULE

     Listen, out in the Belt, we do things differently. Not just from the Inner Worlds, but from each other. No two habitats are the same. We're all little islands of culture and history, separated by hundreds of thousands of kilometers of empty space. But the one thing that does run through all of us is the importance of maintenance. It has to. Where it didn't, habitats failed. Societies collapsed. People died. But it wasn't always like that. Enough failures ensured that trait was selected for.
     Earthers don't get it. They have open sky. Free air. Stable ecology. Sure, they had to learn the hard way the importance of managing all of that on a planetary scale, and their society almost failed because of their negligence, but they really have it good down there. Our margin of error is smaller. Resources are more scarce. We've got to budget accordingly
     It's called the Three-Generation rule. Basically, people get lazy. They get used to the idea of having a stable ecosystem around them. They skimp on the upkeep. Things start failing. The next generation grows up and does the same thing. Eventually, things get bad, quickly. The rule comes from the observation that this tipping point usually happens about three generations in. Some vital resource gets used up, a critical system or component fails. The lucky ones manage to get relief efforts from a nearby charitable habitat, or maybe Mars or Earth. Some immigrate to other habitats. Others just collapse. Every few years there'd be a story on the interplaNet about some colony somewhere in a state of emergency. Not so much now. It used to be that some group of wide-eyed idealists got the idea to move out to the Belt, build themselves a nice habitat, and try to set up their own little world. Later they realized just how difficult it is to manage an entire biosphere and society at the same time without resorting to draconian extremes. Sometimes they got it together and joined the rest of Belt civilization.
     As for the rest, there was a small boom in companies that specialized in “refurbishing” failed habitats. They would go in, clean it out, fix it up, and sell it back to someone else. It seemed rather grisly, but apparently the market existed. Most of them were in good physical condition and still air-tight; they just needed an ecological re-boot.
     That was the history of Freeharbor. Back then it was known as Independence.
     I wasn't there when it was founded. But I was there near the end. By my teens it was already well-passed decline. This was probably somewhere around 2230 or so. After about a decade of general corruption and shenanigans, the Administrator had finally decided to try an experiment in corporate plutocracy. To his credit, he seized power on the promise that he would prioritize life support maintenance, overhaul resource recycling systems, and all the rest. He would make Independence a shining exception to the Three-Generations rule. And for a little while, it actually went surprisingly well. Until things started breaking down a little too often. There was always another crisis that could only be solved through the absolute authority of the Administrator's office.
     Technically there are provisions about printing firearms on habitats, but that didn't stop anyone. Armed riots frequently broke out. I tried to keep my head down, often times quite literally. But you can only stay out of these kinds of things for so long, especially when it's your home getting torn apart. So I fought. I didn't stay, though. I ran. I fought my way to safety somewhere else. I got a group of friends and some of my family and we found a small transport. It had enough delta-V in the tanks to get us to Ceres. I took a few bullets in the arm on the way to the docks trying to get to it. There were enough meds onboard to keep me stable for the several weeks it took to get to Ceres, but I don't really remember much. I was out for most of the flight. The last thing I remember seeing was the habitat's big pair of metal cylinders slowly spinning in the night, their huge mirror rings almost too bright to look at.
     When we got to Ceres they had to amputate my arm. It took almost a month for them to grow me a new one, so I spent most of my time in the hospital with my arm stump submerged in a tank of my own cultured, engineered stem cells as it slowly regenerated.
     I never really returned after that, partly because I felt ashamed for running. Most of us ended up staying on Ceres. There was a small flow of refuges coming from what remained of Independence's imploding society. I paid attention to the situation as little as I could at first, not wanting to think about what I left behind. But curiosity crept its way past my desire to forget, and I suddenly found myself looking up news reports on interplaNet. There was a time when I read or watched little else.
     Apparently in the weeks after we had fled, the various resistance movements had all organized and successfully raided the Administration Tower. When they got to Administrator, the bastard had already killed himself. They blew his body unceremoniously out of the main airlock. Now they were asking for assistance in rehabilitating their habitat. A lot of the ecology had been destroyed in the uprising. For a while it didn't look good.
     Mars was one of the first to come to their aid. They offered advanced biotech to help restart their biosphere and maintain a more self-sustaining ecology. They even offered space for some residents to resettle on Mars itself. Some had taken them up, but most stayed. They learned. They rebuilt. And from their struggle, Freeharbor was born.
     I saw first hand how things can go wrong. I was lucky, and so was my habitat. These dangers aren't gone just because it hasn't happened in recent years. This is space. Outside the hull of your habitat is nothing but life-sucking vacuum. No matter how cushy or green or utopian your orbital might feel, it's an important thing to remember; don't get complacent.

Death by Civil Unrest

A space habitat is not planet. The air, heat, and the rest of the life support does not occur naturally. It has to be created by technology.

And remember Every gram counts. This technology is not going to be armor-plated. It is going to be made out of foil and wires. The infrastructure of a space colony is fragile.

Which means a troubled young man angry at the space colony's government, somebody like Timothy McVeigh, would be capable of much worse than killing a paltry 168 people. Using the same level of effort they could shatter the entire freaking colony and kill over 140,000.

So a space colony that does not want to die screaming all alone in the night is going to need to take some steps. Among them are preventing angry young men from carrying out such dastardly acts, and helping not becoming so angry in the first place.

In asteroid mines or cramped space colonies, perhaps a system like Discworld Mine Signs could be utilized. Or Shipnet. Or something like Twitter hashtags, if you can post anonymously.

A Game of Consequences

There's an old saying that only two things are unavoidable: death and taxes. I think this is wrong—the two unavoidable things are politics, and it's seldom-admitted offspring, bureaucracy. (Their Titan parent is of course economics.)

Politics: you may not like it but you can't ignore it because whenever two or more people have ideas about how to do something requiring the participation of two or more people there's going to be an argument about how to do it.

Bureaucracy: because once the argument is settled you need to coordinate the tasks, and once your community exceeds Dunbar's number you need to develop mechanisms for managing work and social relationships between people who don't know each other.

It's fairly obvious that technology affects the implementation details of politics and bureaucracy (and there's feedback involved too, via market regulators and command economies). And there are scale issues too. Back in the 1670s and 1680s century when Samuel Pepys served as Secretary for the Admiralty, administration for the Royal Navy ran on a handful of staff and relied on disbursement of funds—in cash—to ships' captains to see to their maintenance and the pay of their sailors. Today it's hard to imagine a modern defense ministry running on cash-in-hand: even Da'esh have accountants and an org chart. But the ability to run a modern bureaucratic defense procurement and supply organization is required due to the capital-intensive nature of modern warfare (you try buying an Aircraft Carrier with cash) and relies in turn on availability of modern tools: not just computers, but accounting procedures, project management, quality assurance, process control, and a host of other specialities that simply didn't exist back in the age of sail. On the other hand, back in the 17th century ships and squadrons might be commanded by officers weeks or months from the nearest political point of control and operating on the basis of orders which, although obsolete, had not been countermanded (and it wasn't just at sea: for example, the Battle of New Orleans took place in 1815, weeks after the treaty ending hostilities had been signed).

So. Taking the space cadets seriously for once ...

What are the political problems that would arise from the extension of an Earth-based political framework to governance of off-world space colonies? And what kind of bureaucratic mechanisms might be developed to deal with the arising issues?

Most SF centering on near-future space colonization is regrettably polluted by rose-tinted libertarian bullshit. Let's face it: in the really short term, outposts like the ISS or a near-term return-to-Moon or expedition-to-Mars will be governed by existing legal arrangements made by the national government with jurisdiction over the crew. In practice this means the 1998 ISS agreement, the Outer Space Treaty, and customary international law. And the "colonists" aren't; they're typically highly trained middle-aged scientists, engineers, and bureaucrats-with-other-skills (note how many of NASA's retired astronauts go on to careers in space program senior management or even seats in the Senate or Congress).

Looking further ahead—by which I mean out past 2030 at the very earliest—we might see encampments with a handful of people living and working off-planet semi-permanently, along the lines of an Antarctic research station (albeit in a vastly more hostile environment). "Law enforcement" overlaps messily with psychological healthcare, and generally is a matter of shipping the unruly home for treatment and diagnosis (and, optionally, restraining them en route). Money? Hah! While informal economies eventually emerge once you have a population in double or triple digits (things like trading extra shifts worked, or food, or homebrewed moonshine) it takes a long time to get to the point where "money" is internally useful for anything other than keeping track of interpersonal exchanges of obligations. And as for "no taxation without representation", that's a really long way in the future, and becomes highly problematic when the polity of 3000 who are objecting to remote governance and taxation is reliant on a distant polity of 300,000,000 who built the metal world they live in.

But by the time we look as far as self-sufficient comet-mining or terraforming colonies, a century or two in the future, the questions of political coordination and local vs. remote administration will become pressing. And these questions also apply to long-term colonies and generation ships. Assuming the (huge) obstacles to these are overcome (notably: deleterious medical radiological and microgravity effects of long-duration spaceflight; economic framework for repaying the cost of foundation; ability to maintain a large-scale closed cycle life support ecosystem; ability to replicate all necessary infrastructure components and consumer goods; ability to care for, educate, and train new members of the population and to sustain those who can no longer work or who aren't suitable for work at core survival tasks) ... what, realistically, happens?

I have some starting assumptions. Notably: the traditional right-wing American vision of settlers in space is utterly untenable because it assumes people can "walk away" from local market failures, and that individuals are solely responsible for their own errors. Libertarianism won't fly in space where any "market adjustment" is likely to prove lethal to a significant proportion of the population. Indeed, the American formulation of rugged individualism is horrifically dangerous in such a setting: imagine the mind-set that gives rise to schoolyard shooters, and put it in an environment where the only things holding in the atmosphere are the walls.

Secondly: in the absence of magical scientific breakthroughs, getting home from a fucked-up colony will be hard to impossible. If you colonize the Gobi desert or Phoenix, Arizona, you can probably escape if you have a gassed-up SUV, some cash, and enough water. If you colonize Mars, though, you're going to need a spaceship capable of reaching orbit and at least three months (more likely 18 months) of air and supplies. That's a whole different ball game, and once you realize you're living in a failed world, you're going to be far too late: it makes the plight of the people in the European migrant crisis today look trivial. Space colonies exist, of necessity, in a kind of liminal Gene Cernan voiced "failure is not an option" territory: and this is not a good place to live, much less to raise a family and expect a peaceful retirement.

So I don't see our contemporary interpersonal or cultural relationships working. Some sort of tribal organizational structure might work, by which people could work with distant or unrelated "relatives" within a web of familial obligations; it's a way of diffusing relationships to allow larger groups to work together for joint survival. Look at parts of the middle east for cultures adapted to that way of life ... or better still, don't (if you're attached to the idea of personal autonomy, choosing your own sexual partners, and deciding whether or not to have children or how to work for yourself). I'm only half-kidding: obviously iron-age tribal practices won't help cultures in brittle, high-risk environments mediated by high technology survive ... but neither will what we've got now on the sleepwalking, neoliberalalism-dominated west.

Nor are our current political representative structures, adapted to heterogeneous nations sharing an open, relatively resilient world, necessarily going to work well in a closed system. A space colony can't afford to be governed by ideology in the absence of feedback from instrumentation. But technocracy isn't the answer either; technocracy has nothing to say by way of answering the core questions of human existence, such as "what is best in life?" much less "what is right?" And a space colony probably can't survive a revolution that turns violent.

Any workable form of government for such a fragile environment is going to have to provide mechanisms for prompt and non ideologically-biased responses to deviations from the baseline. It's going to have to provide solutions that work for everybody, because the environment is a lifeboat and if you give up on someone they will die (or worse, having no expectation of living may choose to take everybody else with them). It's going to have to provide a framework for settling arguments where there is no obvious "best" solution without pissing off one faction or the other, and a framework for orderly and non-violent transfers of power (because shaved apes are addicted to up-ending their social hierarchies). The bureaucracy it comes with is going to have to offer mechanisms for delegating authority across vast gulfs of space and time, be relatively lightweight (at least in the early decades of a colony), and should arguably satisfy Rawls' philosophical notion of justice as fairness and provide distributive justice, lest it give rise to grievances leading to instability or revolution. (As a propensity for fairness seems to be wired into primates at a very low level, running on an administrative system that optimizes for fairness seems like an appropriate way to minimize friction.)

Anyway. What other angles am I missing here? You, too, can help design a constitution for a space colony! Just remember two things: it has to be somewhere you'd be comfortable living the rest of your life as an ordinary citizen, and if you get it wrong, you can't walk away.

From A game of consequences by Charles Stoss (2016)
Technological Decline

A more long-term problem is that of Technological Decline. As Joan Vinge pointed out in THE OUTCASTS OF HEAVEN'S BELT: If a planetary colony falls into barbarism, everybody reverts to a non-technological agrarian society.

If an asteroid civilization falls into barbarism, everybody dies.

It takes lots of technology to run the oxygen system, airlocks, spaceships, hydroponics, nuclear reactors, and other items vital for life in space. No technology, no life. In other words, they are a Hydraulic state.

Betha saw suddenly the fatal flaw the original colonizers, already Belters, must never have considered. Without a world to hold an atmosphere, air and water -- all the fundamentals of life -- had to be processed or manufactured or they didn't exist. And without a technology capable of processing and manufacturing, in a system without an Earthlike world to retreat to, any Dark Age would mean extinction.

From THE OUTCASTS OF HEAVEN'S BELT by Joan Vinge

Sample Space Habitat

Long-term plan: large modular habitats

     There are several large habitats proposed, generally by people who are both smarter and better-educated than I am. Wherever possible I prefer to use solutions proposed or developed by others, but I disagree with some of the fundamental assumptions made for structures like the O'Neill cylinder. That will necessarily result in a different outcome, thanks to several design decisions that go in another direction. #1 on that list: There are no windows. None. Don't even think about it; windows in space are incredibly stupid.

The headline results so far are as follows:
Design population: 5,000 people
Maximum population: 5,280 without major changes, up to twice that under emergency conditions
Mass: 142,750 tons shielding, 4,552 tons hull, 2,770 tons air, 350 tons occupants. As-yet unknown masses for furnishings, life support, hydroponics, other systems.
Volume: 2,262,000 m³ (79,882,000 ft³)
Area: 138,000 m² (13.8 hectares / 34 acres) under habitable gravity.

     The structure would require the capture and exploitation of 160,000 to 200,000 tons of asteroidal material, or about 67,000 m³ of carbonaceous chondrites. Only about 600 tons (0.3%) needs to be carbon, but nearly 2,000 tons (1%) needs to be nitrogen. A single 50-meter diameter rock should just about do the trick, roughly the size of the Tunguska meteor. An alternative is sixteen 20-meter diameter rocks (Chelyabinsk sized) with the proper composition on average. There are anywhere from hundreds of thousands to tens of millions of near-Earth asteroids in this size range.

     The two driving forces in my mind are radiation protection and moderate to full gravity. We know that microgravity is very harmful to humans even with the best medical care available and years of preparation in advance of relatively short (6-12 month) exposures; there is every reason to suspect that microgravity is not survivable in the long term. For this reason gravity or pseudogravity is a fundamental requirement. Radiation exposure is also tremendously harmful; current spacecraft are not survivable over the long term. Shielding that reduces the level of radiation exposure to Earth-normal or lower is also a fundamental requirement. The combination of these two requirements means a series of trades in structural and shielding materials. For free-space habitats I've settled on counter-rotating composite habitat modules on a common axis surrounded by non-spinning shielding made of bulk rock with a metal skin. For habitats in small bodies (Phobos, Deimos, other bodies with a few % Earth gravity at most), the habitat sections would be buried and would rely on bulk material for shielding. Bodies with significant gravity are different enough that they need to be addressed with unique designs.

