RocketCat sez

Listen up, space cadets! Here's the deal:

Spaceship and spacestation cabins have air at full pressure. If you use air at low pressure the blasted atmo is pure oxy, which is like swimming in a pool of gasoline while idly flicking your Zippo.

Soft space suits are only terribly encumbering, like wearing three snow suits at once. This is their advantage. Disadvantages include the fact they can be punctured by a pair of kindergarten safety scissors, causing certain death. Oh, and they can only use low pressure because high pressure will make the suit spread-eagle you like a Saint Andrew's Cross. Low pressure means you have to do a few hours of pre-breathing or the suit will kill you with The Bends. Which is a problem if an emergency strikes and you don't have a few hours.

Hard shell space suits advantages are: they can use high pressure atmo so you can't get the bends, you don't need to pre-breathe, and you'd need a freaking handgun to puncture it. Disadvantage is they are monumentally overwhelmingly hideously encumbering like wearing a suit of medieval plate armor made out of solid lead. Soft space suits are only terribly encumbering.

Semi-rigid space suits are a cross between soft and hard shell suits. Like all attempts to have it both ways, it means they have the draw-backs of both and the advantages of neither.

Skintight suits have the advantage of being about as encumbering as a wearing leotards, they are quick to put on, and puncturing them just gives you a space-hickey instead of certain death. Disadvantage is they have to use low pressure so The Bends once again raises its ugly head. Also people have a problem getting anybody to take it seriously ("Aw, c'mon, gimmie a break! Who the heck is your suit designer, Earle K. Bergey? Where's the brass brassière?)

A space suit is a protective garment that prevents an astronaut from dying horribly when they step into airless space.

Also known as atmosphere suit, vac suit, pressure suit, space armor, environment(al) suit, e-suit, EVA suit.

SF author Sir Arthur C. Clarke said "We seldom stop to think that we are still creatures of the sea, able to leave it only because, from birth to death, we wear the water-filled space suits of our skins." SF author Ken MacLeod said that the specification of a human being is "a space suit for a fish."

Current NASA suits look like baggy inflated coveralls with a large back pack and a spherical fishbowl over the head. Often in old illustrations there are accordion bellows at the joints. The accuracy of space suits in science fiction was very much hit or miss. The low budget show Space Academy had "Life Support Bracelets" and the Star Trek Animated series had force-field based "Life Support Belts" as a cheapskate way to avoid the special effect expense of renting or drawing an actual space suit.

NASA astronaut always put on a transdermal dimenhydrinate anti-nausea patch when suiting up in a space suit, in case of drop sickness. The chances of that are slight, but suffocating inside a helmet full of vomit is a nasty way to die.

Most space suits are Full (Body) Pressure-suits: they offer pressurization of the entire body in space for extended periods. Partial (Body) Pressure-suits only pressurize certain parts of the body for a limited time. They are only used as a precaution, worn inside the habitat module during times when there is danger of it springing a leak (such as during lift-off).

Full-(Body) Pressure-suits can be either Low-Pressure (pure oxygen at 32.4 kPa) or High-Pressure (breathing mix at 101.3 kPa, normal Terran atmospheric pressure).

All NASA spacecraft and space station habitat modules are High-Pressure. At least the ones designed after the Apollo 1 tragedy claimed the lives of three astronauts. Ever since NASA has avoided using pure oxygen atmosphere wherever possible, which means using high-pressure.

The problem is if you go from a high-pressure environment (like a habitat module) into a low-pressure environment (like a low-pressure space suit) you run the risk of the bends. To avoid this the astronaut must do pre-breathing for a couple of hours. If you go from a high-pressure habitat module into a high-pressure space suit the bends does not happen. This is why high-pressure space suits are called "zero-prebreathe" suits.

I suppose some space-faring nation could use low-pressure pure-oxygen habitat modules to avoid pre-breathing with low-pressure space suits, but that would be insanely dangerous. It would be the outer-space equivalent of those stubborn elderly hospital patients who insist on smoking cigarettes while wearing oxygen tanks. A disaster just waiting to happen.

NASA tolerates low-pressure pure-oxygen pressurization in their soft space suits because they have no choice. There is not a lot of research, but NASA seems to think that if an astronaut in such a suit got punctured by a micro-meteor and it caught fire, the main hazard is a fire enlarging the diameter of the breach, not an astronaut-shaped ball of flame.

Suits can be Soft, Hard-shell, Semi-Rigid/Hybrid or Skintight.

Soft suits have flexible exteriors. This means they cannot be pressurized to the same level as the inside of the habitat module or the space suited person will be forced into a posture like a star-fish and be unable to bend any joints. Lower pressure means the suit uses pure oxygen unlike the habitat module. And pure oxygen means the astronaut has to do hours pre-breathing before wearing the suit or they will be stricken by The Bends.

Soft suits also take forever to put on, they fight your every movement (making EVA work very fatiguing), and if you tear the suit skin you will die horribly in about 90 seconds. When I say "fight your every movement" I mean "raise the energy expenditure to do a task by about 400%".

Currently most of NASA's space suits are soft suits.

Hard-shell suits have rigid exteriors. The advantage is they can be fully pressurized so no pre-breathing is required. They are also much more tear and puncture resistant than soft suits.

The drawback of hard-shell suits is that they make the "forever to put on" and "fight your every movement" problems much worse.

As far as I know there are no hard-shell suits in active use, they are all experimental.

Semi-rigid or Hybrid suits are a cross between soft and hard-shell. For instance, NASA's EMU has a hard-shell upper torso and soft fabric limbs. Current NASA semi-rigid suits are low pressure, but they are working on a high-pressure model.

Skintight suits are a radical concept that is so crazy it just might work. They make the astronaut's skin into the spacesuit, using high-tech spandex to supply pressure instead of using atmosphere. They can be quickly put on, fight your every movement only to the point of a +20% increase in energy, and if the suit is torn the astronaut only gets a bruise instead of certain death. The suits are also much inexpensive than a soft or hard-shell suit. The major draw-back is they require low pressure breathing mix (or the wearer cannot exhale), so astronauts have to pre-breath or face the Bends.

"Planetary suits" are used when there is an atmosphere, but it isn't breathable. They have a slightly different design from space suits.

(ed note: The crew of the Skylark try to use their newly invented space suits, which have never been actually tested in the field)

DuQuesne reported briefly to the two girls. All three put on space-suits and crowded into the tiny airlock. The lock was pumped down. There was a terrific jar as the two ships of space were brought together and held together. Outer valves opened; residual air screamed out into the interstellar void. Moisture condensed upon glass, rendering sight useless.

'Blast!' Seaton's voice came tinnily over the helmet radios. 'I can't see a foot. Can you, DuQuesne?'

'No, and these joints don't move more than a couple of inches.'

'These suits need a lot more work. We'll have to go by feel. Pass 'em along.'

DuQuesne grabbed the girl nearest him and shoved her toward the spot where Seaton would have to be.

From THE SKYLARK OF SPACE by E. E. "Doc" Smith (1928)

Partial-Pressure Suits

To recap: Partial Pressure suits only pressurize certain parts of the body for a limited time. They are only used as a precaution, worn inside the habitat module during times when there is danger of it springing a leak, such as during lift-off or if an enemy spacecraft is shooting at you. Partial pressure suits are a trade-off: they only protect you for a short time but in exchange they do not encumber you anywhere near as much as a total pressure suit.

The NASA version is the Launch Entry Suit aka "pumpkin suit." It has ten minutes worth of life support internal to the suit, and can be hooked up to the vehicles life support system for longer duration.

The image above from First Men to the Moon is a partial pressure suit based on an old school Air Force high-altitude suit. If the pressure drops, the pressure regulating tubes along the suit's seams inflate to put the suit under tension. The wearer will then put on the oxygen mask attached to the small tank strapped to their leg.

The crew of a combat spacecraft in battle probably will not wear a soft, hard-shell, or semi-rigid suit during battle. This is for the same reasons that the crew of a military submarine do not wear SCUBA gear in battle even though they too are in a craft surrounded by countless miles of unbreathable stuff while being shot at. It gets in the way.

But they might wear a partial-(body) pressure suit or a skintight pressure suit.

Or a skintight partial-(body) hybrid pressure-suit. This might be so unencumbered that it could be used as everday wear. Then if the habitat module loses pressure all you'd need is an oxygen mask and earplugs to survive for a few hours. Wear it with overalls because such a suit will make you almost as naked as wearing nothing but body paint.

Soft Suits

To recap, Soft Suits:

  • Must have lower pressure than the habitat module or the wearer turns into a starfish and cannot bend their limbs. This means the wearer needs an hour of pre-breathing or they will suffer the Bends.
  • In case of emergency, when there is no time for pre-breathing, NASA helpfully directs the astronauts to gulp aspirin, so they can work in spite of the agonizing pain
  • The breathing mix will be close to pure oxygen, with a higher fire risk.
  • Suit encumbrance increases the energy cost to do various tasks by +400%, with a corresponding increase in wearer fatigue.
  • If the soft skin of the suit is torn or punctured, the wearer will die in about 90 seconds.
  • They take forever to put on

For a list of the parameters for a NASA spec space suit, go here.

The only thing that allows an astronaut to bend their limbs at all is the magic of constant volume joints. These are why most pictures of space suits look like the Michelin Man (i.e., like a stack of donuts).

Dan chuckled, then sobered. "Like that, eh? Okay, you won't get any favors. But you'll still stay here today. Look, Jim, when I first came up, there was a guy named Joe with me. The first day he spotted some cargo drifting off and leaped for it. Put out a hand to grab it—and, naturally, when his arm moved one way his body moved the other. His suit hit a sharp edge of metal. A man dies fast out here when the air runs out of his suit, and it's not a pretty thing to see. You stay inside."

Jim practiced dutifully, gaining some proficiency as he did. He had to learn by experience that the twitch of a foot at the wrong moment could throw him off balance.

From STEP TO THE STARS by Lester Del Rey (1954)


In The Millennial Project Savage suggests that the helmet will have an outer layer of five millimeters of high density lead crystal. Inside will be two layers of dense borosilicate glass sandwiched between two layers of Lexan. The middle layer of Lexan will add strength and prevent shattering, the inner will act as a reserve helmet. The outer surface will be gold anodized to block glare, ultraviolet, and infra-red. There may be a nested set of telescoping curved armor plates that can be deployed for further protection.

NASA helmets are not quite so grandiose.

NASA helmets are spherical domes, which hits the sweet spot between low mass, pressure compensation, and field of view. All current NASA suits have the astronaut's head is held facing forwards, you have to turn your entire body in order to look sideways. Astronauts call this "alligator head".

The helmet has to be comfortable to wear, and help in controlling the humidity inside the helmet (so it doesn't fog up). Another important part is the radio communication unit, since the lack of air in space prevents the sound of your voice from reaching anybody. The old tagline to the first ALIEN movie was "In Space No One Can Hear You Scream". Well, no one can hear Floyd asking somebody to pass him a socket wrench either. NASA suits use "Snoopy caps" to hold the communciation earphones and microphones (in NASA-speak this is called the Communications Carrier Assembly (CCA)).

Other items might include windshield wipers (inside for condensation, outside for dust), a build-in set of binoculars, headlights for shadowed areas, a mirrored sun-visor to prevent sunlight from burning out your retinas, a water drink dispenser, and maybe a gadget that can supply various medications (pain relievers, anti-nausea, stimulants).

As previously mentioned, NASA astronaut always put on a transdermal dimenhydrinate anti-nausea patch when suiting up in a space suit, in case of drop sickness. The chances of that are slight, but suffocating inside a helmet full of vomit is a nasty way to die.

Some SF novels have a space helmets equipped with a tiny airlock near the mouth, called a "chow-lock." It is used to allow the astronaut to eat and drink without venting the helmet's air to the vacuum of space. I am uncertain how practical this concept is, or how idiot proof it can be made. It would be a bad thing if trying to get a bite of a candy bar accidentally killed you.


Hell, we’ve been sleeping nine hours out of the eighteen! Heim glanced at the others. Their suits had become as familiar to him as the seldom seen faces. Jocelyn was already unconscious. Uthg-a-K’thaq seemed to flow bonelessly across the place where he lay. Vadász and Bragdon sat tailor style, but their backs were bent. And every nerve in Heim carried waves of weariness. “All right,” he said.

He hadn’t much appetite, but forced himself to mix a little powder with water and squeeze the mess through his chowlock. When that was done, he stretched himself as well as his backpack allowed.

From THE STAR FOX by Poul Anderson (1965)

The path towards today’s helmet style grew out of a number of converging interests. Early Spaceflight Initiative helmets required more bulky hardware than modern compact systems, for example, which consumed and obscured much of the rear volume. Later industrial vacuum suits had the disadvantage of holding the wearer’s head in a forward-facing position, due to cushioning and ancillary equipment, restricting the wearer’s field of view. And then, of course, there were the various RFPs from the nascent Imperial Navy, and specifically the requests from the Flight Operations representatives, who were most insistent that while they were willing if reluctant to concede the impracticability of their traditional silk scarves as a vacuum suit accessory, relegating them to the role of dress uniform only, and even to acknowledge the uselessness of their equally traditional aviator goggles, they would not under any circumstances give up their leather-and-fur flight helmets.

(They had, after all, been presented upon graduation of every Pilot Officer since the first foundation of the Imperial Flying Corps. One might as well, in their view, expect a legionary to go into battle without his sword – or, as Military Service slang prefers to put it in either case – ‘stark ruddy naked’.)

And so we come to the modern bubble helmet, a spherical dome of smartglass sandwiched between high-impact sapphiroid. The outermost layer is gold-anodized, to block glare and harmful radiation (while in theory the smartglass could provide this filtration, the gold anodization is fail-safe, functioning even if suit power or data systems are malfunctioning), and designed to intrinsically shed fluids, dust, and electrical charge. The smartglass is capable of acting as an infinitely configurable variable-filter and information display surface, with HUD and augmented reality functions including night-vision and optical zoom. The view provided is unobstructed all around – even beyond the typical 100 degree head rotation – with the exception of two coin-sized spots above the eyeline and to each side where the headlight/camera modules are mounted. A third light/camera module, rear-mounted, provides a projectable rear view. These modules also include miniature trigraphic projectors, enabling the projection of status, communicative, and affective symbols over the wearer’s head.

The helmet is pressurized with the normal canned life support blend of oxygen and inert-mix, to standard ship’s pressure. (Since modern skinsuits incorporate MEMS-based respiration assistance, it is no longer necessary to use high-oxygen breathing mixes.) This is controlled by the systems torc at the base of the helmet, which locks onto the attachment ring/neck dam at the neck of the vacuum suit (itself connected to many fibers running throughout the suit fabric to prevent accidental detachment). Light nanofluid cushioning that surrounds the neck once the helmet is donned provides additional neck protection and stability.

The primary purpose of the systems torc, apart from this connection, is the containment of the suit’s data systems and mesh communications suite. (Its location permits it direct interface with its wearer’s back-neck laser-port, although an auxiliary manual keypad can be connected and mounted on an arm of the suit if desired.) It also contains a miniature high-pressure oxygen tank and rebreather/dehumidifier system as a final hour’s emergency life-support supply. The torc also contains the connectors for the PLSS backpack, including those which permit water, other beverages, food pastes, and pharmaceuticals to be dispensed to the wearer through a deployable pipette, or additionally in the case of pharmaceuticals, through an autoinjector into a neck vein.

Communications can be provided directly by the torc, either via the laser-port interface or via miniaturized microphones and loudspeakers built into the torc surface. Alternately, many wearers prefer the use of a simple headset worn under the helmet, which connects to the torc using local mesh radio.

– A History of Space Hardware, Orbital Education Initiative

From BUBBLE by Alistair Young (2016)


In NASA-speak, the backpack is called the Personal (or Primary or Portable) Life Support System (PLSS). At a minimum, it provides breathing mix, removes carbon dioxide, and regulates the suit's pressure.

Additionally it may remove humidity, odors, and contaminants from the breathing mix; cools the astronaut's body with oxygen or a liquid cooling garment; provides radio communication; displays and/or does telemetry of suit parameters; displays and/or does telementry of astronaut's health; and/or provides propulsion for EVA.

NASA's current design for PLSS is not foolproof, as astronaut Luca Parmitano discovered on July 16, 2013 when he almost died as his helmet filled up with water. The drum holes in the PLSS water separator got clogged, and the PLSS designers had a mistaken understanding of how water acts in microgravity (the designers thought it was impossible for the water to back up into the helmet).

As is usually the case, the reason astronaut Parmitano is alive today is because he did not panic. He had to move to the airlock and re-enter from memory, since he could not see with 1.5 liters of water covering his eyes.


The gloves are especially a problem. Back in the 1950's it was unclear if space suit gloves were even possible. You need to make the various protective layers thin enough to be able to fit between adjacent fingers. And with miniature constant volume cuffs at each finger joint. Some suit designers took a tip from deep sea diving suits and postulated mechanical pincers instead of gloves.

But as we know NASA did manage to design actual space suit gloves. However, they do not work very well. Almost every single NASA astronaut who has performed EVA has complaints about the difficulty of doing any fine work while wearing those gloves.

If you're headed for space, you might rethink that manicure: Astronauts with wider hands are more likely to have their fingernails fall off after working or training in space suit gloves, according to a new study.

In fact, fingernail trauma and other hand injuries—no matter your hand size—are collectively the number one nuisance for spacewalkers, said study co-author Dava Newman, a professor of aeronautics and astronautics at the Massachusetts Institute of Technology.

"The glove in general is just absolutely one of the main engineering challenges," Newman said. "After all, you have almost as many degrees of freedom in your hand as in the rest of your whole body."

The trouble is that the gloves, like the entire space suit, need to simulate the pressure of Earth's atmosphere in the chilly, airless environment of space. The rigid, balloonlike nature of gas-pressurized gloves makes fine motor control a challenge during extravehicular activities (EVAs), aka spacewalks.

A previous study of astronaut injuries sustained during spacewalks had found that about 47 percent of 352 reported symptoms between 2002 and 2004 were hand related. More than half of these hand injuries were due to fingertips and nails making contact with the hard "thimbles" inside the glove fingertips.

In several cases, sustained pressure on the fingertips during EVAs caused intense pain and led to the astronauts' nails detaching from their nailbeds, a condition called fingernail delamination.

While this condition doesn't prevent astronauts from getting their work done, it can become a nuisance if the loose nails gets snagged inside the glove. Also, moisture inside the glove can lead to secondary bacterial or yeast infections in the exposed nailbeds, the study authors say.

If the nail falls off completely, it will eventually grow back, although it might be deformed.

For now, the only solutions are to apply protective dressings, keep nails trimmed short—or do some extreme preventative maintenance.

"I have heard of a couple people who've removed their fingernails in advance of an EVA," Newman said.


Sticky Boots

Many SF novels have magnetized space boots to allow the rocketeers to adhere to the hull, but magnets do not work very well on hulls composed of titanium, aluminum, or magnesium. If one does have a ferromagnetic hull, it might be best to have magnets just in the boot toes but not the heels, to facilitate walking.

Hard-Shell Suits

To recap, Hard-Shell Suits:

  • Can have the same pressure as the habitat module without the wearer turning into a starfish. The Bends are avoided.
  • The breathing mix will be the same or very close to that of the habitat module. No additional fire risk.
  • Suit encumbrance increases the energy cost to do various tasks by many times that of a soft suit, with a incredible increase in wearer fatigue.
  • The hard shell of the suit is very puncture resistant.
  • They take longer to put on than a soft suit.

Hard-shell suits try to fix the tearing problem at the expense of making the first two problems much worse. True, hard suits do solve the depressurization problem, but at such a cost.

The AX-5 hard suit was developed by Hubert Vykukal at NASA Ames Research center in the 1960's. It was based on deep sea diving suit technology created by Phil Nuytten of Nuytco Research. The rotating joints are angled with respect to a limb, with two halves each comprising a thick wedge section and a thin section. When a limb is bent, the joint rotate so that the thin sections come together, allowing the suit limb to bend in a correspoinding fashion. For more details, refer to The Rocket Company.

Semi-Rigid Suits

Semi-rigid Suits are sort of a cross between soft suits and hard-shell suits, typically with the chest or torso hard and the limbs soft.

The ideal design is to have a hard-shell torso allowing the suit to be high-pressure with zero-prebreathing required, coupled with separately pressurized soft limbs to avoid the encumbrance penalty suffered by full-(body) hard-shell pressure-suits.

Which is why NASA's EMU puzzles me, it is a semi-rigid suit that appears to have the disadvantages of both with the advantages of neither. No doubt there were other considerations that I am unaware of.

The company ILC Dover made the Mark III suit as a technology demonstrator in 1992. It actually was a zero prebreathe suit. It is pressurized to 57 kPa, which is close enough to the 101.3 kPa used in NASA habitat modules so that the bends is not an issue. The Mark III had the shell covering the entire torso, not just the chest like the EMU. There is a hard upper torso, a hard lower torso. There are bearings at shoulder, upper arm, hip, waist, and ankles. There are soft fabric joints at elbow, knee, and ankle. I do not know why there are both types of joints at the ankles.

One of its main drawbacks was that the suit could not separate at the waist like other NASA suits, you had to enter the suit from the backpack. As with all hard-shell and semi-rigid suits, it is heavier than a soft suit (59 kilograms).

NASA decided against further development of the Mark III, for whatever reasons.

Skintight Suits

An innovative alternative approach is the Mechanical Counter Pressure (MCP) Suit. Instead of trying to hold your body intact with air pressure, it holds it in with spandex. It sounds crazy but it just might be crazy enough to work.

