Antimatter

Any Star Trek fan can tell you that when it comes to the most bang for your buck, you can't beat antimatter (sometimes called "Contra-terrene" or "Seetee"). How much bang? Well, in theory if you mix one gram of matter with one gram of antimatter you should get 1.8e14 joules of energy or about 43 kilotons.

Why 1.8e14 joules? Surely you remember Einstein's famous E = Mc2. c is the speed of light which is 299,792,458 meters per second. Squared it is 89,875,517,900,000,000 or about 9.0e16. M is mass in kilograms and E is energy in joules. So 0.002 kilograms (2 grams) times 9.0e16 equals 1.8e14 joules. QED.

Once more, to get some idea of the amount of damage represented by a given amount of Joules, refer to the Boom Table.

And remember from the discussion about nuclear weapons that there are 4.184e12 joules in a kiloton and 4.184e15 joules in a megaton. So simply:

Ekt = M * 42961.6

Emt = M * 43.0

where:

  • Ekt = total annihilation energy (kilotons)
  • Emt = total annihilation energy (megatons)
  • M = mass of antimatter (kilograms) Please note that M is the mass of antimatter, NOT the mass of the matter + the antimatter.

If you are interested, 42961.6 is from (9.0e16 * 2) / 4.184e12 where 9.0e16 = c2, 4.184e12 = joules in a kiloton, 2 = 1 unit of matter + 1 unit of antimatter.

Efficiency

But in practice it ain't gonna be anywhere near that much. The trouble is trying to use this as a bomb. It is much easier to extract all the energy from a matter-antimatter reaction if you do it in a slow controlled fashion, say in a power plant or a propulsion system. An antimatter particle beam is more difficult. Making an explosion (in vacuum) is downright hard.

Consider two bricks, one of matter and one of antimatter. Watch as they hit each other. The atoms and antiatoms just on the surface will come into contact and annihilate each other. This creates an explosion. Which is perfectly placed to push the two bricks apart with incredible force, preventing the rest of the atoms and antiatoms from coming into contact. (Actually it will probably vaporize the bricks and blow the vapor away, which amounts to the same thing.)

You may get close to 100% of the antimatter reacting if you, say, drop the antimatter chunk onto a planet, but getting that efficiency with a warhead exploding in the matter-less depths of deep space is much more difficult. You may be lucky to get 10%. Naturally as the state-of-the-art of antimatter warhead design advances, this percentage will rise.

(ed note: Byron Coffey pointed out that I was being simplistic)

Byron Coffey:

     I noticed an error in your section on antimatter weaponry. You repeated the common belief about the existence of a Leidenfrost effect in antimatter bombs.
     This is not true. See http://yarchive.net/space/exotic/antimatter_bomb.html for details.

yarchive.net/space/exotic/antimatter_bomb.html

Subject: Re: Ion Rockets [[was power]]
From: "Gordon D. Pusch" 
Date: May 31 1996
Newsgroups: sci.space.tech
Henry Spencer:
Very unlikely, actually. Antimatter does not make good bombs. Even more ordinary nuclear bombs can "fizzle" unless carefully designed: the reaction gets going but too slowly, so the bomb blows itself apart before the reaction can proceed very far.
     Ummm... I think I have to disagree with you on a number of points, Henry...
     Fission bombs can "fizzle" because they rely on a chain reaction. Hence, as you say, if the reaction gets going too slowly, one gets an incomplete "burn," since the bomb "catastrophically disassembles itself" — and in this "disassembled" state, the chain reaction stops.
     In the case of fusion bombs, the reaction is strongly temperature- and density-dependent; unless the reactants stay hot enough and dense enough for long enough (Lawson criterion!), the reaction will not go to completion.
     M/AM annihilation, by contrast, is NOT a chain reaction. Furthermore, while the annihilation rate will depend on the temperature of the reactants, the annihilation efficiency will not. Hence, one is guaranteed that 100% of the antimatter WILL annihilate with matter virtually 100% of the time, so long as the bomb and/or detonation environment consists mostly of matter, and the matter and antimatter are well mixed. If both the matter and antimatter are gases or plasmas, it will NOT be hard to ensure good mixing — especially since, barring someone discovering "new physics" that allows matter to be "flipped" or "rotated" into antimatter, it is highly unlikely that we will be able to manufacture and store any form of antimatter other than antihydrogen "ice" in the foreseeable future. Hence, the problem will instead be keeping it cold enough to prevent it from evaporating and mixing !!!
Henry Spencer:
With antimatter this problem is far worse, because while fission and fusion occur throughout the reaction volume, the matter- antimatter reaction occurs only on a contact surface.
     This may perhaps be true of the infamous (and hypothetical) "contraterrene cannonball," but it will certainly NOT be true of antihydrogen gases or plasmas !!! From the LEAR experiments, we know that the annihilation lifetime of a slow antiproton in condensed bulk matter is quite short; hence all that will be required is a way of rapidly mixing the antimatter with matter. For example, one could implode a shell of normal matter onto an antihydrogen ice nugget, and instead of trying to suppress turbulent mixing as one does in inertial confinement fusion, one would instead deliberately induce it; near-complete mixing should be had after only a few Kelvin-Helmholtz instability times. Surround the whole thing with a normal-matter tamper to thermalize some of the emitted radiation, and the mixture should rapidly heat up to the point where thermal diffusion will complete the mixing process.
Henry Spencer:
It's exceedingly difficult to get a major explosion with antimatter. (Tiny ones are not hard, since the square-cube law gives you more surface area per volume as the scale shrinks.).
     The square/cube law will be irrelevant to sufficiently well-mixed gases or plasmas of matter; as I've argued, it should be possible to achieve this on timescales comparable to a few Kelvin-Helmholtz timescales, which can be made short compared to the implosion timescale.
     Regarding production of an explosion: contrary to common belief, the majority of the proton/antiproton annihilation energy is released, not as gammas, but rather in the form of pions (as I believe you yourself have pointed out in other posts). One gets roughly equal numbers of pi+, pi-, and pi0 particles, with energies in the ~400--800 MeV ballpark. The pi0's go to two gammas almost immediately; the gammas will have an attenuation length of only a few tens of gm/cm2 in matter. The pi+'s and pi-'s have a range of only a few tens of meters before they decay to muons, even in vacuum; furthermore, in matter, both pions and muons have a range of only a few tens to hundreds of grams/cm2. Air has a density of about a 1.25 kg/m3; hence, most of the released energy will be deposited within a few tens to hundreds of meters of the bomb; I would expect this to generate a nice, hot fireball, just like a fission or fusion device.
Gordon D. Pusch
Math and C.S. Div., Bldg.203/C254
Argonne National Laboratory

From: "Gordon D. Pusch" 
Newsgroups: sci.space.tech
Subject: Re: Antimatter "bombs" [was Ion Rockets [was power]]
Date: Sat, 15 Jun 1996 02:00:01 -0500
Gordon D. Pusch:
Hence, one is guaranteed that 100% of the antimatter WILL annihilate with matter virtually 100% of the time, so long as the bomb and/or detonation environment consists mostly of matter, and the matter and antimatter are well mixed. If both the matter and antimatter are gases or plasmas, it will NOT be hard to ensure good mixing...
Henry Spencer:
Ah, but on what time scale? That's the heart of my objection. To get an explosion — in other words, a real live bomb — you need not just good mixing, but rapid mixing. And in this case, the reactants will be working pretty hard to keep each other at arm's length.
     RE: the reactants "working to keep each other at arm's length" — I've always found the "Leidenfrost layer argument" to be implausible for mixtures with scales smaller than the mean energy-deposition length of the annihilation pions and gammas.
     In the case of an interface between astrophysical-scale domains of bulk matter and antimatter, I accept Alfven's argument that the "pressure" exerted by the annihilation products at the interface will tend to drive the two domains apart.
     However, as I observed in my earlier post, in the case of a reaction with a "point-like" geometry, the released energy will be deposited over a spherical region tens to hundreds of meters in radius. In such a geometry, I suspect it is more likely that thermalized annihilation radiation will act to contain rather than disrupt the reactants, analogous to radiation-induced compression in a thermonuclear device (particularly if the "bomb" includes a tamper). Since only a miniscule fraction of the annihilation pions and gammas will be reabsorbed by the reactants themselves, I expect the effective "pressure" they exert to disrupt the mixing matter and antimatter will be very much smaller than that of the thermalized radiation, because the thermalized radiation will have a much shorter mean scattering length and hence will transfer momentum much more strongly to the reactants.
     At least, that my gut feel on this problem. To get a definitive answer would probably require certain hardware and substantial modifications to certain software that the U.S. Gov't would rather I not have access to... ;-/
Gordon D. Pusch
Math and C.S. Div., Bldg.203/C254
Argonne National Laboratory

(ed note: I asked Dr. Campbell about this)

A full analysis would probably require a lot of number crunching by a supercomputer. I can make some guesses, however.