     I'll deal with the free-space version first. Shielding is very expensive in mass terms. There are two primary sources of radiation in free space, the solar wind (particularly solar proton events or SPE) and cosmic rays (GCR).
     Cosmic rays are isotropic, so the most efficient shape would be a sphere. The solar wind is highly directional, so the most efficient shape would be a long, thin rod. Spheres are complex and inefficient to turn into living space, so a cylinder is the basic shape of choice. Remember that radiation doesn't turn corners, so we can use unconnected pieces of shielding that allows vessels in and out of the protected area without moving parts.
     We can adjust the relative cost of shielding for the Sun vs. shielding for GCR by changing the aspect ratio (length to width ratio) of the cylinder, but the optimum orientation is for one end of the cylinder to point at the Sun and carry somewhat heavier shielding than the rest of the hull. This imposes a stationkeeping burden to keep the end pointed at the sun. For lower dV costs the structure should be vertical, which means the entire shielded hull will rotate into view of the Sun over the course of a year. There does not seem to be a compelling argument either way except for the slim chance that a catastrophic CME or other solar event might be made survivable by taking shelter at the far end of the rod.
     Human physiology limits the speed of spin gravity, thus setting a lower limit on the diameter of the colony; my design uses a radius of 60 meters and rotation speed of 3.89 RPM for 1g Earth-normal gravity at the outer floor. Biology also sets a lower limit on the population of a self-sustaining colony; research differs on the exact value but 5,000 appears to be safe. I specify a set of four habitat modules each 50 meters long, each to house a nominal population of 1250 people. The structure can grow by adding pairs of habitat modules along the common axis, saving the expense of extra endcaps and costing only the shielding mass for the wall of the outer cylinder.
     The habitats spin inside a stable shielded hull without contacting it; a physical gap of three meters separates the outer walls of the habitats from the inner walls of the hull so either structure can be maintained while under spin. Internal positioning is maintained with magnetic repulsion as necessary, to minimize the torque applied to the outer hull. No isolation is perfect, so the structure will require      thrusters of some kind. Ion would be preferred, using either metals or heavy gases.
     Shielding is composed of 2mm of aluminum with a standoff space (Whipple shield for micrometeoroids), then 1cm of nickel-iron (30/70) followed by 104cm of packed regolith (1.5g/cc density, composition similar to lunar soil or stony asteroids). The outer layer of habitat includes 30cm of water as additional shielding, pump-able counterweight, leak indicator and bulk storage. This combines to provide an attenuation of 4.518 (in units of 1/e^x), blocking 98.91% of radiation. The first floor will still experience slightly more radiation than Earth average. For ideal results an attenuation factor of 5.3 is desirable; longer-term projections indicate that the GCR could potentially be as high as 1500mSv (vs. 740mSv recorded so far) which would suggest a factor of 6.0 attenuation to reach Earth-normal levels. In other words, even with this much shielding there may be times where the inhabitants need to evacuate to the inner floors so the material of the outer floors can protect them from radiation spikes.
     In order to make the most efficient use of this shielded volume the habitats are built in levels or floors of four meters each. Each floor is structural, capable of functioning as the outer hull during the construction phase, capable of independently supporting its own mass and floor loads, and capable of limiting the spread of damage in case of structural failure or impact. The material is UHMWPE, very long-chain polyethylene (Spectra fiber) with an aluminum film liner. This can be manufactured using plants to process CO2 and water (in turn made from any sources of carbon, hydrogen and oxygen). The habitat's hydroponics system is designed to produce plastic for this purpose in addition to food, though during the construction phase the mix of plants will heavily favor plastics.
     The outermost floor is at full Earth gravity, while each floor inward provides progressively less gravity; specific floors can be designed to mimic the gravity of Mars, Venus or the Moon if desired. A microgravity bay in the center of the structure has effectively no gravity; this space can be used as a shirtsleeves environment for building or repairing delicate spacecraft among other things. Total floorspace is 149,540m²; if we define 'habitable' gravity as 0.3g or higher then 138,230m² of that space is habitable. That's eleven floors of useful gravity (including analogs of Earth, Venus and Mars), two more of low gravity (including an analog of the Moon) and one of microgravity.

     A nearly identical design would be built into a pit on Phobos or Deimos. Phobos in particular could host a set of habitat modules in an open pit; if the pit is deep enough and placed to face Mars then the disk of Mars will fully block any views to space. No end-cap would be necessary for radiation protection; further, the vastly greater mass of shielding would mean the habitats would see less radiation than on Earth. One application of this might be as a permanent base at the site of a Phobos-Mars transfer tether. The habitats would be built up over time using materials excavated from the pit, with the option of adding more and more hab modules by excavating the pit deeper and deeper. This technique could be applied to main-belt asteroids like Ceres, Vesta, Pallas, etc.; the floors would need to be tilted slightly to accommodate the gravity of the parent body and a covering shield would be necessary but otherwise a very similar prospect.

     Throughout my design process I have sought to use Earth-normal design standards. This phase of space exploitation is far beyond the early adventurers, meant to be constructed using by-then-proven technologies and inhabited by average people (doctors, mechanics, teachers). Average people like having creature comforts; it's good for our physical and mental health. For example, I assume that each resident requires about 100 m² of space: roughly 32 m² of personal space, 36 m² of public space and 32 m² of work space. This is about 344 ft², or the size of a smallish studio apartment. A family of four would enjoy 128 m² or about 1,378 ft², modest by American standards but ranging from generous to lavish in many other places. Smaller is certainly possible, but that's a size that most people would accept. My research suggests that floor space for growing food, clothing and furnishings will be roughly 20 m² per person; this space is categorized as work space. That leaves another 12 m² per person or 15,000 m² per habitat (160,000 ft²) or roughly one large-ish office building at 32mx32m and 15 floors. The public 36 m² accounts for hallways, engineering spaces (including life support), schools, public eating and/or meeting space and parks. Some of that could be considered 'work' space; I didn't try to stick to some particular metric, but rather used that as a basic assumption. If it turns out that the mix is more like 20 m² public and 48 m² work it makes no difference.

     The internal structure of the habitat starts with the structural hull layer, 7.6mm of PE fiber with an aluminum foil liner to make it gas-tight. This layer is strong enough to handle two atmospheres of pressure; the entire four-meter floor could be flooded with water and still fall within structural limits. This is primarily formed of fibers wound around the cylinder, with secondary layers wound at 45° intervals to provide strength on the axis. These secondary layers flow into the endcap walls or sidewalls and carry the stress of the endwalls through the hull.
     Next is a protective layer. The outer floor uses plastic liners filled with water and plastic-cushioned isogrid aluminum ribs which function like joists. Inner floors use plastic-cushioned planks or deck plates of aluminum or bamboo, potentially over their own isogrid layer for heavy-use areas. This layer protects the hull against abrasion and distributes loads to prevent punctures.
     On top of that floor fits standard furnishings. Walls are thin metal or even Shoji-style paper with foam cores for noise attenuation. This is less about minimizing weight and more about reducing the amount of material used. Each floor has its own unique radius of curvature, so furniture is designed to bear weight along the flat axis and accommodate multiple radii along the curved axis. Still, the structure is designed to handle a floor load of 100kN/m² (nearly 15 psi / 2,160 psf), which is strong enough to drive heavy machinery over without damage. Most objects are made out of 'foamed' aluminum or titanium, or bamboo; the choice of material depends on what resources are most plentiful at the time. Bamboo sinks carbon and nitrogen while foamed metals sink metals; either can be reprocessed back into base material if necessary.
     Furnishings can be painted, anodized or covered in fabrics as appropriate. Bathroom and kitchen facilities will be similar to Earth counterparts, with added efficiency features like auto-off taps. Plumbing would generally be plastic and wiring would generally be aluminum with plastic insulation. Ceramic materials will serve the same purpose as on Earth, so a table setting is likely to have very familiar dishes. Silverware will likely be titanium since that is less complex to produce than stainless steel. Environmental systems will consist of air supply and return, with user-settable temperature and humidity controls. Each compartment will include emergency oxygen supplies and patch-sealing kits, but this is largely a formality.
     The layout of the habitat depends on a number of factors. I've examined dedicated residential and occupational floors but in order to balance the load on environmental systems it may be better to make each floor carry a mix of spaces. There should be a lower limit for gravity in living spaces, and those living in low g should work in higher (and vice versa) if commuting is required. This supports an argument for above-normal gravity in parts of the habitat, but doing this for the entire outer floor would take up a lot of living space at increased gravity. At any rate, some mix of residential and work space will exist, with hallways to connect them and public spaces such as parks to break things up.
     Access between floors would be by elevator at the ends of the cylinder. There should be no penetration of each floor's structural hull; all connections pass through the sidewall at either end and then in or out as needed. The stresses involved are significantly less. In any case, the longest commute to work would be only a few hundred meters at worst; an easy walk.
     Each floor balances its center of gravity by pumping water between storage bags at various points. The elevator system does the same, measuring the mass of occupants for a trip and moving mass on the other side to counterbalance the effect. This allows the structure to respond to shifting mass distribution and maintain balance without requiring significant amounts of power.
     The ends of each cylinder hold other utility connections: air, water, power. Airlock connections to neighboring modules are here. The end habitats have larger airlocks to allow for large equipment to be moved in or out. Each floor handles as much of its own life support and environmental load as possible, but power needs to come in from outside and heat needs to go back out. Power can be transferred through a rotation surface (like a DC brush motor), but      it is more efficient to provide power connections at either end of the cylinder and run electricity through the axis.
     There is no 'central shaft'. Loads are carried through a ring connection between each habitat. This interface is where motors can spin up both members of a habitat pair without needing to use reaction mass. A short nonrotating access tunnel between modules can also accept concentrated sunlight from outside the shield and forward it via waveguide to growing areas. This section carries the load of any position adjustments made using magnetic pads connected to the shield, as well as sensors necessary to determine position and rotation of each module and the shield itself.

     Hydroponics make the most of the available space. Aquaculture tanks will typically occupy the bottom half-meter to meter of the space, with stacked layers of high-intensity hydroponics above. Methods will be specific to each species; leafy greens like lettuce may be grown in float rafts directly in the fish water or in NFT channels while most vegetables will use flood and drain. Grains will generally use sub-irrigation (capillary transport). Racks will be built from extruded aluminum cross-sections that assemble without fasteners. Trays will be either aluminum or plastic sheets, all built to a standard size. Some areas will use motorized tray systems where each tray is passed automatically through a series of racks ending in a harvesting machine. Lighting will be from guided sunlight where feasible and from LED lighting otherwise. LED light sources will be manufactured in the colony's semiconductor facility.
     Edible produce will be routed to food distribution. The specifics depend on culture: do the inhabitants cook their own meals, eat at a cafeteria or some combination of the two? There are some economic questions involved as well, but let's deal with that later. Any harvest waste or surplus that cannot be stored will be converted into feed; part of that stream will be concentrated into high-protein insect meal then mixed back into the rest as appropriate. For production of plastic, sugars and carbohydrates will be fermented into alcohol as a feedstock. The waste from that process is also suitable animal feed. Fibrous production (cotton, bamboo, flax) will be processed as necessary and sent on for spinning and weaving.
     The hydroponics sections will receive waste air from the environmental system. This is high-humidity high-CO2 air that helps maintain an adequate CO2 level for growth (around 1000 ppm). Since plant growth in this system will fix much more carbon than is available from life support, additional carbon must be introduced. All inedible biological waste (including sewage) will be passed through a supercritical water oxidation reactor, which will produce CO2, water and ash (mostly mineral salts). This captures virtually all carbon in the system as CO2, except that which is fixed into structural plastics and similar uses. As a further purification step, the output of these systems will be fed to Spirulina in order to capture any dissolved minerals. The harvested algae can be used as a dietary supplement for people and animals or can be autolyzed into liquid nutrient solution.

     Life support / environmental systems start at the user-facing side with air exchangers. Their purpose is to pass return air through a zeolite bed to extract nearly all CO2, then provide proper humidity and temperature for the supply air. A carbon bed removes odors and VOCs; this is formed from charred plant material and is recycled by burning in the catalytic reactor. Atmospheric bulk is made up with compressed nitrogen tanks as necessary. The hydroponics sections will include oxygen concentrators to provide oxygen-rich air back to residential areas.
     Power to perform this task comes from external systems, and heat extracted plus heat generated by extraction must be rejected to outside systems. Phase-change refrigerants are a convenient way to manage heat transport, so it is expected that either ammonia or light hydrocarbons could be used as working fluids.
     Ultimately all heat produced inside the colony must be rejected to space. This will require a substantial radiator structure that must be sun-shielded. On its way off-station this can be used as process heat for tasks like melting ice or pre-heating ores. The radiators must be highly modular and should limit the amount of coolant in each loop; damage is inevitable so repairs should be straightforward and resources lost to a puncture should be feasible to replace.
     Power for all of this activity comes from concentrating solar PV panels. Reflectors will be built of aluminum, either as sheet or as thin film over plastic. PV cells will be produced in the colony's semiconductor facility and will be actively cooled using the same heat rejection system as environmental (including any process heat applications).

     All of this structure requires a significant industrial base. Materials must be extracted from rock and converted to useful forms, a couple hundred thousand tons of it. The primary tool for this is large-area solar reflectors, so the equipment necessary to build these will be some of the first on the scene. A pre-screen to extract useful metal nodules, volatiles and ice will be done first. The remaining material will be heated and separated into component elements; this process can be stopped while specific oxides are still intact if desired. That yields a stream of nickel-iron, one of volatiles, one of light metals and one of heavier oxides. Trace elements, rare earths and other useful things will be accumulated in the process. Nickel-iron will be separated vial the Mond process, leaving pure iron, pure nickel and assorted iron-phase materials like platinum and rare earths. Rare earth elements and silicon will be processed via zone refining into semiconductor-grade bars and passed to the semiconductor facility to be turned into PV cells, LEDs and microprocessors. Volatiles will be further processed into atmosphere components and water; any hydrocarbons will be fed through the catalytic reactor for reclamation. The leftover slag will be used as shielding material.
     The initial construction of the colony will begin with this kind of industrial equipment, where the first shielding sections will be assembled and the first structural plastics will be prepared. If construction is manned then the initial habitat and greenhouse will start producing plastic as quickly as possible; the greenhouse section would be much larger than necessary for just the construction crew. For an automated 'seed' system, fully chemical means could be used to develop the necessary structural fibers and build the first few floors; with suitable gravity and environmental systems a crew could live and work at the station during the middle construction phase and handle the more complex process of outfitting the internal volume properly as each floor is built. Each new floor would provide higher gravity; the facility could even be spun faster during construction as long as the crew can tolerate it.
     Once a colony is established, it can continue to grow by capturing and processing asteroids into useful material. A wide variety of structures and devices can be built in addition to base materials like water and oxygen. Extra space in the colony can be devoted to food production. Such a facility could serve as a port offering food, medical care, repairs and restocking to spacecraft. Any parts or materials the colony cannot build or acquire for themselves could be bought or traded for valuable metals (platinum, uranium, thorium), bulk PV cells, water, etc.

     The people of the colony will live lives much like we do on Earth, but with a strong reliance on advanced technology for survival. By the time a colony like this is possible, people will be able to live in the worst conditions on Earth: glaciers, deserts and to some extent underwater. It is difficult to predict what might change between now and then; perhaps we will see significant advances in robotic automation to the point that the facility's cleaning and basic maintenance are fully automated. Since I can't guess what the future will look like I've assumed a mostly Earth-normal distribution of occupations, with an emphasis on medical and scientific positions.
     A basic economic system might value a good or service at the number of hours required to create it; time itself then becomes the basis of currency. In one sense, a colony is only possible if the time required to sustain a person is less than or equal to the time it takes them to do their daily work. Using production time as the basis for exchange would provide a starting point; several economic and governmental approaches could be taken from there to make any necessary adjustments and to ensure that enough of the necessary work gets done so the colony survives.
     Construction of such a habitat is likely to be driven for a purpose, whether that be corporate profit, national prestige or religious ideology. It won't be until a significant number of these are built and populations routinely travel among them that people will begin to consider life in space to be normal. Still, there is enough material in the asteroid belt to build colonies for perhaps a few tens of billions of people. Once we include outer bodies and Oort cloud objects that number goes up by a factor of 100 or more. Add in material from various moons and accessible planets and our race's voracious expansion can continue for the next few centuries unabated.

Asteroid Bubble

Larry Niven popularized the "asteroid bubble" technique of creating a huge space habitat. Andrew Love notes that if the asteroid is made of stone, once you start to spin it for artificial gravity it will immediately fly into pieces. As he puts it "there are no stone suspension bridges". Stone is heavy and weak, particularly in tension. A 100 meter external radius asteroid made of granite and spun up to 1 gee would put the granite under stresses about twice the expected strength of granite.

You will note that Larry Niven specifies a asteroid composed of nickle-iron.

The next step up in size is the hollow planetoid. I got my designs from a book of scientific speculation, Islands in Space, by Dandrige M. Cole and Donald W. Cox.

STEP ONE: Construct a giant solar mirror. Formed under zero gravity conditions, it need be nothing more than an Echo balloon sprayed with something to harden it, then cut in half and silvered on the inside. It would be fragile as a butterfly, and huge.

STEP TWO: Pick a planetoid. Ideally, we need an elongated chunk of nickel-iron, perhaps one mile in diameter and two miles long.