To recap, Skintight Suits:

  • Must have lower pressure than the habitat module or the wearer cannot empty their lungs. This means the wearer needs an hour of pre-breathing or they will suffer the Bends. Higher pressure also increases the risk of catastrophic failure of the helmet, i.e., shooting off like a champagne cork and killing the wearer.
  • In case of emergency, when there is no time for pre-breathing, NASA helpfully directs the astronauts to gulp aspirin, so they can work in spite of the agonizing pain
  • The breathing mix will be close to pure oxygen, with a higher fire risk.
  • Suit encumbrance only increases the energy cost to do various tasks by +20%, compared to the +400% of soft suits and the astronomical increase of hard-shell suits.
  • Suit punctures result in bruises on the wearer's skin, instead of certain death.
  • Skintight suits are the most inexpensive of all the space suits, about $60,000 US in 2005 dollars.
  • It tends to grab male wearers uncomfortably in the crotch.

The original concept was created by Dr. Paul Webb in 1968. It is currently being developed by Dr. Darva Newman at MIT, under the name "Bio-Suit".

A skin-tight suit of high tech cloth exerts pressure over the rocketeer's body to provide pressure. A bubble helmet with oxygen supply allows one to breathe. Open pores in the suit actually allow the body to be cooled by perspiration. Tears will cause bruising to the skin, but are not as lethal as they are on a conventional suit. The suit can be quickly put on. They do not interfere as much with movement (+20% energy expenditure, compared with +400% for a NASA suit). And you can store them by folding them up and putting them inside the bubble helmet. The back pack is still bulky, though.

They do need some care in design, though. Any concave areas on the body that the suit does not hug will bulge out under internal body pressure until it fills the void (i.e., your armpits will become armhills). Putty or fluid filled bladders will be needed to prevent this. Care must be taken around those nether regions, the small of the back, and in certain locations of the female chest. Male wearers will need a rather sophisticated cup to cover the genitals. Even with the cup, the suit will tend to grab male wearers uncomfortably in the crotch.

And upon entering vacuum, one will have an instant attack of dire flatulence (aka High-altitude flatus expulsion or HAFE). Don't be polite, let it out right away or you may damage your intestines.

There may be a length of tubing added along the seams of the arms, legs, and torso. The suit will be relaxed for easy dressing, then the tubing will be pressurized to put tension on the fabric (This was used in the g-suits worn by early jet pilots). The tubing will automatically pressurize when the helmet is put on and pressured up.

This used to be a standard feature of partial-(body) pressure suits.

A more advanced design uses a strip of "shape metal alloy'. An applied voltage can toggle the metal strip between expanded and contracted.

Unlike other types of space suits, the helmets for skintight suits require something called a "neck dam." This goes around the neck, and tries to keep an air-tight seal. Otherwise the helmet shoots off like a champagne cork and all the air in the helmet will spray out.

I'm sure the neck dam will be the part of the suit that will cause designers the most headaches. I personally would be in favor of straps that go from the neck dam and loop around ones arm around the armpits, but I'm no expert.

In The Millennial Project Savage suggests that light tungsten armor plates be worn over the suit to give some anti-radiation protection (this would only be needed in high radiation areas, like the Van Allen belts).

A minimal version of the skintight suit can be developed for everyday wear inside a spacecraft, i.e., a Partial-(body) Skintight pressure-suit. In cases of emergency air pressure loss, all you'd need is an oxygen mask and earplugs to survive for hours (This was used in Jerry Pournelle's "Tinker". The suit was worn like long johns under a coverall. The coverall is due to the fact that the suit is about as modest as wearing a coat of paint.).

Amusingly, the skintight suit made an appearance in a 1995 novel and anime television series called Rocket Girls. Maybe not so surprisingly, Japanese media in general is noted for its high standards of scientific accuracy. In this case the anime series had JAXA (the Japanese Aerospace eXploration Agency) and real-life Japanese astronaut Naoko Yamazaki as technical advisors.

The fictitious Solomon Space Association is developing the low-mass suits since their anemic one-lung LS-5 rocket can barely lift itself off the launch pad, let alone any payload. In a further desperate attempt to save on mass, they are reduce to using 16 year old girls as astronauts (which is a predictable development for a Japanese anime). They only weigh 38 kilograms, instead of the sixty-odd kilograms of the adult male astronauts. They take up less room in the control cabin as well.

There has even been some serious discussion given to suits more like those worn by the girls on the covers of magazines. We cannot really wear nothing but bathing suits in space, even with a bubble on our heads to supply oxygen to our lungs. (Pressure from the oxygen on the inside of the lungs must be balanced by pressure outside to make breathing possible for any length of time.) For a very short period, the bathing-suit affair might be enough — or even a normal suit of clothes, with an oxygen helmet. This type, though, would be used only as an emergency affair, and might prove very painful in even a few minutes, if not fatal.

Still, it appears that a suit could be designed which would not require that most of it be inflated at all.

The development of the simpler spacesuit almost certainly is not something that will be accomplished on the first trips into space. That type of suit might never work, but it is worth thinking about.

Suppose we keep the plastic helmet and air supply. Let the section around the lungs be the usual inflated tube, puffed out just a trifle beyond the skin, so that air pressure surrounds the lungs. We are still dealing with only 3 pounds pressure of oxygen. Now taper the inflated tube down at the shoulders and waist and change to an elastic fabric that will be skintight over legs, arms and hips. This fabric can be woven or formed so that it will have almost exactly 3 pounds pressure against the skin for every square inch. Yet when we move, there is no change of air pressure at the joints, because the fabric fits against our skin snugly.

We can still cover the material with reflective paint and weave tiny heating wires through it to take care of the temperature. We can even make it just a bit porous, so that perspiration can work through and evaporate into space — as it will do at once. Our bodies naturally cool themselves and maintain an even temperature by controlling the amount of perspiration. The same thing might happen while wearing our spacesuit. If the body became too warm, we would perspire more, and so increase the cooling. Or if we grew too cold, the perspiration would lessen, reducing the cooling. By using some kind of porous underclothing, the perspiration from even the sections inside the pressurized and inflated part of the suit might reach the cooling sections. There would be some loss of oxygen this way, but it could be kept to a level that would not matter for short periods of time.

Perhaps even the part of the suit over the lungs could be devised of similar elastic material, so that there would be oxygen only in the helmet. In that case, instead of huge, bulky suits, we might have something that looked like the tights male ballet dancers wear.

From ROCKETS THROUGH SPACE by Lester Del Rey (1957)

The pressure suit went on like a diver's wet suit, and looked like one only not so thick. It fit very closely; he had to use talcum power to get into it. Gloves dogged onto the ends of the sleeves, and a seal set firmly around his neck. He slipped into the boots, hung the small equipment bag over his shoulder, and reported back to the technicians.

They pulled and pinched, looking for loose spots. They didn't find any in Kevin's, but the next to come up was the girl he'd seen before, and after a moment they handed her a lump of what looked like clay. "Shove that under your breasts," the technician said. "Yeah, right there. Don't leave any gaps."

"But — " She was obviously embarrassed.

"Lady, you're going into vacuum," the man explained. "Your innards will be pressurized to about seven pounds by the air in your helmet. Outside is nothing. Your skin won't hold that. The suit will, but you've got to be flat against the suit, otherwise you'll swell up to fit any empty spaces. It won't do a lot of good for your figure."

"Oh. Thank you," she said. She turned away and used the clay as she'd been told.

From EXILES TO GLORY by Jerry Pournelle (1977).

On the big screen forward, two men —clad only in T-shirts and tights —are shown in the cramped air lock, struggling with their bright-colored leotard-like space suits, one red and one yellow.

The material of the suits is lightweight, strong, flexible —but not very elastic. Of necessity, it must be tight fitting; it is a second skin. Two sour-looking crewmen are helping them with the sleeves and leggings.

A fifth man is cramped against one wall, adjusting the helmets. He snaps a camera onto the left side of one —whatever the man is looking at will be relayed back to the bridge.

When the men are at last secure in their suits, their helmets are lowered over their heads. The "valets" complete the connections to the mobility and life-support backpack units and check them out. That done, and the units activated, the men snap their face-plates shut, check the helmet seals for security, and lower the appropriate filters into place. They are now bright-colored golems, each with a great dark eye for a face.

"Radio working?" asks one.

The other touches his device-studded "chastity belt," a plastic frame around his waist and genitals. "Right."

A wall panel flashes red —the other crewmen disappear through a hatch which slides impatiently shut after them. A hiss signals that the air is rapidly being drained from the chamber.

The suits do not puff out; only an occasional bubble of air, trapped under their second skins, reveals that the pressure is quickly decreasing. And then even these too evaporate away. "Bridge, we're ready to go."

From YESTERDAY'S CHILDREN by David Gerrolds (1972)

Latex Space Suit: Yep, these (‘skinsuits’, as opposed to ‘hardsuits’) are in common use – by the civilian spacer, anyway, who has no use for, for example, vacuum-sealed hardshell combat armor – although without the ridiculous semi-Stripperiffic elements (Sheer, you say? Heh. That fabric may contain pores, but it also contains MEMS, computer mesh, wound gel vacuoles…) a lot of media justifies them with, and have been in said use right from the earliest days when the Spaceflight Initiative conducted its feasibility studies for Project Phoenix.

They actually look pretty similar to the prototype of such a spacesuit that Dr. Dava Newman is developing at MIT (illustrated at right), although having smartglass around to provide an infinitely configurable variable filter plus display surface lets them use somethng much more like the classic “clear bubble helmet” *there*. Add a small support/systems backpack, and you’ve got it.

Further information on this general type of spacesuit is, of course, available at Atomic Rocket. In the Imperials’ version, though, I should note further that:

  • Skillful use of smart-fabric (a long way from literal latex) and MEMS for mechanical assistance has got the prebreathing/breathing mix problems down to an irreducible minimum, in modern suits at least.
  • Integrated and self-motile nanofluids have replaced the awkward necessity of stuffing clay into relevant places, at least once you overcome any squeamishness at the way the stuff crawls over you to get there.

Janty Yates, the costume designer for "The Martian," originally looked for inspiration to NASA's prototype Z1 and Z2 spacesuits. She worked with NASA officials and engineers, whom she described as "bend-over-backwards helpful." But in the end, she and her team came up with something new for the main spacesuit in "The Martian".

"We basically had to start from scratch," Yates told "We would've loved to use NASA's designs, but in the end, we just couldn't do it.

"The Martian" director Ridley Scott needed great visuals of Watney's face (as well as the faces of his crewmates) from a variety of angles, and the Z1 and Z2 — which both feature helmets that meld into the shoulder region of the suit — could not meet that requirement, Yates said.

"Ridley needed to see his actors in profile; he needed to see them moving their heads; he needed close-ups on the eyes," said Yates

Aesthetics were also an issue; Scott didn't find the Z-2 spacesuit visually striking enough, Yates said.

Yates worked with concept artists to draw up a variety of basic designs for the suit worn by Watney and his crewmates on the Martian surface, then presented them to Scott for approval. The body-hugging, black-white-and-orange suit showcased in the film emerged by process of elimination. (Interestingly, the movie's suit superficially resembles the Biosuit, a real space garment being developed by researchers at the Massachusetts Institute of Technology.)

So, while NASA didn't come up with the surface suit featured in "The Martian," agency officials did approve the astronaut apparel.

"As we went along, we had to submit the designs for their approval," Yates said. "And they approved along the way, as did the [film's] art department."

"The Martian" features one other spacesuit in addition to the surface suit — a bulky white extravehicular activity (EVA) suit the astronauts wear in space. The film's EVA suit is modeled closely on the one NASA astronauts wear on spacewalks outside the International Space Station, Yates said.

"We kept that very much to NASA style, but we made it a lot more streamlined," she said.


     At least there was no smoke on the bridge. The ventilation system had cleared it. Death by smoke inhalation was almost as bad as death by vacuum. Sandoval fancied she could hear the vacuum on the other side of the hatch scratching to get in and kill them all.
     The Captain and Luch were going over the readings and checking the view on the rest of the deck. Finally the Captain looked up and rubbed his eyes. "Okay. We have a direct hit on this deck which, aside from letting the air out and messing our quarters up did not real harm. But we took that hit right before we went to FTL. Good job on that Sandy. Now we gotta get to the main damage control locker and the space suits there and get them back in here. Then we can see about patching that hole before it lets FTL space in ... that isn't good. And there's ten meters or so of indoor vacuum between us and that locker."
     Sandoval shuddered a bit. FTL entering STL space was never good. As a navigator she knew enough of the theory of FTL to know that. Non-biological entities, jump trauma, flash fever ... the list went on.
     The bridge damage control locker had compressor masks that could be hooked up to a small air tank or air line. No space suits though. In a perfect world they'd be suited up already and at their stations for a hazardous operation. The bridge was too cramped for a locker to hold their suits. It was only designed to keep them alive when things were killing them slowly.
     Using a breathing mask in a vacuum was a good way to kessler your lungs. Absently Sandoval began rooting through the locker, digging through the various odds and ends accumulated over the years. Power bars, lanyards, vacc tape spilled out. What was she looking for? A new hyperdrive to get them to port and a rescue ship?
     "Well I was told this sort of freighter was designed to explode on a direct hit killing us all cleanly," Luch said in mock anger. "I get out of this I'm suing the f*ck*ng shipyard."
     The Captain administered a dopeslap that forced Luchador to adjust the mask he never removed, for no one knew what reason. Sandoval never thought it was polite to ask. "Not the time Luch," the Captain reproved.
     "Sorry sir. A little gallows humor. On the bright side we could hide in the electronics hole and prolong life a few more hours. None of these doors are completely airtight but we could get by."
     "How long till we break out, Sandy?" the Captain asked.
     "At least six days," the small woman answered toying with the materials she'd pulled from the locker. They all knew the air was going to leak out before then. Even with the last refuge of the computer and sensor service crawspace they had maybe a day of air. Air tight doors everywhere was too expensive.
     It wasn't fair. She'd plotted that jump perfectly and in half the time. The ship had ducked missiles and beams like a courier on uppers. They had all performed so well in the face of an invasion and an enemy determined to kill them. It just wasn't good enough. But to die knowing there was a locker full of air tanks not ten meters away was galling.
     Luch grabbed a roll of tape. "We can seal the hatch with this. Buy us a few more hours. We could just say screw it, hit the overrides and open the hatch now. At least it'd be fast. Why do we have so many damn rolls of vacc tape anyway? Your previous quartermaster was a tool, Captain! And this damn ship ... you do everything on the cheap! We're going to die because you didn't spring for some extra spacesuits!"
     The Captain grabbed Luch by the arm and hauled him as far from Sandoval as he could. It wasn't very far. Urgent and harsh whispering followed. The Captain finally ordered the Steward/Mechanic to take a seat and eat a power bar. Sandoval toyed with an old wallet someone had constructed out of tape. Probably an attempt to stave off boredom on a watch during FTL, much like this but without a hole in the hull dooming them all.
     "Hey ... Captain!"
     Adhesive tape was invented in 1845 by Dr. Horace Day. Clear adhesive or tape was made by Richard Drew in 1922 and the Holy Grail: duct tape appeared in 1942. By TL 8 in the year 20-mumblety-rhubarb we have Vacc Tape!
     The salient feature of vacc tape is it works in vacuum. More primitive tapes use adhesives that boil off in vacuum or are destroyed in extreme temperatures. Vacc tape works in extreme temperatures and vacuum ... for a while. By TL 10 synthetic adhesives are able to keep a bond and even strengthen under temperatures extremes to rock hard consistency.
     The other feature of vacc tape is not obvious at first. It changes color in vacuum. A roll of red tape turns a bright blue. Exposure to oxygen turns it red again. Seal a hole with it and air leaking out will turn the tape red making it easy to judge the worth of your damage control. Air bubbles can be spotted and reinforced before they burst. Savvy spacers in an unstable situation or hull will lay strips around the door to the living section. A blue strip around the door indicates vacuum on the other side. Suit up. Some spacers put a strip around the wrist of their space suit as a final check that an airlock that says it is pressurizing is pressurizing.
     Needless to say the stuff also spawns its own craft industry. Spacers make all manner of things, wallets, bags even clothing, slippers and more ...
     "The breathing mask is not ... optimal," Sandoval said. The Captain's voice rattled in her earbud. "Explain?"
     "It's fogging like a sonuvabitch. Also the soft helmet part is inflating. I'm dizzy," she said walking down the corridor. To compound matters, her tape slippers were slippery: a small etymological irony and she was dragging an air line behind her. The journey of ten meters seemed very long.
     She was sure she was starting to feel the bends despite the Captain lowering the bridge's air pressure and switching to a pure oxygen mix.
     It was only logical they use her for a subject. She was the smallest, letting them layer the tape the thickest over her. She was female and needed less oxygen. She thought up the crazy plan.
     She knew her mask was filling with carbon dioxide, or was it monoxide? She always confused the two.  The mask's exhausts were puttied shut. To make maters worse the tape covering every inch of her below the neck constricted like a ... constricting animal thing. that monoxide dioxide was really messing with her.
     Applying the stuff was the most undignified ordeal of her young life. The Captain and Luch applied the tape in rings around her torso and extremities. Luchs made sure the strip ends overlapped a lot. Then they reinforced the rings in the first layer with a layer of vertical strips. That was bad enough. But Luchs wanted to make sure the tape wouldn't peel up from curvy places and had puttied them up but good. It didn't help that Luchs was asexual. She'd blushed down to her toes. It didn't help when Luchs said there were establishments that would pay a few hundred credits to people submitting to such treatment.
     The Captain's dopeslap was perfectly timed and thump on Luch's head was most satisfying. They actually all managed a laugh.
     To make matters worse her nose was itchy. Her nose was itchy. She was having all manner of trouble breathing and now had the figure of a twelve year old boy and her neck felt like it measured 70 centimeters because that pulchtritude had to go somewhere.
     Her goddam nose itched. Was an itchy nose a symptom of suffocation/asphyxiation?
     She was at the damage control locker! The door opened to her frenzied yanking and curses. Cursing helped all manner of things. She grabbed a spacesuit and turned to scramble back to the bridge. The door was open and looked inviting even though the vacuum was as hard on the other side of it. The Captain and Luchs were waiting in the electronics hole and were pretty screwed if she messed up. Lugging the suit and the air hose she slipped and slid back to the bridge. At least they still had gravity. That alone indicated the hull couldn't be that badly holed.
     Sandoval threw the suit into the pilot seat. Her vision was blurring and not from a fogged mask as she reached for the hot key they'd set up. She hit it before she reeled and crashed to the deck.
     She woke up in the deluxe stateroom's master's bed. Usually the captain took the cabin over when he couldn't fill it.
     Luchs was sitting on the bed shaking her foot. "How are ya?" he asked. Sandoval stretched and saw tape still covered her arms. She moved her feet and realized it still covered most of her. She saw a very careful slit was made down her sternum letting her breathe. "I have the best vat steak in the galley cooking for you with your favorite sides. The Captain is still working on damage control but we're holding air. The beam went through the hull at stateroom three. There's a big hole on the outer hull and a nasty on on the hatch. He slapped patches on them and is welding the cabin's hatch shut."
     "Sounds good. Can I get up?" Sandoval said. She really was enjoying the bed though. Much better than a bunk.
     "Sure Sandy ... but here's the bad news: that tape has to come off you before it cuts off circulation."
     "Mmm ..."
     "On three ..." Luchs said.
     He yanked the first strip off on 'one'.
     The Captain heard her scream through one deck and his helmet.

From VACC TAPE by Rob Garitta (2017)

Going Outside

Suiting Up

I had an awful time getting into it - dressing in an upper berth is a cinch by comparison. The photographer said, "Just a minute, kid. I've seen 'em do it at Wright Field. Mind some advice?"

"Uh? No. I mean, yes, tell me."

"You slide in like an Eskimo climbing into a kayak. Then wiggle your right arm in-"

It was fairly easy that way, opening front gaskets wide and sitting down in it, though I almost dislocated a shoulder. There were straps to adjust for size but we didn't bother; he stuffed me into it, zippered the gaskets, helped me to my feet and shut the helmet.

. . .

But I didn't get tired of it; a space suit is a marvelous piece of machinery - a little space station with everything miniaturized. Mine was a chrome-plated helmet and shoulder yoke which merged into a body of silicone, asbestos, and glass-fibre cloth. This hide was stiff except at the joints. They were the same rugged material but were "constant volume" - when you bent a knee a bellows arrangement increased the volume over the knee cap as much as the space back of the knee was squeezed. Without this a man wouldn't be able to move; the pressure inside, which can add up to several tons, would hold him rigid as a statue. These volume compensators were covered with dural armor; even the finger joints had little dural plates over the knuckles.

It had a heavy glass-fibre belt with clips for tools, and there were the straps to adjust for height and weight. There was a back pack, now empty, for air bottles, and zippered pockets inside and out, for batteries and such.

The helmet swung back, taking a bib out of the yoke with it, and the front opened with two gasketed zippers; this left a door you could wiggle into. With helmet clamped and zippers closed it was impossible to open the suit with pressure inside.

Switches were mounted on the shoulder yoke and on the helmet; the helmet was monstrous. It contained a drinking tank, pill dispensers six on each side, a chin plate on the right to switch radio from "receive" to "send," another on the left to increase or decrease flow of air, an automatic polarizer for the face lens, microphone and earphones, space for radio circuits in a bulge back of the head, and an instrument board arched over the head. The instrument dials read backwards because they were reflected in an inside mirror in front of the wearer's forehead at an effective fourteen inches from the eyes.

Above the lens or window there were twin headlights. On top were two antennas, a spike for broadcast and a horn that squirted microwaves like a gun-you aimed it by facing the receiving station. The horn antenna was armored except for its open end.