I will assume the matter and antimatter are in solid form — if, as likely, only antihydrogen is available, it will be frozen.

The initial contact between the matter and antimatter would produce a flash of nuclear fragments from the shattered nuclei of the matter particles. These would penetrate some distance (0.1 to 1 mm) into both the matter and the antimatter at sufficient intensities to bring the irradiated layers to x-ray hot plasma temperatures. The x-rays will spread by radiation diffusion to evaporate a somewhat thicker region. This occurs on a time scale too fast for significant bulk motion of either matter or antimatter.

What happens next depends on how much turbulence you get at the boundary between the matter and antimatter.

With little turbulence, the antimatter and matter separate as both clouds of gas/plasma expand.

With high levels of turbulence, the two materials mix and you get on-going annihilation, resulting in more radiation that evaporates the rest of the antimatter and nearby matter.

My guess is that you could design the warhead to enhance turbulent mixing, increasing the yield. You probably will need significantly more matter than antimatter in the warhead, however.

Luke Campbell

The second problem is that not all the energy from the blast is dangerous. Some of it is in the form of neutrinos, which are utterly harmless (you know, those slippery little customers who can fly through one light year of solid lead like nothing is there).

First off, a particle will only annihilate with the corresponding anti-particle. This means if an electron hits an anti-proton, they will just bounce off each other (actually, protons and antineutrons sometime annihilate, and vice versa).

The good news for antimatter bomb makers is that electron-positron annihilations create flaming death in the form of a pair of deadly gamma rays. However, this is tempered by the unfortunate fact that electrons and positrons are approximately 1/1836 the mass of protons and other nucleons, and there are about 2.5 times as many nucleons as electrons. This means we can more or less ignore the energy contribution from electron-positron annihilation. Unless you want to just use pure positrons instead of anti-atoms of actual anti-hydrogen. Which means you'll need about 1836 times as many positrons as you would anti-hydrogen atoms to get the same boom.

The trouble is with proton-antiproton annihilations. This produces (on average) two neutral and three charged pions. The neutral pions cooperate by almost instantly decaying into gamma rays.

The charged pions though, are a pain in the posterior, er, ah, behave most inconveniently. Assuming that they are zipping along at about 0.94c, they will on average only make it to about 21 meters from ground zero before decaying into mostly harmless muons and neutrinos. If the intended target is farther away than that, the blast energy that is composed of charged pions is totally wasted. Accurate figures are hard to come by, but from what I've managed to dig up, something like 30% of the energy from proton-antiproton annihilation is going to be wasted as harmless muons and neutrinos. At worst, 4/9ths of the energy (44.4%) will be deadly (3/9ths are the helpful neutral pions decaying into gamma rays, 1/9th are muons decaying into electrons). At best, 100% of the energy will be deadly. My expert said that the deadly energy percent will normally be over 70%. So conservatively one can take 70% as the deadly percent, or optimistically take 85% (the average of 70% and 100%) as the percent. You can read all the gory details here.

Putting it all together, our new (conservative) formulae will be:

EktB = M * 42961.6 * 0.7 * Rf

or

EktB = M * 30073.1 * Rf

EmtB = M * 43.0 * 0.7 * Rf

or

EmtB = M * 30.1 * Rf

where:

  • EktB = deadly blast energy (kilotons)
  • EmtB = deadly blast energy (megatons)
  • M = mass of antimatter (kilograms)
  • Rf = reaction factor, percentage of the matter and antimatter that manages to annihilate before the rest is blown apart. 1.0 if you are an optimist, 0.1 if you are a pessimist, or a point in between that varies according to the technological level of the bomb-maker.
Example

Given a warhead with one gram of antimatter, an optimist will say it will blow up with a force of 0.001 * 30073.1 * 1.0 = 30.1 kilotons and a pessimist will say 0.001 * 30073.1 * 0.1 = 3.0 kilotons.

Also note that, for the most part, antimatter particle beam weapons are a waste of good antimatter.

As a side note, SF Author Colin Kapp often had ships armed with "Diffract Meson" warheads (what splendid technobabble!), presumably based on an as-yet undiscovered scientific principle. I always thought that there was some room for a warhead type in between the 10% efficient thermonuclear warhead and the 100% efficient antimatter warhead. Say Diffract Meson warheads are 50% efficient.

Annihilation Notes

The gamma-ray flux from an antimatter annihilation can be strong enough to transmute some elements into radioactive isotopes. This happens by the phototransmutation process. The cross-section of this is quite low, but the gamma-ray flux can be quite high. And I am also informed that the charged pions may be short-lived, but they have a high cross-section and will do all sorts of interesting things to atomic nuclei. Apparently the higher the mass of the element transmuted, the longer lived it is as a radioisotope. I will get back to you when I manage to find some hard numbers.

As a side note, electron-positron annihilation produces two gamma rays with precisely an energy of 511 keV. Which means this is a dead giveaway for antimatter use. As you zip along in your antimatter powered rocket, everybody within a couple of light-years will be able to see a fool broadcasting the fact that their rocket contains militarily significant amounts of antimatter. If you head towards an alien race's home planet, you may inadvertently frighten them into giving you a very hot reception.

Containment

Unsurprisingly, it is very difficult to safely contain antimatter. Earnshaw's theorem proves that no set of static charges can be used to create a stable trap. The best you can do is metastable, and the vast majority of configurations are actively unstable. You need to cheat with nonstationary fields, as in a Penning Trap.

Dr. Robert Forward spoke of storing antimatter in the form of a frozen snowball of anti-hydrogen at temperatures below two Kelvin, levitated in a magnetic field to avoid contact with the chamber wall. In a vacuum, of course. The cold temperature is to keep the blasted stuff from sublimating any anti-atoms from the surface and starting an annihilation reaction with the chamber. There will be some infrequent annihilation events caused by stray cosmic rays, but these should not be a problem.

If you are using your ball of antimatter as a fuel source instead of a bomb, Dr. Forward suggests extracting antimatter fuel from the chamber by using ultraviolet lasers. The lasers ionize a bit of anti-hydrogen from the snowball, which is captured by tailored electrostatic fields and piped to the engine. To insure the snowball's mass is not removed asymmetrically (which would destabilize the magnetic levitation), it is spun on its axis while under the laser.

Current particle accelerators are horribly inefficient at generating antimatter, but Dr. Forward says this is because they were designed by physicists, not industrial engineers. He is of the opinion that a dedicated antimatter factory built with current technology could approach 0.01% efficiency (which isn't good but is still about 6000 times better than Fermilab). The theoretical maximum is 50% efficiency due to the pesky Law of Baryon Number Conservation (which demands that when turning energy into matter, equal amounts of matter and antimatter must be created).

Relativistic Weapons

For relativistic combat between Bussard Ramjet starships, go here.

Relativistic weapons are kinetic-kill weapons where the projectile moves faster than 14% the speed of light (42,000 kilometers per second or so) although the real fun doesn't start until about 90% the speed of light. Refer to the gamma chart. They are sometimes called "R-bombs." Such weapons do incredible amounts of damage, but by the same token they require absurd amounts of energy (refer to second equation below). They are very likely to remain science-fictional for centuries to come.