STEP THREE: Bore a hole down the long axis.

STEP FOUR: Charge the hole with tanks of water. Plug the openings, and weld the plugs, using the solar mirror.

STEP FIVE: Set the planetoid spinning slowly on its axis. As it spins, bathe the entire mass in the concentrated sunlight from the solar mirror. Gradually the flying iron mountain would be heated to melting all over its surface. Then the heat would creep inward, until the object is almost entirely molten.

STEP SIX: The axis would be the last part to reach melting point. At that point the water tanks explode. The pressure blows the planetoid up into an iron balloon some ten miles in diameter and twenty miles long, if everybody has done their jobs right.

The hollow world is now ready for tenants. Except that certain things have to be moved in: air, water, soil, living things. It should be possible to set up a closed ecology. Cole and Cox suggested setting up the solar mirror at one end and using it to reflect sunlight back and forth along the long axis. We might prefer to use fusion power, if we’ve got it.

Naturally we spin the thing for gravity.

Living in such an inside-out world would be odd in some respects. The whole landscape is overhead. Our sky is farms and houses and so forth. If we came to space to see the stars, we’ll have to go down into the basement.

We get our choice of gravity and weather. Weather is easy. We give the asteroid a slight equatorial bulge, to get a circular central lake. We shade the endpoints of the asteroid from the sun, so that it’s always raining there, and the water runs downhill to the central lake. If we keep the gravity low enough, we should be able to fly with an appropriate set of muscle-powered wings; and the closer we get to the axis, the easier it becomes. (Of course, if we get too close the wax melts and the wings come apart…)

From Bigger than Worlds by Larry Niven (1974)

Confinement Asteroid is unique.

Early explorers had run across a roughly cylindrical block of solid nickel-iron two miles long by a mile thick, orbiting not far from Ceres. They had marked its path and dubbed it S-2376.

Those who came sixty years ago were workmen with a plan. They drilled a hole down the asteroid’s axis, filled it with plastic bags of water, and closed both ends. Solid fuel jets spun S-2376 on its axis. As it spun, solar mirrors bathed it in light, slowly melted it from the surface to the center. When the water finished exploding, and the rock had cooled, the workmen had a cylindrical nickel-iron bubble twelve miles long by six in diameter.

It had been expensive already. Now it was more so. They rotated the bubble to provide half a gee of gravity, filled it with air and with tons of expensive water covered the interior with a mixture of pulverized stony meteorite material and garbage seeded with select bacteria. A fusion tube was run down the axis, three miles up from everywhere: a very special fusion tube, made permeable to certain wavelengths of light. A gentle bulge in the middle created the wedding-ring lake which now girdles the little inside-out world. Sunshades a mile across were set to guard the poles from light, so that snow could condense there, fall of its own weight, melt, and run in rivers to the lake.

The project took a quarter of a century to complete.

Thirty-five years ago Confinement freed the Belt of its most important tie to Earth. Women cannot have children in free fall. Confinement, with two hundred square miles of usable land, could house one hundred thousand in comfort; and one day it will. But the population of the Belt is only eight hundred thousand; Confinement’s score hovers around twenty thousand, mostly women, mostly transient, mostly pregnant.

From World of Ptavvs by Larry Niven ()

Tensegrity

As RocketCat has been reminding you every five minutes Every gram counts. So when building a structure you want the sweet spot between the strongest struture and the lowest mass.

Structures are generally build out of compression members (i.e., girders or struts) and tension members (i.e., cables or tendons). On a planet or moon with an appreciable gravity there is a maximum size limit on compression members, since they have to support their own structual weight as well as whatever they are propping up (does not apply in free-fall since it has no weight). Tension members have no such limit, they can theoretically be of any size.

Compression members push, while tension members pull.

One technique right in the sweet spot is the radical art of "tensegrity" or "floating compression". This was invented in the late 1940s by either Kenneth Snelson or Buckminster Fuller.

Wikipedia says tensegrity is a structural principle based on the use of isolated components in compression inside a net of continuous tension, in such a way that the compressed members do not touch each other and the prestressed tensioned members delineate the system spatially. As you can see from the pictures a tensegrity structure looks like girders floating in the air, captured in a web of cables. Because of the arrangement none of the structural members experiences a bending moment.

Buckminster Fuller allegedly said that a tensegrity structure can be of any size, covering a city or encasing all of Terra. However I have not managed to find a citation yet.

I also did some speculation on using space opera tractor and pressor beams in a tensegrity structure.


Naturally a conventional structure (such as a skyscraper built of girders) tends to collapse if any of the girders break. A tensegrity structure tends to collapse if any of the girders break or if any of the cables snap.

A good low-mass way to prevent cables from failing catastrophically is to use Hoytethers (cables that are elongated Hoytubes). Strengthening a cable by increasing its diameter quickly becomes too expensive in terms of mass. A Hoytether on the other hand is a low mass network of redundant cables that fails gracefully.


A consortium of scientist are working on the SuperBall Bot Planetary Lander which is basically a tensegrity robot. The robot uses a network of cables and struts to roll over terrain, adapting to uneven ground that would trap a conventional wheeled robot.


Currently (2016) a company named Skyframe Research has received $500,000 in second-phase funding from NASA’s Innovative Advanced Concepts program to develop their tensegrity based space habitat design.

GROWTH-ADAPTED TENSEGRITY STRUCTURES

This proposal seeks to design a rotating habitat with a robotic system that constructs the structure and provides a habitat growth capability. The tensegrity technology allows minimum mass of both the habitat and the robotic system.

This proposal solves three unsolved space travel problems: a) growth, b) radiation protection, and c) gravity. Our innovative tensegrity-based evolvable habitat designs will solve three critical technical problems that NASA must address: the biological effects of microgravity on humans in long duration space flight, the long duration biological effects of ionizing radiation on human physiology in deep space (beyond the Earth’s magnetosphere) and, the need for outposts in deep space to evolve dynamically over time as mission needs grow.

Our technologies fit hand in glove with NASA's new strategy and will be a key enabler in making NASA's vision of pioneering the space frontier a reality because they are the only economically feasible approach to building habitats that can grow, spin, and manufacture in space. This NIAC Phase II effort will perform critical proof of concept studies, analysis, and ground demonstrations to prove the feasibility of Growth-Adapted Tensegrity Structures (GATS) and their benefit for NASA's evolvable proving ground approach to human exploration.

As part of this effort we will conduct mission studies showing how a version 1.0 outpost in Lunar Distance Retrograde Orbit (LDRO) made from GATS can grow and evolve while utilizing asteroid resources for radiation shielding and later integrate with an asteroid ISRU system such as the NIAC funded ApisT M architecture proposed by Sercel. We will perform mission analysis in collaboration with Sercel showing how asteroid regolith slag left over from the production of rocket propellant can be accumulated over time in LDRO and integrated as radiation shielding into the structure of the GATS based evolvable outpost thereby saving many billions of dollars in launch costs and helping to make NASA’s program of human exploration more affordable.

The critical enabling technology for our GATS technology is Tensegrity Engineering, where new design methods, new dynamic models, and new control approaches are specialized for networks of axially-loaded elements, allowing the structural mass to be minimized, while the dynamic response can be controlled with minimal energy, with repairable, growable structural methods, using tractable analytical tools that are now available.

We also capitalize on asteroid resources for radiation shielding of our habitat. This NIAC Phase II effort will perform critical proof of concept studies, analysis, and ground demonstrations to prove the feasibility of Growth-Adapted Tensegrity Structures (GATS) and their benefit for NASA's evolvable proving ground approach to human exploration.

Solar System Colonization

In the near term days before the invention of faster-than-light starships, our own Solar System will be the focus of colonization.

Solar system details, maps, regions, spherical bodies.

Naturally colonizing the solar system is a lot easier if there is in place plenty of space infrastructure. Especially businesses catering to colonists.

In the "disadvantages" section for each location, you can take it as a given that there is no naturally occuring breathable atmosphere. I'm not going to bother adding it to each entry.

Mercury

Jim Shifflett has an in-depth analysis here of a the pros and cons of a Mercury colony. He goes into much more detail than I do.


Mercury (stats)

Advantages

  • Crust is probably rich in iron and magnesium silicates. Mercury possibly has the highest concentration of heavier elements in the solar system.
  • There is some evidence that the polar areas have ice and other volatiles hidden in permanently shadowed craters. There certainly isn't any closer to the equator, the solar heat will vaporize it like snowflakes under an acetylene torch.
  • The solar constant is a whopping 6.3 to 14.5 kW/m2, or an average of 6.5 times that of Terra. This makes for abundant solar power. Since Mercury's axial tilt is so low (0.01°) there is a possibility of polar peaks of eternal light.
  • Solar Energy Beamed Power Stations
  • Installations producing commercial quantities of antimatter
  • Other power-hungry operations

Disadvantages

  • Mercury is the most expensive planet to soft-land on in the solar system (3,006 m/s delta V). All other planets either have lower gravity (for a lower energy cost) or possess an atmosphere usable for aerobraking (which gives you free delta V you don't have to pay for with rocket thrust).
  • Mercury is deep within Sol's gravity well, which increases the delta-V cost to travel to and from.
  • The solar heat can drive temperatures on the equator up to 700 K (427°C), hot enough to melt lead. The equatorial day-night temperature variation will be hard on equipment and habitats. Polar temperatures only get to 273 K (0°C) which is more reasonable for a habitat.

Be aware that there is a lot of science fiction written before scientists discovered that Mercury was NOT tidally locked to the sun with a permanent brightside and darkside. Pre-1965 mostly. The classic is Alan E. Nourse's short story Brightside Crossing, which is still a very entertaining read. Scientists discovered that Mercury actually rotations in a 2:3 resonance with Sol. Sorry, Alan.

There are a few post 1965 SF stories where the equator of Mercury is totally plated over with solar power cells, generally place by Von Neumann self-replicating machines. This is to provide incredible amounts of energy for some great undertaking, which generally turns out to be the large scale production of antimatter.

I don’t think any of us really trusted the Nerva-K under our landing craft.

Think it through. For long trips in space, you use an ion jet giving low thrust over long periods of time. The ion motor on our own craft had been decades in use. Where gravity is materially lower than Earth’s, you land on dependable chemical rockets. For landings on Earth and Venus, you use heat shields and the braking power of the atmosphere. For landing on the gas giants—but who would want to?

The Nerva-class fission rockets are used only for takeoff from Earth, where thrust and efficiency count. Responsiveness and maneuverability count for too much during a powered landing. And a heavy planet will always have an atmosphere for braking.

Pluto didn’t.

For Pluto, the chemical jets to take us down and bring us back up were too heavy to carry all that way. We needed a highly maneuverable Nerva-type atomic rocket motor using hydrogen for reaction mass.

And we had it. But we didn’t trust it.

(ed note: though as it turns out, Mercury has about six times the surface gravity of Pluto, and Mercury also does not have an atmosphere for braking. When this story was written it was thought that Pluto had a much higher gravity)

From Wait It Out by Larry Niven (1968)
RENDEZVOUS WITH RAMA

For a long time nobody—not even Conrad Taylor—spoke a word. All the members of the Committee were marshalling their thoughts about those difficult people the Hermians, so ably represented here by their Ambassador.

To most people, Mercury was a fairly good approximation of Hell; at least, it would do until something worse came along. But the Hermians were proud of their bizarre planet, with its days longer than its years, its double sunrises and sunsets, its rivers of molten metal. By comparison, the Moon and Mars had been almost trivial challenges. Not until men landed on Venus (if they even did) would they encounter an environment more hostile than that of Mercury.

And yet this world had turned out to be, in many ways, the key to the solar system. This seemed obvious in retrospect, but the Space Age had been almost a century old before the fact was realized. Now the Hermians never let anyone forget it.

Long before men reached the planet, Mercury’s abnormal density hinted at the heavy elements it contained; even so, its wealth was still a source of astonishment, and had postponed for a thousand years any fears that the key metals of human civilization would be exhausted. And these treasures were in the best possible place, where the power of the Sun was ten times greater than on frigid Earth.

Unlimited energy, unlimited metal; that was Mercury. Its great magnetic launchers could catapult manufactured products to any point in the solar system. It could also export energy, in synthetic transuranium isotopes or pure radiation. It had even been proposed that Hermian lasers would one day thaw out gigantic Jupiter, but this idea had not been well received on the other worlds. A technology that could cook Jupiter had too many tempting possibilities for interplanetary blackmail.

That such a concern had ever been expressed said a good deal about the general attitude towards the Hermians. They were respected for their toughness and engineering skills, and admired for the way in which they had conquered so fearsome a world. But they were not liked, and still less were they completely trusted.

At the same time, it was possible to appreciate their point of view. The Hermians, it was often joked, sometimes behaved as if the Sun was their, personal property. They were bound to it in an intimate love-hate relationship—as the Vikings had once been linked to the sea, the Nepalese to the Himalayas, the Eskimos to the Tundra. They would be most unhappy if something came between them and the natural force that dominated and controlled their lives.


Some psychologists had claimed that it was almost impossible to understand fully the mentality of anyone born and bred on Mercury. Forever exiled from Earth by its three-times-more-powerful gravity, Hermians could stand on the Moon and look across the narrow gap to the planet of their ancestors, even of their own parents, but they could never visit it. And so, inevitably, they claimed that they did not want to.

They pretended to despise the soft rains, the rolling fields, the lakes and seas, the blue skies—all the things that they could know only through recordings. Because their planet was drenched with such solar energy that the day time temperature often reached six hundred degrees, they affected a rather swaggering roughness that did not bear a moment’s serious examination. In fact, they tended to be physically weak, since they could only survive if they were totally insulated from their environment. Even if he could have tolerated the gravity, a Hermian would have been quickly incapacitated by a hot day in any equatorial country on Earth.

Yet in matters that really counted, they were tough. The psychological pressures of that ravening star so close at hand, the engineering problems of tearing into a stubborn planet and wrenching from it all the necessities of life—these had produced a spartan and in many ways highly admirable culture. You could rely on the Hermians; if they promised something, they would do it, though the bill might be considerable. It was their own joke that, if the sun ever showed signs of going nova, they would contract to get it under control—once the fee had been settled. It was a non-Hermian joke that any child who showed signs of interest in art, philosophy or abstract mathematics was ploughed straight back into the hydroponic farms. As far as criminals and psychopaths were concerned, this was not a joke at all. Crime was one of the luxuries that Mercury could not afford.

From RENDEZVOUS WITH RAMA by Arthur C. Clarke (1973)

Venus

Venus (stats)

Advantages

  • Venus' gravity is 0.904 g. This is practically the same as Terra, and is certainly large enough to prevent bone decalcification and other hazards of low gravity.
  • Venus is conveniently located with respect to Terra. Hohmann launch windows occur every 584 days (compared to every 780 days for Mars). Hohmann transfer time is about 5 months (compared to 6 months for Mars).
  • Venus' atmosphere is mostly carbon dioxide. This can be used to grow food. CO2 is also heavier than the nitrogen-oxygen breathing mix humans use, which means an nitrogen-oxygen filled balloon will float in Venus' atmo.

Disadvantages

  • The temperature at the equator is actually higher than at Mercury, 723 K (450°C). Higher than the melting point of lead and much higher than the temperatures used in hospitals to sterilize surgical instruments. This is due to the greenhouse effect, mentioned in 1950's school children's astronomy texts decades before the invention of the term "global warming".
  • The atmospheric pressure at the surface is about 92 times that of Terra. This is about the same as the pressure under Terra's ocean at the depth of a kilometer. Humans exposed to this will implode. The Soviet Venera 5 and Venera 6 probes only got down to 18 km above the surface before they imploded.
  • Venus' atmosphere contains clouds of sulfur dioxide and droplets of sulfuric acid. Which will dissolve metals at positions above copper in the reactivity series (iron, aluminium, titanium, etc.).
  • The winds at cloud level are about 300 km/h.
  • If the colony is a floating cloud city, trying to mine the surface for resources will be a nightmare.

Some scientists (most notably Geoffrey A. Landis of NASA's Glenn Research Center) have suggested colonizing Venus by using aerostat habitats and floating cities. In Venus' carbon dioxide atmosphere, a balloon full of a human breathable 21:79 oxygen/nitrogen mix will float. Actually it will have over 60% of the lifting power that pure helium has on Terra.

If a breathable mix balloon could loft a city to an altitude of 50 kilometers above the surface, it would find the environment to be the most Terran-like in the entire solar system. The pressure is about 1 bar (the same as at Terra's surface), temperature in the range of 0°C to 50°C, and about the same protection against cosmic rays.