This sounds as crowded as a lady's purse but everything was beautifully compact; your head didn't touch anything when you looked out the lens. But you could tip your head back and see reflected instruments, or tilt it down and turn it to work chin controls, or simply turn your neck for water nipple or pills. In all remaining space sponge-rubber padding kept you from banging your head no matter what. My suit was like a fine car, its helmet like a Swiss watch. But its air bottles were missing; so was radio gear except for built-in antennas; radar beacon and emergency radar target were gone, pockets inside and out were empty, and there were no tools on the belt. The manual told what it ought to have - it was like a stripped car.

Carry steel bottles on your back; they hold "air" (oxygen and helium) at a hundred and fifty atmospheres, over 2000 pounds per square inch; you draw from them through a reduction valve down to 150 p.s.i. and through still another reduction valve, a "demand" type which keeps pressure in your helmet at three to five pounds per square inch-two pounds of it oxygen. Put a silicone-rubber collar around your neck and put tiny holes in it, so that the pressure in the body of your suit is less, the air movement still faster; then evaporation and cooling will be increased while the effort of bending is decreased. Add exhaust valves, one at each wrist and ankle-these have to pass water as well as gas because you may be ankle deep in sweat.

The bottles are big and clumsy, weighing around sixty pounds apiece, and each holds only about five mass pounds of air even at that enormous pressure; instead of a month's supply you will have only a few hours - my suit was rated at eight hours for the bottles it used to have.

. . .

To make darn sure that you're getting enough (your nose can't tell) you clip a little photoelectric cell to your ear and let it see the color of your blood; the redness of the blood measures the oxygen it carries. Hook this to a galvanometer. If its needle gets into the danger zone, start saying your prayers. (ed. note: in Heinlein's other novels, instead of a galvanometer they use an "anoxia warning light")

. . .

Air sighed softly into the helmet, its flow through the demand valve regulated by the rise and fall of my chest - I could reset it to speed up or slow down by the chin control.

. . .

I didn't bother with a radar target or beacon; the first is childishly simple, the second is fiendishly expensive. But I did want radio for the space-operations band of the spectrum - the antennas suited only those wavelengths.

. . .

The only thing that complicated the rest of the electrical gear was that everything had to be either "fail-safe" or "no-fail"; a man in a space suit can't pull into the next garage if something goes wrong - the stuff has to keep on working or he becomes a vital statistic. That was why the helmet had twin headlights; the second cut in if the first failed - even the peanut lights for the dials over my head were twins. I didn't take short cuts; every duplicate circuit I kept duplicate and tested to make sure that automatic changeover always worked.

Mr. Charton insisted on filling the manual's list on those items a drugstore stocks - maltose and dextrose and amino tablets, vitamins, dexedrine, dramamine, aspirin, antibiotics, antihistamines, codeine, almost any pill a man can take to help him past a hump that might kill him.

. . .

I made it a dress rehearsal - water in the drinking tank, pill dispensers loaded, first-aid kit inside, vacuum-proof duplicate (I hoped it was vacuum-proof) in an outside pocket. All tools on belt, all lanyards tied so that tools wouldn't float away in free fall.

. . .

I ran into a snag. The spare bottles I had filched from those ghouls had screw-thread fittings like mine - but Peewee's bottles had bayonet-and-snap joints. Okay, I guess, for tourists, chaperoned and nursed and who might get panicky while bottles were changed unless it was done fast - but not so good for serious work.

. . .

"Mind your pressure. Kip. You're swelling up too fast." I kicked the chin valve while watching the gauge - and kicking myself for letting a little girl catch me in a greenhorn trick. But she had used a space suit before, while I had merely pretended to.

From HAVE SPACE SUIT - WILL TRAVEL by Robert A. Heinlein, 1958.

(ed note: this is a bit dated since it was written in 1939, but still surprisingly good)

"This is a standard service type, general issue, Mark IV, Modification 2." He grasped the suit by the shoulders and shook it out so that it hung like a suit of long winter underwear with the helmet lolling helplessly between the shoulders of the garment. "It's self-sustaining for eight hours, having an oxygen supply for that period. It also has a nitrogen trim tank and a carbon dioxide water-vapor cartridge filter."

He droned on, repeating practically verbatim the description and instructions given in training regulations. McCoy knew these suits like his tongue knew the roof of his mouth; the knowledge had meant his life on more than one occasion.

"The suit is woven from glass fibre laminated with nonvolatile asbesto-cellutite. The resulting fabric is flexible, very durable; and will turn all rays normal to solar space outside the orbit of Mercury. It is worn over your regular clothing, but notice the wire-braced accordion pleats at the major joints. They are so designed as to keep the internal volume of the suit nearly constant when the arms or legs are bent. Otherwise the gas pressure inside would tend to keep the suit blown up in an erect position and movement while wearing the suit would be very fatiguing.

"The helmet is moulded from a transparent silicone, leaded and polarized against too great ray penetration. It may be equipped with external visors of any needed type. Orders are to wear not less than a number-two amber on this body. In addition, a lead plate covers the cranium and extends on down the back of the suit, completely covering the spinal column.

"The suit is equipped with two-way telephony. If your radio quits, as these have a habit of doing, you can talk by putting your helmets in contact. Any questions?"

"How do you eat and drink during the eight hours?"

"You don't stay in 'em any eight hours. You can carry sugar balls in a gadget in the helmet, but you boys will always eat at the base. As for water, there's a nipple in the helmet near your mouth which you can reach by turning your head to the left. It's hooked to a built-in canteen. But don't drink any more water when you're wearing a suit than you have to. These suits ain't got any plumbing."

Suits were passed out to each lad, and McCoy illustrated how to don one. A suit was spread supine on the deck, the front zipper that stretched from neck to crotch was spread wide and one sat down inside this opening, whereupon the lower part was drawn on like long stockings. Then a wiggle into each sleeve and the heavy flexible gauntlets were smoothed and patted into place. Finally an awkward backward stretch of the neck with shoulders hunched enabled the helmet to be placed over the head.

Libby followed the motions of McCoy and stood up in his suit. He examined the zipper which controlled the suit's only opening. It was backed by two soft gaskets which would be pressed together by the zipper and sealed by internal air pressure. Inside the helmet a composition mouthpiece for exhalation led to the filter.

From MISFIT by Robert Heinlein (1939)

(ed note: The people are using powered-armor spacesuits on planets where the temperature hovers around -270°C, 8 K)

"Now, you didn't get much in-suit training Earthside. We didn't want you to get used to using the thing in a friendly environment. The fighting suit is the deadliest personal weapon ever built, and with no weapon is it easier for the user to kill himself through carelessness. Turn around, Sergeant.

"Case in point." He tapped a large square protuberance between the shoulders. "Exhaust fins. As you know, the suit tries to keep you at a comfortable temperature no matter what the weather's like outside. The material of the suit is as near to a perfect insulator as we could get, consistent with mechanical demands. Therefore, these fins get hot especially hot, compared to darkside temperatures—as they bleed off the body's heat.

"All you have to do is lean up against a boulder of frozen gas; there's lots of it around. The gas will sublime off faster than it can escape from the fins; in escaping, it will push against the surrounding ice, and fracture it … and in about one-hundredth of a second, you have the equivalent of a hand grenade going off right below your neck. You'll never feel a thing.

"Variations on this theme have killed eleven people in the past two months. And they were just building a bunch of huts. (imagine how dangerous it will be when the enemy is shooting at you)

"Now everybody pay close attention. I'm going out to that blue slab of ice"—it was a big one, about twenty meters away—"and show you something that you'd better know if you want to stay alive."

He walked out in a dozen confident steps. "First I have to heat up a rock—filters down." I squeezed the stud under my armpit and the filter slid into place over my image converter. The captain pointed his finger at a black rock the size of a basketball, and gave it a short burst. The glare rolled a long shadow of the captain over us and beyond. The rock shattered into a pile of hazy splinters.

"It doesn't take long for these to cool down." He stopped and picked up a piece. "This one is probably twenty or twenty-five degrees (Kelvin, -248°C). Watch." He tossed the "warm" rock onto the ice slab. It skittered around in a crazy pattern and shot off the side. He tossed another one, and it did the same.

"As you know, you are not quite perfectly insulated. These rocks are about the temperature of the soles of your boots. If you try to stand on a slab of hydrogen, the same thing will happen to you. Except that the rock is already dead.

"The reason for this behavior is that the rock makes a slick interface with the ice—a little puddle of liquid hydrogen—and rides a few molecules above the liquid on a cushion of hydrogen vapor. This makes the rock or you a frictionless bearing as far as the ice is concerned, and you can't stand up without any friction under your boots.

"After you have lived in your suit for a month or so you should be able to survive falling down, but right now you just don't know enough. Watch."

The captain flexed and hopped up onto the slab. His feet shot out from under him and he twisted around in midair, landing on hands and knees. He slipped off and stood on the ground.

"The idea is to keep your exhaust fins from making contact with the frozen gas. Compared to the ice they are as hot as a blast furnace, and contact with any weight behind it will result in an explosion."

From THE FOREVER WAR by Joe Haldeman (1975)

Besides the usual cargo lock we had three Kwikloks. A Kwiklok is an Iron Maiden without spikes; it fits a man in a suit, leaving just a few pints of air to scavenge, and cycles automatically. A big time saver in changing shifts. I passed through the middle-sized one; Tiny, of course, used the big one. Without hesitation the new man pulled himself into the small one.

From Delilah and the Space-Rigger by Robert Heinlein (1949)

Safety Check

First Jamieson, then Wheeler, chanted the alphabetic mnemonic - "A is for air-lines, B is for batteries, C is for couplings, D is for D.F. loop ..." which sounds so childish the first time one hears it, but which so quickly becomes part of the routine of lunar life - and is something nobody ever jokes about.

From EARTHLIGHT by Sir Arthur C. Clarke. 1955.

And in Clarke's "The Haunted Spacesuit" aka "Who's There?" they chant "FORB" for Fuel, Oxygen, Radio, Batteries.

[Steve and Nadia] donned the heavily-insulated, heated suits, and Stevens snapped into their sockets the locking plugs of the drag line.

"Hear me?" he asked. "Sound-disks all x?"

"All x."

"On the radio-all x?"

"All x."

"I tested your tanks and heaters-they're all x. But you'll have to test..."

"I know the ritual by heart, Steve. It's been in every show in the country for the last year, but I didn't know you had to go through it every time you went out-of-doors! Valves, number one all x, two all x, three all x..."

"Quit it!" he snapped. "You aren't testing those valves! That check-up is no joke, guy. These suits are complicated affairs, and some parts are apt to get out of order. You see, a thing to give you fresh air at normal pressure and to keep you warm in absolute space can't be either simple or foolproof. They've worked on them for years, but they're pretty crude yet. They're tricky, and if one goes sour on you out in space it's just too bad-you're lucky to get back alive. A lot of men are out there somewhere yet because of sloppy check-ups."

" 'Scuse it, please-I'll be good," and the careful checking and testing of every vital part of the space-suits went on.

From SPACEHOUNDS OF IPC by E.E. "Doc" Smith, 1931.

The instructor ordered his group to "Suit upl" without preliminary, as it was assumed that they had studied the instruction spool.

The last of the ship's spin had been removed some days before. Matt curled himself into a ball, floating free, and spread open the front of his suit. It was an unhandy process; he found shortly that he was trying to get both legs down one leg of the suit. He backed out and tried again. This time the big fishbowl flopped forward into the opening.

Most of the section were already in their suits. The instructor swam over to Matt and looked at him sharply. "You've passed your free-fall basic?"

"Yes," Matt answered miserably.

"It's hard to believe. You handle yourself like a turtle on its back. Here." The instructor helped Matt to tuck in, much as if he were dressing a baby in a snow suit. Matt blushed.

The instructor ran through the check-off list -- tank pressure, suit pressure, rocket fuel charge, suit oxygen, blood oxygen (measured by a photoelectric gadget clipped to the earlobe) and finally each suit's walky-talky unit. Then he herded them into the airlock.

From SPACE CADET by Robert Heinlein (1948)

In spite of the fail-safe design of the P-suits— so loss of pressure in one part of the suit won't result in a total loss of suit pressure—we lost a rigger yesterday for a stupid reason.

Riggers working in P-suits are required to use the Buddy System—checking each other's gear before cycling to vacuum. But this crew was in a hurry to get on the job. So the buddy didn't check both of the helmet pressurizing lines where the fittings go into the helmet. From what Pratt determined by studying the P-suit later, neither line was inserted in the fitting past the detent. I've got to admit, it's difficult to tell when you've twisted the fitting past the detent, especially if you're already wearing P-suit gloves.

Out in vacuum, the guy snagged one of the lines and pulled it out of the helmet fitting. The check valve closed when the line left the fitting, just as it's supposed to do. But when he heard the line come out of the fitting, he turned, caught the other line on the same beam element, and pulled the second line far enough out of the fitting so it blew most of his back-pack oxygen supply out into space . . . and at the same time failed to come out of the fitting far enough to activate the check valve. He lost helmet pressure in a few seconds. By the time his buddy got to him, he died from what Fred termed "traumatic abaryia," or rapid and terminal loss of pressurization.

Another case was perhaps worse from our point of view because, although the man was alive when we got him, he was too far gone to save. Writers often talk about the "primordial cold of outer space." But we lost this man to hyperpyrexia—overheating.

P-suit backpacks are designed to get rid of the metabolic heat generated by the individual, plus the environmental heat load from outside. There's a limit to the backpack's capability. Everybody's trained to recognize the symptoms of potential overload—a rise in P-suit temperature, hyperventilation, headache, et cetera. When it starts to happen, you slow down, rest, relax— or you're dead very quickly. This poor guy never had a chance, and it was a genuine industrial accident thai finished him.

While a photovoltaic power module's brought up from LEO Base, where it's assembled, it converts sunlight to electricity, which is used to power the electric thrusters which propel it to GEO Base. The structure isn't metal; it's a carbon-reinforced composite plastic.

The riggers had docked the new module to the main array, and Lucky's crew moved in to make the electrical switchover. Supposedly, it's impossible to create an electric arc in a vacuum, but GEO Base is surrounded by a halo of escaped life-support-system gases, outgas-sing products from materials, and other things that make the vacuum less than perfect. This is a construction site, and I've never seen a clean construction site anywhere.

During one of the switchover sequences, part of an insulator failed and an arc jumped across the rest of the insulator to the structure. It vaporized the carbon-composite plastic, which in turn vapor-deposited on everything within fifty feet, including the P-suit of the man who was nearby. It blackened his P-suit within a fraction of a second. He was in full sunlight at the time. Within ten seconds his suit and backpack were too hot for the backpack system to handle. He practically fried in less than thirty seconds.

"Med Unit, Central!" the intercom rasped. "Accident in vacuum! Reported P-suit fire! Location Array Subassembly Module One Zero Seven. Repeat: One Zero Seven!"

One of the P-suited individuals was obviously unconscious. Tom surmised this from the limp, rag-doll posture and random small movements of the limbs of the P-suit. He looked at the faceplate and discovered that the inside surface was covered with a brownish-black deposit, The injured man was no longer being supported by his own backpack. It had been disconnected, and he had been buddy-coupled to another individual's pack.

"What happened?" Tom asked.

"Fire in the backpack," somebody announced on the radio.

"Jed hollered that's what happened before he choked," another voice cut in. "Pete got him hooked up buddy-style (cross-connect) in about twenty seconds."

It didn't take more than thirty seconds to repressurize the Pumpkin (ambulance). Then Tom opened the faceplate of the injured man's P-suit helmet. The man had had a beard that had been singed off. There were first- and second-degree burns on his face. The most severe burns were in the vicinity of the oxygen inlet couplings from the backpack to the helmet. Tom had no way of knowing the nature or extent of possible burns in the lungs or airways.

It didn't take long to determine the source of the fire. Each backpack contains two high-pressure-oxygen storage bottles. A pressure switch valves a full bottle into the system when it senses the on-line bottle's pressure has dropped below a preset limit. The high-pressure oxygen then flows through a regulator that drops the pressure to about five psi absolute. The plastic O-ring that seals the upstream side of the regulator may have had a trace of contamination on it; the culprit seems to be aluminum shaved off the fitting when a maintenance tech over-tightened it. When the pressure sensor switched tanks, a shock wave of high-pressure oxygen hit the upstream side of the regulator fitting and was heated by shock compression. This action ignited whatever was on the O-ring. The aluminum of the regulator body then began to burn in the hot, oxygen-rich atmosphere, and, in turn, sent an oxygen-rich flame right down the breathing pressure lines to the interior of Hobart's helmet.

A fifty-cent O-ring and an uncalibrated torque wrench killed a man. It could also call a halt to a multibillion-dollar project.

Pratt says it's a simple fix. He's got his maintenance techs replacing O-rings and installing a diffuser upstream of the regulator as each backpack comes in from vacuum for refurbishment at the end of each shift.

From SPACE DOCTOR by Lee Correy (G. Harry Stine) 1981

First things first, and the first thing you need in space is a space suit. Apart from its necessity for working on space projects (building space stations, etc.) it is absolutely vital for examining the outside of your ship in case of damage from meteorites, etc. It may even be necessary to abandon ship, in extreme cases, and in this event your very existence depends upon its efficiency. You see me here in a self-contained, total-vacuum, mark-seven suit. Below you will find listed some of its most important features:

  1. Radio mast of ultra short-wave radio.
  2. Compressed air cylinder of closed-circuit air supply.
  3. Jet on universal mounting and chemical-fuel container.
  4. All joints reinforced. A punctured space suit means death!
  5. Reinforced plastic boots with electro-magnetic soles.
  6. Large universal-vision, anti-cosmic "Plastilight" helmet.
  7. Scaling ring to visor, metal with rubber "hose" lining, inflated from air supply.
  8. Miniature tele-view tray (referred to as the "T" tray).
  9. Control stick to jet (3). Twist grip rotates jet for manœuvring in space.
  10. Hydro-ammonal container and feed line to flame gun.
From Ron Turner's SPACE ACE POP UP BOOK (1953).

Buddy System

While wearing a space suit in vacuum, the iron-clad rule is The Buddy System. There are many mishaps that are trivial if you have a companion but fatal if you don't. Imagine that your suit springs a slow leak on your back just where you can't reach it with a repair patch. Oops.

In cases of emergency, two space suited people can "cross-connect" their oxygen supplies. This is generally done when one of them runs out of breathable gas, the other shares their oxygen until they get to shelter.

ed note: Kip (a college student) and Peewee (a little girl) are wearing spacesuits and are engaged in a forced march across the surface of Luna. Unfortunately the spare oxygen bottles the are carrying have connections incompatible with Peewee's suit. Kip uses surgical tape as an adapter to recharge Peewee's bottle. Peewee has tied the spare bottles to Kip's front. Oh, and Kip named his spacesuit "Oscar")

We were about halfway down the outer slope when Peewee slowed and stopped—sank to the ground and sat still.

I hurried to her. “Peewee!”

“Kip,” she said faintly, “could you go get somebody? Please? You know the way now. I’ll wait here. Please, Kip?”

“Peewee!” I said sharply. “Get up! You’ve got to keep moving.”

“I c-c- can’t!” She began to cry. “I’m so thirsty … and my legs—” She passed out.

“Peewee!” I shook her shoulder. “You can’t quit now! Mother Thing! —you tell her!”

Her eyelids fluttered. “Keep telling her, Mother Thing!” I flopped Peewee over and got to work. Hypoxia hits as fast as a jab on the button. I didn’t need to see her blood-color index to know it read DANGER; the gauges on her bottles told me. The oxygen bottles showed empty, the oxy-helium tank was practically so. I closed her exhaust valves, overrode her chin valve with the outside valve and let what was left in the oxy-helium bottle flow into her suit. When it started to swell I cut back the flow and barely cracked one exhaust valve. Not until then did I close stop valves and remove the empty bottle.

I found myself balked by a ridiculous thing.

Peewee had tied me too well; I couldn’t reach the knot! I could feel it with my left hand but couldn’t get my right hand around; the bottle on my front was in the way—and I couldn’t work the knot loose with one hand.

I made myself stop panicking. My knife—of course, my knife! It was an old scout knife with a loop to hang it from a belt, which was where it was. But the map hooks on Oscar’s belt were large for it and I had had to force it on. I twisted it until the loop broke.

Then I couldn’t get the little blade open. Space-suit gauntlets don’t have thumb nails.

I said to myself: Kip, quit running in circles. This is easy. All you have to do is open a knife—and you’ve got to … because Peewee is suffocating. I looked around for a sliver of rock, anything that could pinch-hit for a thumb nail. Then I checked my belt.

The prospector’s hammer did it, the chisel end of the head was sharp enough to open the blade. I cut the clothesline away.

I was still blocked. I wanted very badly to get at a bottle on my back. When I had thrown away that empty and put the last fresh one on my back, I had started feeding from it and saved the almost half-charge in the other one. I meant to save it for a rainy day and split it with Peewee. Now was the time—she was out of air, I was practically so in one bottle but still had that half-charge in the other—plus an eighth of a charge or less in the bottle that contained straight oxygen (the best I could hope for in equalizing pressures), I had planned to surprise her with a one-quarter charge of oxy-helium, which would last longer and give more cooling. A real knight-errant plan, I thought. I didn’t waste two seconds discarding it.

I couldn’t get that bottle off my back!

Maybe if I hadn’t modified the backpack for nonregulation bottles I could have done it. The manual says: “Reach over your shoulder with the opposite arm, close stop valves at bottle and helmet, disconnect the shackle—” My pack didn’t have shackles; I had substituted straps. But I still don’t think you can reach over your shoulder in a pressurized suit and do anything effective. I think that was written by a man at a desk. Maybe he had seen it done under favorable conditions. Maybe he had done it, but was one of those freaks who can dislocate both shoulders. But I’ll bet a full charge of oxygen that the riggers around Space Station Two did it for each other as Peewee and I had, or went inside and deflated.