Even more so than kinetic-kill weapons, an actual warhead adds very little to the total damage inflicted. Note that at 86.6% the speed of light the amount of kinetic energy is equal to the rest mass, which means that the projectile will inflict upon the target the same energy as if it was composed of pure antimatter. Well, actually it will just contain that much energy, as Ken Burnside mentions about kinetic penetrator effects, in many cases the projectile will penetrate the target and exit the back of the ship while still containing joules of damage it failed to inflict on the target.

At such speeds, the kinetic kill equation is no longer accurate. Instead, the following equation is used. Remember that this not only tells how much kinetic damage the projectile will do to the target, it is also the minimum amount of energy the weapon will consume when it fires a round.

Again, to get some idea of the amount of damage represented by a given amount of Joules, refer to the Boom Table.

Ker = ((1/sqrt(1 - (V2/C2))) - 1) * M * C2

Ker = ((1/sqrt(1 - (V2/9e16))) - 1) * M * 9e16

Ker = ((1/sqrt(1 - P2)) - 1) * M * 9e16

where:

  • Ker = relativistic kinetic energy (Joules)
  • M = mass of projectile (kg)
  • V = velocity of projectile relative to target (m/s)
  • P = velocity of projectile relative to target (percentage of c, e.g., three quarters lightspeed = 0.75)
  • C = speed of light in m/s = 3e8

And as before

Wp = Ker * (1 / We)

where:

  • Wp = power required by weapon to fire one projectile (Joules)
  • Ker = kinetic energy of one weapon projectile (Joules)
  • We = efficiency of the weapon (0.0 = 0%, 1.0 = 100%)
Example

How much damage would the 7 kilograms of used kitty litter from Sneaky the cat's litterbox inflict if it was traveling at a velocity of 90% c?

Ker = ((1/sqrt(1 - P2)) - 1) * M * 9e16

Ker = ((1/sqrt(1 - 0.92)) - 1) * 7 * 9e16

Ker = 8.2e17 Joules, about 195 megatons.

Not bad, for kitty litter.

But a civilization that does gain the ability to create relativistic kinetic-kill weapons becomes a deadly threat to any and all alien civilizations in range.

Poor Man's R-Bomb

Iain Paterson did some calculations which produced some surprising results.

I had this image of putting a relatively small payload on top of a bloody massive conventional booster and firing it of -- the poor mans R-bomb i guess -- but after looking at some calculations this doesn't look likely.

From the kinetic energy equation and Tsiolkovsky's equation you get:

E = 1/2 * Mpayload * (Vexhaust * ln(R))2

E = 1/2 * (Mtotal / R) * (Vexhaust * ln(R))2

Differentiating with respect to R and setting equal to zero gives the mass ratio that gives the maximum energy. Canceling terms gives that:

R = E * 2

Vfinal_Ideal = 2 * Vexhaust

This is rather surprising to me though I suppose it makes sense: at higher velocities there is a greater kinetic energy per mass but it requires a huge amount of fuel to get to that velocity. After reaching this velocity any additional acceleration REDUCES the energy impacted on the target so you might as well shut off the engines and let it coast.

I worked it out for other cases as well, for 2 ships that are approaching each other before one fires a missile you get

R = e(2-γ)

where γ (gamma) is the ratio of the approach velocity to the exhaust velocity although this again gives that the missile should impact with a relative velocity of twice its exhaust velocity.

The final case is for relativistic velocities (although being fired from ships that are stationary with respect to each other otherwise the maths is really nasty!) and you get:

R = ((c + Vexhaust) / (c - Vexhaust))2

Vfinal_ideal = 2 * Vexhaust / (1 + (Vexhaust / c)2)

note that for V«c, Vf = 2 * Vexhaust. And for V~c, Vf = c.

So is it just me or does this completely defy the concept of the poor-mans R-bomb so that instead it requires some sort of some handwavium total-conversion drive?

Also this shows that to be effective a kinetic-missile must have a high exhaust velocity, not just a lot of fuel. While I suppose in order to evade point defense they need to be going faster but every extra second of thrust would reduce the damage inflicted to the target.

Iain Paterson

Mr. Paterson is optimizing a more plausible scenario. His "poor man's R-bomb" is constrained by a particular exhaust velocity, and the question is how to squeeze the maximum kinetic energy into the payload. I'm not sure whether his analysis is correct, but it seems plausible.

The optimum energy efficiency would actually be reached at an terminal velocity equal to the exhaust velocity. But that doesn't seem to be the objective of the poor man's R-bomb. The poor man's R-bomb seems to be limited by loaded mass rather than energy budget. You don't use any sacrificial propellant at all, you just use pure fuel at the maximum exhaust velocity you can manage all the way.

Mr. Paterson writes: So is it just me or does this completely defy the concept of the poor-mans R-bomb so that instead it requires some sort of some handwavium total-conversion drive?

His conclusion is essentially correct, if we assume the poor man's R-bomb must be internally powered.

Still, this is nothing new to those of us who have seriously considered the problem of fast interstellar propulsion. We gave up on the idea of internal power for fast interstellar propulsion years ago, on the pretty obvious grounds that no fuel has a sufficient (usable) energy density. If you want to reach high relativistic speeds, you should use external power--either in the form of a laser beam or particle beam or "runway" track or relativistic kinetic impactors.

Isaac Kuo

The Killing Star

From The Killing Star by Charles Pelligrino and George Zebrowski (you really should read this book):

All the energy put into achieving that velocity had transformed the Intruder into a kinetic storage device of nightmarish design. If it struck a world, every gram of the vessel's substance would be received by that world as the target in a linear accelerator receives a spray of relativistic buckshot. Someone, somewhere, had built and was putting to use a relativistic bomb -- a giant, roving atom smasher aimed at worlds...


The gamma-ray shine of the decelerating half was also detectable, but it made no difference. One of the iron rules of relativistic bombardment was that if you could see something approaching at 92 percent of light speed, it was never where you saw it when you saw it, but was practically upon you...


In the forests below, lakes caught the first rays of the rising Sun and threw them back into space. Abandoning the two-dimensional sprawl of twentieth-century cities, Sri Lanka Tower, and others like it, had been erected in the world's rain forests and farmlands, leaving the countryside virtually uninhabited. Even in Africa, where more than a hundred city arcologies had risen, nature was beginning to renew itself. It was a good day to be alive, she told herself, taking in the peace of the garden. Then, looking east, she saw it coming -- at least her eyes began to register it -- but her optic nerves did not last long enough to transmit what the eyes had seen.

It was quite small for what it could do -- small enough to fit into an average-sized living room -- but it was moving at 92 percent of light speed when it touched Earth's atmosphere. A spear point of light appeared, so intense that the air below snapped away from it, creating a low-density tunnel through which the object descended. The walls of the tunnel were a plasma boundary layer, six and a half kilometers wide and more than 160 deep -- the flaming spear that Virginia's eyes began to register -- with every square foot of its surface radiating a trillion watts, and still its destructive potential was but fractionally spent.

Thirty-three kilometers above the Indian Ocean, the point began to encounter too much air. It tunneled down only eight kilometers more, then stalled and detonated, less than two-thousandths of a second after crossing the orbits of Earth's nearest artificial satellites.

Virginia was more than three hundred kilometers away when the light burst toward her. Every nerve ending in her body began to record a strange, prickling sensation -- the sheer pressure of photons trying to push her backward. No shadows were cast anywhere in the tower, so bright was the glare. It pierced walls, ceramic beams, notepads, and people -- four hundred thousand people. The maglev terminal connecting Sri Lanka Tower to London and Sydney, the waste treatment centers that sustained the lakes and farms, all the shops, theaters, and apartments liquefied instantly. The structure began to slip and crash like a giant waterfall, but gravity could not yank it down fast enough. The Tower became vapor before it could fall half a meter. At the vanished city's feet, the trees of the forest were no longer able to cast shadows; they had themselves become long shadows of carbonized dust on the ground.