Since the pressure inside and outside the balloon are about the same, any rips or tears will only slowly diffuse the gases (instead of causing the entire balloon to instantly pop). This will give plenty of time for repairs.

At cloud levels the wind blows about 95 m/s (about 300 km/h). It circles the planet in about four Terran days. A colony floating in this wind would experience a Venusian day of about four Terran days in duration. This is a vast improvement on the Venusian day on the planet's surface, which is about 243 Terran days long.


Thinking more grandly, others have suggested terraforming Venus. These include various proposals to drastically lower the atmospheric pressure and increase the levels of oxygen.

Sol-Venus Lagrange Points

Lagrange Points

"Venus Equilateral".

Cis-Lunar Space

Terra Orbit

Terra-Luna Lagrange Points

Lagrange Points

Terra-Luna L1 is a good location for a way station/cargo transhipment point. From L1 the delta-V to travel to either Terra or Luna is modest.


Terra-Luna L2 is a good location for a communication satellite covering Luna's far side.

L2 is also a good location for an orbital propelant depot, perhaps supplied from Lunar polar ice. This is because L2 is practically at Terra escape velocity already. L2 is sometimes called the "gateway to the Solar System". It is a good place to have a filling station.

It is also an ideal location to initiate an Oberth maneuver to get some free delta-V when traveling to another planet. To do an Oberth, the ship performs a parabolic dive from L2 into a close pass by Terra, and does the burn at the closest approach. Typically an Oberth maneuver around Terra can augment the delta V by a factor of 2 to 7. A typical Mars departure requires a delta V of 4.3 km/s, doing an Oberth the ship can get 4.3 km/s by only doing 1 km/s worth of burn!

Propellant depots will also have a longer life at L2 compared to having them located in LEO. L2 has lower micrometeor levels, lower thermal stress (reducing cryogenic propellant boil off), and lower amounts of corrosive atomic oxygen.


Gerard O'Neill's original plan for a space colony had them located at L5. As a matter of fact, his O'Neill cylinder habitats are commonly called "L5 Colonies." Either L4 or L5 is a good spot since they are stable. In science fiction, often one spot or the other is claimed by rival superpowers (e.g., USA and Russia, or the various nations of Gundam).

The Kordylewski clouds may or may not occupy the Terra-Luna L4 and L5 points.

All of the Lagrange points provide gateways into the Interplanetary Transport Network.

Luna

Luna (stats)

Advantages

  • Mining the Lunar Ice might be the key to the inner planets.
  • Lunar Mineral Mining
  • On the one hand the regolith contains valuable Helium 3, useful for fusion reactors using the 3He+D reaction. On the other hand the He3 found on the surface of Luna is so sparse that it is not worth mining unless you are absolutely desperate. 15 to 50 ppb is pathetically low grade ore.
  • Lava Tubes are ready-made underground caves providing shielding from cosmic radiation. Otherwise digging the caverns for an underground city would be somewhat a chore.
  • Thorium deposits, with the highest concentration at Lalande Crater. That is one reason why that crater is the location of choice for the first lunar colony according to the Virtual Lunar Colony Project.
  • Plentiful supplies of the raw material for Aluminum-Oxygen and other ISRU-Oxygen rocket fuel. Just add electricity or solar heat to separate the oxygen from the metal.
  • Titanium from Lunar Ilmenite ore. On Luna a "High titanium basalt" is one with more than 6% titanium by weight, it can go up to 8%. Other than Terra there are no other known sources.
  • Located conveniently close to Terra. Short Hohmann transit times (about 3 days) and Hohmann launch windows are frequent (every 29.5 days).

Disdvantages

  • Radiation

There are details about lunar mining here.

The Ring of Charon

(ed note: Central City is a lunar city. It is totally underground. The "tourist dome" is a tiny glass dome on the surface where tourists can be impressed by the view. "Conners" are lunar colonists. In this quote, there has been a moon-quake.)

Central City was built underground, a series of lens-shaped hollows, kilometers across, known as Sub-Bubbles. The tourist dome sat on the surface, fifty meters directly above one edge of a lens, connected to the interior’s ground level by a long ramp running between the surface level and the airlock. The city side of the airlock complex had been designed with tourists in mind. One whole wall was made up of huge view windows that canted in from the ceiling toward the floor, overlooking Amundsen SubBubble, affording a splendid vista of the bustling city below.

Except now the view windows were shattered heaps of glass on the ground and jagged knife-edges sprouting up from window frames. A sooty wind swept into the overlook chamber.

The city below looked like a war zone. Smoke billowed up from at least three separate fires, only to be caught in a violent wind that flattened it into the sky blue ceiling of the bubble. Wind.

Nothing scared a Conner more than a leak. Lucian forced the worry from his mind. Either the repair crews were handling it or they weren’t. Lucian’s gaze left the ceiling and he looked down at the city again. The lush greenery that the city took such pride in was still more or less there, but whole garden sections had slumped over. Landslides had carried off hillside trees.


As with the chamber itself, the wall facing the dome interior was made entirely of glass. That was both for the benefit of tourists and because there was nothing cheaper than glass on the silica-rich Moon. Whatever the reason, it left Lucian leading twenty-eight people, most of whom barely knew how to walk in low gee, down an incline littered with razor-sharp fragments of glass, trying to stay out of a howling wind that blew through where the glass wall should have been. Somehow he got them down without anyone slicing open an artery.

From The Ring of Charon by Roger MacBride Allen (1990)

Near-Terra Asteroids

Near-Terra Asteroids

Advantages

Disadvantages

  • They require relatively low delta-V to perturb their course into a civilzation-destroying collision with Terra. The Spaceguard will be keeping a very close watch on these. Especially 99942 Apophis.

Asteroid 3753 Cruithne is sort of but not quite at a Lagrange point. It is often incorrectly called the "second moon of Terra."

Sol-Terra Lagrange Points

Lagrange Points

Sol-Terra L1 never has its view blocked by Sol or Terra. This makes it a good site for solar observatories as an early warning storm monitor for deadly proton storms and other solar disturbances.

Sol-Terra L3 would be a great place for a early warning storm monitor. It could spot large active sunspot regions before Sol's rotation aimed them at Terra. It would also function as the L1 early warning for any spacecraft that happened to be on the opposite hemisphere with respect to Terra. L1 and L3 as a team could provide warnings for the entire solar system.

In old pulp science fiction, Sol-Terra L3 was a popular location for "counter-Earth", a sinister planet hidden from Terran astronomers by Sol (e.g., Gor, Journey to the Far Side of the Sun, or the home of the High Evolutionary). But now satellites and gravitational studies have revealed that there is no planet there. Which is a good thing since L3 is a gravitationally unstable position.

Asteroid 2010 TK7 occupies the Sol-Terra L4 point.

Mars

Mars (stats)

Advantages

  • Deimos is the smaller of the two moons of Mars. In terms of delta-V cost, Deimos is the closest hydrated body to LEO. Since water is one of the most valuable in situ resources, this makes Deimos valuable. There is water ice on Phobos as well, but it is buried more deeply. On Deimos the ice is within 100 meters of the surface at the equator, and within 20 metrers at the poles.
    Rob Davidoff and I worked up an entire future history centered around Deimos, called Cape Dread
  • Martian Mining
  • The Mars-5 space probe did detect uranium and thorium on Mars.
  • The Martian atmosphere does contain about 2.5 percent valuable nitrogen.
  • Mars does have valuable water.

Disadvantages

  • For Hohmann trajectories originating from or heading to Terra/cis-Lunar space, Mars has the longest delay between Hohman launch windows (2 years, 1.6 months) of any of the planets in the solar system.
  • The atmosphere of Mars is about 99% vacuum, but it is thick enough to make pesky dust storms (lasting weeks at a time) that can cut down solar cell power to zero, and coat the solar cells with dust that has to be removed somehow.
  • Surface gravity is 3.7 m/s2 (38% Terra), which might be too low for health.
  • Resource-wise, Luna seems richer than Mars, while also having a lower escape delta-V cost.

Sol-Mars Lagrange Points

Lagrange Points

(121514) 1999 UJ7 occupies the Sol-Mars L4 point. Asteroids 5261 Eureka, (101429) 1998 VF31, and (311999) 2007 NS2 occupy the Sol-Mars L5 point.

Asteroid Belt

Asteroid Belt (stats on select asteroids)

Advantages

See Space Habitat especially Asteroid Bubble

The Millennial Project

Pilgrims with itchy feet and travelin' bones will head for the high frontier; wherever they find it, they'll push it back. These trail blazers, on their way to conquer new lands, will come to the Martian moons in an ever-growing stream. Like the boomers going to Saint Joe, Mo., these space settlers will outfit themselves at the 'rail-head' on Deimos. They will convert their hard-won grubstakes into tools and provisions, and strike out for the new territories. Most will head for the myriad micro-worlds of the asteroid belt. Other hardy souls will venture further afield, to the Trojan asteroids, and even the moons of Jupiter.

Many of these outbound immigrants will be moved by the simple desire to flee the cloying multitudes of the inner worlds. Others will be impelled by that unfailing motivator of mankind: greed. Settlement of the solar system will be greatly encouraged by the adoption of a Millennial Mining Law. The administrative code underpinning the Law can be complex in its particulars, but the essence of the Law itself should be utter simplicity: "First in time is first in right."

If you are the first person to reach a satellite, and stake and register your claim with the Solar Mining Office, it's yours! It is unlikely that an individual could mount a solo expedition to the asteroid belt; so you would probably have to sell shares in your venture to get the capital. At any rate, you and your partners are now the proud owners of a celestial mother lode.

Lets say you've staked your claim to an average carbonaceous chondrite in the outer asteroid belt. What's it worth? Much interesting speculation about asteroid mining has centered on those of the metallic variety.490 When one visits asteroids at the museum, it certainly appears that the nickel-iron types would be worth the most. After all, metals form the back-bone of industrial infrastructure, and their extraction and refinement is at the root of civilization. That is true enough today, but in the New Millennium, metals will be a side show. The real money is in water, carbon, nitrogen, sulfur, and the other light elements that make up the substance of animate matter. There will be claims staked on metallic asteroids to be sure, but in the first great "land rush", the savvy entrepreneurs will be after carbonaceous chondrites.

If you managed to be the first claimant on a typical smallish asteroid—10 km. in diameter—you would possess a trillion tons of the most valuable resources in the solar system. If, after paying for extraction and transportation costs, consumers in the realms of Asgard and Avallon paid an average of only one dollar per kilogram for light elements, your asteroid would be worth over one hundred trillion dollars.


There are millions of asteroids that are more than a few kilometers in diameter, and billions and billions of smaller ones. Eventually, they will all be claimed, mined, and settled. As the human race grows to maturity, filling up the solar system, the market for asteroid organics will expand continually. Any asteroid prospector can stake his claim with full confidence that eventually there will be a demand for his minerals. It may take time. But asteroid settlers will be some of the only people in the solar system who can live with near perfect self-sufficiency. They can afford to wait.

Like all pioneers, the first settlers in the asteroid belt must be hardy souls with iron wills and rawhide constitutions. They must be capable of facing isolation and deprivation; they must be able to fend for themselves; and most importantly they should be endowed with infinite faith in the future. Like Europeans headed for the California gold fields in 1849, new immigrants to the asteroid belt will flood in from the Old World. They will book their passage on the trans-oceanic vessels of their time—orbital habitats cycling between Earth and Mars. When the pioneers arrive on Deimos, they will equip themselves for their perilous expedition to the new frontier. The planetary civilization on Mars will be able to provide all the technology needed to successfully homestead an asteroid.

In all likelihood, these space pilgrims will join up in "wagon trains" for the trip out. Each band of hardy trail blazers will form their own society, agreeing among themselves on its structure and systems of self-governance.

Each family buys a launch pod and a cargo pod, both tanked up with enough fuel for rendezvous maneuvers. In addition to housekeeping basics, each adult carries the obligatory space suit— the only major piece of equipment brought from Earth. The group pools its resources to buy the essentials: a small ecosphere habitat (with CELSS), a semi-autonomous robotic miner, a pair of multi-purpose utility vehicles, a universal fabricator, and some power bubbles with thermionic generators.

The colonists arrange financing for their expedition long before leaving Earth. All the adults in the group have special skills, and like most people in the Third Millennium, they customarily work as telecommuters. In the group there are engineers, designers, writers, counselors, researchers, and consultants. All of these people work by logging on to interactive telecommunications networks. Most of their jobs are insensitive to short time delays, so they can work without regard to their location in the solar system. The data professionals in such groups have all been selected as much for their ability to work through telepresence as anything else. As telecommuters, they can continue to work in their careers despite being on their way to the asteroid belt.

This has important economic ramifications for the colonists. First, they do not face a cut off in earnings during the two years or so it takes them to reach their destination. Second, it means that they can continue to work and generate revenue after their arrival, even though otherwise isolated on a barren asteroid. This ability to participate in the general economy while physically isolated, is one of the most important factors enabling our rapid expansion into space.

InVestament Bankers

Financial institutions in the Earth-Moon system have very little interest in bankrolling colonists headed for the asteroid belt; too remote, too risky. There is, however, a ready source of funding. The first big colonial push out to the asteroids targeted the giant asteroid Vesta. Vesta orbits close to Mars and is a big asteroid with a unique and valuable composition. The original Vestans flourished, building their tiny world into a major economic force in the outer solar system. Very quickly, the Vestans realized that the highest returns could be made by financing other colonists who desired to settle the wide frontier of the asteroid belt. Psychological barriers and remoteness from the inner worlds, plus very real risks, kept home-world banks out of the game. This allowed the Vestans to charge very high interest rates for colonization loans.

The inVestament bankers understood that loans made to colonists were doubly lucrative. First, the colonists invariably consist of highly motivated groups of mature professionals. (This Darwinian selection is self-enforcing; groups not meeting the rigorous standards are simply not approved for loans.) These hard­core groups inevitably hit the ground running, and very quickly transform their new habitats into productive resource mines. The telecommuting professionals give the groups an economic underpinning which allows them to carry heavy interest burdens. New productivity from asteroid resources enables them to pay back their loans very quickly. The asteroid bankers are consequently able to turn their capital over rapidly, so the investment pool doubles in size every five to ten years. Second, each new group of colonists adds a jolt of synergy to the whole economy of the region, bringing with them demands for goods and services which can be supplied by yet other colonists.

This double-barreled effect—rapid capital turn-over plus exploding demand—creates a very powerful positive feedback loop in the economy. As the Vestans make more and more money on their loans, the investment pool grows, making it possible to make more loans, generating greater profits, in turn increasing the investment pool available for loans, etc. The result is runaway growth of real wealth.

The settlers find it fairly easy, therefore, to borrow substantial amounts of money with no more collateral than their resumes. Colonists typically head out to the edge of the new frontier with an ample stock of capital equipment and a generous line of credit at the FIBV (First Interplanetary Bank of Vesta).


Space Family Robinson

(Let's join a group of these pioneers, and go along to see what it's like to settle a virgin asteroid.)

Long before their expedition even started out, the Robinson group had targeted their bit of celestial real estate. They selected a destination only after detailed consultations with the solar mining office. They chose an asteroid of moderate size—10 km. in diameter—orbiting in the middle of the belt. This particular asteroid is already owned by its original claimant who is in residence there. The leaders of the expedition have been in radio negotiations with the old prospector and have come to terms. The new colonists have agreed to pay the owner an up-front cash bonus and a royalty of 8% on all exports.

There are still many millions of unclaimed asteroids; but this is a group of families and they don't want to face the extra risks of an unknown planetoid. The Solar mining office has conducted extensive surveys and has detailed spectroscopic information on almost every asteroid larger than a few kilometers in diameter. Little else is known about the unclaimed asteroids. By contrast, this asteroid—Sykes 1011—has been pretty thoroughly evaluated. In order to hold his claim, Sykes has been "proving up" his asteroid ever since he first staked it fifteen years before. He has done extensive exploratory drilling, made detailed assays of his cores, taken seismic readings, and otherwise scrutinized his private little world.

The old prospector's diligence has paid off. The rich data base has served its purpose and has attracted a well-heeled group of settlers, Sykes, who has lived for a decade and a half in almost complete isolation, now anticipates a rich pay day. He is going to be amply recompensed for his years of unrequited labor. The prospector's risky investment will pay rich dividends for the rest of his life.