If I ever get a chance, I’ll change that. Everything you have to do in a space suit should be arranged to do in front — valves, shackles, everything, even if it is to affect something in back. We aren’t like Wormface, with eyes all around and arms that bend in a dozen places; we’re built to work in front of us — that goes triple in a space suit.

You need a chin window to let you see what you’re doing, too! A thing can look fine on paper and be utterly crumby in the field.

From HAVE SPACE SUIT - WILL TRAVEL by Robert Heinlein, 1958



When you gotta go, you gotta go. A sudden urgent need to urinate or defecate when you are in a space suit during an EVA is a major problem.

NASA became aware of the need for space diapers on May 5, 1961. Freedom 7 was about to launch with astronaut Alan Shepard. NASA figured there was no need for a potty break, er, ah, "bladder evac" since the flight was only going to take 15 minutes. Alas there were several delays so poor Alan was on the pad for eight hours. He had to ask ground control for permission to pee in his suit, which was granted. Shorted out some of his medical sensors, though.

For the Gemini and Apollo programs they had a system for urination only. It was functionally equivalent to a condom (a "cuff") attached to a tube. The tube drained into a containment bag through a one-way valve. The cuff fit had to be snug or there would be dangerous leakage. The cuffs came in three sizes.

The space suit designers demonstrated a stunning ignorance of macho astronauts when they labeled the sizes "small", "medium", and "large".

Predictably, when asked which size they needed, all the testosterone-poisoned Right Stuff astronauts answered "Large, of course."

After a few nasty incidents of space suits filling up with urine due to poorly fitting sheaths, the technicians re-named the sizes "large", "gigantic", and "humongous."

Unfortunately the best technology NASA currently has to offer is the "Maximum Absorbency Garment" (MAG). Which is basically a high-tech diaper. The MAG is full of sodium polyacrylate, which can absorb 300 times its weight in water. The MAG can hold about two liters of urine, blood, and/or feces. It was a challenge since conventional incontinence pants require gravity in order to operate.

Astronauts in free fall tend to have lots of urine to void when they finally feel the urge to go. Under normal gravity urine collects at the bottom of the bladder, triggering the urge when the bladder is one-third full. But in zero gee, urine in the bladder is floating around. The urge only comes when the bladder is almost totally full, causing pressure on the sides. Which is a problem since that much urine can press the urethra shut, making it hard to urinate. Astronauts are advised to schedule regualar pee breaks even if they do not feel the need.

The first time the condom and bag device was used in space was in John Glenn's 1962 orbital flight. He voided a full 27 ounces of urine in one go, which is about seven ounces more than the capacity of the average human bladder.

Schweickart: Yeah, it's not that much. But it's a fairly critical time, you know. When you're in there you don't have much choice, so you've got to design for it. Okay. So in the suit, for urine you use like a motorman's bag, which is basically composed of a bladder that holds about — boy, my numbers are really slipping Peter — but something between a liter and two liters, if I remember. A rubber bladder type of thing that sort of fits around your hips, and a rollon cuff which is essentially a condom with the end cut out that's rolled over a flapper-type valve, you know, just a rubber flapper valve. It forms a one-way check valve.

Warshall: Oh, I see, so you don't have to do anything.

Schweickart: No, you don't do anything. You just roll it on as part of the suit-donning procedure, and then urinate into it through the one-way valve. There are lots of little cute problems and uncertainties Unless you're an extremely unusual person, since the time you were about a year and a half old or so, you probably have not taken a leak laying flat on your back. And if you think that's easy, let me tell you, you've got some built-in psychological or survival programs, or something which you've got to overcome. So that's a tricky little thing. And then there's always the possibility that in maneuvering around in a suit you can end up pulling off the condom, and there's always — we have three sizes you know, small, medium and large — in diameter, and there's always this little ego thing about which one you do pick. of course the smart guy picks the right size, because it's very important. But what happens is, if you get too small a size it effectively pinches off the flow and you just turn yellow because you can't go; and if, on the other hand you've got an ego problem and you decide on a large when you should have a medium, what happens is you take your first leak and you end up with half of the urine outside the bag on you. And that's the last time you make that mistake. So it's a cute little trick there.

In terms of defecation inside the suit, there ain't no graceful way to do it. So what we do is, we wear what's affectionately called a fecal containment system. The good old FCS is essentially like a pair of bermuda shorts with a hole for your penis to stick out of to roll on this other thing, but fairly well sealed around there.

It's a tight fitting elastic type garment, and it fits especially tight around the thighs and around the waist. And it's just like a pair of diapers is what it is. made of material which obviously is non-permeable but still breathes and all it does is contain it. Now, to my knowledge, nobody's ever had to use that. But you wear it, because if you don't wear it, the consequences are rather drastic. Okay. So that sort of takes care of the in-the-suit situation.

From "THERE AIN'T NO GRACEFUL WAY" Astronaut RUSSELL SCHWEICKART talking to Peter Warshall, collected in CoEvolution Quarterly Winter 1976-77

On Earth, Andrew Lear's habits would have been no more than a character trait. In a hurry, he might choose mismatched socks. He might put off using the dishwasher for a day or two if he were involved in something interesting. He would prefer a house that looked "lived in." God help the maid who tried to clean up his study. He'd never be able to find anything afterward.

He was a brilliant but one-sided man. Backpacking or skin diving might have changed his habits -- in such pursuits you learn not to forget any least trivial thing -- but they would never have tempted him. An expedition to Mars was something he simply could not turn down. A pity, because neatness is worth your life in space.

You don't leave your fly open in a pressure suit.

A month after the landing, Childrey caught Lear doing just that.

The "fly" on a pressure suit is a soft rubber tube over your male member. It leads to a bladder, and there's a spring clamp on it. You open the clamp to use it. Then you close the clamp and open an outside spigot to evacuate the bladder into vacuum.

Similar designs for women involve a catheter, which is hideously uncomfortable. I presume the designers will keep trying. It seems wrong to bar half the human race from our ultimate destiny.

Lear was addicted to long walks. He was coming back from a walk, and he met Childrey coming out. Childrey noticed that the waste spigot on Lear's suit was open, the spring broken. Lear had been out for hours. If he'd had to go, he might have bled to death through flesh ruptured by vacuum.

From THE HOLE MAN by Larry Niven. 1974

Once I had one arm out it was pretty easy; I just crawled forward, putting my feet on the suit’s shoulders, and pulled on his free arm. He slid out of the suit like an oyster slipping out of its shell.

I popped the spare suit and after a lot of pulling and pushing, managed to get his legs in. Hooked up the biosensors and the front relief tube. He’d have to do the other one himself; it’s too complicated. For the nth time I was glad not to have been born female; they have to have two of those damned plumber’s friends, instead of just one and a simple hose.

I left his arms out of the sleeves. The suit would be useless for any kind of work, anyhow; waldos have to be tailored to the individual.

From THE FOREVER WAR by Joe Haldeman. 1975

Many people have written in to ask, “What is that silvery, liquescent lining inside the pants of spacesuits we occasionally see on your broadcasts?”

Well, viewers, that’s the sanitary nanopaste. You see, back in what we might call the pointy-stick era of spaceflight, the problem of the crew having to take a ‘fresher break while stuck in their vacuum suits for hours on end was handled by catheterization – it was necessary for astronauts to insert catheters into their urethra, rectum, cloaca, and/or any other excretory or partially-excretory orifices they might have in order to convey waste products to reservoirs for later disposal, and prevent them from contaminating the interior of the suit.

Apart from the occasional technical problems this had with leakage and providing pathways for infection, it was not a solution that was comfortable for anyone, or that anyone was comfortable with.

Fortunately, modern nanotechnology has provided the answer. Sanitary nanopaste selectively infiltrates one’s excretory orifices in a much more gentle manner than gross apparati (the sensation, I am told, being akin to mild tickling that rapidly becomes imperceptible), interfacing with the body’s own systems, and breaking down and compressing the body’s wastes in situ and conveying them directly and continuously, by molecular pass-the-parcel, to the vacuum suit’s recycling apparatus. In short: now, you simply never feel the need to excrete as long as you’re in your suit.

This is a much more elegant solution, obviously, and has satisfied virtually everyone – or at least everyone who isn’t overcome with squeamishness at the thought of microscopic robots roaming around in their bowels.

– Ixril Valenarius, Spaceflight Initiative Public Relations,
“This Week in Orbit”

Visual Identification

Once people are suited up, it does become hard to tell who is who. In Destination Moon, there were four spacemen, and each had a uniquely colored suit. Kind of like colored tooth-brushes. But this won't work if you have more than a few spacemen, er, spacepeople. The person's name stenciled in large letter across the front and back is a possibility.

In Piers Anthony's The Kirlian Quest, he notes that this problem has occurred before: knights in armor are similarly anonymous. The solution is coat of arms and heraldry. The knights wear their coats of arms on their shields, tabards, and horse barding, to identify themselves.

In other words, heraldry was a medieval form of an Identification Friend Or Foe system.

When a proposed heraldic "device" (coat of arms) is submitted to the college of heralds, it is compared with all existing devices. The new device must have at least one major and one minor point of visual difference from those already registered. Otherwise it would be too easy to confuse the two devices in the heat of battle. Mistaking a foe for a friend could be fatal. It is also a good idea if the device can be recognized at a distance.

As an amusing side note, a heraldic device has a "blazon". This is a verbal description of the heraldic device done in heraldic terminology. If you give a herald a blazon, they can reproduce the original device even if they had never seen it before. Just remember that the "blazon" is the verbal description and "to emblazon" means to draw, paint or otherwise make a graphic representation of the device (called an "emblazonment").

Heraldry developed as a way to be seen and identified across a battlefield, in the clash of war. This requires high-contrast designs whose elements are clearly recognizable.

The first step in recognizability is to use the stylized heraldic forms of things. The second is to make your charges as big and bold as possible in the space you have available.

Modern corporate logos usually follow the same rules that heraldic artists used, because they want their product logo to stand out, to be identifiable even at a distance, and to be recognizable. Consider the logos of Shell, Diamond Shamrock, BMW, Dodge, Purina, CBS — all of these follow the styles and rules of heraldry.

In Larry Niven's Protector, the Belters of the asteroid belt spend most of their lives inside their space suit. They have a tendency to paint their suits in extravagant colors. One of the characters had Salvador Dali's Madonna of Port Lligat on the front of their suit. In an interesting psychological quirk, Belters also tend to be nudists when in a pressurized environment.

And if you find any illustrations of the game Warhammer 40,000, you will quickly see that the Space Marines are big fans of heraldry. Even though you can generally idenifty the bad Marines by the tentacles, weeping open sores, and other Marks of Chaos. Otherwise, if the opponents look like skeletons they are Necrons; if they are tall, skinny, and distainful they are Eldar; if they are green with tusks they are Orks; and if they look like Giger's Alien xenomorph on bad LSD and are eating everything they are Tyranids. They are all enemies, so the basic rule is if it does not look like a Space Marine, shoot it with your bolter.

Most Belters decorated their suits. Why not? The interior of his suit was the only place many a Belter could call home, and the one possession he had to keep in perfect condition. But even in the Belt, Nick Sohl's suit was unique.

On an orange background was the painting of a girl. She was short; her head barely reached Nick's neck ring. Her skin was a softly glowing green. Only her lovely back showed across the front of the suit. Her hair was streaming bonfire flames, flickering orange with touches of yellow and white, darkening into red-black smoke as it swept across the girl's left shoulder. She was nude. Her arms were wrapped around the suit's torso, her hands touching the air pac on its back; her legs embraced the suit's thighs, so that her heels touched the backs of the flexible metal knee joints. It was a very beautiful painting, so beautiful that it almost wasn't vulgar. A pity the suit's sanitary outlet wasn't somewhere else.

From PROTECTOR by Larry Niven. 1973

(ed note: In the Cluster novels, the quotation mark symbols denote which species-language is being used. " is for humans, * is for Asts (looks like a mass of coils), / is for Slashes (looks like a living disk harrow, shooting laser beams), and :: is for Quadpointers (looks like a slug with four chisles on its nose). The protagonist Herald the Healer is a Slash.)

Whorl twined to another section of his convolute residence, and Herald followed. Here in the living rock bordering a corkscrew chamber was emblazoned in relief a creature-sized Shield of Arms.

It was beautiful. The outer shield was in the shape of an ellipse set at an angle, representing Galaxy Andromeda, bordered inside by a wreath of intertwining serpents to designate Sphere Ast. Within that were the Family Arms of Precipice, resembling an ornate overhanging cliff. Herald moved his loops across it, savoring its aspects. It had superior form, texture, and color, and was, in its fashion, a genuine work of art. The King of Arms of Ast was certainly a master!

*What do you find?* The query was urgent.

/I find an excellent and flawless emblazon./

*Did you not say 'blazon' before?*

The tedious questions of amateurs! But Herald repressed his annoyance, for courtesy was vital to his profession.

/I did, Whorl. The 'blazon' of a Shield of Arms is the precise linguistic specification of its elements. To 'emblazon' is to render this description into physical actuality./

*I comprehend. The one is the description, the other is the carving. I feared for a moment there was something wrong with it.*

/No, your Achievement is quite in order. Azurine, a cliff of thirty-seven rocks and forty-two rills, alternately thirteen, twelve, thirteen, seven, eleven, twenty-three, pearline, all within a bordure of the Serpents Rampant./

Herald winced inwardly as he communicated, for the old-style heraldic term "rampant" was restricted to certain quadrupedal beasts of prey, standing erect on the left foot raising the right foot in stride, balancing with the left forefoot outthrust, the right raised to strike. It was technically impossible for a legless serpent to be "rampant." But the broadening of the system to include diverse Cluster cultures had forced the fudging of some terms. However, as he had informed Whorl, the local Colleges of Arms defined legitimacy. So he had to accept it, nonsensical as it was in derivation. Regardless, this remained an excellent Shield of Arms, in concept and execution.

In a moment she was back on the subject. ::How did heraldry start?::

/Many species, in their pretechnical phases, wore special apparel to protect them from the attacks of physical weapons. This apparel was called 'armor,' and it was so encompassing that it became impossible to recognize the individual entity within it, the 'knight,' which figure is also represented in the Tarot deck. Therefore it became necessary to decorate his shield with some characteristic design, typical of his household and affiliation, so that friend could be distinguished from enemy. This eliminated the awkwardness of a knight lining up behind the formation of his enemy, supposing he was among friends. Or even attacking his friends, thinking they were enemies. The markings on the shield made everything instantly clear, even when the knights were not personally known to each other. This was the origin of heraldry. Today, all great families of all species in the Cluster have their registered Shields of Arms, even though they may never engage in combat./

::My family has a Shield! I never knew what it meant.::

/Come, I will explain what it means./ Following her directions, Herald located the Metamorphic Shield and placed it against the wall where both could view it. /Note that the shape of this Shield is elliptical, a kind of angled oval that signifies Galaxy Andromeda./

::But Andromeda is a spiral!::

/So it is. But from Milky Way it appears elliptical. (Since Andromeda lost the Wars of Energy, we suffer the additional humiliation of the ellipse. The Milky Way Shield is the fundamental shape, flat across the top, round or partly pointed across the bottom. Other Galaxies have other shapes.) Within this is the band of prints, the little four-point patterns, signifying Sphere Quadpoint. In Milky Way there are two bands, since that Galaxy is organized into segments and Spheres, but it is the same idea. Then the main design, the symbol of Family Metamorphic: a lump of edible rock superimposed on the geologic flowchart of its derivation. A distinctive Achievement—that is what the complete affair is called—recognizable anywhere in the Cluster./

::Can you recognize any Shield of Arms in the whole Cluster?:: she asked, a bit awed.

/Within certain broad categories, yes. It is my business. And this is true generally. Two completely alien sapients could meet on a barren planetoid, perhaps shipwrecked from different vessels, possessing no common language, form or status, and they could recognize each other by their Shields of Arms. That would provide their common experience. Each would know the other was sapient and civilized, and where he was from, and that he honored Cluster conventions of behavior./

From KIRLIAN QUEST by Piers Anthony ()

The tiger stripes on Jim's mask, the war paint on Frank's, and a rainbow motif on Phyllis's made the young people easy to identify. The adults could be told apart only by size, shape, and manner; there were two extras, Doctor MacRae and Father Cleary.

He poked his head inside, seemed about to leave, then came inside. He pointed to their outdoor suits, hanging on hooks by the clothes locker. 'Why haven't you removed those barbaric decorations from your masks?'

The boys looked startled; Howe went on, 'Haven't you looked at the bulletin board this morning?'


1. The practice of painting respirator masks with so-called identification patterns will cease. Masks will be plain and each student will letter his name neatly in letters one inch high across the chest and across the shoulders of his outdoors suit.

(ed note: headmaster Howe is a stupid little power-mad bureaucrat who does not understand the realities of life out on the frontier)

From RED PLANET by Robert Heinlein. 1949

Safety Line

For strict safely, static lines or safety lines are mandatory. The line will have to be made of special materials, since most terrestrial ropes and cables will turn glass-like and shatter in vacuum.

The spacecraft should have plenty of small steel rings bolted at regular intervals over the hull for spacemen to attach their safety lines to. Without a static line, an astronaut who manages to get both magnetic boots separated from the hull will suddenly find themself on a slow impromptu tour of the solar system. If their spouses are real lucky the bodies might actually be eventually recovered for burial.

In the real world NASA generally always insisted that astronauts performing a spacewalk be tethered to the spacecraft or station. The first NASA untethered spacewalk was Bruce McCandless II's little jaunt with NASA MMU in Challenger mission STS-41-B.

Another useful item is a "line throwing gun". This allows one to shoot a safety line from one spacecraft to another.

There was an impressive use of tethers in episode #4 of The Expanse.

Our heroes are in the hangar bay of the Martian battleship Donnager. The ship has been boarded by hostiles, the captain is poised to scuttle, and our heroes had better get into the escape ship fast unless they want to die in the scuttling.

The Donnager is under 1 g acceleration so there is artficial gravity. Our heroes have been instructed to turn off their boot magnets and run as fast as they can across the gantry into the escape ship, while dodging gunfire.

Alas our heroes Naomi and Holden are only half way across the gantry when the Donnager is forced to turn off its engines. They are suddenly in free fall, and float helpessly away from the gantry.

But Holden is a seasoned, cool-thinking, steely-eyed spaceman. He grabs Namoi, attaches a tether connecting the two, then kicks Naomi upwards away from the gantry. Newton's Third Law to the rescue! Holden recoils to the gantry, his magnetic boots latch on, then he uses the tether to haul Naomi down to the gantry.

Brilliant use of a tether, and a astonishing use of real physics in a TV show.

     Holden grabbed for Naomi. He struggled to orient himself as the two of them spun across the bay with nothing to push off of and nothing to arrest their flight. They were in the middle of the room with no cover.
     The blast had hurled Kelly five meters through the air and into the side of a packing crate, where he was floating now, one magnetic boot connected to the side of the container, the other struggling to connect with the deck. Amos had been blown down, and lay flat on the floor, his lower leg stuck out at an impossible angle. Alex crouched at his side.
     Holden craned his neck, looking toward the attackers. There was the boarder with the grenade launcher who had blasted Kelly, lining up on them for the killing shot. We 're dead, Holden thought. Naomi made an obscene gesture.
     The man with the grenade launcher shuddered and dissolved in a spray of blood and small detonations.
     "Get to the ship!" Gomez screamed from the radio. His voice was grating and high, half shrieking pain and half battle ecstasy.
     Holden pulled the tether line off Naomi's suit.
     "What are you...?" she began.
     "Trust me," he said, then put his feet into her stomach and shoved off. Hard. He hit the deck while she spun toward the ceiling. He kicked on his boot mags and then yanked the tether to pull her down to him.
     The room strobed with sustained machine gun fire — Holden said, "Stay low," and ran as quickly as his magnetic boots would allow toward Alex and Amos. The mechanic moved his limbs feebly, so he was still alive. Holden realized he still had the end of Naomi's tether in his hand, so he clipped it on to a loop on his suit. No more getting separated.
From LEVIATHAN WAKES: Book One of The Expanse by James A. Corey (2011)

Fred braced himself in the open hatch and fired the line-throwing gun. The foam plastic projectile sailed slowly across the void, trailing the line it pulled from the container on the gun. A P-suited figure reached out and caught the slow-moving plastic blob as it sailed past. Fred snubbed the line on a cleat inside the hatch as the other person whipped it through and around a beam of the array. Torn had his running safety line snapped around the main line as quickly as it was secured at both ends. He pushed off and sailed down the line. Fred was behind him.