In Kandy and Columbo, where sidewalks steamed, the relativistic onslaught was unfinished. The electromagnetic pulse alone killed every living thing as far away as Bombay and the Maldives. All of India south of the Godavari River became an instant microwave oven. Nearer the epicenter, Demon Rock glowed with a fierce red heat, then fractured down its center, as if to herald the second coming of the tyrant it memorialized. The air blast followed, surging out of the Indian Ocean -- faster than sound -- flattening whatever still stood. As it slashed north through Jaffna and Madurai, the wave front was met and overpowered by shocks rushing out from strikes in central and southern India.

Across the face of the planet, without warning, thousands of flaming swords pierced the sky...


Then out of no where -- out of the deep impersonal nowhere -- came a bombardment that even the science fiction writers had failed to entertain.

Just nine days short of America's tricentennial celebrations, every inhabited planetary surface in the solar system had been wiped clean by relativistic bombs. Research centers on Mars, Europa, and Ganymede were silent; even tiny Phobos and Moo-kau were silent. Port Chaffee was silent. New York, Colombo, Wellington, the Mercury Power Project and the Asimov Array. Silent. Silent. Silent.

A Valkyrie rocket's transmission of Mercury's surface had revealed thousands of saucer-shaped depressions where only hours before had existed a planet-spanning carpet of solar panels. The transmission had lasted only a few seconds -- just long enough for Isak to realize there would be no more of the self-replicating robots that had built the array of panels and accelerators, just long enough for him to understand that humanity no longer possessed a fuel source for its antimatter rockets -- and then the transmission had ceased abruptly as the Valkyrie disappeared in a silent white glare.

Presently, most of the station's scopes and spectrographs were turning Earthward, and Isak found it impossible to believe what they revealed. The Moon rising over Africa from behind Earth was peppered with new fields of craters. The planet below looked like a ball of cotton stained grayish yellow. The top five meters of ocean had boiled off under the assault, and sea level air was three times denser than the day before -- and twice as hot...


The sobering truth is that relativistic civilizations are a potential nightmare to anyone living within range of them. The problem is that objects traveling at an appreciable fraction of light speed are never where you see them when you see them (i.e., light-speed lag). Relativistic rockets, if their owners turn out to be less than benevolent, are both totally unstoppable and totally destructive. A starship weighing in at 1,500 tons (approximately the weight of a fully fueled space shuttle sitting on the launchpad) impacting an earthlike planet at "only" 30 percent of lightspeed will release 1.5 million megatons of energy -- an explosive force equivalent to 150 times today's global nuclear arsenal... (ed note: this means the freaking thing has about nine hundred mega-Ricks of damage!)

The most humbling feature of the relativistic bomb is that even if you happen to see it coming, its exact motion and position can never be determined; and given a technology even a hundred orders of magnitude above our own, you cannot hope to intercept one of these weapons. It often happens, in these discussions, that an expression from the old west arises: "God made some men bigger and stronger than others, but Mr. Colt made all men equal." Variations on Mr. Colt's weapon are still popular today, even in a society that possesses hydrogen bombs. Similarly, no matter how advanced civilizations grow, the relativistic bomb is not likely to go away...

From The Killing Star by Charles Pelligrino and George Zebrowski

Space Hackers

Spacecraft in a war zone had better have military-grade firewalls on their internal computer networks. Space hackers can try to crack the network through a radio link and issue a variety of computer commands. Such as vent the atmosphere, scram the reactor, or induce the warheads in the magazine to detonate. Not to mention uploading all the classified information in the data banks. This is an old trick, seen in such movies as The Wrath of Khan (where Admiral Kirk uses the "prefix code" to turn off the deflectors on Khan's ship), Independence Day, TV shows like the latest incarnation of Battlestar Galactica (where the Galactica's computers are NOT networked since the Cylons are just a little too good at hacking), and in novels such as Vernor Vinge's A Fire Upon The Deep, Ken MacLeod's The Cassini Division and James P. Hogan's Giant's Star.

Paul Zimmerle points out that Battlestar Galactica does get the threat slightly wrong. It is not networked computers per se that are at risk, it is computers with some kind of data connection to the outside world that is the threat. Removing the network connection just slows the rate of contagion.

The Desert of Stars

(ed note: The Apache is part of a task force attacking a task force of enemy Han warships. The Han launch a spread of missiles, then turn tail and run. The task force the Apache is part of closes in for the kill, when suddenly...)

“Wait, one, sir — ” Neil said before he was thrown painfully against his chair straps. The collision warning sounded, and a petty officer fell and struck the floor, hard. He cursed and picked himself up.

“What the hell, Propes?” Captain Howell shouted.

“Sir, the computer took control from me and executed an emergency turn and thrust,” Ensign Cohen, the propulsion officer, said. “I don’t know why. Says we almost hit another ship, but the Maryland is almost thirty klicks away.”

Neil raced through sensor reports on his console. “Confirm, there’s nothing outside. All the other American ships in the fleet are maneuvering, sir — looks random!”

“Get me the flag!” Howell shouted.

“External comms are down, sir,” an astronaut responded.

Cohen added, “The computer’s not giving me back control, sir. I don’t understand it.”

“Some of my point defense batteries just went offline, and I’ve got a yellow on two of the counterbattery turrets,” Jessica said. “Did our warranty just expire?”

Howell grimaced. “People, explain this.”

Neil chased a flashing light on his console. “Just before the thrust, we picked up a hefty EM pulse from the direction of the planet.”

That sent Cohen scanning through her logs. “That’s it! The collision warning … Eagle told us it was about to crash into us! The computer ignored the sensor data and reacted.”

“And it looks like they got a virus into our systems,” the systems officer said. “I’m after it.”

We update the handshake codes constantly, so the Hans can’t get anything through our receivers during normal communications, Neil thought. But the anti-collision systems are a safety system and run separately in case the main network goes down, and we make it easy for our ships to warn each other off. I guess they figured out how to trip that system from Eagle. And they bollixed every American ship in the fleet.

The incoming missiles were eight minutes away.

The strain on the Command Deck of the Shapieron had been hovering around breaking point for days. Eesyan was standing in the center of the floor gazing up at the main display screen, where an enormous web of interconnected shapes and boxes annotated with symbols showed the road map into JEVEX that ZORAC had laboriously pieced together from statistical analyses and pattern correlations of the responses it had obtained to its probe signals. But ZORAC was not getting through to the nucleus of the system, which it would have to penetrate if it was going to disrupt JEVEX'S h-jamming capability. Its attempts had been repeatedly detected by JEVEX'S constantly running self-checking routines and thwarted by automatically initiated correction procedures. The big problem now was trying to decide how much longer they could allow ZORAC to try before the tables of fault-diagnostic data accumulating inside JEVEX alerted its supervisory functions that something very abnormal was happening. Opinions were more or less evenly divided between Eesyan's scientists from Thurien, who already wanted to call the whole thing off, and Garuth and his crew, who seemed willing to risk almost anything to pursue what was beginning to look, the more Eesyan saw of it, like some kind of death wish.

"Probe Three's function directive has been queried for the third time," one of the scientists announced from a nearby station. "Header response analysis indicates we've triggered a veto override again." He looked across at Eesyan and shook his head. "It's too dangerous. We'll have to suspend probing on this channel and resume regular traffic only."

"Activity pattern correlates with a new set of executive diagnostic indexes," another scientist called. "We've initiated a high-level malfunction check."

"We have to shut down on Three," another, standing by Ecsyan, pleaded. "We're too exposed as it is."

Eesyan stared grimly up at the main screen as a set of mnemonics unrolled down one side to confirm the warning.

"What's your verdict, ZORAC?" he asked.

"I've reduced interrogation priority, but the fault flags are still set. It's tight, but it's the nearest we've come so far. I can try it one more time and risk it, or back off and let the chance go. It's up to you."

Eesyan glanced across to where Garuth was watching tensely with Monchar and Shilohin. Garuth clamped his mouth tight and gave an almost imperceptible nod. Eesyan drew a long breath. "Give it a try, ZORAC," he instructed. A hush fell across the Command Deck, and all eyes turned upward toward the large screen.