The colonists—named for the largest family, the Robinsons— have been willing to pay a premium price for Sykes' asteroid. His certified assays show that S1011 has an especially high water content of 18%, and unusually high concentrations of tantalum, and cobalt. For extra bonus money and a higher royalty, Sykes has been willing to assign all future development rights to the Robinson group. The Robinsons have done detailed modeling of the economics of their risky venture; they have good reason to believe that they too will ultimately enjoy rich rewards.

The Robinsons launch from Deimos in a replay of their flight from Avallon. Families are catapulted off in their individual pods, and the wave riders skim across the top of Mars' thickening atmosphere, picking up a slingshot boost from the red planet's gravity well. The pods shoot off at precisely calculated trajectories to rendezvous with an orbital habitat cycling between Mars and the main asteroid belt. Unmanned cargo pods, bearing precious equipment follow. After a few days in cramped discomfort on the wave riders, the colonists rendezvous with a cycling habitat. They dock their riders and move into temporary but homey quarters in the outbound ecosphere. There they live comfortably for the 15 to 20 months it takes to reach the asteroid belt. During that time, educations, and careers carry on, without much interruption.

After the cycling habitat reaches an optimal point in its orbit, the colonists will jump off to their destination asteroid. The entire journey has been carefully timed to minimize the duration and energy requirements of this final leg. Everything has gone according to the schedule—arranged years in advance. Delays at any stage of their odyssey could have stranded the travelers at some intermediate point for years. As it is, the colonists are in a perfect position to rendezvous with their chosen planetoid. The Robinsons again board their wave riders and make the short hop to Sykes 1011, arriving at the asteroid with only a few kilograms of propellant left.

Touching down on their new world is more like docking with a giant ship than landing on a planet. The gravity is less than a thousandth of that on Earth. The little convoy sets -down in the midst of a scene of splendid desolation. The horizons of the little world crowd close, unbroken by anything but Syke's radio strobe and a hand-made banner with "Wellcum Robinsuns" spelled out in strips of gold foil.

Like the pioneers of another age—who on arrival in their new Canaans, unhitched the oxen from the wagon and immediately yoked them to the plow—this new breed of settlers also sets promptly to work. The Robinson's group leader, Dr. Zachariah Smith, meets with Sykes—a grizzled old varmint who looks four centuries out of place. Sykes has spent 15 years on the asteroid, living in an empty propellant tank buried under the regolith. He has been utterly alone except for the company of a holographic dog named Rimmer. From the musky smell inside the old prospector's digs, Dr. Smith judges that Sykes hasn't been out of his space suit in the past decade. True to form, Sykes conducts the entire closing over the upturned bottom of a supply canister, never-removing anything but his helmet. 'How in the world,' Dr. Smith wonders, looking at the old character's stained beard, 'can any one chew tobacco gum inside a space helmet?'

With legal formalities out of the way, the first order of business is to launch power bubbles. The group has brought three thermionic generators, each with enough capacity to provide all of the colony's power needs. Fuel is pooled for one of the wave riders, and the generators are towed into close polar orbits around the asteroid. This takes just a small amount of propellant as orbital velocity is only a few meters per second. Once the generators are in stable orbits outside the asteroid's shadow, the bubble reflectors are inflated around them. Properly focused and adjusted, the generators begin to crank out power. The electricity is converted to a narrow beam of microwaves and is transmitted directly to receiving antennas strung along the asteroid's equator.

Useful Materials Produced by Robotic Miner Every Day
Elementkg/day
Oxygen1,152
Silicon576
Water518
Iron430
Magnesium403
Carbon57
Calcium52
Sulfur52
Nickel32
Aluminum45
Sodium23
Chromium12
Cobalt5
Manganese5
Nitrogen5
Titanium4
Phosphorus3
Potassium2
Copper0.3

With a good supply of power now at their disposal, the colonists begin to transform their Lilliputian planet. They set up and activate the mining station. The robotic augers immediately begin shunting loose regolith into the maw of the machine. Inside the miner, the soil is heated in a plasma arc furnace. As the temperature rises, steam hisses out of the hot ore, and the vapor is pulled off and condensed. When the first silver trickle of liquid water begins to dribble into the transparent collection tanks, a cheer bursts from the jubilant colonists. At this point they know they have succeeded. Their years of sacrifice and hard work have paid off. They have water. Where there is water there is life. Now they know they can survive on this orbital slag heap. They have everything they need to sustain life and build a new world.

The robotic miner is not a large machine; its throughput is only a couple of kilograms per minute. Watching powdered regolith pass through the holding bin is like watching sand trickle through a big hour glass. Even so, the machine produces over 500 kilograms of distilled water and half a ton of oxygen per day. In a highly efficient process, the crushed asteroid ore is melted and most of its usable elements extracted. The molten rock preheats the incoming ore stream and is then extruded from the miner in the form of cooled bricks, slabs, and other structural components.

The colonists garner everything they need from the asteroid. At this stage of development, the principal commodities required by the colony: power, oxygen, and water, are available in abundance.

The next pressing project is to erect a temporary habitat. The temporary structure is just a large fabric bubble with a cable net thrown over the top. The colonists hastily level the bottom of a small crater with their utility vehicles. The bubble is inflated and regolith is shoveled in to cover the whole thing three meters deep. Though palatial by Sykes' standards, it will be rough living for many months, until a proper ecosphere can be built. The colonists move into their temporary domicile, pitching their family tents inside the Spartan space. The temporary habitat is not roomy, and is harshly lit by yellow tritium bulbs. It provides a shirt-sleeve environment nonetheless. On the face of this hostile bit of real estate, adrift in the void, even this rough bubble is a welcoming haven.

Establishing a self-sustaining ecocycle to produce food and recycle wastes is now the colonist's top priority. Coils of algae tubing are deployed and an ecocycle centered on a super critical water oxidizer is organized. At this point, the colonists are dug in for the long haul.

Now they can turn their attention to raising the colony's standard of living. The first step in that direction is the construction of a proper ecosphere. The surface of the asteroid, closely resembles that of the Martian moon Deimos. It is pocked with craters of various sizes, up to a kilometer in diameter. A crater 200 meters in diameter is chosen, and work begins to transform it into a permanent ecosphere. The robotic miner forms a ring of fused regolith around the crater rim while the utility tractors terrace the inner slopes. While forming the foundation ring, the miner extrudes bulk materials and some simple finished goods like reinforcing cable and anchoring bolts.

Refined silicon and other elements are fed into the uni-fab (universal fabricator) which produces the silicone bubble membrane. The uni-fab is a remarkable piece of machinery and represents one of the colony's most expensive and valuable capital assets. The uni-fab is capable of producing virtually any material or machine component. All it requires is a supply of the appropriate raw materials and detailed design instructions for its computer.

The fabricator uses MBE (Molecular Beam Epitaxy) technology to produce parts and materials. MBE is extremely simple in concept: a beam of charged atoms is sprayed onto a substrate, not unlike painting a car. Successive layers of atoms are beamed on until the desired thickness is built up. The composition of the molecular beam can be varied at will, as can the shape and thickness of the final products. With the right materials and instructions, the uni-fab can produce anything, from ball bearings to saran wrap.

The only materials the uni-fab can't produce are living tissues. You could feed in the appropriate instructions and materials needed to form a frog, but all you would get is frog soup.

The uni-fab can, however, easily manufacture just about anything else. It could readily produce all the parts of a camera, for example. You would still have to assemble the components, but all the lenses, fittings, and tiny screws could be manufactured by the uni-fab. Depending on its design, it could be a very fine camera. All the parts would be made with a finish and precision accurate to a couple of angstroms—the width of a single atom. The uni-fab enables the colonists to be self-sufficient in virtually all manufactured products, from toys to computer chips.

While the uni-fab produces the ecosphere's dome material, work progresses on crater preparation. When the inner terraces and anchoring ring are completed, the bubble membrane is installed, and inflation of the ecosphere begins.

An ecosphere 200 meters in diameter will require about half a million kilograms of oxygen. It will take the robotic miner a little over a year to produce this much air. As the ecosphere is inflated, the crater is terraformed to provide a life-rich habitat. Trees, grass, and flowers are planted in profusion. An open stream meanders across the terraces and slowly cascades down the slopes to a small pond. A fountain sprays water in dramatic slow-motion arcs. The soft splashing of water gently falling through the micro gravity will fill the interior with the unmistakable sounds of Earth. Slowly, the robotic miner will produce enough water to form a water shield for the crater dome. When complete, the shield will allow the colonists to pitch pavilions in the gardens and live in the open, among the eight acres of grass and trees under the dome.

The Robinsons will construct the first ecosphere for somewhat the same reasons that Sykes did his core drilling—to attract new settlers. With the ecosphere completed, the otherwise barren little asteroid now beckons with the welcoming green glow of a miniature Eden.

New colonists, looking for opportunities, but less willing than Sykes or the Robinsons to face risk and hardship, will be attracted to the new habitat. This first permanent ecosphere is easily large enough for dozens of families. Several groups of immigrants join the growing colony. This third wave of settlers does not face the harsh wilderness that greeted old Sykes and the Robinsons.

These newcomers can move right in to a comfortable habitat, resuming their lives without much of an interruption. Since the hazards and discomforts are low, individual families, even single people, will be able to immigrate to the new colony.

Despite this lack of hardship, the new colonists will enjoy a large share of the asteroid's abundant wealth. The new comers will pay cash bonuses to the Robinson group. They will literally be buying a 'piece of the rock'. In return, they are supplied with dwelling space, food, water, energy, and amenities. The new arrivals also get a stake in the colony. They earn a position in the corporate identity of the colony and a share of future royalties and profits.

As more and more colonists arrive, the earlier waves grow wealthier. Sykes becomes rich as Midas, but he never does move out of his rickety fuel cylinder. The Robinson group took a big gamble and hit the jackpot. The Robinson's and the other foun­ding families become enormously wealthy, building their own private compounds in some of the asteroid's choicest craters. For generations to come, the descendants of these pioneers will enjoy the status and bank accounts that go with "old money".

New Bern

As the growing community accrues wealth, dramatic new projects can be undertaken. The first of these will be—as on most new worlds—the construction of a mass launcher. The launcher will be built almost entirely of local materials. For example, low-temperature superconducting electromagnets can be made of Alnico—an alloy of aluminum, nickel, iron, and cobalt. All these metals are available on the asteroid. Ultra-low temperatures can be maintained in the magnets by shielding them from radiant heat under a blanket of vacuum insulated regolith and by circulating liquid hydrogen at -252°C. Once the mass driver is complete, the asteroid colony can begin to export commodities profitably.

There will always be an insatiable demand for water and other light elements back in the Earth-Moon system, but importing hydrogen from the asteroids will not be cheap. It requires a change of velocity (Δv) of 11 kilometers per second (kps) to move payloads from the inner asteroid belt to the Earth's orbit. That is the same Av required to lift payloads off the Earth. This fact will put a premium on the cost of living in the vicinity of the Earth. Escaping this cost penalty will be one of the motivations fueling immigration to the asteroid belt. In the self-sufficient colonies of the asteroids, the cost of living will be attractively low. There will always be people willing to pay the premium to live near the Earth, however; so the thirst for hydrogen from the asteroid belt is apt to remain unquenchable.

The colonists on Sykes 1011—now renamed New Bern— produce elemental hydrogen which they liquefy and hurl into space in vacuum insulated canisters of chromium cobalt alloy. The canisters need not be propelled to 11 kps—a very energy intensive proposition. Instead, they are impelled at a few tenths of a kps onto an orbital path that rendezvouses with the large asteroid Ceres. On Ceres there is a large interplanetary mass driver with huge cargo capacity. Hydrogen, metals, and other commodities from all over the asteroid belt are consolidated into bulk shipments. Big cargo carriers are flung off on journeys to the inner planets that can take years. The colonists' shipments of hydrogen, vitallium and other commodities are automatically credited to their accounts on Vesta.

The economy of New Bern thrives. Underpinned by the work of telecommuters, and supplemented by commodity exports, the colony grows richer. The colonists invest heavily in semi-autonomous factories. Highly specialized products are manufactured for niche markets all over the Solar system. The colonies on New Bern specialize in precision medical instruments and implants. Their vitallium endoskeletons come to be highly prized by people going through trans-geriatric metamorphosis.

New ecospheres spring up. All the best crater sites on the asteroid are domed over. As new immigrants arrive and children are born, the population burgeons. There is no shortage of room on the asteroid. It seems a tiny world, but it is big enough to accommodate a large city. The surface area of the asteroid is 314 million square meters. That is enough room for a population of three million people. It's hard to fathom, but even this many colonists wouldn't be crowded. Each person would have as much room as the marine colonists on Aquarius, where almost 40% of the area is dedicated to park land and open space. The same ratios would apply on the surface of the asteroid. Half the surface area could be dedicated to gardens, lakes, playing fields, and other open spaces, and there would still be ample room for a large population. All the industry, and much of the colony's supporting infrastructure, is put underground. The surface is left free for living.

Eventually, the whole surface of the asteroid is enclosed inside an ecosphere. With a membrane surrounding the asteroid, the whole surface can be terraformed and inhabited. Lush plant life will cover the asteroid's surface. People will live in their pavilions, set among the trees and flowers blanketing the once barren landscape.

A water shield for an ecosphere 12 kilometers in diameter would weigh 2.25 billion tons. This would require just over two percent of the asteroid's water supply. Inside the bubble membrane will be an oxygen atmosphere amounting to 86 million tons—requiring only a tiny fraction of the asteroid's oxygen.

The ecosphere will provide a tremendous volume of livable space. At some places, the asteroid's 'sky' will be two or three kilometers high. Trees will be able to grow thousands of meters tall, dwarfing even the Never-trees in the craters of the Moon.497 In the minuscule gravity, flight will be almost effortless. As in Lothlorien, many people will live in the branches and hollow trunks of the gigantic trees. Swiss Family Robinson will have come full circle.

As mining progresses, the asteroid's interior will become honeycombed with caverns and tunnels. Robotic miners will cut through the rich carbonaceous ore of the planetesimal like termites boring through fruit cake. Even after the asteroid is fully enclosed in an ecosphere, mining will continue deep in the interior. Exports will be spit out through rigid magnetic launch tubes that penetrate the outer shield membrane. Over time, the interior of the asteroid will be hollowed out and terraformed.

A large fraction of the asteroid's bulk will be converted into the living substance of people, plants, and animals. Every kilogram of water or metal ever removed from New Bern will be found somewhere in the solar system: bound up in the radiation shield of some other colony, rustling in the leaves of a tree, or coursing through the veins of a child. Nothing will be wasted, but everything will be transformed.

Over time, New Bern will mature into a vibrant miniature world. It will possess a unique history and culture all its own. The process that creates New Bern will be played out all over the asteroid belt at various times. The transformation of the belt will begin in the inner zones closest to the Sun and will proceed apace until the remotest asteroids have been settled, encapsulated, and terraformed. As the human population grows, each planetesimal will become the center of an expanding community, nourished and sustained by its asteroid's resources. As Solaria blossoms and ripens, the entire asteroid belt will become thickly sprinkled with free-floating ecospheres and terraformed asteroids.

From The Millennial Project by Marshall Savage (1992)
Tour of Our Terraformed Solar System: The Asteroids

Ah, the asteroid belt. There’s not a lot to see here; the view out of our windows as we arrive looks about as empty as everywhere else. And yet, this bleak void is the birthplace of humanity’s space colonization efforts. These boring space rocks were gold to the early spacefarers – well, platinum to be specific.

The Early Mining Colony

We set down in a hollow asteroid barely a thousand years after humanity first began to explore the void. Even now, we’re traipsing about in a tourist trap. The mineral resources and strategic location of this rock are a thing of the past; the cramped living quarters and maintenance tunnels are packed with floating tourists from Earth and Mars.

The tour guide tells us that “colonies” such as this weren’t that impressive at first; just temporary quarters for highly-paid remote-mining equipment operators. (A bit of a gender politics question: men are overwhelmingly overrepresented in very high-risk occupations, and suffer far more work-related injuries. In a (presumably) much more egalitarian future, will this still be the case? What will the gender breakdown of the early asteroid miners look like? Just one of those fun questions sci-fi writers get to answer.) Over time, the living space grew and the meager stations evolved into full-fledged communities. Yet even now, only a handful could be considered comfortable or urban – and only the largest bother producing their own centripetal “gravity.” We travel through the large common area on guide ropes strung between rooms. We could “free-fly” in this low-gravity environment, like the ancient miners did, but the last thing the station managers want is a bunch of landlubber tourists with no sense for gravity-free environments literally bouncing off the walls.

Traveling In Style: Inside an Asteroid

We’re done with this tourist trap; there’s more than one asteroid colony, and we’re sick of hearing tour-guides talk about the “ancient space miners” – we want to see some real mining in action. And if you want action these days, you head to Vesta.