From SPACE DOCTOR by Lee Correy (G. Harry Stine) 1981

     I knew exactly where Mac had gone, but I had a hard time seeing him. The rock slide had carried with it a mixture of small and large fragments, from gravel and pebbles to substantial boulders. His struggles to climb the slope had only managed to embed him deeper in loose materials. Now his suit was three-quarters hidden. His efforts also seemed to have carried him backwards, so with a thirty degree gradient facing him I didn't think he'd ever be able to get out alone. And further down the slope lay a broad fissure in the surface, of indeterminate depth.
     He was facing my way, and he had seen me too. "Jeanie, don't come any closer. You'll slither right down here, the same as I did. There's nothing firm past the ledge you're standing on."
     "Don't worry. This is as far as I'm coming." I backed up a step, nearer to a huge rock that must have weighed many tons, and turned my head so the chest of Mac's suit sat on the crosshairs at the exact center of my display. "Don't move a muscle now. I'm going to use the Walton, and we don't have time for second tries."
     I lifted the crosshairs just a little to allow for the effects of gravity, then intoned the Walton release sequence. The ejection solenoid fired, and the thin filament with its terminal electromagnet shot out from the chest panel on my suit and flashed down towards McAndrew. The laser at the tip measured the distance of the target, and the magnet went on a fraction of a second before contact. Mac and I were joined by a hair-thin bond. I braced myself behind the big rock. "Ready? I'm going to haul you in."
     "Aye, I'm ready. But why didn't I think of using the Walton? Damnation, I didn't need to get you back here, I could have done it for myself."
     I began to reel in the line, slowly so that Mac could help by freeing himself from the stones and gravel. The Izaak Walton has been used for many years, ever since the first big space construction jobs pointed out the need for a way to move around in vacuum without wasting a suit's reaction mass. If all you want is a little linear momentum, the argument went, why not take it from the massive structures around you? That's all that the Waltons do. I'd used them hundreds of times in free fall, shooting the line out to a girder where I wanted to be, connecting, then reeling myself over there. So had Mac, and that's why he was disgusted with himself. But it occurred to me that this was the first time I'd ever heard of a Walton being used on a planetary surface.
     "I don't think you could have done it, Mac," I said. "This big rock's the only solid one you could see from down there, and it doesn't look as though it has a high metal content. You'd have nothing for the magnet to grab hold of up here."
     "Maybe." He snorted. "But I should have had the sense to try. I'm a witless oaf."
     What that made me, I dreaded to think. I went on steadily hauling in the line until he had scrabbled his way up to stand by my side, then switched off the field. The line and magnet automatically ran into their storage reel in my suit, and we carefully turned and headed back to the other two.

From ROGUEWORLD by Charles Sheffield (1983 )

Things get real nasty if the ship is a tumbling pigeon or otherwise rotates to provide artificial gravity. The poor EVA spacemen have to swing from hand-hold to hand-hold like trapezes artists. From their viewpoint, the spacecraft is overhead and below is a long fall to infinity. For details read Heinlein's short story "Ordeal in Space".


Astronauts also have to watch what they say. There is no air in space, so unless you are touching helmets together, you cannot talk with others without a radio. But while speaking on Terra means your voice becomes fainter with distance, over a radio it will be loud and clear out to the limit of the radio's range. This means cursing under your breath or muttering behind somebody's back will not work. There might be several channels to allow a bit of privacy, or if several conversations are going on at once.

"Do you think they're listening to us? Suppose someone's got a watch on this frequency—they'll have heard every word we've said. After all, we're in direct line of sight."

"Who's being melodramatic now? No one except the Observatory would be listening on this frequency, and the folks at home can't hear us as there's rather a lot of mountain in the way. Sounds as if you've got a guilty conscience; anyone would think that you'd been using naughty words again."

This was a reference to an unfortunate episode soon after Wheeler's arrival. Since then he had been very conscious of the fact that privacy of speech, which is taken for granted on Earth, not always available to the wearers of spacesuits, whose every whisper can be heard by anyone within radio range.

From EARTHLIGHT by Sir Arthur C. Clarke (1955)


Sometime people on a space walk want to communicate but do not want to use radio. This can be either due to the sad fact that one or both of the radio sets are out of order, or if the two have a strong motive not to broadcast their conversation to everybody in the universe within radio range.

  • Some SF novels suggest that two space suited people might turn off their raidos, and touch helmets. The theory is that the sound of the conversation will be conducted through the contact between helmets. However, others maintain that the area of contact will be so small (since the helmets are basically spherical) that no audible sound will manage to pass.

  • In Poul Anderson's TAU ZERO, he suggests astronauts will learn how to read lips. In the weaving sheds and cotton mills of Lancashire, workers developed an exaggerated form of speech and gesture called mee-mawing to facilitate lip-reading.

  • They can use a vacuum-rated marker pen to write words or Spacer's Runic.

  • Morse Code is another possibility, via flashlight or a mirror reflecting Sol. If they are connected by something that will transmit vibration (like a girder) they can use tap codes (Morse won't work with percussion because while you can tap a "dot" you cannot tap a "dash").

  • In The Expanse Belters use specialized hand gestures similar to those used by scuba divers and harbor crain longshoremen. These can also be used like Emoticons to supplement radio communication, e.g., using a fist to make a "nod-your-head-yes" gesture (non-verbal so radio doesn't send it, and mostly invisible unless you can see inside their helment). In The Expanse, Belters tend to use hand gestures even when not wearing a space suit, shrugging with their hands instead of their shoulders for instance.

  • Actually, NASA is looking into creating some "official" hand signals. The link shows some proposed signals.

  • One can use deaf sign language or a manually coded oral language. It is difficult to do full blown sign language in a space suit. Sign languages have complicated, nuanced signs that would get lost by the highly restricted motion of the suits. Only big motions would be visible.

  • If the two are connected by a tether, they can use scuba diver rope signals.

  • Sawmill workers had their own specialized hand signal language, because the noise in the mill is too loud for speaking. Something similar is used in steel pipe mills, where even radios are worthless due to the background noise.
Lip Reading 1

Lindgren and Reymont exchanged a look above his bent back. She shaped unspoken words. Once he had taught her the Rescue Corps trick of lip reading when spacesuit radios were unusable. They had practiced it as something that made them more private and more one.

From TAU ZERO by Poul Anderson (1970)
Lip Reading 2

     A weaving shed in full song is a noisy animal, the roar would be disconcerting to anyone not used to it. None of the weavers wore ear defenders and many had a low level of hearing loss after years of exposure. Many thousands of pounds were spent on experiments to lessen the noise but all of them failed and right to the end of the industry the Lancashire loom made as much noise as it did when it was first invented.
     There was one small consolation, the noise was low frequency and nowhere near as damaging as modern high speed looms so it wasn’t as bad as some would like to portray it. However, it made communication in the shed by normal speech almost impossible.
     The weavers found a way round this, they used to ‘mee maw’ to each other. This was using exaggerated lip movements With no sound so they can lip-read each other. If a weaver wanted to say something privately to another weaver she would place her mouth very close to her friend’s ear so nobody could see her lip movements. If I wanted to spread a message round the shed, say if I was stopping early for some reason, all I had to do was go to the door of the shed, mee maw my message to the first weaver inside the door and before I had walked back to the engine house everyone in the shed had the message.

From BANCROFT by Stanley Graham (2009)

"We'll already have stopped," Holden said, and McDowell patted at the air with his wide, spidery hands. One of the many Belter gestures that had evolved to be visible when wearing an environment suit.

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

     In the 1970s, sawmill workers could talk about technical matters or insult each other in their own special sign language.
     When the linguists Martin Meissner and Stuart Philpott first started visiting sawmills in British Columbia in the 1970s, they thought they’d find workers communicating without speaking, probably with some simple gestures that contained technical information. There was a long history of such communication in the face of extreme noise: For centuries, American mill workers had used systems of hand signals to tell each other, across the unending roar of the saws, how to cut wood.
     What they discovered, though, floored them. The researchers witnessed a sign language system complete enough that workers could call each other “you crazy old farmer,” tell a colleague that he was “full of crap,” or tell each other when the foreman was “f*****g around over there.”
     Outside of deaf communities, hearing people sometimes develop what are now often called “alternate sign languages” to communicate when words will not do. In monasteries, monks uses signs to communicate in areas where speech is forbidden, for instance. In industries where machines made speaking impossible—in ships’ engine rooms, in steel mills, textile mills, and sawmills—workers also found ways to communicate with their hands.
     In 1955, when Popular Mechanics covered these industrial sign languages, many were already disappearing. But in the 1970s, Meissner and Philpott found a sign language still used in sawmills. Their research further honed in on the culture of one particular mill where workers had developed a system of 157 signs that they used not just to communicate about their work but to trade small talk, tell crude jokes and tease each other.
     The linguist were struck by the language’s “ingenuity and elegance,” they wrote. It was also a secret hidden in plain sight: the mill workers’ bosses, it seems, had almost no idea what they were saying.
     The core of the sawmill workers’ sign language was a system of numbers, standardized across the industry. Those signs were shared in a technical notebook, and, the linguists wrote,”in the view of the management, that was about all there was to the language.” But it covered much more ground than technical communication. Workers could talk about quitting time, lunch time, and cigarette breaks. They could talk about sports and the bets they placed on games. They could talk about their wives, cars, and colleagues. They could tell jokes and comment on what was going on around them without their bosses ever knowing.

     Compared to a fully developed sign language, which can have thousands of signs, this one was limited in its scope. It did provide these men with a way to cover the basic grounds of collegial small talk, and in at least one case, sawmill sign language also worked in the home. A couple of years after Meissner and Philpott published their research on British Columbia’s mills, another linguist, Robert Johnson, found a retired sawmill worker in Oregon who had lost his hearing and used a variant on sawmill sign language to communicate with his wife and son, who was also deaf. About three-quarters of their corpus of 250 signs overlapped with the British Columbia sawmill signs Meissner and Philpott had collected. There was also significant overlap with American Sign Language.


RocketCat sez

This, space cadets, is a Radar Gun. Don't roll your eyes at this thing, newbie, I know whatcha thinking and you're dead wrong. Emphasis on "dead."

You think you're some kind of Lensman Kimball Kinnison with a "Look of Eagles" who don't need no stupid kindergarten training-wheels radar gun to tell your closing rate. You think you can just eyeball it.

You also think you're actually going to survive longer than five minutes in your first EVA because you are a clueless newbie with delusions of competence. Do a search in InterPlaNetPedia for the Dunning-Kruger effect and you'll see a picture of you.

Just ask Vasily Tsibliyev.

On 25 June 1997 those bean-counting morons at Roscosmos thought they could save a few rubles by eliminating the Kurs automated docking system and instead do it manually. When the Soviet Union disintegrated in 1991 the Kurs network became the property of the Ukraine, who immediately started price-gouging Roscosmos. So the bean counters figured to heck with the Ukraine, who needs that fancy-smancy Kurs anyway? Our boys in Roscosmos have the Look of Eagles, they can just eyeball it. For free.

Poor Vasily got stuck with the honor of being the first to try it. He was tasked with the job of sitting in the Mir space station and trying to dock the Progress M-34 by remote control. By eyeball, with no Kurs automated docking system for help.

What a smash up!

Vasily couldn't even begin to tell by eye the distance or closing rate. When he suddenly realized that the Progress was up to ramming speed, he floored the braking rockets, but it was too late. Progress clobbered a solar panel then plowed into Mir's Spektr module. It ruined the solar panel, crumpled a radiator, and punched a hole in Spektr’s hull which immediately started spewing vital breathing mix into the depths of space. Oh, and it put the entire station into a tail spin as well, because the ruined solar panel was the one powering the gyros which ordinarily prevented just such an occurrence. The spin made the remaining solar panels not facing the sun anymore, so now there was no solar power at all.

The cosmonauts managed to radio ground control enough info on the station's spin so it could be stopped, which is the only reason they didn't all die. That and their frantic efforts to plug the air leak.

After all the finger pointing and recriminations had died down a bit, Roscosmos did some ground simulations with five veteran cosmonauts to see if the concept would work in theory. Because they really hated being gouged by the Ukraine. And the bean counters really wanted to deflect the blame aimed at them so it would land on poor Vasily.

Unfortunately for the bean-counters, all five cosmonauts crashed their ships in the ground simulators. Now the bean-counters faced awkward questions about "why the flaming frak didn't you idiots try ground simulations first before you tried it live?"

The point is, you newbie, the human eye was not built to judge ranges and closing rates in airless space. It is used to judging distance by how the dusty air obscures things with distance. AND IF YOU HAVEN'T FIGURED IT OUT BY NOW THERE AIN'T NO FREAKING AIR IN SPACE!

Just be sure you have your last will and testament on file at the front office.

Astronauts may also need a "beeper". This is a low powered radar used to locate small objects nearby (like that zero-recoil wrench you let go of "just for a minute" which seems to have run away). You wave it around until is starts beeping (heard over your suit radio). As you approach the object the beep rate increases.

If you are doing space construction work or asteroid mining, you'll need a radar range-and-rate gun. This is similar to the radar guns the highway patrol uses to catch speeders, but it also tells the range. It gives you the precise distance to the object and the current closing rate between you and the object, using radar for range and doppler radar for closing rate.

This is important because it is almost impossible to tell the range to an object by eye in space. And even more impossible to tell how fast it is approaching or receding from you. This is a standard instrument on spacecraft and space taxis but not on a space suit.


'I'll borrow a Beeper from Stores,' replied Peter. 'Joe Evans will let me sign for one.'

A Beeper, I should explain, is a tiny radar set, not much bigger than a hand-torch, which is used to locate objects that have drifted away from the Station. It's got a range of a few miles on anything as large as a space-suit, and could pick up a ship a lot farther away. You wave it around in space and when its beam hits anything you hear a series of 'Beeps'. The closer you get to the reflecting object, the faster the beeps come, and with a little practice you can judge distances pretty accurately.

From ISLANDS IN THE SKY by Arthur C. Clarke, 1952.

(ed note: Coyote Westlake is in a small habitat module attached to the asteroid RA45, with her ship the Vegas Girl parked nearby. When she wakes up, she is startled to discover that the Vegas Girl is now far away from the asteroid.)

How the hell could this have happened? She had left the Vegas Girl in a perfectly matched orbit relative to RA45. There was no way she could have drifted that far while Coyote was asleep.

Unless she had been sleeping for one hell of a long time. She checked her watch and compared it to the time display on the hab shed’s chronometer. She even checked the date, just to be sure she hadn’t slept around the clock. But no, she had been out only a few hours. How far had her ship drifted?

Coyote grabbed the radar range-and-rate gun out of its rack and aimed it through the spaceward viewport, lining up the sights on the Girl. It was a low-power portable unit, not really meant to work at long range. Normally she used it to establish distance from and velocity toward an asteroid, but it could track her ship just as handily. She got the blinking strobe in the sights and pulled the trigger.

The gun pinged cheerfully twice to indicate it had gotten a good range and rate on its target. Coyote checked the gun’s tracking data display.

And her heart nearly stopped. The Vegas Girl was over one hundred kilometers astern, and the ship was moving away at over three hundred meters a second.

But wait a moment. The tracker just showed relative velocity, not which object was doing the moving. She peered out the port again, and spotted the triple-blink beacon she had left on RA46, the last rock she had worked. She swore silently. RA46 was in the wrong part of the sky. She fired a ranging pulse at it and got back virtually the same velocity value. The Girl was stationary relative to RA46. So it wasn’t the ship moving. It was this rock.

From THE RING OF CHARON by Roger MacBride Allen (1990)

spotter (n.): An ancient spacer’s tool, dating back almost as far as the navigator’s sextant, the engineer’s multi, or the medtech’s hand effector, used for locating and profiling distant objects in space: a boon to anyone who has to manage a docking bay, shift cargo in microgravity, perform extravehicular activities in crowded neighborhoods, or engage in the smallest of small-craft operations, which is to say, riding a candle.

The original spotters were no more than handheld radar transceivers with direct audio feedback into the user’s helmet interface. Wave it around, and when you hear beeping, it’s pointing at something. The faster the beeping, the closer that something is to you. Learning what a particular rate meant in terms of range, and keeping an ear on the change of beep rate, were left as skills for the user to develop.

The modern spotter is a rather more sophisticated device, thanks to miniaturization and commercial development. HUD feedback now monitors its position relative to your body to provide a more accurate sense of direction, and even the most basic models provide precise range and closing rate information. More advanced models use a phased-array antenna to sweep the beam across a target once detected, providing a profile for target recognition purposes and an estimate of spin.

Of course, there is in theory very little use for a spotter in the current age of space, since all spacecraft from the largest to the smallest include a transponder, and are further constructed from LOP-compliant hardware which will obligingly disclose its location upon receiving a network request. The Grand Survey has detailed charts of every object in space larger than a child’s ball. All objects within range should therefore, says theory, already be highlighted on your HUD.

It is a sign of the tremendous respect that spacer culture has for theory that there are at least a brace of spotters stored in every airlock and docking bay from the Core to the Rim.

– A Star Traveler’s Dictionary

From PING by Alistair Young (2016)

Cherry Picker

Sometimes astronauts have to repair or service items that are not directly connected to their spacecraft. Breaking contact with the ship is possible by using an MMU, but is always risky. A useful compromise is using the cherry picker concept, having the astronaut's feet attached to a aerial work platform based on the spacecraft, and the platform's arm maneuvers to position the astronaut.

On the International Space Station, this is done with the amazing Canadarm2 (successor to the original Canadarm).

Suit Into Ship

As one adds more gadgets and attachments to a space suit, it gradually morphs into a tiny spaceship. It starts with spring-loaded broomsticks and picks up speed with the addition of tiny attitude jets and maneuvering rockets. As a parallel development, a rocket engine with a skeletal frame to hold astronauts is the first "space taxi". When a space suit is massive enough that one climbs into it instead of putting it on like clothing, equipped with mechanical arms and waldoes, you suddenly have a space pod. Then if the pod grows to the size of a baby spaceship, but with massive over-sized engines, you finally have a space tug.


A broomstick is a spring loaded gizmo used by astronauts to launch themselves from place to place, and to bring themselves to a stop upon arrival.

... This was where the broomsticks came in.

Commander Doyle had invented them, and the name, of course, came from the old idea that once upon a time witches used to ride on broomsticks. We certainly rode around the station on ours. They consisted of one hollow tube, sliding inside another. The two were connected by a powerful spring, one tube ending in a hook, the other in a wide rubber pad. That was all there was to it. If you wanted to move, you put the pad against the nearest wall and shoved. The recoil launched you into space, and when you arrived at your destination you let the spring absorb your velocity and bring you to rest. Trying to stop yourself with your bare hands was liable to result in sprained wrists.

It wasn't quite as easy as it sounds, though, for if you weren't careful you could bounce right back the way you'd come.

From ISLANDS IN THE SKY by Arthur C. Clarke, 1952.

There are some professions which have evolved unique and characteristic tools — the longshoreman's hook, the potter's wheel, the bricklayer's trowel, the geologist's hammer. The men who had to spend much of their time on zero-gravity construction projects had developed the broomstick.

It was very simple — a hollow tube just a metre long, with a footpad at one end and a retaining loop at the other. At the touch of a button, it could telescope out to five or six times its normal length, and the internal shock-absorbing system allowed a skilled operator to perform the most amazing manoeuvres. The footpad could also become a claw or hook if necessary; there were many other refinements, but that was the basic design. It looked deceptively easy to use; it wasn't.

Everything happened in about five seconds. Brailovsky triggered his broomstick, so that it telescoped out to its full length of four metres and made contact with the approaching ship. The broomstick started to collapse, its internal spring absorbing Brailovsky's considerable momentum; but it did not, as Curnow had fully expected, bring him to rest beside the antenna mount. It immediately expanded again, reversing the Russian's velocity so that he was, in effect, reflected away from Discovery just as rapidly as he had approached. He flashed past Curnow, heading out into space again, only a few centimetres away. The startled American just had time to glimpse a large grin before Brailovsky shot past him.

A second later, there was a jerk on the line connecting them, and a quick surge of deceleration as they shared momentum. Their opposing velocities had been neatly cancelled; they were virtually at rest with respect to Discovery. Curnow had merely to reach out to the nearest handhold, and drag them both in.

From 2010: Odyssey Two by Arthur C. Clarke, 1982.

Rocket Pack

While engaging in extra-vehicular activity, our space-suited rocketeers may use a "broomstick", or some kind of small jets (a Manned Maneuvering Unit or MMU). NASA has also developed a nitrogen-gas propelled unit that fits on the backpack, called the Simplified Aid for Extravehicular Activity Rescue (SAFER). The SAFER can help an astronaut return to the shuttle or station in the event that they gets separated from the spacecraft. SAFER has a deltaV capacity of 3 m/s.

In the movie 2010 they retained Brailovsky's shared momentum trick, but replaced the broomstick with a thruster pack. The broomstick automatically retains the exact velocity, with a thruster you have to be sure to do a precise burn of the same magnitude in the opposite direction.

"The trick to jetting yourself in space,"—he went on, 'lies in balancing your body on the jet—the thrust has to pass through your center of gravity. If you miss and don't correct it quickly, you start to spin, waste your fuel, and have the devil's own time stopping your spin. "It's no harder than balancing a walking stick on your finger—but the first time you try it, it seems hard.

"Rig out your sight." He touched a stud at his belt; a light metal gadget snapped up in front of his helmet so that a small metal ring was about a yard in front of his face. "Pick out a bright star, or a target of any sort, lined up in the direction you want to go. Then take the ready position— no, no! Not yet—I'll take it."

He squatted down, lifted himself on his hands, and very cautiously broke his boots loose from the side, then steadied himself on a cadet within reach. He turned and stretched out, so that he floated with his back to the ship, arms and legs extended. His rocket jet stuck straight back at the ship from the small of his back; his sight stuck out from his helmet in the opposite direction.

He went on, "Have the firing switch ready in your right hand. Now, have you fellows ever seen a pair of adagio dancers? You know what I mean—a man wears a piece of leopard skin and a girl wearing less than that and they go leaping around the stage, with him catching her?"

Several voices answered yes. Hanako continued, "Then you know what I'm talking about. There's one stunt they always do—the girl jumps and the man pushes her up and balances her overhead on one hand. He has his hand at the small of her back and she lays there, artistic-like. "That's exactly the way you got to ride a jet. The push comes at the small of your back and you balance on it. Only you have to do the balancing—if the push doesn't pass exactly through your center of gravity, you'll start to turn. You can see yourself starting to turn by watching through your sight. "You have to correct it before it gets away from you. You do this by shifting your center of gravity. Drag in the arm or leg on the side toward which you've started to turn. The trick is—"

"Just a second, Sarge," someone cut in, "you said that just backwards. You mean; haul in the arm or leg on the other side, don't you?"

"Who's talking?"

"Lathrop, number six. Sorry."

"I meant what I said, Mr. Lathrop."