In the next second or two a billion bits of information flew back and forth between ZORAC and a Jevienese communications relay hanging distantly in space. Then, suddenly, a new set of boxes appeared in the array. The symbols inside them were etched against bright red backgrounds that flashed rapidly. One of the scientists groaned in dismay.

"Alarm condition," ZORAC reported. "General supervisor alert triggered. I think we just blew it." It meant that JEVEX knew they were there.

Eesyan looked down at the floor. There was nothing to say. Garuth was shaking his head dazedly in mute protest as if refusing to accept that this could be happening. Shilohin moved a step nearer and rested a hand on his shoulder. "You tried," she said quietly. "You had to try. It was the only chance."

Garuth was staring around him as if he had just awakened from a dream. "What was I thinking?" he whispered. "I had no right to do this."

"It had to be done," Shilohin told him firmly.

"Two objects a hundred thousand miles out, coming this way fast," ZORAC reported. "Probably defensive weapons coming to check out this area." It was serious. The screen hiding the Shapieron would never stand up to probing at close range.

"How long before we register on their instruments?" Eesyan asked hoarsely.

"A couple of minutes at most," ZORAC replied...

..."So this is our ultimatum to you: either you withdraw from Thurien now, and agree to place your entire military command under our jurisdiction unconditionally, or the Thuriens will transfer through to Jevlen a combined Terran force that will blow you to stardust - you, your whole planet, and that laughable aggregation of scrap that you call a computer network."

Somewhere deep inside JEVEX something hiccupped. A million tasks that had been running inside the system froze in the confusion as directives coming down from the highest operating levels of the nucleus redefined the whole structure of priority assignments to force an emergency analysis of the new data. And in the middle of it all, the routines that had been scanning for inquisitive probes through h-space faltered. It was only for a few seconds, but...

..."It's busy," ZORAC's voice answered. "Don't ask me what's happened, but yes it was. Something deactivated the self-checking functions, and I've switched off the jamming routine. We're through to Thurien."

While ZORAC was speaking, VISAR decoded the access passwords into JEVEX's diagnostic subsystem, erased a set of data that it found there, substituted new data of its own, and reset the alarm indicators. Inside the Jevienese Defense Sector Five control center, a display screen changed to announce a false alarm caused by a malfunctioning remote communications relay. Far off in space, the two destroyers turned away to return to their stations and resume routine patrolling. Already VISAR was pouring volumes of information into JEVEX that it had not time to explain, not even to ZORAC. At the same time it broke its way into JEVEX's communications subsystem and gained control of the open channel to Earth.

From Giant's Star by James P. Hogan (1981)

And never lose sight of the reason for haste: the frigate. It had switched to rocket drive, blasting heedless away from the wallowing freighter. Somehow, these microbes knew they were rescuing more than themselves. The warship had the best navigation computers that the little minds could make. But it would be another three seconds before it could make its first ultradrive hop.

The new Power had no weapons on the ground, nothing but a comm laser. That could not even melt steel at the frigate's range. No matter, the laser was aimed, tuned civilly on the retreating warship's receiver. No acknowledgement. The humans knew what communication would bring. The laser light flickered here and there across the hull, lighting smoothness and inactive sensors, sliding across the ship's ultradrive spines. Searching, probing. The Power had never bothered to sabotage the external hull, but that was no problem. Even this crude machine had thousands of robot sensors scattered across its surface, reporting status and danger, driving utility programs. Most were shut down now, the ship fleeing nearly blind. They thought by not looking that they could be safe.

One more second and the frigate would attain interstellar safety.

The laser flickered on a failure sensor, a sensor that reported critical changes in one of the ultradrive spines. Its interrupts could not be ignored if the star jump were to succeed. Interrupt honored. Interrupt handler running, looking out, receiving more light from the laser far below... a backdoor into the ship's code, installed when the newborn had subverted the human's groundside equipment...

...and the Power was aboard, with milliseconds to spare. Its agents - not even human equivalent on this primitive hardware - raced through the ship's automation, shutting down, aborting. There would be no jump. Cameras in the ship's bridge showed widening of eyes, the beginning of a scream. The humans knew, to the extent that horror can live in a fraction of a second.

There would be no jump. Yet the ultradrive was already committed. There would be a jump attempt, without automatic control a doomed one. Less than five milliseconds till the jump discharge, a mechanical cascade that no software could finesse. The newborn's agents flitted everywhere across the ship's computers, futilely attempting a shutdown. Nearly a light-second away, under the gray rubble at High Lab, the Power could only watch. So. The frigate would be destroyed.

So slow and so fast. A fraction of a second. The fire spread out from the heart of the frigate, taking both peril and possibility.

From A Fire Upon the Deep by Vernor Vinge (1992)

EMP Weapons

These are designed to create strong electro-magnetic pulses designed to fry electronics and electrical equipment. Many e-bomb designs are not nuclear, they use a conventional high-explosive charge in an armature to generate the pulse. These tend to be short range, on the order of hundreds of meters, and they do obey the inverse square law. The defense is enclosing all electrical devices in Faraday cages. It is amusing to note that vacuum tube technology is much less vulnerable to EMP than are transistors.

Fiber optic cables are immune to EMP, unfortunately they are not shock tolerant. Specifically they have poor shear tolerance. Fiber can withstand a certain amount of flex, but it's resistance to "instantaneous flex" (like you'd see with a conventional missile hit) is not good. Ordinary twisted pair wires will stretch with the displacement from the explosion (assuming a hit close enough to warp the local supports but far enough not to directly break the cables) but are vulnerable to EMP. A sharp strike, bend or flex to fiber optic cable will shatter the individual strands across the grain, and destroy the cable.

Conventional nuclear weapons will also produce an EMP under certain circumstances.

Propulsion Systems

If your torchship's exhaust is pumping out a few terawatts, it might occur to you that your enemy would be real unhappy if you hosed them with your tail flame.

This is called "The Kzinti Lesson", from a Larry Niven short story called "The Warriors". Most science fiction fans have the mistaken belief that Niven first came up with the idea, even though John W. Campbell Jr. used it in his short story Solarite in 1930 (collected in The Black Star Passes).

The Kzinti Lesson states:

Kzinti Lesson

A reaction drive's efficiency as a weapon is in direct proportion to its efficiency as a drive.

Larry Niven

The warlike Kzinti invaded the solar system, figuring that humanity would be a pushover since the pacifist humans of the time had no weapons. Humans showed the Kzin the error of their ways by annihilating Kzinti warships with laser arrays used for solar sails, multi-million degree fusion exhausts, and photon drives that were basically titanic lasers. The humans did indeed have no weapons, technically. But any machine with that much energy at its disposal can be re-purposed.

So keep in mind that the higher the exhaust velocities of the rocket engine, the more damage it will do to anything unfortunate enough to be in the path of the exhaust.

Having said that, realize that as a general rule propulsion exhaust is poorly collimated, which means after a very short range it will have expanded and dissipated into harmlessness.

For examples of this in science fiction, consult the ever informative TV Tropes under Weaponized Exhaust.

Any army man can tell you it is an extraordinarily bad idea to stand directly behind an MLRS or any other rocket-propelled weapon. The backblast will cook you. And a soldier firing a man portable rocket weapon had better not have a wall close behind, or the wall will reflect the flaming backblast all over the stupid soldier.

Sometimes it works the other way. If you are attacking an Orion drive spacecraft with nuclear warheads, they will just point their pusher plate at the missiles and laugh at you. Though come to think, any propulsion system that uses a stream of detonating nuclear warheads should be easy to weaponize. In Larry Niven and Jerry Pournelle's Footfall they use the x-ray bursts from nuclear propulsion charges to pump x-ray lasers.

In The Outcasts of Heaven's Belt by Joan Vinge, warships attacking a visiting Bussard Ramjet starship get a rude surprise when the starship shows them its tail. The starship's fusion drive is quite deadly at close range. Things are more extreme in the anime Space Battleship Yamato (later watered down and made politically correct for viewers in the US under the name Star Blazers). The battleship's propulsion system is the incredibly powerful "wave-motion engine". But if attacked, the thrust is vectored out the nose of the ship to create the equally incredibly powerful "wave-motion cannon".