How are we getting there? Well, we could just take our spacetimeship, but while we’re here in the asteroid belt, we might as well see what it’s like to travel in an actual asteroid. Eventually we find what we’re looking for: a colossal, spinning stone cylinder with a huge docking port on one end. We transmit credit information, fly through a series of airlocks, and find ourselves in a vast green-and-blue tube. We’re in a spinning paradise where travelers en route to Vesta can enjoy a quiet stroll through the garden, or gaze up at the “stars”: overhead streetlights and lanterns. The gravity is low-tech and the ride is slow, but nothing beats a hollowed-out asteroid for safety (putting half a mile of solid rock or ice between you and the radiation-rich void of space is a good idea for a lot of reasons), efficiency (carving out the middle of an asteroid and throwing an airlock on the top of the hole is a lot easier than constructing a starship from scratch – plus, you can sell all the platinum you just dug out"), and luxury (did I mention the view? The view of a tiny garden world curving all around the horizon is impressive, if a bit disorienting. Halo players may have a feel for what this looks like.).

Getting a Glimpse of Vesta

When we visited Mars, newswaves were abuzz about the Vesta (4 Vesta is the second-most massive asteroid in the Asteroid Belt, and only one of two with a differentiated metal core: it has an outer rocky layer covering a deliciously lucrative metal center.) project. And now, gazing at the camera monitors that pass for windows here, you see why. You’re witnessing the largest-scale mining operation in the history of mankind: the complete disassembly and processing of Vesta’s metal-rich core. It’s an unfathomably vast reservoir of raw metal, but considering the scale of some of humanity’s recent undertakings,(enormous solar panels near the Sun, colossal space stations orbiting Earth like extra moons, generation ships for traveling to a recently-discovered Earthlike planet many light-years away, etc.) it’s only just enough.

We dock at a half-asteroid space station with a good view of the action, and chat up some miners over dehydrated ice cream sandwiches. They’re really more like remote-control robotics operators and zero-G detonation experts than miners; actual humans almost never set foot on half-disassembled Vesta itself. Most of the personnel here are international observers, safety bureaucrats, heritage engineers extracting and safeguarding Vesta’s old colonies, and protesters from HACS: the Historical Asteroid Conservation Society. As we chat, we see bright flares in the distance. The miners fill us in: these are carefully positioned detonations for weakening and blasting away Vesta’s crust, and shuttles firing their engines to intercept any large pieces that drift past the perimeter control drones.

Skipping Ahead to Full Terraforming

It’s been a fun trip so far, but nothing in the current asteroid belt seems terraformed per se; some of the hollow asteroids are filled with little scraps of wilderness, but they’re more like terrariums (Terrarriums are exactly the name Kim Stanley Robinson gives these hollow-cylinder asteroids in his novel 2312. This novel wasn’t the first to feature mobile, Earth-like asteroid habitats, but it arguably discusses them with the most rigor and detail.) or zoos than whole worlds with ecosystems. (The lack of natural sunlight doesn’t help matters.) Even Ceres, largest and most planet-like of the belt asteroids, is too small for meaningful terraforming; there’s a large dome city and a few low-gravity skiing resorts, but nobody expects that it will ever resemble Earth in any meaningful way.

We’ve traveled space long enough – it’s time to travel, well, time. Let’s visit a small asteroid colony in the far-distant future. Skeptics, are you ready to be pedantic and annoying? Because we’re going to a blue-and green EARTH-LIKE asteroid. Sorry, but we’re going there. On the other hand, if you like The Little Prince or Super Mario Galaxy, this is the trip for you.

It’s the distant future’s distant future. The current biohacking trends make humanity nearly unrecognizable. Being entirely blue is in fashion now; last year it was scales and prehensile hair. Impossibly large solar collectors ring the sun… mostly as relics, since everyone uses direct matter-to-energy fusion cells now. We’ve passed a number of ships that look like ancient sailing vessels, complete with a full crew on deck. It’s hard to tell whether they’re air-agnostic androids or if the ship is surrounded by a pocket of air held in via an invisible shield. It looks like these “sailing” ships, the space whale, and dozens of other oddities that hardly appear spacefaring to our ancient eyes are headed to the same place we are. TerraTwin Corporation has invited the whole Solar System to witness the unveiling of their latest vanity project: the smallest-ever fully habitable Earth!

They have the resources, the talent, the power, and most importantly, the tech. Gravity is now bound to humanity’s leash. (A staple for most space-based sci-fi, even the near-future and semi-low-tech settings (for example, Firefly and Battlestar Galactica) have largely mastered gravity. The science is a bit iffy, but less impossible than FTL travel. Simple action-at-a-distance gravity control is possible if we combine a complete understanding of gravity with cheap fusion power; if we’re lucky, this could happen less than a century from now.) This has a number of bizarre implications, and we’re about to see the latest example. The company de-lenses the light just outside the port window, revealing… the Earth. Well, a version of the Earth that’s barely ten times the size of your ship.

It’s a legacy model; Greenland and Antarctica are white with what looks like real snow (the snowman on Greenland is a nice touch). Small cottages dot the tiny “continents” where the major cities would be: the vacation homes of ultra-rich celebrities and TerraTwin executives.

We’re allowed to land – because hey, who’s going to say no to time travelers (You have such nice, loving grandparents; it would be a shame if they’d never met.) – and we find the world to be both gorgeous and disorienting. This place is NOT for the agoraphobic; the horizon falls away much too quickly, giving the sensation of being atop a hill with nothing but space below. The gravity and the sky seem exactly Earth-like, but as you pick up the Rock of Gibraltar and give it a throw, you see it follow a bizarrely curved trajectory – it disappears behind the horizon before you can see where it landed.

More curious is the Sun. We’re in the far reaches of the Asteroid belt, yet the sun looks as big and bright as it does on Earth. Now the little moonlet we saw orbiting this miniature Earth makes sense: it’s an orbiting spotlight – an artificial sun. After all these years, humanity has decided to spite Galileo and prove Aristotle right. (Aristotle’s heliocentric theory of the solar system (whereby the sun and all planets orbited the earth) was so influential that it even became enshrined in Catholic doctrine. Galileo was put under house arrest until he died when he spoke out against this theory.) This fake sun orbits in such a way that it covers up the actual sun (two suns would break Earth canon, you see).

The asteroids may be barely-noticeable space grit in the 21st century, but their mineral wealth (mostly their abundance of platinum-group elements, which are exceptionally rare on Earth) and accessibility predestines them to undergo the Solar System’s most remarkable transformations. Over the centuries, they will be mining outposts, military bases, tourist traps, enormous hollow ships, quaint homesteads, impossible-looking cities, and even gardens.

Ceres

Ceres

Advantages

  • Strategic Location could make it the main base for asteroid mining infrastructure.
  • Strategic Location could make it a transport nexus to send mineral resources to Mars, Luna, and Terra.
  • Large deposits of valuable water ice (possibly up to 200 million cubic kilometers of water) coupled with a very low escape velocity (514 m/s) make it a useful source water, hydrogen, and oxygen; as well as an orbital propellant depot. Ceres might have more fresh water than Terra (but Terra has far more brackish salt-water).
  • Low gravity well makes delta V cost of coloniziation lower than all planets and most moons (including Luna).
  • A colonized Ceres could assist with the colonization of the Jovian moons, or other outer solar system objects.
  • Ceres' orbit has a greater semi-major axis than Mars, so it has much more frequent Hohmann launch windows to/from cislunar space (every 1 year, 3.3 months) than Mars does (every 2 years, 1.6 months). Of course the transit time is higher (cislunar-Ceres 1 y, 3.5 m; cislunar-Mars 8.5 m), and delta V cost is higher due to Ceres' orbital inclination (cislunar-Ceres 9,477 m/s; cislunar-Mars 5,748 m/s).

Disadvantages

  • Solar power available at Ceres aphelion is 150 W/m2 (1/9th power available at Terra, 1/4th power available at Mars). Which is very low but still workable.
  • Surface gravity is 0.27 m/s2 (2.8% Terra), which is probably too low for health.
  • Ceres has no magnetic field to ward off cosmic rays. Colony will require shielding and/or be buried underground.

Jovian System

Jupiter, Ring, Galilean Satellites, Io, Europa, Ganymede, Callisto, Moons (stats on Galilean Satellites, stats on all Jovian Moons, stats on Jupiter)

Advantages

  • Jupiter's magnetic field can be used
    • As a power source. 2.0 × 1013 watts potential between Jupiter and Io.
      This can be harvested with electrodynamic tethers.
      Alternatively, you mount microwave beamers on copper rods and launch them from Io at Jupiter. As the rods cut the magnetic lines of force they generate electricty. This is converted into microwave and beamed back to Io. Rod is destroyed when it hits Jupiter, but so what, they are cheap.
    • For transportation
    • For spallation of useful elements into needed isotopes
  • Harvesting Jupiter's Atmosphere
  • Nitrogen for fertilizer from Jupiter's atmospheric ammonia.
  • Callisto's Water Ice.
  • Ganymede's Water Ice.
  • Europa's Water Ice.

Disadvantages

  • Jupiter's radiation belt is about a million times more intense (and deadly) than Terra's Van Allen radiation belts. Europa, Io, and Ganymede are inside the radiation belt, Callisto is outside.
Manned exploration of Jupiter and Radiation hazard

Here's a quick analysis for planning and realism purposes for manned exploration of Jupiter's Galilean satellites:

Satellite Daily
radiation
rate (Sv)
Yearly
rate (Sv)
Single-year
limit
5-year
cumulative
limit
Mild
sickness
LD
10/30
LD
35/30
LD
50/30
LD
60/30
LD
100/14
LD
100/7
LD
100/2
Io 36 13149 2 min 4 min 20 min 40 min 1.33h 2 h 2.67h 4 h 6.67h 33.33h
Europa 5 1972 13.33 min 26.66 min 2.22h 4.44h 8.89h 13.33h 17.78h 26.67h 44.44h -
Ganymede 0.08 29.22 15h 30h 6.25d 12.5d 25d 37.5d 50d 75d - -
Callisto 0.0001 0.037 1.37y 2.74y - - - - - - - -

The single year limit is 50 mSv, while the maximum 5-year cumulative exposure is 100 mSv (or 20 mSv per year). LD stands for Lethal Dose, LD x/y means "x" percent of individuals die within "y" days. LD 50/30 thus means half of people exposed at this level of radiation would die within 30 days. Some values have been omitted as the time required to reach the lethal dose level exceeds the time for lower lethal dose rates to be achieved or, in the case of Callisto, because it would simply be unreachable with the low radiation rate observed.

A few observations point to the obvious:

Astronauts on Io would experience fierce radiation flux, reaching their maximum cumulative radiation dose accepted by various safety regulations for a period of 5 years in only 4 minutes outside on the surface!!! Europa isn't much better, with less than half an hour of exposure. Ganymede is also a fierce environment, despite radiation being much less intense than at Io. With minimal shielding, Callisto would provide a safe working environment no worse than a nuclear power plant or research facility.

For shielding purposes to limit exposure to below regulatory levels for 5-year periods, the number of halving thickness of shielding material stands as follows:

Satellite Number of
shielding
layers
Liquid
water
thickness
Io 20 3.6 m
Europa 17 3.06 m
Ganymede 11 1.98 m
Callisto 1 18 cm

As ice is less dense than water, about 10% more would be required.

Sol-Jupiter Lagrange Points

The Jupiter Trojan asteroids are composed of the Greek node at L4 and the Trojan node at L5. Surveys suggest that counting asteroids with a diameter of two kilometers or more, the Greek node contains 6.3 ± 1.0×104 and the Trojan node contains 3.4 ± 0.5×104. The largest trojan is 624 Hektor of the Greek node, with a average diameter of 203 ± 3.6 km.

The Hilda familiy are asteroids sort of in L3. They are actually in a 3:2 mean-motion resonance with Jupiter. There are about 1,100 known asteroids in the familiy, with the largest being 153 Hilda with a diameter of 171 km. 153 Hilda is a carbonaceous asteroid.

Saturnian System

Saturnian Moons (stats on Titan, stats on all Saturnian Moons, stats on Saturn's Rings, stats on Saturn)

Advantages

  • Nitrogen for fertilizer from Saturn's atmospheric ammonia.
  • Nitrogen for fertilizer from Titan's Atmosphere. The stratosphere is 98.4% nitrogen, the only dense nitrogen-rich atmosphere in the Solar System outside of Terra.
  • The atmosphere of Saturn is a rich source of Helium-3, valuable as fuel for fusion reactors using the 3He+D reaction. It can be harvested by atmospheric scooping.
    Jupiter is closer to Terra and has 3He as well. But Jupiter's gravity is fierce! If the scoopships used solid core nuclear thermal rockets they'd need a whopping mass ration of 20 to escape back to orbit (43 km/s delta V). They wouldn't be able to carry enough 3He to be economical. Saturn on the other hand has a much lower gravity. NTR scoopships could manage with a mass ratio of 4 (26 km/s delta V), which is much more reasonable.
    Tanker ships would need only 18 km/s delta V to travel from Saturn to Terra.
    I worked up a sketchy future history centered around Saturn, called Ring Raiders.
  • According to Robert Zubrin, terraforming Mars could require large crashing ice asteroids onto its surface. The farther out the asteroid's orbit is from the Sun, the less delta V is required to re-direct it to Mars impact. Saturn would do nicely. Most of the ring fragments are solid ice, and Saturn is quite far from the Sun. And you can be quite sure that the Spaceguard will closely monitor the operation.
  • Titan Space Plastic using the hydrocarbon seas as feedstock.
  • From an author's standpoint, civilization in Saturn's rings would resemble a classic Niven-like "Belter" asteroid civilization.
    According to Jerry Pournelle in a gas giant's system of moons, Hohmann delta V requirements are quite reasonable. This contrasts with the excessive Hohmann requirements for, say, travel among the asteroids. Crude NERVAs using various ices as reaction mass work just fine. Indeed, in the outer moons, a backyard kerosene rocket will do. Most of the Saturnian moons are almost entirely composed of ices so there is plenty of reaction mass for a fleet of ships.
    Hohmann transit times are relatively short, as are synodic periods of launch windows.
    Gas giants are also pretty far away from Terra, to encourage wars of liberation and local autonomy or other entertaining events that ordinarily Terra would put a stop to.
    While Jupiter is closer, it also has a nasty radiation belt. Saturn doesn't. Saturn's radiation belt is far weaker than Jupiter's blue glowing field of radioactive death, being more on par with Terra's Van Allen belt. This would mean that the various moons of Saturn could be independent nations, fighting each other over "whatever" without having to worry about interference from Terra.
  • From an author's standpoint, Saturn and its moons have all sorts of anomalous weird features that can be inspirations for novels and short stories.
Delta V required for travel using Hohmann orbits: Moons of Saturn
Created by Erik Max Francis' Python Hohmann orbit calculator.
EpimetheusJanusMimasEnceladusTethysDioneRheaTitanIapetus
Epimetheus15721,5213,1564,3745,5526,7689,2308,481
Janus17261,5153,1494,3685,5466,7629,2248,475
Mimas1,4281,416921,6762,9434,1885,5148,3027,703
Enceladus3,0443,0311,4901121,3842,6534,0777,2496,827
Tethys4,1214,1082,6171,0232581,5682,9696,4226,132
Dione5,2165,2033,7802,2179713331,8915,5595,391
Rhea6,3406,3285,0163,5532,2971,1164224,5654,469
Titan7,3677,3556,3695,2924,3213,3712,2761,8323,977
Iapetus8,1048,0937,2586,3595,5234,6983,6811,736360
  • Start and destination planets are labeled along axes.
  • Values are in m/s.
  • Values below the diagonal in blue are delta V's needed to go from orbit around one satellite to orbit around the other, landing on neither.
  • Values above the diagonal in red are delta V's needed to go from the surface of one satellite to the surface of the other, taking off and landing.
  • Diagonal values in gold are delta V's needed to take off from the surface of a satellite and go into circular orbit around it, or to land from a circular orbit.

A backyard kersosene rocket (exhaust velocity 3,330 m/s) with a mass ratio of 2 will have about 2,300 m/s of deltaV, mass ratio of 3 will have 3,660 m/s, and a mass ratio of 4 will have 4,620 m/s. As you can see this could easily do almost half of the possible trips.

A NERVA rocket using water as reaction mass (exhaust velocity 4,042 m/s) with a mass ratio of 2 will have about 2,800 m/s of deltaV, mass ratio of 3 will have 4,440 m/s, and a mass ratio of 4 will have 5,600 m/s.