"Go ahead, do it your way. The rest of the class will do it my way. Let's not waste time. Any questions? Okay, stand clear of my jet."

The half circle backed away until stopped by the anchored static lines. A bright orange flame burst from the sergeant's back and he moved straight out or "up," slowly at first, then with increasing speed. His microphone was open; Matt could hear, by radio only, the muted rush of his jet-and could hear the sergeant counting seconds: "And . . . one! . . . and . . . two! . . . and . . . three!" With the count of ten, the jet and the counting stopped.

Their instructor was fifty feet "above" them and moving away, back toward them. He continued to lecture. "No matter how perfectly you've balanced you'll end up with a small amount of spin. When you want to change direction, double up in a ball—" He did so. "—to spin faster—and snap out of it when you've turned as far as you want." He suddenly flattened out and was facing them. "Cut in your jet and balance on it to straighten out on your new course—before you drift past the direction you want."

He did not cut in his jet, but continued to talk, while moving away from them and slowly turning. "There is always some way to squirm around on your axis of rotation so that you can face the way you need to face for a split second at least. For example, if I wanted to head toward the Station—" Terra Station was almost a right angle away from his course; he went through contortions appropriate to a monkey dying in convulsions and again snapped out in starfish spread, facing the Station—but turning slow cartwheels now, his axis of rotation unchanged.

"But I don't want to go to the Station; I want to come back to the ship." The monkey died again; when the convulsions ceased, the sergeant was facing them. He cut in his jet and again counted ten seconds. He hung in space, motionless with respect to the ship and his class and about a quarter mile away. "I'm coming in on a jet landing, to save time." The jet blasted for twenty seconds and died; he moved toward them rapidly.

When he was still a couple of hundred feet away, he flipped over and blasted away from the ship for ten seconds. The sum of his maneuvers was to leave him fifty feet away and approaching at ten feet per second. He curled up in a ball again and came out of it feet toward the ship.

Five seconds later his boots clicked to steel and he let himself collapse without rebound. "But that is not the way you'll do it," he went on. "My tanks hold more juice than yours do—you've got fifty seconds of power, with each second good for a change of speed on one foot-second—that's for three hundred pounds of mass; some of you skinny guys will go a little faster.

"Here's your flight plan: ten seconds out, counted. Turn as quick as you can and blast fifteen seconds back. That means you'll click on with five foot-seconds. Even your crippled grandmother ought to be able to do that without bouncing off. Lathrop! Unhook—-you're first."

As the cadet came up, Hanako anchored himself to the ship with two short lines and took from his belt a very long line. He snapped one end to a hook in the front of the cadet's belt and the other to his own suit. The student looked at it with distaste. "Is the sky hook necessary?"

Sergeant Hanako stared at him. "Sorry, Commodore—regulations. And shut up. Take the ready position."

Silently the cadet crouched, then he was moving away, a fiery brush growing out of his back. He moved fairly straight at first, then started to turn.

He pulled in a leg—and turned completely over.

"Lathrop—cut off your jet!" snapped Hanako. The flame died out, but the figure in the suit continued to turn and to recede. Hanako paid out his safety line. "Got a big fish here, boys," he said cheerfully. "What do you think he'll weigh?" He tugged on the line, which caused Lathrop to spin the other way, as the line had wound itself around him. When the line was free he hauled the cadet in.

Lathrop clicked on. "You were right, sergeant. I want to try it again—your way."

"Sorry. The book says a hundred per cent reserve fuel for this drill; you'd have to recharge." Hanako hesitated. "Sign up for tomorrow morning—I'll take you as an extra."

"Oh—thanks, Sarge!"

"Don't mention it. Number one!"

From Space Cadet by Robert Heinlein. 1948

Jim's job turned out to be running a small welder that operated on compressed oxygen and acetylene. "Youll be working on some tricky alloys," Bart told him. "Keep the oxygen supply a little under what you need for the best burning. And before you turn it on, get a good grip. It's a small rocket, and don't forget that!"

They filed out. Some of the men seemed to be fully at home already, and simply dived off into space, kicking themselves toward the work. They carried tiny rocket tubes which could be used to kick themselves back in case they misjudged, but it wasn't something Jim cared to try yet. He was glad to see that others pulled themselves along the girders hand over hand.

Everything seemed to be done by hand power. Men were moving out to the piles of material scattered about, sorting them, and attaching cords before pulling them back by hand. There was no weight, but the inertia of the objects sometimes required the power of several men to overcome it. Once in motion, anything tended to keep that motion, and jockeying the parts into place and holding them there was a tricky business.

The welding proceeded well enough, however. Out here without air, the metals could never tarnish. They were given a brightening before being assembled to remove any corrosion from Earth's atmosphere, and then remained bright until they would be welded. Even aluminum and the titanium alloys were manageable.

Bart came over after a few minutes and inspected his work. "Good enough. But don't sit facing the same way so long. That Sun's hotter than you think. Sit too long in one direction and you'll heat one side of your suit near melting, while the other side freezes stiff. How do you feel?"

Jim had almost stopped thinking about that, under the pressure of the work. A boy who'd collapsed on the previous shift had put the welding behind the assembly, and Jim was driving himself to catch up. Bart clapped him on the shoulder and started to move on. Then he swung back.

"Jim, don't ever let me find you with your belt unfastened on the job again!" He snapped the silicone-plastic strap around the girder and to a hook in the suit. "I told you that torch was a small rocket! Let go, and you'll sail out like a bird if you're not strapped down."

"I guess I forgot this time," Jim admitted. "Sorry, Bart!"

The welding went on for several hours, until he finished what was ready. Part of the time, he'd been within reach by radio of one of the young college boys, and had struck up a conversation, forcing himself to stop being a lone wolf. He'd found that there was a sound reason for using the oxyacetylene welder instead of an electric rig. The compressed gases were lighter than batteries, and the station was still underpowered. They'd put up a sun mirror out of sheets of station walls and had used sections of pipe to make a boiler where the heat converged. It was driving a small steam plant and generator, but there were only about ten kilowatts to power the whole station until they could get the main power plant going much later.

The work went on more easily in the following days. New men came up from Earth, and most of them went back. One of them did almost the same thing Jim had done, but turned his rocket tube on while it was still pointing toward his helmet. Nobody got much work done that day, and there was no conversation at dinner.

From Step to the Stars by Lester Del Rey. 1954


Many early designs of spacesuits for use in free fall were lacking legs. This simplifies the design. This gradually becomes a hard suit which allows an astronaut to work in a pressurized environment and so avoid the bends.

The Haunted Space Suit

At this point, perhaps I should remind you that the suits we use on the station are completely different from the flexible affairs men wear when they want to walk around on the Moon. Ours are really baby space ships, just big enough to hold one man. They are stubby cylinders, about seven feet long, fitted with low-powered propulsion jets, and have a pair of accordion-like sleeves at the upper end for the operator's arms.

As soon as I'd settled down inside my very exclusive space craft, I switched on power and checked the gauges on the tiny instrument panel. All my needles were well in the safety zone, so I gave Tommy a wink for luck, lowered the transparent hemisphere over my head and sealed myself in. For a short trip like this, I did not bother to check the suit's internal lockers, which were used to carry food and special equipment for extended missions.

As the conveyor belt decanted me into the air lock, I felt like an Indian papoose being carried along on its mother's back. Then the pumps brought the pressure down to zero, the outer door opened, and the last traces of air swept me out into the stars, turning very slowly head over heels.

The station was only a dozen feet away, yet I was now an independent planet—a little world of my own. I was sealed up in a tiny, mobile cylinder, with a superb view of the entire universe, but I had practically no freedom of movement inside the suit. The padded seat and safety belts prevented me from turning around, though I could reach all the controls and lockers with my hands or feet.

In space the great enemy is the Sun, which can blast you to blindness in seconds. Very cautiously, I opened up the dark filters on the "night" side of my suit, and turned my head to look out at the stars. At the same time I switched the helmet's external sunshade to automatic, so that whichever way the suit gyrated my eyes would be shielded.

Presently, I found my target—a bright fleck of silver whose metallic glint distinguished it clearly from the surrounding stars. I stamped on the jet control pedal and felt the mild surge of acceleration as the low-powered rockets set me moving away from the station. After ten seconds of steady thrust, I cut off the drive. It would take me five minutes to coast the rest of the way, and not much longer to return with my salvage.

From Who's There? aka The Haunted Space Suit by Sir Arthur C. Clarke (1958)
The Sands of Mars

All his life Gibson had been fascinated by gadgets, and the spacesuit was yet another to add to the collection of mechanisms he had investigated and mastered. Bradley had been detailed to make sure that he understood the drill correctly, to take him out into space, and to see that he didn’t get lost.

Gibson had forgotten that the suits on the Ares had no legs, and that one simply sat inside them. That was sensible enough, since they were built for use under zero gravity, and not for walking on airless planets. The absence of flexible leg-joints greatly simplified the designs of the suits, which were nothing more than perspex-topped cylinders sprouting articulated arms at their upper ends.

Along the sides were mysterious flutings and bulges concerned with the air conditioning, radio, heat regulators, and the low-powered propulsion system. There was considerable freedom of movement inside them: one could withdraw one’s arms to get at the internal controls, and even take a meal without too many acrobatics.

Bradley had spent almost an hour in the airlock, making certain that Gibson understood all the main controls and catechising him on their operation. Gibson appreciated his thoroughness, but began to get a little impatient when the lesson showed no sign of ending. He eventually mutinied when Bradley started to explain the suit’s primitive sanitary arrangements. “Hang it all!” he protested, “we aren’t going to be outside that long!”

Bradley grinned. “You’d be surprised,” he said darkly, “just how many people make that mistake.”

He opened a compartment in the airlock wall and took out two spools of line, for all the world like fishermen’s reels. They locked firmly into mountings on the suits so that they could not be accidentally dislodged.

“Number One safety precaution,” he said. “Always have a lifeline anchoring you to the ship. Rules are made to be broken— — but not this one. To make doubly sure, I’ll tie your suit to mine with another ten metres of cord. Now we’re ready to ascend the Matterhorn.”

The outer door slid aside. Gibson felt the last trace of air tugging at him as it escaped. The feeble impulse set him moving towards the exit, and he drifted slowly out into the stars.

The friction of the reel had checked his momentum when the cord attaching him to Bradley gave a jerk. He had almost forgotten his companion, who was now blasting away from the ship with the little gas jets at the base of his suit, towing Gibson behind him.

Gibson was quite startled when the other’s voice, echoing metallically from the speaker in his suit, shattered the silence.

“Don’t use your jets unless I tell you. We don’t want to build up too much speed, and we must be careful not to get our lines tangled.”

“All right,” said Gibson, vaguely annoyed at the intrusion into his privacy. He looked back at the ship. It was already several hundred metres away, and shrinking rapidly.

“How much line have we got?” he asked anxiously. There was no reply, and he had a moment of mild panic before remembering to press the “TRANSMIT” switch.

“About a kilometre,” Bradley answered when he repeated the question. “That’s enough to make one feel nice and lonely.”

“Suppose it broke?” asked Gibson, only half joking.

“It won’t. It could support your full weight, back on Earth. Even if it did, we could get back perfectly easily with our jets.”

“And if they ran out?”

“This is a very cheerful conversation. I can’t imagine that happening except through gross carelessness or about three simultaneous mechanical failures. Remember, there’s a spare propulsion unit for just such emergencies— — and you’ve got warning indicators in the suit which let you know well before the main tank’s empty.”

“But just supposing,” insisted Gibson.

“In that case the only thing to do would be to switch on the suit’s S.O.S. beacon and wait until someone came out to haul you back. I doubt if they’d hurry, in such circumstances. Anyone who got himself in a mess like that wouldn’t receive much sympathy.”

From The Sands of Mars by Sir Arthur C. Clarke (1951)

Space Taxi

A space taxi is a short ranged orbit to orbit vehicle used to carry astronauts and small amounts of cargo. At its simplest, it is a frame that astronauts attach themselves to, with a rocket engine at one end. More complicated taxis have an enclosed hull which may or may not be pressurized. Do keep in mind that the direction of "down" will appear to be in the same direction the rocket exhaust shoots.

Orion Space Taxi
Specific Impulse450 s
Exhaust Velocity4,500 m/s
Wet Mass1,584 kg
Dry Mass759 kg
Mass Ratio2.0
ΔV3,120 m/s
Payload136 kg (2 people)
Length3 m
Diameter1 m wide
General Dynamics 2-Man Space Taxi
Specific Impulse450 s
Exhaust Velocity4,500 m/s
Wet Mass361 kg
Dry Mass155 kg
Propellant Mass206 kg
Mass Ratio2.3
ΔV3,750 m/s
Height3.5 m

In this document about Orion drive spacecraft, they mention a space taxi. It carries two crew members, has a hardware mass of 623 kilograms, and a propellant mass of 825 kilograms. As near as I can measure from the diagram, it can be approximated as a cylinder with a height of two meters and a radius of 0.5 meters, with a hemisphere of radius 0.5 meters on each end.

This gives it an internal volume of 2 m3. Assuming it has chemical propulsion, the propellant would take up about 0.8 cubic meters, and the two crew would take up 0.14 cubic meters. Carrying two crew, it would have a mass ratio of about 2, and thus a deltaV of about 3,120 m/s.

In Volume 10: "Space Age in Fiscal Year 2001". Proceedings of the Fourth AAS Goddard Memorial Symposium, 15-16 March 1966, Washinton DC Krafft Ehricke has a diagram featuring what appears to be the same space taxi.

General Dynamics had designs for one and two-man space taxis that again appear to be the same ones. The two man version was described to have a dry mass of 155 kg and 206 kg of propellant (probably space storage hpergolic propellants). This would give it a mass ratio of 2.3 and thus a deltaVof about 3,750 m/s. For more details refer to US Spacecraft Projects #01 by Scott Lowther.


candle (n.): A candle, or putt-putt, is the simplest transport spacecraft that can be devised, consisting essentially of a tank of hypergolic rocket fuel powering a thrust motor and a simple reaction-control frame. The pilot, supported by their vacuum suit, rides the candle — the tank itself — in much the same manner as a velocipede.

The additional accoutrements and controls of a candle vary widely by type. Most common are stabilization gyros, to make their handling less temperamental in the face of mass shifts. Commercial models often include a range of accessories: fly-by-wire navigation, Orbital Positioning Systems (space version of GPS), a comfortable saddle and space for passengers, cargo panniers, canned life support reserves, and so forth.

But the virtue of a candle is its simplicity. One can be put together out of parts readily obtainable from even a half-stocked chandler, or for that matter from those lying around any wreckyard, or even crash site. Such a scrap-candle may consist of little more than the tank and motors, with handhold bars and lash-downs for bagged cargo welded on where they might be useful. Some go so far as to strip the navigation system down to a row of firing switches for each motor, requiring the pilot to figure burn times and vectors by eye, or at least by pocket-contents.

Indeed, in many spacer cultures across the Worlds, building one’s first candle from parts, salvaged, scrounged, and where necessary even purchased, is considered a rite of passage for the young. More cynical observers consider the true rite of passage being making one’s first candle flight without having to be ignominiously hauled home by the Orbit Guard.

- A Star Traveller’s Dictionary


Matt pulled himself along, last in line, and found the scooter loaded. He could not find a place; the passenger racks were filled with space-suited cadets, busy strapping down.

The cadet pilot beckoned to him. Matt picked his way forward and touched helmets. "Mister," said the oldster, "can you read instruments?"

Guessing that he referred only to the simple instrument panel of a scooter, Matt answered, "Yes, sir."

"Then get in the co-pilot's chair. What's your mass?"

"Two eighty-seven, sir," Matt answered, giving the combined mass, in pounds, of himself and his suit with all its equipment. Matt strapped down, then looked around, trying to locate Tex and Oscar. He was feeling very important, even though a scooter requires a co-pilot about as much as a hog needs a spare tail.

The oldster entered Mart's mass on his center-of-gravity and moment-of-inertia chart, stared at it thoughtfully and said to Matt, "Tell Gee-three to swap places with Bee-two."

Matt switched on his walky-talky and gave the order. There was a scramble while a heavy-set youngster changed seats with a smaller cadet. The pilot gave a high sign to the cadet manning the hangar pocket; the scooter and its launching cradle swung out of the pocket, pushed by power-driven lazy tongs.

A scooter is a passenger rocket reduced to its simplest terms and has been described as a hat rack with an outboard motor. It operates only in empty space and does not have to be streamlined.

The rocket motor is unenclosed. Around it is a tier of light metal supports, the passenger rack. There is no "ship" in the sense of a hull, airtight compartments, etc. The passengers just belt themselves to the rack and let the rocket motor scoot them along.

From SPACE CADET by Robert Heinlein. 1948

The taxi looked like a huge, short salami, twenty feet long and eight in diameter. There was a small dome for the pilot to see out, and an air lock at the front, while the rear carried a small rocket motor. They went through the lock. Inside were two seats, fuel tanks, and steering assembly, as well as cargo space.

Jerry blasted off, after cranking a hand gyroscope to turn them. It was a weak, cautious blast that used little fuel. "Better to take your time and not waste fuel," he explained. "Once you get moving, there's nothing to stop you."

They drifted toward the rocket, turning over by the use of the gyroscope, and Jerry brought them to a stop with a single quick blast of the rocket tube. It was precise, beautiful work. They coasted a few feet away, while he turned them over again until the nose pointed to the rocket's lock, which was open.

"Slip your helmet back on, Jim," Jerry ordered. "Go out into the lock and catch that rope."

The man in the ship ahead had already thrown the cord. Jim found the end and fastened it to a bite inside the lock. The taxi was pulled up to the main lock, where it fitted snugly against the silicone-rubber gasket to make an airtight seal.

They took the passengers back, and then began making trips to ferry the supplies. These were dumped out of the big rocket by the pilot and his men. Apparently they put on space suits, evacuated the air from the cargo section and lock, and simply pitched the crates and pieces into space. It was Jim's job to go out of the taxi and secure these with cords to a ring on the back of the taxi, leaving enough distance so the rocket blast wouldn't hurt them.

From STEP TO THE STARS by Lester Del Rey (1954)

Captain Stone sighed. "I'm going with you. Will your scooter take three?"

"Sure, sure! It's got Reynolds saddles; set any balance you need."

Hazel allotted one-fourth her fuel as safety margin, allotted the working balance for maximum accelerations, figuring the projected mass-ratios in her head.

Hazel worked the new mass figures over; with Edith, her suit, and the spare bottle subtracted she had spare fuel.

She lined up on City Hall by flywheel and stereo, spun on that axis to get the sun out of her eyes, clutched her gyros, and gave it the gun. The next thing she knew she was tumbling like a liner in free fall. She remembered from long habit to cut the throttle but only after a period of aimless acceleration, for she had been chucked around in her saddle, thrown against her belts, and could not at first find the throttle.

Quickly she checked things over. There was not much that could go wrong with the little craft, it being only a rocket motor, an open rack with saddles and safety harness, and a minimum of instruments and controls. It was the gyros, of course; the motor had been sweet and hot. They were hunting the least bit, she found, that being the only evidence that they had just tumbled violently. Delicately she adjusted them by hand, putting her helmet against the case so that she could hear what she was doing.

Only then did she try to find where they were and where they were going. Let's see—the Sun is over there—and that's Betelgeuse over yonder—so City Hall must be out that way. She ducked her helmet into the hemispherical "eye shade" of the stereo. Yup! there she be!

The Eakers place was the obvious close-by point on which to measure her vector. She looked around for it, was startled to discover how far away it was. They must have coasted quite a distance while she was fiddling with the gyros. She measured the vector in amount and direction, then whistled. There were, she thought, few grocery shops out that way—darn few neighbors of any sort.

But she kept trying to call Mrs. Eakers, or anyone else in range of her suit radio while she again lined up the ship for City, with offset to compensate for the new vector. She was cautious and most alert this time—in consequence she wasted only a few seconds of fuel when the gyros again tumbled.

She unclutched the gyros and put them out of her mind, then took careful measure of the situation. The Eakers dump was now a planetary light in the sky, shrinking almost noticeably, but it was still the proper local reference point. She did not like the vector she got. As always, they seemed to be standing still in the exact center of a starry globe—but her instruments showed them speeding for empty space, headed clear outside the node.

Carefully she lined up the craft by flywheel; carefully she checked it when it tried to swing past. She aimed both to offset the new and disastrous vector and to create a vector for City Hall. She intentionally left the gyros unclutched. Then she restrapped Lowell in his saddle, checked its position. "Hold still," she warned. "Move your little finger and Grandma will scalp you."

Just as carefully she positioned herself, considering lever arms, masses, and angular moments in her head. Without gyros the craft must be balanced just so. "Now," she said to herself, "Hazel, we find out whether you are a pilot—or just a Sunday pilot." She ducked her helmet into the eyeshade, picked a distant blip on which to center her crosshairs, and gunned the craft.

The blip wavered; she tried to rebalance by shifting her body. When the blip suddenly slipped off to one side she cut the throttle quickly. Again she checked her vector. Their situation was somewhat improved. Again she called for help, not stopping to cut the child out of hearing. He said nothing and looked grave.

She went through the same routine, cutting power again when the craft "fell off its tail." She measured the vector, called for help—and did it all again. A dozen times she tried it. On the last try the thrust stopped with the throttle still wide open.

With all fuel gone there was no need to be in a hurry. She measured her vector most carefully on the Eakers' ship, now far away, then checked the results against the City Hall blip, all the while calling for help. She ran through the figures again; in a fashion she had been successful. They were now unquestionably headed for City Hall, could not miss it by more than a few miles at most—almost jumping distance. But, while the vector was correct in direction, it was annoyingly small in quantity—six hundred and fifty miles at about forty miles an hour; they would be closest in about sixteen hours.