In the Space 1999 episode "Voyager's Return" the hapless inhabitants of Moonbase Alpha are alarmed to see the infamous Voyager One space probe approaching. The probe's propulsion system is the dreaded "Queller Drive", which uses a deadly radioactive stream of fast neutrons. The first test of the Queller drive accidentally killed everyone at a lunar colony. Lucky for the Alphans the inventor of the drive is actually hiding in Moonbase Alpha in a version of the witness protection program, since everybody who had relatives at the dead colony wants to kill him. Dr. Queller manages to turn Voyager off before it can fry everybody in Alpha.

But things go from bad to worse when they notice three alien warships following Voyager. As it turns out the aliens are seeking vengeance for millions of their citizens who were killed when the incompetently programmed Voyager One came blundering through their empire. Voyager One was programmed to turn off the Queller drive so as to avoid torching any inhabited planets, but Dr. Queller's software had a few bugs.

DRIVING JETS ARE WEAPONS

(ed note: "Storm" Cloud and his newly assembled crew has to destroy the planetary fortress of the evil Nhalians. Said fortress is protected by a strong technobabble force screen. Cloud plans to dive on the fort with his cruiser, using the exhaust from his propulsion system to overload the fortress' force screen.)

     High above the stratosphere, inert, the pilot found his spot and flipped the cruiser around, cross-hairs centering the objective. Then, using his forward, braking jets as drivers, he blasted her straight downward.
     She struck atmosphere almost with a thud. Only her fiercely-driven meteorite-screens and wall-shields held her together.
     'I hope to Klono you know what you're doing, chum,' the Chickladorian remarked conversationally as the fortress below leaped upward with appalling speed. 'I've made hot landings before, but I always had a hair or two of leeway. If you don't hit this to a couple of hundredths we'll splash when we strike. We won't bounce, brother.'
     'I can compute it to a thousandth and I can set the clicker to within five, but it's you that'll have to do the real hitting.' Cloud grinned back at the iron-nerved pilot. 'Sure a four-second call is enough to get your rhythm, allow for reaction time and lag, and blast right on the click?'
     'Absolutely. If I can't get it in four I can't get it at all. Got your stuff ready?'
     'Uh-huh.' Cloud, staring into the radarscope, began to sway his shoulders. He knew the exact point in space and the exact instant of time at which the calculated deceleration must begin; by the aid of his millisecond timer—two full revolutions of the dial every second—he was about to set the clicker to announce that instant. His hand swayed back and forth—a finger snapped down—the sharp-toned instrument began to give out its crisp, precisely-spaced clicks.
     'Got it!' Cloud snapped. 'Right on the middle of the click! Get ready, Thlaskin—seconds! Four! Three! Two! One! Click!'
     Exactly with the click the vessel's brakes cut off and her terrific driving blasts smashed on. There was a cruelly wrenching shock as everything aboard acquired suddenly a more-than-three-times-Earthly weight...
     ...Downward the big ship hurtled, toward the now glowing screens of the fortress. Driving jets are not orthodox weapons, but properly applied, they can be deadly ones indeed: and these were being applied with micromatric exactitude.
     Down! DOWN! ! The threatened fortress and its neighbors hurled their every beam; Nhalian ships dived frantically at the invader and did their useless best to blast her down.
     Down she drove, the fortress' screens flaming ever brighter under the terrific blast.
     Closer! Hotter! Still closer! Hotter still! Nor did the furious flame waver—the Chickladorian was indeed a master pilot.
     'Set up a plus ten, Thlaskin,' Cloud directed. 'Air density and temperature are changing. Their beams, too, you know.'
     'Check. Plus ten, sir—set up.'
     'Give it to her on the fourth click from ... this.'
     'On, sir.'
     The vessel seemed to pause momentarily, to stumble; but the added weight was almost imperceptible.
     A bare hundred yards now, and the ship of space was still plunging downward at terrific speed. The screens were furiously incandescent, but were still holding.
     A hundred feet. Velocity appallingly high, the enemy's screens still up. Something had to give now! If that screen stood up the ship would vanish as she struck it, but Thlaskin the Chickladorian made no move and spoke no word. If the skipper was willing to bet his own life on his computations, who was he to squawk? But... he must have miscalculated!
     No! While the vessel's driving projectors were still a few yards away the defending screens exploded into blackness; the awful streams of energy raved directly into the structures beneath. Metal and stone glared white, then flowed—sluggishly at first, but ever faster and more mobile—then boiled coruscantly into vapor.
     The cruiser slowed—stopped—seemed to hang for an instant poised. Then she darted upward, her dreadful exhausts continuing and completing the utter devastation.

From THE VORTEX BLASTER by E. E. "Doc" Smith (1960)
SOLARITE

(ed note: Our heroes are in a spacecraft that has auxiliary oxygen - atomic hydrogen chemical rocket engines. They are confronting an enemy aircraft with a wingspan of three quarters of a mile, with ten inch thick armor)

What could the Solarite do against the giant monoplane? Evidently Arcot had a plan. Under his touch their machine darted high into the sky above the great plane. There was a full mile between them when he released the sustaining force of the Solarite and let it drop, straight toward the source of the battle—falling freely, ever more and more rapidly. They were rushing at the mighty plane below at a pace that made their hearts seem to pause—then suddenly Arcot cried out, “Hold on—here we stop!”

They seemed a scant hundred feet from the broad metal wings of the unsuspecting plane, when suddenly there was a tremendous jerk, and each man felt himself pressed to the floor beneath a terrific weight that made their backs crack with the load. Doggedly they fought to retain their senses; the blackness receded.

Below them they saw only a mighty sea of roaring red flames—a hell of blazing gas that roared like a score of bombs set off at once. The Solarite was sitting down on her rocket jets! All six of the rocket tubes in the base of the ship had been opened wide, and streaming from them in a furious blast of incandescent gas, the atomic hydrogen shot out in a mighty column of gas at 3500 degrees centigrade. Where the gas touched it, the great plane flared to incandescence; and in an immeasurable interval the fall of the Solarite ended, and it rebounded high into the air. Arcot, struggling against the weight of six gravities, pulled shut the little control that had sent those mighty torches blasting out. An instant later they sped away lest the plane shoot toward the gas columns.

From a safe distance they looked back at their work. No longer was the mighty plane unscathed, invulnerable, for now in its top gaped six great craters of incandescent metal that almost touched and coalesced. The great plane itself reeled, staggering, plunging downward; but long before it reached the hard soil below, it was brought into level flight, and despite many dead engines, it circled and fled toward the south. The horde of small planes followed, dropping a rain of bombs into the glowing pits in the ship, releasing their fury in its interior.

From SOLARITE by John W. Campbell Jr. (1930). Collected in The Black Star Passes
WHEN WORLDS COLLIDE

(ed note: When a crazed army of survivors attacks the site where the Space Arks are being built, things look bleak until one of the main characters starts up the almost-complete first Ark, sets the atomic engines to "1 G", and floats over the attacking hordes in blowtorch mode)