A NERVA rocket using hydrogen as reaction mass (exhaust velocity 8,093 m/s) with a mass ratio of 2 will have about 5,600 m/s of deltaV, mass ratio of 3 will have 8,890 m/s, and a mass ratio of 4 will have 11,200 m/s.

Synodic Periods and Transit Times for Hohmann Travel table for Moons of Saturn
Created by Erik Max Francis' Python Hohmann orbit calculator.
EpimetheusJanusMimasEnceladusTethysDioneRheaTitanIapetus
Epimetheus1405d, 13h2d, 16h1d, 10h1d, 2h22h20h17h17h
Janus8h2d, 16h1d, 10h1d, 2h22h20h17h17h
Mimas10h10h3d, 1h1d, 21h1d, 11h1d, 5h1d, 0h23h
Enceladus12h12h14h5d, 0h2d, 18h1d, 23h1d, 12h1d, 9h
Tethys15h15h17h19h6d, 2h3d, 6h2d, 3h1d, 22h
Dione19h19h21h1d, 0h1d, 4h6d, 23h3d, 7h2d, 20h
Rhea1d, 4h1d, 4h1d, 6h1d, 10h1d, 13h1d, 19h6d, 7h4d, 19h
Titan3d, 9h3d, 9h3d, 12h3d, 16h3d, 22h4d, 5h4d, 20h19d, 23h
Iapetus14d, 22h14d, 22h15d, 3h15d, 11h15d, 19h16d, 8h17d, 6h21d, 20h
  • In both sections, "d" means "days", and "h" means "hours"
  • Synodic periods (i.e., Hohmann launch window frequency) are above the diagonal in red
  • Transit times are below the diagonal in blue

Titan

Titan is the huge moon of Saturn with at atmosphere even denser than Terra. A person cannot breath it since it is 98.4% nitrogen, but that atmosphere makes it about an order of magnitude easier to establish a colony compared to, say, Mars. With respect to Mars the main drawback to Titan is the longer transit time for the colonist with the accompanying increased radiation exposure.

Advantages

  • Denser atmosphere than Terra (surface pressure 1.45 atm) makes Titan easier to colonize than Mars or any airless moon. High pressure makes construction easier, and the atmosphere provides plenty of radiation shielding from cosmic rays.
  • Nitrogen for fertilizer from Titan's Atmosphere. The stratosphere is 98.4% nitrogen, the only dense nitrogen-rich atmosphere in the Solar System outside of Terra.
  • Titan Space Plastic using the hydrocarbon seas as feedstock.

Examples of colonizing Titan in science fiction include Imperial Earth by Arthur C. Clarke, Bio of a Space Tyrant series by Piers Anthony, Titan by Stephen Baxter, 2312 by Kim Stanley Robinson, and Saturn and Titan by Ben Bova.


ENERGY OPTIONS FOR TITAN COLONISTS

The paper Energy Options for Future Humans on Titan has some interesting possiblities.

Nuclear Power
Radiogenic argon in Titan's atmosphere indicates the moon contains radioactive ores. Unfortunately current planetary models indicate such ores are buried under hundreds of kilometers of ice and water. But they are there if the colonists get desperate.
Chemical Power
While the atmosphere contains methane and it rains ethane into the hydrocarbon seas, the sad fact of the matter is there is no oxygen to burn with these fuels. Electrolysis can produce oxygen, but more energy is needed for that than you will get from hydrocarbon burning. A net loss of energy, so what's the point? Oxygen can also be produced by growing plants, but natural plant photosynthesis is so inefficient it will still be a net loss. Unless you do some serious genetic engineering on the plants.

More promising is the fact that Titan's atmosphere is almost 0.2% hydrogen, and there are traces of acetylene. These can be extracted from the atmosphere using low energy methods. The hydrogenation of acetylene is a splendidly exothermic reaction that produces 376 kJ/mole of energy. If the acetylene is too scare, it is possible to produce the stuff by the pyrolysis (heat it up real hot, 1000°C) of the abundant atmospheric methane (1.4%). This takes energy, but less than the energy produced by hydrogen-acetylene reactions.

It is also possible to hydrogenatize nitrogen into ammonia. This only produces a paltry 92.4 kJ/mole of energy. On the other hand the atmosphere is 98.4% nitrogen so you ain't gonna run out of that. Both gases can be easily extracted from the atmosphere with low energy methods. And 92.4 kJ/mole of energy is far better than nothing.
Hydropower
Titan has abundant lakes and seas of methane/ethane which can be turned into hydropower (methanopower?) with just a dam, a turbine, and a generator intercepting the flow downhill. The main problem is the lakes and seas are in the polar regions, and they are apparently topographically lower than Titan's lower latitudes. Neither water nor methane will flow uphill, not when they are liquid at any rate. There might be some spots where it will work but it will require much more high-resolution topographical data that we currently have. If not, the topography may have to be adjusted, say with a few precisely sited nuclear explosives.

The report gives an equation for hydropower power generation, given density of the fluid, gravitational acceleration, flow rate, height difference, and efficiency of the turbine. Assuming an efficiency of 0.85 and a height of 145 meters, a Terran hydropower system will produce 97 megawatts while a Titan methanopower system will produce about 9 megawatts. If the Terran system was fed by Lake Superior (with it never being replenished) it would produce 1×1019 Joules total energy over 3,450 years. If the Titan system was fed by Kraken Mare it would produce about 4.6×1019 J total energy over 242,580 years.
Wind Power
Titan's atmospheric density is five times higher than Terra (good for wind power) but the average winds speeds are about 0.025 of Terra (bad for wind power). At Titan's ground level wind speeds average 0.5 to 1.0 m/s, while on Terra they are more like 20 m/s. The report gives an equation for wind power generation. Assuming a turbine rotor diameter of 90 meters, a Titan windwpower plant would produce a meager 3.2 kilowatts while the same plant on Terra would produce more like 5,000 kilowatts (5 megawatts).

Titan's wind speeds are about 2 m/s at an altitude of 3 kilometers, and 20 m/s at an altitude of 40 kilometers. If you had your windpower plant on a blimp or a tethered balloon the plant would crank out hundreds of megawatts due to Titan's denser atmosphere.
Solar Power
Solar power on Titan is savagely punished by the tyranny of the Inverse Square Law, but it is still viable. Barely. Since Titan's distance from Sol varies from 9 to 10 astronomial units, the solar flux reaching Titan is from 1/81th to 1/100th of what reaches Terra. Another annoying aspect is the steady drizzle of tholin crap raining down on the solar panels. This reddish-brown sticky mess will have to be periodially scraped off. Tholins are the reason Titan's atmosphere is orange and murky.

At the top of Terra's atmosphere the average solar energy is about 1,400 J/m2-s, Titan gets 14 to 17 J/m2-s depending on its current distance to Sol. Titan's atmosphere transmits red and near infrared light but absorbs blue light, about 10% of the solar flux makes it to the surface (1.4 to 1.7 J/m2-s). Amorphous silicon or cadmium telluride photovoltaic cells are best for this spectrum, they have an efficiency of 13% to 20% but their performance at Titan temperatures is unknown (the report conservatively estimates it to be 10%). And for low to mid latitudes the sun will be up for 1/3rd of a Titan day (not counting seasonal variations or eclipses by Saturn. Not to mention cloud cover and ethane rain).

As an example the researchers assumed that the Titan colonists consume 1.4×1019 J/year (about the same as the United States). To meet this need with solar power would require 8×1012 square meters of panels, about 89% of the surface area of the US, but only 10% of Titan's total surface area.
Geothermal Power
Jupiter's moon Io has a heat flux of 2.25 W/m2, but poor Titan only has 0.005 W/m2. Presumably more power could be obtained from a geothermal hot spot but so far none have been detected.
FORGET MARS—LET’S GO COLONIZE TITAN

For a while now, there's been a debate in the US over how to direct NASA's next major human spaceflight initiative. Do we build an outpost on the Moon as a step towards Mars, or do we just head straight for the red planet? Which ever destination we choose, it'll be viewed as the first step toward a permanent human presence outside of the immediate neighborhood of the Earth.

All of that indecision, according to a new book called Beyond Earth, is misguided. Either of these destinations presents so many challenges and compromises that attracting and supporting anything more than short-term visitors will be difficult. Instead, Beyond Earth argues, we should set our sights much farther out in the Solar System if we want to create a permanent human presence elsewhere. The authors' destination of choice? Titan, the largest moon of Saturn.

The case for Titan

Colonizing Titan seems like an outrageous argument, given that the only spacecraft we've put in orbit around Saturn took seven years to get there. Why should anyone take Beyond Earth seriously? Well, its authors aren't crackpots or mindless space fans. Amanda Hendrix is a planetary scientist who's worked at the Jet Propulsion Laboratory and the Planetary Science Institute. For the book, she's partnered with Charles Wohlforth, an environmental journalist who understands some things about establishing a livable environment. And the two of them have conducted extensive interviews, talking to people at NASA and elsewhere about everything from the health complications of space to future propulsion systems.

The resulting book is a mix of where we are now, which problems need to be solved to make a home elsewhere, and a future scenario that drives us to solve those problems. In this sense, Beyond Earth is a bit like the recent National Geographic effort Mars, which blended present-day documentary with a fictionalized future. But the book is a little easier to swallow then the miniseries, which shunted viewers between footage of real-life rockets and CGI dust storms.

So, why Titan? The two closer destinations, the Moon and Mars, have atmospheres that are effectively nonexistent. That means any habitation will have to be extremely robust to hold its contents in place. Both worlds are also bathed in radiation, meaning those habitats will need to be built underground, as will any agricultural areas to feed the colonists. Any activities on the surface will have to be limited to avoid excessive radiation exposure.

Would anyone want to go to a brand-new world just to spend their lives in a cramped tunnel? Hendrix and Wohlforth suggest the answer will be "no." Titan, in contrast, offers a dense atmosphere that shields the surface from radiation and would make any structural failures problematic, rather than catastrophic. With an oxygen mask and enough warm clothing, humans could roam Titan's surface in the dim sunlight. Or, given the low gravity and dense atmosphere, they could float above it in a balloon or on personal wings.

The vast hydrocarbon seas and dunes, Hendrix and Wohlforth suggest, would allow polymers to handle many of the roles currently played by metal and wood. Drilling into Titan's crust would access a vast supply of liquid water in the moon's subsurface ocean. It's not all the comforts of home, but it's a lot more of them than you'd get on the Moon or Mars.

There is the distance thing, which Hendrix and Wohlforth acknowledge, but they argue it's a bit besides the point. The radiation and lack of gravity that make long-range space travel a risk would all bite anyone we sent to explore Mars. NASA assumes it'll find solutions, but the authors are critical of the Agency promoting a journey to Mars without already having solved them. Whether we go to Mars or Titan, the solution is speed: less time in space means less risk. And, if we could rocket along fast enough so that a round-trip to Mars with time spent exploring was safe, then we could do a one-way trip to Titan.

Have some Fi with that Sci

So, Beyond Earth is a good look at the current state of human space-exploration technology, as well as how that will hold us back from doing the things we want to do. It's both thoughtful and thought-provoking.

Mixed in with that, however, is a scenario under which Earth will get its act together and do what needs to be done to overcome these technological hurdles. That scenario is driven in part by a very believable desperation, caused by unaddressed climate change that drives wars and radicalization. Low Earth orbit becomes cheap, and then an efficient new thruster is developed. (Unfortunately, the thruster of choice in this scenario is unlikely to ever work.)

The Earth's governments bands together in a massive effort to send colonists to Titan, who almost immediately begin to view themselves as pioneers who boldly settle a new world with no help from anyone. Tensions and cultural differences ensue. This part of the book is a fun yarn, and plenty of it involves believable extrapolations from our current state. Whether it adds to Beyond Earth overall will probably be a matter of personal taste.

While the focus of the book is on leaving Earth, it's hard to escape the sense that Beyond Earth is an extensive argument for staying put. As Hendrix and Wohlforth repeatedly drive home, there's no place we could go in our Solar System that offers anything close to what the Earth provides for us. Going anywhere else would involve a cost that could go a long way toward making our existence here much more sustainable. While I'm all for eventually establishing a presence elsewhere, it would be nice to do so by choice, rather than end up being forced to do so due to our carelessness on Earth.

SETTLING TITAN, SCHNEIER’S LAW, AND SCENARIO THINKING

Charles Wohlforth and Amanda R. Hendrix want us to colonize Titan. The essay irritated me in an interesting manner.

Full disclosure: they interviewed me while they were writing their book Beyond Earth: Our Path to a New Home in the Planets, which I have not read yet, and I will only be basing the following on the SciAm essay. It is not really about settling Titan either, but something that bothers me with a lot of scenario-making.

A weak case for Titan and against Luna and Mars

Basically the essay outlines reasons why other locations in the solar system are not good: Mercury too hot, Venus way too hot, Mars and Luna have too much radiation. Only Titan remains, with a cold environment but not too much radiation.

A lot of course hinges on the assumptions:

We expect human nature to stay the same. Human beings of the future will have the same drives and needs we have now. Practically speaking, their home must have abundant energy, livable temperatures and protection from the rigors of space, including cosmic radiation, which new research suggests is unavoidably dangerous for biological beings like us.

I am not that confident in that we will remain biological or vulnerable to radiation. But even if we decide to accept the assumptions, the case against the Moon and Mars is odd:

Practically, a Moon or Mars settlement would have to be built underground to be safe from this radiation.Underground shelter is hard to build and not flexible or easy to expand. Settlers would need enormous excavations for room to supply all their needs for food, manufacturing and daily life.

So making underground shelters is much harder than settling Titan, where buildings need to be isolated against a -179 C atmosphere and ice ground full with complex and quite likely toxic hydrocarbons. They suggest that there is no point in going to the moon to live in an underground shelter when you can do it on Earth, which is not too unreasonable – but is there a point in going to live inside an insulated environment on Titan either? The actual motivations would likely be less of a desire for outdoor activities and more scientific exploration, reducing existential risk, and maybe industrialization.

Also, while making underground shelters in space may be hard, it does not look like an insurmountable problem. The whole concern is a bit like saying submarines are not practical because the cold of the depths of the ocean will give the crew hypothermia – true, unless you add heating.

I think this is similar to Schneier’s law:

Anyone, from the most clueless amateur to the best cryptographer, can create an algorithm that he himself can’t break.

It is not hard to find a major problem with a possible plan that you cannot see a reasonable way around. That doesn’t mean there isn’t one.

Settling for scenarios

Maybe Wohlforth and Hendrix spent a lot of time thinking about lunar excavation issues and consistent motivations for settlements to reach a really solid conclusion, but I suspect that they came to the conclusion relatively lightly. It produces an interesting scenario: Titan is not the standard target when we discuss where humanity ought to go, and it is an awesome environment.

Similarly the “humans will be humans” scenario assumptions were presumably chosen not after a careful analysis of relative likelihood of biological and postbiological futures, but just because it is similar to the past and makes an interesting scenario. Plus human readers like reading about humans rather than robots. All together it makes for a good book.

Clearly I have different priors compared to them on the ease and rationality of Lunar/Martian excavation and postbiology. Or even giving us D. radiodurans genes.

In The Age of Em Robin Hanson argues that if we get the brain emulation scenario space settlement will be delayed until things get really weird: while postbiological astronauts are very adaptable, so much of the mainstream of civilization will be turning inward towards a few dense centers (for economics and communications reasons). Eventually resource demand, curiosity or just whatever comes after the Age of Ems may lead to settling the solar system. But that process will be pretty different even if it is done by mentally human-like beings that do need energy and protection. Their ideal environments would be energy-gradient rich, with short communications lags: Mercury, slowly getting disassembled into a hot Dyson shell, might be ideal. So here the story will be no settlement, and then wildly exotic settlement that doesn’t care much about the scenery.

But even with biological humans we can imagine radically different space settlement scenarios, such as the Gerhard O’Neill scenario where planetary surfaces are largely sidestepped for asteroids and space habitats. This is Jeff Bezo’s vision rather than Elon Musk’s and Wohlforth/Hendrix’s. It also doesn’t tell the same kind of story: here our new home is not in the planets but between them.

My gripe is not against settling Titan, or even thinking it is the best target because of some reasons. It is against settling too easily for nice scenarios.

Beyond the good story

Sometimes we settle for scenarios because they tell a good story. Sometimes because they are amenable to study among other, much less analyzable possibilities. But ideally we should aim at scenarios that inform us in a useful way about options and pathways we have.