Roger Stone explained. The twins looked at each other. "Dad," Castor said painfully, "you mean Hazel took Mother out in our scooter?"

"Certainly." The twins questioned each other wordlessly again. "Why shouldn't she? Speak up."

"Well, you see . . . well, it was like this—"

"Speak up!"

"There was a bearing wobble, or something, in one of the gyros," Pollux admitted miserably. "We were working on it." "You were? In Charlie's place!"

"Well, we went over there to see what he had in the way of spare parts and, well, we got detained, sort of."

Their father looked at them for several seconds with no expression of any sort. He then said in a flat voice, "You left a piece of ship's equipment out of commission. You failed to log it. You failed to report it to the Captain." He paused. "Go to your room."

"But Dad! We want to help!"

"Stay in your room; you are under arrest."

Castor thought about it. "That's bad. That could be really bad." He added suddenly, "But quit jittering, just the same. Start thinking instead. What happened? We've got to reconstruct it."

"'What happened?' Are you kidding? Look, the pesky thing tumbles, then anything can happen. No control."

"Use your head, I said. What would Hazel do in this situation?"

They both kept quiet for some moments, then Pollux said, "Cas, that derned thing always tumbled to the left, didn't it? Always."

"What good does that do us? Left can be any direction."

"No! You asked what Hazel would do. She'd be along her homing line, of course—and Hazel always oriented around her drive line so as to get the Sun on the back of her neck, if possible. Her eyes aren't too good."

Castor screwed up his face, trying to visualize it. "Say Eakers' is off that way and City Hall over here; if the Sun is over on this side, then, when it tumbles, she'd vector off that way." He acted it with his hands.

"Sure, sure! When you put in the right coordinates, that is. But what else would she do? What would you do? You'd vector back—I mean vector home."

"Huh? How could she? With no gyros?"

"Think about it. Would you quit? Hazel is a pilot. She'd ride that thing like a broomstick." He shaped the air with his hands. "So she'd be coming back, or trying to, along here—and everybody will be looking for her 'way over here."

Castor scowled. "Could be."

"It had better be. They'll be looking for her in a cone with its vertex at Eakers'—and they ought to be looking in a cone with its vertex right here, and along one side of it at that."

When Charlie had dug his scooter out of the floating junkyard moored to his home they soon saw why he had refused to lend it. It seemed probable that no one else could possibly pilot it. Not only was it of vintage type, repaired with parts from many other sorts, but also the controls were arranged for a man with four hands. Charlie had been in free fall so long that he used his feet almost as readily for grasping and handling as does an ape; his space suit had had the feet thereof modified so that he could grasp things between the big toe and the second, as with Japanese stockings.

The crate was old but Charlie had exceptionally large tanks on it; it could maintain a thrust for plenty of change-of-motion. Its jet felt as sweet as any. But it had no radar of any sort. "Charlie, how do you tell where you are in this thing?"


"That" proved to be an antiquated radio compass loop. The twins had never seen one, knew how it worked only by theory. They were radar pilots, not used to conning by the seats of their suits. Seeing their faces Charlie added, "Shucks, if you've got any eye for angle, you don't need fancy gear. Anywhere within twenty miles of the City Hall, I don't even turn on my suit jet—I just jump."

They cruised out the line that the twins had picked. Once in free fall Charlie taught them how to handle the compass loop. "Just plug it into your suit in place of your regular receiver. If you pick up a signal, swing the loop until it's least loud. That's the direction of the signal—an arrow right through the middle of the loop."

"But which way? The loop faces both ways."

"You have to know that. Or guess wrong and go back and try again."

Charlie, anticipating what would be needed, had swung ship as soon as he had quit accelerating. Now he blasted back as much as he had accelerated, bringing them dead in space relative to City Hall and the node. He gave it a gentle extra bump to send them cruising slowly back the way they had come. Pollux listened, slowly swinging his loop. Castor strained his eyes, trying to see something, anything, other than the cold stars.

"Got it again!" Pollux pounded his brother.

Old Charlie killed their relative motion; waited. Pollux cautiously tried for a minimum, then swung the loop, and tried again. He pointed, indicating that it had to be one of two directions, a hundred and eighty degrees apart.

"Which way?" Castor asked Charlie.

"Over that way."

"I can't see anything."

"Me neither. I got a hunch."

Castor did not argue. Either direction was equally likely. Charlie gunned it hard in the direction he had picked, roughly toward Vega. He had hardly cut the gun and let it coast in free fall when Pollux was nodding vigorously. They coasted for some minutes, with Pollux reporting the signal stronger and the minimum sharper . . . but still nothing in sight. Castor longed for radar. By now he could hear crying in his own phones. It could be Buster—it must be Buster.

"There she is!"

It was Charlie's shout. Castor could not see anything, even though old Charlie pointed it out to him. At last he got it—a point of light, buried in stars. Pollux unplugged from the compass when it was clear that what they saw was a mass, not a star, and in the proper direction. Old Charlie handled his craft as casually as a bicycle, bringing them up to it fast and killing his headway so that they were dead with it. He insisted on making the jump himself.

From THE ROLLING STONES by Robert Heinlein (1952)

(ed note: Cot-Vee = Cargo Orbital Transfer Vehicle {COTV}, Pot-Vee = Personnel Orbital Transfer Vehicle {POTV})

There were few amenities on the Pot-Vee Edison. But since the transition to GEO Base took several hours, the craft did have a bathroom of sorts—nothing more than a simple adaptation of the proven technology of the SkyLab "waste management system," as the old NASA circumlocution labeled it. The Personnel Orbital Transfer Vehicle itself was just a double-decked cylindrical cabin section eighteen feet in diameter and fifty-five feet long with a control compartment, docking air lock, and tunnel forward. On its aft end was the cylindrical hydrogen-oxygen propulsion module, the common orbital propulsion module used for both Pot-Vees and Cot-Vees.

"Easy flight today," Jackson remarked. "Three hours, fourteen minutes dock to dock. Relax and enjoy." (ed note: transit from LEO to GEO)

"Pretty short time for such a high lift, isn't it?" Stan Meredith asked. "Planning on high boost?"

"Naw! This flying sewer pipe is boost-limited to point-one-five gees because of its structure," Jackson explained. "Besides, we don't need the boost that's required for Earth-to-orbit. You'll hardly notice it now—but, man, it'll feel like a rock dropped on you after you've spent six weeks in weightlessness!"

The Ancient Astronaut was right. There were some bangs, clanks, muffled clunks, and gentle jolts as the Edison undocked from LEO Base. And when the thrust of the oxygen-hydrogen rocket engines came on, there was the gentlest of accelerations, accompanied by a slight vibration and a damped shaking.

"Combustion noise being transmitted through the thrust structure, plus a little bit of damped pogo oscillation," Fred Fitzsimmons explained.

"Why didn't they get the pogo out of these ships before they put them into operation?" Dave Cabot asked. "Didn't pogo oscillations give the engineers all sorts of trouble on Saturn and the Space Shuttles?"

Fred smiled. "Welcome to private-enterprise astronautics! There's worse vibrations in an airplane. It costs so much to get all pogo oscillations out of a design under all sorts of load conditions—and these Pot-Vees operate with all kinds of loads—that it's more cost-effective to let them shake . . . within reasonable limits, of course."

"But won't this thing eventually shake apart?" A note of anxiety entered Dave's voice.

"Nope," Fred replied. "Never had a Pot-Vee crumple yet. The engines are de-rated so much that the pogo doesn't affect them, and the engines themselves are modernized versions of very old, well-proven designs that never gave a bit of trouble."

"RL-10s," Stan put in.

There were no cabin windows in the Pot-Vee, so it was a three-hour flight without a view.

Stan and Fred discovered that it took almost nineteen minutes just to get to Charlie Victor, Mod Four Seven. There were a lot of hatches to go through and a lot of modules to traverse. "Fred, if we don't find some faster way to move around this rabbit warren, a lot of people are going to be dead before we reach them," Stan pointed out, finally opening the hatch to Mod Four Seven.

Fred was right behind him through the hatch. "I'll ask Doc to see Pratt about getting us an Eff-Mu."

"What's that?"

"Extra Facility Maneuvering Unit. A scooter to anybody but these acronym-happy engineers."

"You want an Eff-Mu so you can get around GEO Base faster."

"Right. We lost the hyperpyrexia case because we couldn't get there fast enough. It takes forever to go through all the hatches and corridors of GEO Base."

"Stan, I agree on both counts," Tom replied. "You need an Eff-Mu, and all of us need to be able to get around GEO Base faster in emergencies. But do you think a standard two-man Eff-Mu will really do the job?"

"Why not?"

"Why don't Earth-bound paramedics use motorcycles?"

"I see what you mean. We need room for the patient."

"Roger. Eventually maybe not, but right now we've got to provide that, too. Is there any Eff-Mu type that'll handle the two of you plus a patient?"

Pratt called him. "Doc, your special ambulance is coming up in the next Cot-Vee supply ship. Should be docking in six hours at Portlock Foxtrot. We're also putting a docking collar module on the free end of your med module, so don't be disturbed when you hear noises. You'll be able to dock right to your sick bay."

(ed note: one hex module is a hexagonal prism, about 3.7 meters wall to wall (12 feet), 15.2 meters long (50 feet), and has a volume of 241 cubic meters (8,500 cubic feet)

The Pumpkin turned out to be a masterpiece of quick-and-dirty engineering. It was half a hex module outfitted with a StarPacket vernier engine as its main propulsion system and a series of electric thrusters for maneuvering. It had no direct view to the outside universe, only an array of video displays—large windows in space were a constant trouble source because the state of the art couldn't keep them from leaking, and the Pumpkin's life-support consumables were limited to twenty-four man-hours with no recycling. The unit sported a universal docking collar on the end of the hex module opposite the StarPacket vernier engine.

Tom went with Fred and Stan to take delivery of their new gadget and bring it around to the med module dock. Pratt's men had latched the half hex of a docking port and pressure lock to the med module a few hours earlier in an operation that took only twenty minutes. GEO Base had been designed like an Erector set with plug-in modules; there was no time to build pretty or permanent space facilities on this job.

He looked over the panel. "Attitude indicator. Four relative velocity indicators linked to eight search radars and three lidars at will. Beacon transponders. You know, this really isn't that much different from flying airplanes on instruments."

And it wasn't. They returned for their P-suits, loaded another twenty-four man-hours of oxygen aboard, then checked out the Pumpkin—propellant load, battery-charge level, life-support-system consumables level, and the rest of a three-page checklist that someone had managed to put together for the Pumpkin when it was assembled at LEO Base. The controls had been highly simplified and were like those of a helicopter, with two sidearm controllers and two foot pedals to provide control in roll, pitch, yaw, and translation in six degrees of freedom. The StarPacket vernier engine offered enough thrust to get the Pumpkin moving for fast sprints, while the electric thrusters—the same kind used to propel the SPS array modules from LEO Base—permitted the gentlest of velocity changes.

The Pumpkin's saved a couple of people already. Three of us have learned how to operate it: Stan, Fred, and myself. Now I understand why space pilots are people who are instrument-rated airplane pilots and also own their own boats. "Flying" the Pumpkin is like flying an airplane by instruments; you must believe what those gauges are telling you, and you can't pay any attention to the inputs from your vestibular apparatus or from kinesthetic senses. Docking and undocking the Pumpkin is like bringing the S.S. Patrick Miller alongside and gently docking to a pier; the Pumpkin has far less momentum, however, and is probably more like docking a row boat. There isn't anything difficult about it provided you aren't in a hurry.

That's going to be the biggest problem with the Pumpkin. When Fred and Stan are on a call, they're in a hurry. I expect to get reports of hard docks. I hope they don't crumple too much stuff until they learn how to handle the Pumpkin under the stress of an emergency. I'm not too worried about them crumpling the Pumpkin; all the stress is column loading on that hex module, and it'd take a big bump to make the structure fail in that mode.

Together, they went through the power-up checklist. Total time, forty-two seconds. Less than three minutes after the call, Fred retracted the docking latches and backed the Pumpkin away from the med module on thruster power. While Fred was doing that, Tom interfaced the ship's computer with the one in GEO Base via radio link; he called up a three-dimensional display of the current GEO Base configuration and had the computer call out the location of the accident site.

"Computer has fed course parameters to the guidance system," Tom reported. Fred slued the ship and coupled the autopilot.

"Roger! Autopilot locked on. Stand by for thrust."

Tom spoke over the radio. "Traffic, Pumpkin. Emergency. Departing med module under primary thrust for Array Subassembly Module One Zero Seven. Are we clear to boost?"

Fred held his finger over the abort switch in anticipation of a possible Traffic delay. But it didn't come. "Pumpkin, Traffic. Clear to boost."

The boost came with a little fishtailing. "Dammit!" Fred swore. "Doc, this autopilot doesn't warm up fast enough. We'll have to go manual follow-up."

"I'll take it, Fred." Flying the Pumpkin wasn't as hard as flying a light airplane on instruments through an overcast at night. In this case, with the course already plotted by the computer, all Tom had to do was keep the marker bugs centered on the attitude-situation and relative-velocity displays. With the sidearm controller in one hand and the thruster and vernier throttles in the other, Tom didn't let the red Xs of the marker bugs deviate from the center of the display.

They picked up the group of P-suited figures on video long before the computer called for retros. To keep the thruster and vernier discharges away from the P-suited workers, Tom slued the Pumpkin in yaw and applied retro thrust by vector.

The paramedic didn't say anything, but reached over and activated Tom's P-suit backpack. Tom did the same for Fred. Only then did they disconnect from the Pumpkin's life-support system.

"Dump pressure, Fred."

Tom felt his suit pressurise as the atmosphere of the Pumpkin was dumped into space through spill valves that equalized the thrust produced. Normal procedure wouldn't have permitted dumping of pressure, nitrogen being the one gas that had to be brought up from Earth. In addition, the venting created a gas halo around the ship that might have permitted arcing of electrical equipment on the SPS array. But in an emergency where the Pumpkin had to be depressurized rapidly, there was no alternative.

From SPACE DOCTOR by Lee Correy (G. Harry Stine) 1981

(ed note: Keven, Glenda, and Jacob have been stranded on a tiny asteroid orbiting Ceres by the Bad Guys. They are in a mostly stripped base, trying to figure out how to get down to Ceres using only what is available)

Kevin prowled through the corridors of their prison. There has to be some way, he told himself. Ceres mocked him from below, less than three hundred kilometers down. It hung huge in the night sky.

Three hundred kilometers down, and we're moving about half a kilometer a second relative to Ceres, Kevin thought. That's not very much velocity. Under a thousand miles an hour. It doesn't take much energy to get to that speed. How much gasoline does it take to accelerate a car on Earth up to a hundred miles an hour—a gallon or so? We only need ten times that, not even that much.

There's plenty of hydrogen and oxygen. Marvelous rocket fuels if we only had a rocket. More than enough to get us down, except that the temperature of hydrogen burning in oxygen is a lot hotter than anything we have to contain in it—

No. That's not right. The fuel cells do it. But they do it by slowing down the reaction, and they can't be turned into rocket engines.

He remembered the early German Rocket Society experiments described by Willy Ley. The Berliners had blown up more rockets than they flew, and they were only using gasoline, not hydrogen. Liquid-fuel rockets need big hairy pumps, and Kevin didn't have any pumps.

What did he have? Fuel cells, plenty of them, and so what? An electric-powered rocket was theoretically possible, but Kevin didn't have the faintest idea of how to build one, even if there was enough equipment around to do it with. He wasn't sure anyone had ever built one—certainly he couldn't.

Back to first principles, he thought. The only way to change velocity in space is with a rocket. What is a rocket? A machine for throwing mass overboard. The faster the mass thrown away goes in one direction, the faster the rocket will go in the other, and the less you have to throw. All rockets are no more than a means of spewing out mass in a narrow direction. A rocket could consist of a man sitting in a bucket and throwing rocks backward.

That might get a few feet per second velocity change, but so what? There simply wasn't enough power in human muscles—even if he did have a lot of rocks. Was there any other way to throw them? Not fast; and unless the thrown-away mass had a high velocity, the rocket wouldn't be any use. He went on through the tunnels, looking at each piece of equipment he found, trying to think of how it might be used.

You can throw anything overboard to make a rocket. Hydrogen, for example. That's all Wayfarer's engines did, heat up hydrogen and let it go out through the rocket nozzle. We have hydrogen under pressure— Not enough. Nowhere near enough hydrogen and nowhere near enough pressure, not to get velocity changes of hundreds of miles an hour. Ditto for oxygen. Gas under compression just can't furnish enough energy. What would? Chemical energy; burning hydrogen in oxygen would do it, but it gave off too much; there was nothing to contain that reaction except the fuel cells and they did it by slowing the reaction way down and—

And I'm back where I started, Kevin thought. Plenty of energy in the fuel cells if I could find a way to use it. Could I heat a gas with electricity? Certainly, only how—

His eye fell on the hot-water tank in the crew quarters. An electric hot-water tank. There was a pressure gauge: forty pounds per square inch. Forty p.s.i.—He looked at the tank as if seeing it for the first time, then went running back to the others.

"Glenda, Jacob, I've got it."

"Sure it works." Kevin grinned. "Steam at forty p.s.i. will come out fast. About a kilometer a second."

"I believe you," Glenda said. "But it sounds silly. Steam rockets?"

Kevin shrugged. "It is silly. There are a lot more efficient systems. But this will work—"

"In a low g field," Jacob said. "You will not have much thrust. Of course you won't need much."

"I'm sure it works," Kevin said. "Now all we have to do is build it." He made himself sound confident; he knew how much room for error there was in his figures. "Look, it takes nine hundred and eighty calories to turn a gram of water into steam. We heat that steam up another thirty or forty degrees and let it out. The energy is moving molecules. We know the molecular weight of water, so we can figure the number of molecules in a gram and—"

They disconnected the hot-water tank and drilled holes in it. Several turns of heating wire went through the holes, then they sealed them in epoxy. At one end of the tank they drilled a large hole and threaded a pipe into it, threaded a large valve onto the pipe, and welded a makeshift rocket nozzle beyond that.

When it was done they tethered the tank and filled it with water, then connected a fuel cell to the heating leads. "Here goes," Kevin said. He threw the switch to start the heaters.

Slowly the water inside heated, then began to boil. The pressure shown on the gauge began to rise. In half an hour they had forty-five pounds of pressure. "All right, let's try it," Kevin said.

Glenda turned the valve to let out steam. A jet of steam and water shot out across the surface of the moonlet. Ice crystals formed in space and slowly settled to the rocket surface. The jet reached far away from them, well off the moonlet itself. The tank pulled against its tether lines, stretching the rope.

"It works!" Kevin shouted. "Damn it, we're going to make it!" He shut off the electricity. "Let's get her finished."

It didn't look like a spaceship. It didn't even resemble a scooter, crude as those were. It looked like a hot-water tank with fuel cells bolted onto it. For controls it had vanes set crosswise in the exhaust stream, spring-loaded to center, with two tillers, one for each vane; a valve to control steam flow; and switches to connect the fuel cells to the heaters. Nothing else.

The tank itself was fuzzy: They'd sprayed it with Styrofoam, building it up in layers until they had nearly a foot of insulation. There were straps on opposite sides of the tank to hold two passengers on.

The tank held nearly a hundred gallons of water. Kevin calculated that they had more than enough energy to boil it all in their two fuel cells, and they would only need sixty gallons to get to Ceres. The number was so small that he ran it four times, but it was correct.

The strangest part was the stability system: a pair of wheels taken from a mining cart and set up in front of the water tank. Electric motors rotated the wheels in opposite directions.

The total mass of Galahad with full water tank was just under 550 kilograms.

It took only a gentle effort to push the steam rocket away from the moonlet, but the cartwheel-gyros resisted any effort to turn it. Finally they got it oriented properly in space. Then they climbed aboard.

"Full head of steam," Kevin said. "Almost fifty pounds. Ready?"


He twisted the steam valve. At first both steam and water were expelled from the tank, but as they began to accelerate, the water settled and the exhaust valve let out only steam. C-2 dropped away. They missed it. It was a prison, but a safe one; now they had only their makeshift steam rocket.

Galahad showed a tendency to tumble, but with the gyros resisting, they were able to control it with the steering vanes. A plume of steam shot from the tank, rapidly crystallizing into ice fog that engulfed them.

"Damn. That's going to make it hard to see," Kevin said. "Nothing we can do about it." He peered down toward Ceres. It didn't seem any closer. Jacob's farewell faded in their headsets.

Norsedal's calculations had shown that twenty minutes' thrust should be enough to cancel all their orbital velocity. It would use up just about half their fuel. Once Galahad was stopped dead in orbit above Ceres, they would fall toward the asteroid, and they would have half their steam left to counteract that.

The trouble was that Jacob couldn't calculate how high above Ceres they would be when the twenty minutes were finished. As they lost velocity, they would lose altitude, and their orbit would no longer be a smooth circle, but an ellipse intersecting Ceres—somewhere. At the end of twenty minutes Kevin cut the power off. He was pleased that they still had thirty pounds of steam pressure.

"Yes, but that's what the numbers say."

"All right."

And a year ago I was working equations in school, Kevin thought. Numbers to crunch and write down for examinations. Now they're something to stake your life on.

From EXILES TO GLORY by Jerry Pournelle (1977).

The long-distance shuttle, the Rather Not, had its permanent mooring in the hollow center of the Orb. A four-legged strutwork held it in place against the gentle centrifugal tug, so it remained fixed over a repair berth. Mara clipped onto a mooring line that ran out to the Rather Not and adroitly pushed off from the Orb’s inner wall. Tsubata watched her movement with a critical eye. After a moment of coasting she flexed and turned so that her feet pointed toward the shuttle. She squirted her jets and slowed perceptibly. As an extra fillip, she unclipped from the mooring lines a few meters away and landed catlike on the tail section.