     "To the ship! Into the ship!" Tony cried to them. "Everybody into the ship! Spread the word! Jack! . . . Everybody, everybody into the ship!" There was no alternative.
     Three-fourths of the camp was in the hands of the horde; and the laboratories could not possibly beat off another rush. They could not have beaten back this, if it had been more organized.
     Bullets flew through the dark.
     "To the ship! To the ship!"
     Creeping on hands and knees, from wounds or from caution, and dragging the wounded with them, the men started the retreat to the ship. Women were helping them.
     Yells and whistles warned that another rush was gathering; and this would be from all sides; the laboratories and the ship were completely surrounded.
     Tony caught up in his arms a young man who was barely breathing. He had a bullet through him; but he lived. Tony staggered with him into the ship.
     Hendron was there at the portal of the great metal rocket. He was cooler than any one else. "Inside, inside," he was saying confidently...
     ...The second rush was coming. No doubt of it, and it would be utterly overwhelming. There would be no survivors—but the women. None. For the horde would take no prisoners. They were killing the wounded already—their own badly wounded and the camp's wounded that they had captured.
     Eliot James, a bullet through his thigh, but saved by the dark, crawled in with this information. Tony carried him into the ship.
     They were all in the ship—all the survivors. The horde did not suspect it. The horde, as it charged in the dark, yelling and firing, closed in on the laboratories, clambered in the windows, smashing, shooting, screaming. Meeting no resistance, they shot and bayoneted the bodies of their own men and of the camp's which had been left there.
     Then they came on toward the ship. They suddenly seemed to realize that the ship was the last refuge. They surrounded it, firing at it. Their bullets glanced from its metal. Somebody who had grenades bombed it.
     A frightful flame shattered them. Probably they imagined, at first, that the grenade had exploded some sort of a powder magazine within the huge metal tube, and that it was exploding. Few of those near to the ship, and outside it, lived to see what was happening.
     The great metal rocket rose from the earth, the awful blast from its power tubes lifting it. The frightful heat seared and incinerated, killing at its touch. A hundred of the horde were dead before the ship was above the buildings.
     Hendron lifted it five hundred feet farther, and the blast spread in a funnel below it. A thousand died in that instant. Hendron ceased to elevate the ship. Indeed, he lowered it a little, and the power of the atomic blast which was keeping two thousand tons of metal and of human flesh suspended over the earth, played upon the ground—and upon the flesh on the ground—as no force ever released by man before.
     Tony lay on his face on the floor of the ship, gazing down through the protective quartz-glass at the ground lighted by the garish glare of the awful heat.
     In the midst of the blaring, blinding, screaming crisis, a man on horseback appeared. His coming seemed spectral. He rode in full uniform; he had a sword which he brandished to rally his doomed horde. Probably he was drunk; certainly he had no conception of what was occurring; but his courage was splendid. He spurred into the center of the lurid light, into the center of the circle of death and tumult, stiff-legged in stirrups of leather, like one of the horrible horsemen of the Apocalypse.
     He was, for a flaming instant, the apotheosis of valor. He was the crazed commander of the horde.
     But he was more. He was the futility of all the armies on earth. He was man, the soldier.
     Probably he appeared to live after he had died, he and his horse together. For the horse stood there motionless like a statue, and he sat his horse, sword in hand. Then, like all about them, they also crumpled to the ground.
     Half an hour later, Hendron brought the ship down.

From WHEN WORLDS COLLIDE by Philip Wylie and Edwin Balmer (1933)
LET THERE BE LIGHT

Lucifer VI-class Starwisp Tender

With the ongoing spread of the stargate plexus, it became rapidly apparent to the Imperial Exploratory Service that it would rapidly become impracticable to continue to launch trans-horizon probes from its existing fixed facilities, and indeed that to construct new launch facilities at the current edge of the stargate plexus would, in the long term, be economically foolish as growth continued to render them obsolete in turn.

To resolve this problem, they commissioned the design of the Lucifer-class starwisp tender, now in its sixth design iteration. The tender is essentially a complete phased-array laser capable of accelerating a starwisp (probe or otherwise) to not only normal relativistic velocities, but to the high-relativistic range (0.95 to 0.99 lights), coupled to a deployable solar swarm capable of generating sufficient power, when in close solar orbit, to power the laser array, all mounted upon a fusion torch drive sufficient to move the tender between systems, albeit slowly and with low maneuverability at best. A hangar and maintenance facility suitable for housing and readying for deployment the starwisps themselves awkwardly perched on the side of the core ship completes the design. No quarters for biosapient crew are provided on the Lucifer-class; it is intended for long-term deployment under full automation, with only the occasional presence of infomorph crew required for optimal operation.

29 Lucifer-class vessels are in commission at the present date, of which 24 are attached to the Exploratory Service in its joint program (with Ring Dynamics, ICC) of probing highly-rated prospect systems in the Outback to plan future plexus expansion. The remaining five vessels are registered to various private relativistic-trade consortia. Of these, 20 are of the Lucifer VI-class, seven of the preceding Lucifer V-class, and two, the oldest, of the Lucifer IV-class. Lucifer itself, class prototype for the first design iteration, is permanently stationed at Almeä L4 as a museum ship. All other Lucifer-class starships are believed to have been decommissioned.

It is also worth noting that reading the class specifications, which are precisely correct in stating the Lucifer-class’s lack of formal weaponry and civilian classification, appears to generate in some few pirates and hijackers (those, for instance, responsible for the attacks on Photophoros, Luminary, and Radiance) the incautious ambition necessary to pick a fight with an 864 terawatt highly-collimated laser intended for use over interstellar distances – thus clearly demonstrating, perhaps, the distinction between knowledge and wisdom.

- Fíerí’s Starships of the Associated Worlds, 421st ed.;
Vol. IX: Esoterica

Anti-Kzinti Lesson

Jonathan Cunningham notes that sometimes the opposite is true as well.

Anti-Kzinti Lesson

A weapon's output is in direct proportion to its potential as a maneuvering thruster.

Jonathan Cunningham

The effect is strongest with kinetic kill weapons of course, but will still be noticeable with particle beam weapons or even lasers. It will be less of an issue for missile launchers, assuming the missile don't begin full thrust until after they've left the tubes.

Any force acting through the center of a body affects the movement of that body. Any force acting anywhere else on a body will affect its rotation. The more powerful the beam, the stronger the thruster effect. The further away from the center of mass, the greater the lever arm, and the greater the rotational effect.

So when the Space Cruiser Virtuous has X turret cuts lose with a high energy broadside against the flagship of the Insidious Empire, the ship starts spinning until it comically slices its own escorts in half. The Despicable Lord cackles and returns fire from one of several fixed mounted emplacements, each one aligned through the center of mass, likes quills on a porcupine. Foolish humans...

TV Tropes calls this concept "Exhaustized Weapons".

Of course, if the weapon has low power compared to the mass, or fires in a short enough burst the effect is minimized. But not removed. During the Apollo 13 mission, NASA was mystified as to why the powerless craft kept drifting off course. It turns out that normal, periodic venting of water was enough to strike panic in the hearts of distant controllers who gasped, "Now what?"

Jon's Law

This is a more general concern. As propulsion systems get more powerful, the more energy they contain, and the worse the damage if an accident occurs. This is known as Jon's Law for science fiction authors.

Jon's Law

Jon's Law, part 1: Any interesting space drive is a weapon of mass destruction. It only matters how long you want to wait for maximum damage.

Jon's Law, part 2: Interesting is equal to "whatever keeps the readers from getting bored."

Jon Souza

As an example, a spacecraft with an ion drive capable of doing a meager 0.0001g of acceleration may be scientifically realistic and the exhaust is relatively harmless. However, to most of the audience it will not be interesting. "Nine months just to travel to Mars? How boring!"

The author, not wanting his book sales to go flat, hastily re-fits the hero's spacecraft with a fusion drive and makes it into a torchship. The good news is that the ship can make it to Mars in twelve days flat. The bad news is that the ship's exhaust is putting out enough terawatts of energy to cut another ship in two, or make the spaceport look like it was hit by a tactical nuclear weapon.

The author can still use the drive, but must consider the logical ramifications of the wide-spread civilian availability of the equivalent of thermonuclear weapons. How would you like to have the captain of the Exxon Valdez skippering a tramp freighter with an antimatter drive? That brilliant mushroom cloud you see marks the former location of Clinton-Sherman spaceport. The more devastation a propulsion system can wreck, the shorter the leash the captains will be on.

So one of the logical ramification is that if drives are too powerful, there won't be any colorful tramp freighters or similar vessels. As a matter of fact, civilian spacecraft will probably by law be required to have a remote control self-destruct device that the orbital patrol can use to eliminate any ship that looks like it is behaving erratically or suspiciously.

Or even more severe: logically torchships would be strictly forbidden for civilian ownership, they would be reserved for the military. Which is also boring.