That includes making assumptions wide enough to cover relevant options, even the less glamorous or tractable ones.

That requires assuming future people will be just as capable (or more) at solving problems: just because I can’t see a solution to X doesn’t mean it is not trivially solved in the future.

(Maybe we could call it the “Manure Principle” after the canonical example of horse manure being seen as a insoluble urban planning problem at the previous turn of century and then neatly getting resolved by unpredicted trams and cars – and just like Schneier’s law and Stigler’s law the reality is of course more complex than the story.)

In standard scenario literature there are often admonitions not just to select a “best case scenario”, “worst case scenario” and “business as usual scenario” – scenario planning comes into its own when you see nontrivial, mixed value possibilities. In particular, we want decision-relevant scenarios that make us change what we will do when we hear about them (rather than good stories, which entertain but do not change our actions). But scenarios on their own do not tell us how to make these decisions: they need to be built from our rationality and decision theory applied to their contents. Easy scenarios make it trivial to choose (cake or death?), but those choices would have been obvious even without the scenarios: no forethought needed except to bring up the question. Complex scenarios force us to think in new ways about relevant trade-offs.

The likelihood of complex scenarios is of course lower than simple scenarios (the conjunction fallacy makes us believe much more in rich stories). But if they are seen as tools for developing decisions rather than information about the future, then their individual probability is less of an issue.

In the end, good stories are lovely and worth having, but for thinking and deciding carefully we should not settle for just good stories or the scenarios that feel neat.

IMPERIAL EARTH

(ed note: alas, this novel was written back in those early years when astronomers thought the atmosphere of Titan was mostly hydrogen, instead of mostly nitrogen as we now know to be true. But this is still interesting from a MacGuffinite standpoint, demonstrating how to set up an interplanetary economy.)

      Then, out of that silence, came something new.
     It was faint and distant, yet conveyed the impression of overwhelming power. First there was a thin scream that mounted second by second in intensity, but somehow never came any closer. The scream rose swiftly to a demonic shriek, with undertones of thunder—then dwindled away as quickly as it had appeared. From beginning to end it lasted less than half a minute. Then there was only the sighing of the wind, even lonelier than before.

     “Oh. I know what made that noise,” said Karl smugly. “Didn’t you guess? That was a ram-tanker making a scoop. If you call Traffic Control, they’ll tell you where it was heading.”

     But like all healthy ten-year-olds, Duncan was resilient. The magic had not been destroyed. Though the first ship had lifted from Earth three centuries before he was born, the wonder of space had not yet been exhausted. There was romance enough in that shriek from the edge of the atmosphere, as the orbiting tanker collected hydrogen to power the commerce of the Solar System.
     In a few hours, that precious cargo would be falling sunward, past Saturn’s other moons, past giant Jupiter, to make its rendezvous with one of the fueling stations that circled the inner planets. It would take months—even years—to get there, but there was no hurry. As long as cheap hydrogen flowed through the invisible pipeline across the Solar System, the fusion rockets could fly from world to world, as once the ocean liners had plied the seas of Earth.
     Duncan understood this better than most boys of his age; the hydrogen economy was also the story of his family, and would dominate his own future when he was old enough to play a part in the affairs of Titan. It was now almost a century since Grandfather Malcolm had realized that Titan was the key to all the planets, and had shrewdly used this knowledge for the benefit of mankind—and of himself.

     Malcolm Makenzie had been the right man, at the right time. Others before him had looked covetously at Titan, but he was the first to work out all the engineering details and to conceive the total system of orbiting scoops, compressors, and cheap, expendable tanks that could hold their liquid hydrogen with minimum loss as they dropped leisurely sunward.
     Back in the 2180s, Malcolm had been a promising young aerospace designer at Port Lowell, trying to make aircraft that could carry useful payloads in the tenuous Martian atmosphere.
     When he had finished his calculations and stolen enough drafting-computer time to prepare a beautiful set of drawings, young Malcolm had approached the Planning Office of the Martian Department of Transportation. He did not anticipate serious criticism, because he knew that his facts and his logic were impeccable.
     A large fusion-powered spaceliner could use ten thousand tons of hydrogen on a single flight, merely as inert working fluid. Ninety-nine percent of it took no part in the nuclear reaction, but was hurled from the jets unchanged, at scores of kilometers a second (exhaust velocity of 20,000 m/s or more, egads!), imparting momentum to the ships it drove between the planets.
     There was plenty of hydrogen on Earth, easily available in the oceans; but the cost of lifting megatons a year into space was horrendous. And the other inhabited worlds—Mars, Mercury, Ganymede, and the Moon—could not help. They had no surplus hydrogen at all. (again, since the novel was written astronomers have discovered frozen water in polar lunar craters that are perpetually sunless)
     Of course, Jupiter and the other Gas Giants possessed unlimited quantities of the vital element, but their gravitational fields guarded it more effectively than any unsleeping dragon, coiled round some mythical treasure of the Gods. In all the Solar System, Titan was the only place where Nature had contrived the paradox of low gravity and an atmosphere remarkably rich in hydrogen and its compounds.
     Malcolm was right in guessing that no one would challenge his figures, or deny the feasibility of the scheme, but a kindhearted senior administrator took it upon himself to lecture young Makenzie on the political and economic facts of life. He learned, with remarkable speed, about growth curves and forward discounting and interplanetary debts and rates of depreciation and technological obsolescence, and understood for the first time why the solar was backed, not by gold, but by kilowatt-hours.
     “It’s an old problem,” his mentor had explained patiently. “In fact, it goes back to the very beginnings of astronautics, in the twentieth twentieth century. We couldn’t have commercial space flight until there were flourishing extraterrestrial colonies—and we couldn’t have colonies until there was commercial space transportation. In this sort of bootstrap situation, you have a very slow growth rate until you reach the takeoff point. Then, quite suddenly, the curves start shooting upward, and you’re in business.
     “It could be the same with your Titan refueling scheme—but have you any idea of the initial investment required? Only the World Bank could possibly underwrite it….”
     “What about the Bank of Selene? Isn’t it supposed to be more adventurous?”
     “Don’t believe all you’ve read about the Gnomes of Aristarchus; they’re as careful as anyone else. They have to be. Bankers on Earth can still go on breathing if they make a bad investment….”
     But it was the Bank of Selene, three years later, that put up the five megasols for the initial feasibility study. Then Mercury became interested—and finally Mars. By this time, of course, Malcolm was no longer an aerospace engineer. He had become, not necessarily in this order, a financial expert, a public-relations adviser, a media manipulator, and a shrewd politician. In the incredibly short time of twenty years, the first hydrogen shipments were falling sunward from Titan.

From IMPERIAL EARTH by Arthur C. Clarke (1975)

Uranian and Neptunian Moons

Uranian Moons (stats on all Uranian Moons, stats on Uranian Rings, stats on Uranus)

Advantages

Neptunian Moons (stats on all Neptunian Moons, stats on Neptunian Rings, stats on Neptune)

Advantages

Neptune Trojans

Trans-Neptuian Objects

Kuiper Belt

Scattered disc

Sednoid

Oort Cloud

Interstellar Colonization

When it comes to interstellar colonizations, the distances are so long, the delta V requirements so astronomical, and the travel times are so prolonged that you'd better be blasted sure there is actually a planet there to colonize.

Excitingly the astronomical state of the art has advanced to the point where they can actually detect the presence of extrasolar planets. Currently the NASA Exoplanet Archive is listing 3,431 of the sightings as "confirmed."

The Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo continually studies the data, and has a small number classified as "Conservatively Potentially Habitable Exoplanets" and a larger number classified as "Optimistically Potentially Habitable Exoplanets". Please note that "habitable" means "it is not totally impossible to live there." It does NOT mean it is a tropical paradise, or even that it won't kill you if you step out of the spacecraft in your shirt-sleeves.

"Conservatively Potentially Habitable Exoplanets" means very likely to be of rocky composition (instead of being a worthless gas giant) and very likely to maintain surface liquid water (instead of being permanent ice or pure life steam). The definition of "rocky composition" is planet radius between 0.5 and 1.5 Earth radii and planet minimum mass between 0.1 and 5.0 Earth masses. The definition of "surface liquid water" is planet orbiting within the conservative habitable zone.

"Optimistically Potentially Habitable Exoplanets" has standards that are a bit more lax. This means the planet is less likely to have a rocky composition and less likely to maintain surface liquid water. The definition of "rocky composition" is planet radius between 1.5 and 2.5 Earth radii and planet minimum mass between 5.0 and 10.0 Earth Masses (i.e., a "super-earth") The definition of "surface liquid water is a planet orbiting within the optimistic habitable zone.

As of 2016 these are the conservatively and optimistically potentially habitable planets listed by the Planetary Habitability Laboratory:

Conservatively Potentially Habitable Exoplanets

NameTypeMass
(ME)
Radius
(RE)
Flux
(SE)
Teq
(K)
Period
(days)
Distance
(ly)
ESI
001. Proxima Cen bM-Warm Terran≥ 1.3 0.8 - 1.1 - 1.4 0.70227 11.24 0.87
002. GJ 667 C cM-Warm Terran≥ 3.8 1.1 - 1.5 - 2.0 0.88247 28.122 0.84
003. Kepler-442 bK-Warm Terran 8.2 - 2.3 - 1.0 1.3 0.70233112.31115 0.84
004. GJ 667 C f*M-Warm Terran≥ 2.7 1.0 - 1.4 - 1.8 0.56221 39.022 0.77
005. Wolf 1061 cM-Warm Terran≥ 4.3 1.1 - 1.6 - 2.0 0.60223 17.914 0.76
006. Kepler-1229 bM-Warm Terran 9.8 - 2.7 - 1.2 1.4 0.49213 86.8769 0.73
007. Kapteyn b*M-Warm Terran≥ 4.8 1.2 - 1.6 - 2.1 0.43205 48.613 0.67
008. Kepler-62 fK-Warm Terran 10.2 - 2.8 - 1.2 1.4 0.39201267.31200 0.67
009. Kepler-186 fM-Warm Terran 4.7 - 1.5 - 0.6 1.2 0.29188129.9561 0.61
010. GJ 667 C e*M-Warm Terran≥ 2.7 1.0 - 1.4 - 1.8 0.30189 62.222 0.60

Optimistically Potentially Habitable Exoplanets

NameTypeMass
(ME)
Radius
(RE)
Flux
(SE)
Teq
(K)
Period
(days)
Distance
(ly)
ESI
001. Kepler-438 bM-Warm Terran 4.0 - 1.3 - 0.6 1.1 1.38276 35.2473 0.88
002. Kepler-296 eM-Warm Terran 12.5 - 3.3 - 1.4 1.5 1.22267 34.1737 0.85
003. Kepler-62 eK-Warm Superterran 18.7 - 4.5 - 1.9 1.6 1.10261122.41200 0.83
004. Kepler-452 bG-Warm Superterran 19.8 - 4.7 - 1.9 1.6 1.11261384.81402 0.83
005. K2-72 eM-Warm Terran 9.8 - 2.7 - 1.2 1.4 1.46280 24.2181 0.82
006. GJ 832 cM-Warm Superterran≥ 5.4 1.2 - 1.7 - 2.2 1.00253 35.716 0.81
007. K2-3 dM-Warm Terran 11.1 1.5 1.46280 44.6137 0.80
008. Kepler-1544 bK-Warm Superterran 31.7 - 6.6 - 2.6 1.8 0.90248168.81138 0.80
009. Kepler-283 cK-Warm Superterran 35.3 - 7.0 - 2.8 1.8 0.90248 92.71741 0.79
010. tau Cet e*G-Warm Terran≥ 4.3 1.1 - 1.6 - 2.0 1.51282168.112 0.78
011. Kepler-1410 bK-Warm Superterran 31.7 - 6.6 - 2.6 1.8 1.34274 60.91196 0.78
012. GJ 180 c*M-Warm Superterran≥ 6.4 1.3 - 1.8 - 2.3 0.79239 24.338 0.77
013. Kepler-1638 bG-Warm Superterran 42.7 - 7.9 - 3.1 1.9 1.39276259.32866 0.76
014. Kepler-440 bK-Warm Superterran 41.2 - 7.7 - 3.1 1.9 1.43273101.1851 0.75
015. GJ 180 b*M-Warm Superterran≥ 8.3 1.3 - 1.9 - 2.4 1.23268 17.438 0.75
016. Kepler-705 bM-Warm Superterran? - 12.7 - 4.8 2.1 0.83243 56.1818 0.74
017. HD 40307 g*K-Warm Superterran≥ 7.1 1.3 - 1.8 - 2.3 0.68227197.842 0.74
018. GJ 163 cM-Warm Superterran≥ 7.3 1.3 - 1.8 - 2.4 0.66230 25.649 0.73
019. Kepler-61 bK-Warm Superterran? - 13.8 - 5.2 2.2 1.27267 59.91063 0.73
020. K2-18 bM-Warm Superterran? - 16.5 - 6.0 2.2 0.92250 32.9111 0.73
021. Kepler-1606 bG-Warm Superterran? - 11.9 - 4.5 2.1 1.41277196.42869 0.73
022. Kepler-1090 bG-Warm Superterran? - 16.8 - 6.1 2.3 1.20267198.72289 0.72
023. Kepler-443 bK-Warm Superterran? - 19.5 - 7.0 2.3 0.89247177.72540 0.71
024. Kepler-22 bG-Warm Superterran? - 20.4 - 7.2 2.4 1.11261289.9619 0.71
025. GJ 422 b*M-Warm Superterran≥ 9.9 1.4 - 2.0 - 2.6 0.68231 26.241 0.71
026. K2-9 bM-Warm Superterran? - 16.8 - 6.1 2.2 1.38276 18.4359 0.71
027. Kepler-1552 bK-Warm Superterran? - 25.2 - 8.7 2.5 1.11261184.82015 0.70
028. GJ 3293 c*M-Warm Superterran≥ 8.6 1.4 - 1.9 - 2.5 0.60223 48.159 0.70
029. Kepler-1540 bK-Warm Superterran? - 26.2 - 9.0 2.5 0.92250125.4854 0.70
030. Kepler-298 dK-Warm Superterran? - 26.8 - 9.1 2.5 1.29271 77.51545 0.68
031. Kepler-174 dK-Warm Superterran? - 14.8 - 5.5 2.2 0.43206247.41174 0.61
032. Kepler-296 fM-Warm Superterran 28.7 - 6.1 - 2.5 1.8 0.34194 63.3737 0.60
033. GJ 682 c*M-Warm Superterran≥ 8.7 1.4 - 1.9 - 2.5 0.37198 57.317 0.59
034. KOI-4427 b*M-Warm Superterran 38.5 - 7.4 - 3.0 1.8 0.24179147.7782 0.52

Table Legend:

  • Name - Name of the planet. This links to the data of the planet at the Extrasolar Planets Encyclopaedia or NASA Exoplanet Archive.
  • Type - PHL's classification of planets that includes host star spectral type (F, G, K, M), habitable zone location (hot, warm, cold) and size (miniterran, subterran, terran, superterran, jovian, neptunian) (e.g. Earth = G-Warm Terran, Venus = G-Hot Terran, Mars = G-Warm Subterran).
  • Mass - Minimum mass of the planet in Earth masses (Earth = 1.0 ME). Estimated for a pure iron, rocky, and water composition, respectively, when not available.
  • Radius - Radius of planet in Earth radii (Earth = 1.0 RE). Estimated for a pure iron, rocky, and water composition, respectively, when not available.
  • Flux - Average stellar flux of the planet in Earth fluxes (Earth = 1.0 SE).
  • Teq - Equilibrium temperature in kelvins (K) assuming a 0.3 bond albedo (Earth = 255 K). Actual surface temperatures are expected to be larger than the equilibrium temperature depending on the atmosphere of the planets, which are currently unknown (e.g. Earth mean global surface temperature is about 288 K or 15°C).
  • Period - Orbital period in days (Earth = 365 days).
  • Distance - Distance from Earth in light years (ly).
  • ESI - Earth Similarity Index, a measure of similarity to Earth that summarizes how similar are these planets to the stellar flux, mass, and radius of Earth (Earth = 1.0). Results are sorted by this number. Planets more similar to Earth are not necessarily more habitable, since the ESI does not consider all factors necessary for habitability.

I took the stars that were closer than 13 parsecs (42 light-years) and played with the data. I tried to make some connection charts to show the direction of colonization. Note that there are about 900 known stars in this volume. I am trying to make a baby-step map with the path between the zillions of empty stars leading to the good ones. This is going to take a while so be patient.

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