“Good enough. Don‘t move till I get there,” Tsubata said over suit radio.

“Okay.” Mara watched him swim easily across the twenty meters between them. He probably wanted her to mess up the maneuver; it would be easy to document if he had a friend watching on 3-D and would make a good first entry in a file. She knew enough about organizations to guess that, if Tsubata wanted to get rid of her, he would have to build a thick folder of instances to prove incompetence.

As Tsubata moved toward her, Mara glanced around and attached her suit tie-line to the nearest pipe. Most shuttles she had seen were different, each thrown together from cannibalized spare parts that came to hand. The Rather Not had a few customized pieces and the magnetic shielding coils were considerably larger, but otherwise it was like the others—all bones and no skin. The pilot couch was located at dead center of gravity in the middle, surrounded by struts, tanks, pipes, hauling collars, and storage lockets, all placed to obscure as littie of the view as possible. A large ion engine was mounted behind the couch in gray housing. It was lumpy but balanced; it wouldn't go into spinover if a pilot made a wrong move.

As Tsubata touched down she glided away from him, perching on top of the pilot couch backrest.

“I told you not to move.” Tsubata came after her.

“You’re going to have to give me more latitude than that. I know you’re not exactly tingling with anticipation to see me out here, but that’s the way it’s got to be.”

Tsubata said nothing, waving a hand to dismiss the subject. “First, I’m going to make sure you know what every piece of equipment on this shuttle is for.”

Mara had expected to know most of it, but there was a bewildering maze of detail. There were systems for fuel feed, a pipe complex regulating attitude jets, three different super-conducting magnet configurations for screening against Van Allen belt particles, two overlapping electrical systems, navigation index, vector integrater, multiple communications rigs, an emergency high-gain antenna for work when the Orb and shuttle were not in line of sight, gyros, radio, hauling apparatus, repair parts, life support—all this had to be integrated so that a change in one system didn’t cause a malfunction in another. In the next three hours Mara gained considerable respect for Tsubata and his work. He made it clear to her that a shuttle could not be run by the book; like most human creations, it demanded intuition, craft, and a certain seat-of-the-pants shrewdness.

It wasn’t until two days later that Tsubata considered her competent enough to take the Rather Not out on a routine flight.

From IF THE STARS ARE GODS by Gregory Benford & Gordon Eklund (1977)

Lunar Escape System

This is an emergency lunar escape vehicle concept, in case an Apollo Lunar Module crashed upon landing. It was designed to be assembled from various parts canibalized from the wreck. Note that in the two-man version, the pilot gets an acceleration chair, but the poor second astronaut is slung under the chair by straps. You can read more about this here, and here.

Space Pod

A space pod is a small pressurized vehicle with one or more waldoes or mechanical arms. They are often used for space construction and maintenance. In the movie 2001 A Space Odyssey, they were referred to as "EVA pods." In Wernher von Braun and Disney's Man In Space series, they were called "bottle suits." They are also known as "closed-cabin cherry picker", "manned autonomous work system", and the ever popular "man-in-a-can." One of their main advantages over a soft space suit is that they solve the depressurization problem.

I'm back to trying to put together some semi-realistic design for near-future space flight. In this case, I'm mainly trying to tackle a couple of problems. The first is the restrictions put on by current EVA technology. There's no such thing as being able to put on your spacesuit, go out the airlock and deal with an emergency these days. A minimum of about 20 hours of slow decompression and prebreathing pure oxygen is required before anyone goes out into space. Thats because the cabin environment of the Space Station, and the Shuttle is oxygen/nitrogen at sea level pressure, while the suits operate with pure oxygen at 5 p.s.i. They do that because, with present, vintage 1980 space suits, the arms and legs become impossible to bend if the pressure is any greater. The other problem is radiation shielding. For long stays outside, or any meaningful work beyond the Earth's ionosphere, the present suits just have inadequate radiation protection.

The potential solution is MAWS. It will have the same internal pressure as the station, or whatever long duration habitat we have in the future, because it doesn't have flexible joints. Instead it uses a couple of miniature versions of the station's robot arm. Its possible to put much better radiation shielding around MAWS, too. Probably the first exploration of asteroids or moons of Mars will be done in something like this design.

So this is the baseline look of the MAWS, as loosely worked out by NASA. Should it have a second set of heavier arms? Where would EVA equipment be attached? In general, what do you think of the idea?

From Manned Autonomous Work System by Tom Peters (2010)

Discovery's extravehicular capsules or "space pods" were spheres about nine feet in diameter, and the operator sat behind a bay window which gave him a splendid view. The main rocket drive produced an acceleration of one-fifth of a gravity—just sufficient to hover on the Moon—while small attitude-control nozzles allowed for steering. From an area immediately beneath the bay window sprouted two sets of articulated metal arms or "waldoes," one for heavy duty, the other for delicate manipulation. There was also an extensible turret carrying a variety of power tools, such as screwdrivers, jack-hammers, saws, and drills. Space pods were not the most elegant means of transport devised by man, but they were absolutely essential for construction and maintenance work in vacuum. They were usually christened with feminine names, perhaps in recognition of the fact that their personalities were sometimes slightly unpredictable. Discovery's trio were Anna, Betty, and Clara.

Once he had put on his personal pressure suit—his last line of defense—and climbed inside the pod, Poole spent ten minutes carefully checking the controls. He burped the steering jets, flexed the waldoes, reconfirmed oxygen, fuel, power reserve.

From 2001 A Space Odyssey by Sir Arthur C. Clarke (1969)

Grumman DC-5 EVA Craft

     Mass at Earth Gravity: 1,387 Kg.
     Overall Diameter: 1.98 m.
     Capacity: One Person Standard; Three Person Emergency
     Propulsion systems: Ten Mk 12 (140 Kgs. Thrust) for major course changes along all axes; Eight Mk 17 (35 Kgs. Thrust) for precision maneuvers; Eight Mk 8 micro-thrusters (10 Kgs.) for low-gravity station-keeping; Five Mk 14 (80 Kgs. Thrust) provide roll; One Mk 37 (500 Kgs. Thrust) for use in emergency.
     Life Support: 12 Hrs. (One Person)
     Radar: Grumman EPS-2D; Long Range; Active Pulse
     Other Equipment: Explosive Bolt Door Separation*; Short-range Object Approach System and Transponder; Complete HAL 9000 Data link System; Automatic Thruster Control; Auto Hover; Eight-Channel communication system; Advanced Manipulator Control System; Two-hour Oxygen Reserve System.
     Notes: The Grumman DC-5 carries can carry little in the way of food and water stocks, due to short life support capacity. A single air conditioning vent is provided.
     Misc. Technical Information: (From Frederick Ordway and the British Interplanetary Association)
     Propulsion: A subliming solid system provides vernier propulsion, wherein the solid propellent sublimes at a constant pressure and is emitted from a nozzle. Such reaction jets will last for long periods of time, have great reliability and use no mechanical valves. The main propulsion system is powered from by storable liquids.
     Mechanical Hand Controls: Selection controls are placed on each side so that the appropriate hand must be removed from the manipulator to select a tool or to park. Selection of a tool returns the arm to the 'park' position, where it leaves the 'hand', then the arm goes to the appropriate tool and plugs in. In doing so, it inhibits the 'finger' controls on the manipulator, so that when the operator returns his hand into the glove he can only move a solid object, not individual fingers.
     Television: It was found possible to produce all-round TV coverage with eight fixed cameras. This, however, did not give a sufficiently accurate picture for docking or selecting a landing space. For this purpose, the field of view can be narrowed or orientated; controls are included for this purpose.
     Normally, the TV link is occupied by the internal camera, so that the parent craft can monitor the pod interior. The pilot can switch in any other camera for specific purposes (survey, etc.) reverting to interior camera for normal work.
     Proximity Detector: This is the safety system with omnidirectional coverage working from the main communication aerials. It gives audible warning when the pod approaches a solid object. This is necessary as a safety measure as the pilot cannot monitor seven or eight TV displays continuously. The system also detects an approach to an object, the speed of which is too high to be counteracted by the vernier thrust settings on the control system. In this event, full reverse thrust is applied, overriding the manual control setting. The system depends upon a frequency modulated transmission and under safe conditions results in a low, soft audible background signal. This continuous signal is considered necessary in order to provide a continuous check on a vital safety system. If the speed of an approach to an object becomes dangerous compared with the distance from it, the tone becomes louder and higher pitched, and, if unchecked, end in a shrill note accompanied by reverse thrust. The system also works in conjunction with a transponder (to the give the necessary increased range) to measure distance from the Discovery.
     Flying Controls: Manual controls are considered necessary both as a standby and for local maneuvers. Two hand control sticks, each with two degrees of freedom and fitted with twist grips, provide the necessary control about six axes.
     Analog information is presented for attitude, heading rate and distance; these can be referred to local ground (for landing, takeoff, etc.), course (which enables the pilot to face forward, head up, on any preselected course, or parent ship (for docking, local maneuvers, etc.) This data has to be presented, as the pilot has to act immediately on them. This is the most easily assimilated display. A variation in full scale rate, which can be applied by the control sticks, is included; this allows the full stick movements to result in any proportion of vernier motor thrust, thus giving a 'fine' control for local maneuvers.

He was nearer to the sun than any man had ever been. His damaged space-pod was lying on no hill, but on the steeply curving surface of a world only two miles in diameter.

Even then, it was still possible for men in the tiny self-propelled space-pods — miniature spaceships, only ten feet long — to work on the night side for an hour or so, as long as they were not overtaken by the advancing line of sunrise.

He was still not quite sure what had happened. He had been replacing a seismograph transmitter at Station 145, unofficially known as Mount Everest because it was a full ninety feet above the surrounding territory. The job had been a perfectly straightforward one, even though he had to do it by remote control through the mechanical arms of his pod. Sherrard was an expert at manipulating these; he could tie knots with his metal fingers almost as quickly as with his flesh-and-bone ones.

He had aimed the pod with its gyros, set the rear jets at Strength Two, and pressed the firing button. There had been a violent explosion somewhere in the vicinity of his feet and he had soared away from Icarus—but not toward the ship. Something was horribly wrong; he was tossed to one side of the vehicle, unable to reach the controls. Only one of the jets was firing, and he was pinwheeling across the sky, spinning faster and faster under the off-balanced drive. He tried to find the cutoff, but the spin had completely disorientated aim. When he was able to locate the controls, his first reaction made matters worse—he pushed the throttle over to full, like a nervous driver stepping on the accelerator instead of the brake. It took only a second to correct the mistake and kill the jet, but by then he was spinning so rapidly that the stars were wheeling round in circles.

Everything had happened so quickly that there was no time for fear, no time even to call the ship and report what was happening. He took his hands away from the controls; to touch them now would only make matters worse. It would take two or three minutes of cautious jockeying to unravel his spin, and from the flickering glimpses of the approaching rocks it was obvious that he did not have as many seconds. Sherrard remembered a piece of advice at the front of the Spaceman’s Manual: "When you don’t know what to do, do nothing." He was still doing it when Icarus fell upon him, and the stars went out.

It had been a miracle that the pod was unbroken, and that he was not breathing space. (Thirty minutes from now he might be glad to do so, when the capsule’s heat insulation began to fail… .) There had been some damage, of course. The rear-view mirrors, just outside the dome of transparent plastic that enclosed his head, were both snapped off, so that he could no longer see what lay behind him without twisting his neck. This was a trivial mishap; far more serious was the fact that his radio antennas had been torn away by the impact. He could not call the ship, and the ship could not call him. All that came over the radio was a faint crackling, probably produced inside the set itself. He was absolutely alone, cut off from the rest of the human race.

It was a desperate situation, but there was one faint ray of hope. He was not, after all, completely helpless. Even if he could not use the pod’s rockets—he guessed that the starboard motor had blown back and ruptured a fuel line; something the designers said was impossible—he was still able to move. He had his arms.

He slipped his fingers into the controls that worked his mechanical limbs. Outside the pod, in the hostile vacuum that surrounded him, his substitute arms came to life. They reached down, thrust against the iron surface of the asteroid, and levered the pod from the ground. Sherrard flexed them, and the capsule jerked forward, like some weird, two-legged insect… first the right arm, then the left, then the right… .

It was less difficult than he had feared, and for the first time he felt his confidence return. Though his mechanical arms had been designed for light precision work, it needed very little pull to set the capsule moving in this weightless environment. The gravity of Icarus was ten thousand times weaker than Earth’s: Sherrard and his space-pod weighed less than an ounce here, and once he had set himself in motion he floated forward with an effortless, dreamlike ease.

Yet that very effortlessness had its dangers. He had traveled several hundred yards, and was rapidly overhauling the sinking star of the Prometheus, when overconfidence betrayed him.

From "Summertime on Icarus" by Sir Arthur C. Clarke (1960)

Space Tug

A space tug is a tiny spacecraft with over-sized engines and some means of grappling another spacecraft. If the tug pushes its cargo,it will have a massive push plate on its bow, with a core of structural members to transmit the thrust of its engines to the push plate. If the tug pulls its cargo, it will have cables and winches on its stern, and the engines will be vectored to fire backwards at an angle so it does not torch the ship it is dragging. The engines will suffer a reduction thrust penality proportional to the cosine of the engine angle.

Note that if nuclear propulsion spacecraft are involved, the tugs and the spacecraft will generally be designed to dock bow to bow. Otherwise you will be exposing the other ship to the radiation from your engine.

According to the Technovelgy site, the term "space tug" was invented in 1942 by Eric Frank Russell in his short story "Describe a Circle"

The Last Great War

(ed note: Nuclear Salt Water powered Frigate New Jersey wants to dock with colony on asteroid 624 Hektor. Nuclear Lightbulb powered Tug Brutus assists. Remember, with nuclear drive rockets using shadow shields the only safe way to dock is nose-to-nose.)

"Conn, tug Brutus requests permission to dock."

"Permission granted. Close the fuel valves."

As New Jersey shut down her main engine, the powder blue UN tug approached on thrusters. Fitzthomas watched on external cameras, never liking it when his ship was in others' hands, but powerless to do anything about it. The traffic rules within 100 k-klicks of Hektor were as plain and draconian as those of LEO: no unauthorized burns, and no open cycle nuclear reactors in operation under any circumstances. And the UN tug drivers were pretty good.

"Conn, Brutus is making her final approach. Docking in one minute."

"XO (executive officer), signal all hands."

"Aye sir." A moment later, Allen's voice came over the shipwide intercom. "All hands, prepare for ship to ship dock." He switched back to his private channel to the captain. "Let's hope whatever blue hat is driving that donkey cart knows how to actually fly a spaceship."

As it turned out, he could. Brutus and New Jersey touched nose to nose at barely a meter per second. Heavy duty docking latches locked the ships together, and Brutus extended a fiber optic probe into a receptacle inside New Jersey's docking ring.

"Conn, we have hard dock with Brutus. They are requesting propulsion access."

Fitzthomas removed a hard blue plastic key from his extensive key ring and inserted it into a blue lock. "Transferring propulsion access on my mark....mark." He turned the key and the clear plastic ring around the lock lit up blue. Brutus's pilot now had control over New Jersey's maneuvering thrusters. For the duration of the ride, Fitzthomas's hand would hover over the key, ready to cut Brutus out of the system, just in case.

Brutus's pilot could now also see what New Jersey's docking radar and aft cameras saw, a necessity since the bulk of the frigate would block the tug's line of sight—visual or otherwise—while they maneuvered. Brutus was little more than a nuclear engine (closed cycle, which meant no reactant could escape with the exhaust, at the cost of about half the ship's specific impulse, which didn't matter for a short range, low speed tugboat) with a sturdy docking ring and a cockpit jammed in between. In some operations, the tug was unmanned and guided by computer or radio control operator until it docked with the target ship, and then the tug would relinquish control of its systems to the target ship's pilot, or a harbor pilot brought on board for the purpose, saving some of the mass of reactor shielding for the cockpit and some of the ulcers for shipmasters, but the UN insisted on doing things the old fashioned way. Fitzthomas had heard of tugs which did the entire trip by remote control or onboard computer, but he'd rot in hell before he let some toe-picker play model airplane with his spaceship, and the United States Space Guard agreed.

New Jersey's thrusters fired, heeling the ship around 180 degrees, so that her bow, with the tug latched on, faced Hektor. Brutus then fired her main engine, continuing the deceleration burn New Jersey had started. Fitzthomas felt himself lift ever so slightly out of his chair. His ship's decks were aligned so "down" when they were under thrust was towards her main engine. With Brutus docked with her nose and her thruster pointing the other way, "down" was now, temporarily, in the direction of the overhead. One more thing for Fitzthomas not to like about the tugboat.

"Approaching Hammarskjöld docks. Ten minutes to docking."

From The Last Great War by Matthew Lineberger (not yet published)


For all the specific details on this 1970s era design, see the main article here.

Tinsley Tug

Space tug concept by Frank Tinsley. Tug has grapples and grippers on its stern. The four square plates around its waist are ion drive units (The crewman's hatch is unfortunately placed right in the line of fire of one of the ion drives).

The petals near the bow are heat radiators. Sadly the radiators are spaced too closely. In reality one would want two radiators at 180° or at the most four radiators at 90°. The arrangement shown would have the heat from one radiator impinging on its neighbors.

And at the tip of the pointed prow would be the tiny nuclear reactor. It would be nice to include a small shadow shield to protect the crew from nuclear radiation.

Lockheed Tug

Details are sparse on this 1963 design. Click on blueprints for larger image. Blueprint is written in Italian but it has been translated for the website by Alberto Bursi. The engines are around the waist, on swivels. The designers also appear to have a flippant attitude towards maintaining a sense of up and down. If the pilot turns his head he will see his copilot's feet.

Boeing Tug Concept

The diagram for a Boeing Intra-Orbit Personnel/Cargo Tug concept (1981) is from here. Annoyingly it included lots of facts and figures about the tug, then said and here is a diagram of a totally unrelated Boeing concept that we will not give you any data for. I do like the slanted windows, allowing the crew to view the docking port.

This is from a Johnson Space Center report Initial technical environmental, and economic evaluation of space solar power concepts. Volume 2: Detailed report. It looks remarkably like the Boeing cargo tug. The tug design will be used to assist construction of a gigantic solar power station. The spacecraft is called a Personnel Orbital Transfer Vehicle (POTV) or a Cargo Orbital Transfer Vehicle (COTV), depending upon whether a personnel or cargo module is docked to the crew module.

You can find more details here.

This is General Dynamics concept art. The front cabin sure looks similar to the Boeing concept.

Parkinson Tug

This 1975 design from Dr. R. C. Parkinson was faintly seen in an article The Resources of the Solar System by Dr. R. C. Parkinson (Spaceflight, 17, p.124 (1975)). It was off in the corner of a small diagram. I had an old photocopy of the article in my files since the late 1970's. I supplied them to William Black and he made stunning images of Dr. Parkinson's lighter and tanker. These images attracted the attention of a former colleague of Dr. Parkinson, a certain Dr. James Garry. He kindly introduced us to Dr. Parkinson and provided contact information. Dr. Parkinson generously supplied us with never before published diagrams and commentary.

In a private correspondence, Dr. Parkinson told William Black and I: “As a matter of interest, the "Space Tug" & Lunar Lander were based on some earlier design work done in Europe when it looked as if a cryogenic Space Tug might be the European contribution to the Space Shuttle program (those were the days!).”

In his visualization, William Black added additional engineering details. He put more struts to support the reaction-control jets and liquid oxygen tanks. Dr. Parkinson's notes indicated that the manned capsule had its own propulsion, so William added a single gimbaled low-thrust engine. He also added: a high-gain antenna for communications and a radar dish; forward-facing view ports for visual orientation during docking maneuvers; four forward-facing and four aft-facing cameras to aid in docking procedures.

Other Tugs

Waldoes And Drones

For maximum protection of the astronauts, it is best to help them avoid leaving the spacecraft at all. They can stay in the relative safety of the habitat module while using waldo robot arms or free-flying drone pods to get the job done.

Waldoes are also used for berthing a spacecraft (not docking, berthing).


Mobile Servicing System (MSS)

The MSS is composed of three components — the Space Station Remote Manipulator System (SSRMS), known as Canadarm2 (successor to the original Canadarm), the Mobile Remote Servicer Base System (MBS) and the Special Purpose Dexterous Manipulator (SPDM, also known as Dextre or Canada hand).

Canadarm2 is usually attached to the MBS, which moves along a rail. However, Canadarm2 can detach and literally walk on the surface of the station to where it is needed, moving end-over-end like a giant metal inch worm. Either end can plug into special sockets ("power data grapple fixtures") built at strategic spots on the surface of the station. The only draw-back is that Canadarm2 cannot carry any equipment while in inch-worm mode, hence the MBS.

The main limitation is that each "step" must end at a socket, but this is due to power and control signal issues. A more advanced version might be self contained enough to not require sockets, just hand-holds or other protrusions that it could grab.

Canadarm 2 is quite large, 17.6 meters (57.7 feet) long when fully extended.


This is From Nuclear Shuttle Systems Definition Study Phase III Final Report Volume II Concept and Feasibility Analysis Part A - System Evaluation and Capability. Thanks to Erin Schmidt for bringing this report to my attention.


DARPA’s Robotic Servicing of Geosynchronous Satellites (RSGS) program is to develop technologies that would enable cooperative inspection and servicing satellites in GEO.

1964 Lockheed unmanned SCHMOO drone: "Space Cargo Handler and Manipulator for Orbital Operations"

G.E. Remote Manipulator Spacecraft (1968)

Skeletons And Spacesuits

I noticed a couple of pulp covers with skeletons in spacesuits. So I looked on Google image search. I had no idea it was such a wide-spread meme.

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