And considering Jon's Law and the assumption that any Torch Drive or Torch-Rated Rocket engine is going to be extremely complex to build and maintain, such timescales would be out of the reach for much of interplanetary commerce and shipping for some time to come. Chances are that military armed forces (and some government agencies that have the budget and need) will be the chief, if not sole users of Torch Drives. Everyone else from high speed passenger spacecraft to freight-cargo will have to deal with Hohmann Orbits and launch windows.

Having said that, trying to use a high-powered rocket exhaust like a giant blow-torch to deliberaly destroy a city is more likely to destroy the rocket. Depending upon the type of propulsion system.

A 1 TW torchship hovering over a city will be putting out the energy of a 1 kiloton blast every four seconds, of a Hiroshima bomb every minute. I imagine this would not be good for property values.

However, the exhaust will be quite diffuse. A quick back-of-the-envelope calculation assuming a 1 TW power output and a 100 ton craft hovering in 1 gravity gives it putting out about half a kilogram of exhaust per second, as a low density jet. This will not travel very far through the air, imparting most of its energy into a fireball at the exhaust nozzle of the spacecraft. It will be the torch-ship that will be absorbing the full brunt of the 1 Hiroshima per minute fireball, while the city below it will only need to worry about the radiated heat.

I even have my doubts that the drive would work at all in an atmosphere — air might well flood the reaction chamber, interfering with the ability of the plasma to reflect off the magnetic nozzle.

Using torch drives to fry cities, like dropping boulders on them, is one of those Rube Goldberg things that fascinates the SF imagination. If you are out to destroy human beings and their works in large numbers, just nuke 'em.

That said, even a 'true' torch drive might have 100 times the power output of the Saturn V, and would make a considerable mess of the launch area.

On the third hand, I agree with Luke that these drives might not work in the atmosphere anyway. Trying to run a torch immersed in cold, dense gas is a bit like trying to run a jet engine underwater.

Space Fighters

I know all you Battlestar Galactica fans are not going to want to hear it, but looking from a cost/benefit analysis, space fighter craft do not make any sense. Go to the Future War Stories blog and read the post Hard Science Space Fighters, read the entry in the The Tough Guide to the Known Galaxy "SPACE FIGHTERS", and the essay in Rocketpunk Manifesto Space Fighters, Not. You might also want to review the section on Respecting Science. On the TV Tropes website there is a nice analysis of possible situations where space fighters might just possibly make sense.


Keep in mind that even if you have space fighters, they are not going to fly like winged fighters in an atmosphere. I don't care how the X-wing and Viper space fighters maneuvered. It is impossible to make swooping maneuvers without an atmosphere and wings.

You also cannot turn on a dime. The faster the ship is moving, the wider your turns will be. Your spacecraft will NOT move like an airplane, it will act more like a heavily loaded 18-wheeler truck moving at high speed on a huge sheet of black ice.

And another thing: if you maneuver, you are NOT going to be slammed into walls by high gee forces like a NASCAR race car driver. It doesn't work that way unless you have an atmosphere and wings. The only thing you will feel is a force in the same direction that the rocket exhaust is shooting, which will be equal to magnitude to the acceleration the engine is producing. Since Rockets Are Not Boats, the force generally be in the direction the crew considers as "down", as defined by the rocket's design. It will never be "sideways" (except under silly situations, like occupying a spinning centrifugal gravity ring while the rocket is accelerating).

It doesn't matter if you are thrusting in some other direction that the rocket's direction of travel (see Rockets Are Not Arrows) nor does it matter the rocket's current velocity (relative to what?). If the rocket engine cannot provide more than 0.5 gs of acceleration, the crew is never going to feel more than 0.5 gs of acceleration. Even if the ship is moving at a large fraction of the speed of light.

Rick Robinson: Fighters substantially outperforming big ships can be justified, though. Big ships (presumably) need crew habitability for extended voyages, fuel for same, usually an FTL gizmo, and crew including maintenance types, etc. All of which are mass penalties. A fighter is pretty much just drive engine, enough delta v for its mission profile, minimal habitability for a minimal crew, and ordnance carried.

(Being a spoil-sport, I said:)

Winchell Chung: The question then becomes why doesn't the designers replace the minimal habitability crew space with some electronics and turn the fighter into a missile bus?

Rick Robinson: What a rude question. {grin}

( But then he got me, by invoking Burnside's Zeroth Law of Space Combat. SF fans don't want to read about the life and times of a nuclear missile, therefore space fighters will exist.)

In the 1970's, DARPA was looking into a crude spacecraft called the "High Performance Spaceplane" that looked suspiciously like a space fighter, you can read about the details here and here. However, it was more like a manned missile than it was a Viper from Battlestar Galactica.

Four things have triggered a growing interest in the real possibility of a space fighter:

  • The NASA Space Transportation System, otherwise popularly known as the space shuttle, proved once and for all that it was possible to orbit a manned winged space vehicle and return it safely to an aircraft-type landing for re-use.
  • The Lockheed SR-71 Blackbird Mach-3 high-altitude spy plane has since 1962 shown that such high-speed high-altitude manned reconnaissance vehicles had utility beyond what could be accomplished by unmanned orbiting recon satellites.
  • The Soviet Union began testing a small winged reuseable "spaceplane" in about 1976. (ed note: the MiG-105 "Spiral". Cancelled in 1978)
  • The development of the simple "space cruiser" concept by Fred W. "Bud" Redding, an aerospace designer with the DCS Corporation, caught the eye of the United States Air Force because of an article about it by this author in the November 1983 issue of Omni magazine. (ed note: the DARPA "High Performance Spaceplane" mentioned above)

These things are leading to the impending birth of the space fighter. Quite apart from the utility of a space fighter in outer space itself, the vehicle has a definite series of missions it can perform in close proximity to the Earth. Students of aviation history as well as military history knew that early airplanes co-opted the role of the horse cavalry in scouting as well as general harassment of the enemy's rear because of mobility and use of the principle of surprise. Only later did aircraft also assume the role of load-carriers, vehicles capable of delivering either cargoes or bombs over ranges far beyond those of ground vehicles or artillery guns. Helicopters have taken over the tactical scouting and harassment roles today on the battlefields of Earth, but aircraft have kept the art of scouting, harassment, and load delivery alive by doing these things at higher and higher altitudes and faster and faster speeds. The space fighter concept extends them into space itself, but a space fighter must not be considered a load-carrier like the space shuttle orbiter.

The operational requirements for a space fighter, especially the ones we're likely to see in the next 25 years, are simple to set forth and not technically as difficult to achieve as might be assumed. A space fighter should be capable of being launched on a few minutes' notice from the surface of Earth, from an airborne platform, or from a space facility such as the space shuttle or a space base. It should be capable of entering any orbit and making several changes of orbital altitude and inclination. It should have suitable aerodynamic characteristics—primarily a high ratio between lift and drag—so that it can maneuver in the upper atmosphere of the Earth by means of aerodynamic controls, primarily stubby delta wings.

Thus, the space fighter should be able to appear suddenly in the high atmosphere over any nation at any time moving in any direction at a wide variety of speeds. A system of defense against such a space fighter will be extremely expensive in comparison to the cost of the space fighter. In fact, even the detection system necessary to find one and track it will be costly. For operations in the near-Earth orbital region, a capability to change its velocity ("delta-vee") of about 2,500 feet per second (760 m/s) is necessary. For operation in the Earth-Moon system, a delta-vee of 20,000 feet per second (6000 m/s) would be more than adequate.

The space fighter should be a completely self-contained manned vehicle with a life support capability of at least 24 hours. Finally, the space fighter should be able to return to a number of bases or landing sites and terminate its mission in a reusable condition.

In 1965, these requirements were technologically difficult if not impossible. Now they are "state of the art" if clever engineering is used. It looks as though the Soviet Union has already embarked on a "spaceplane" if not a space fighter program with its small shuttle. France is considering the development of the "Hermes," a delta-winged mini-shuttle intended to be launched into low Earth orbit by the Eurospace "Ariane" rocket. And the United States Department of Defense has embarked upon at least two admitted spaceplane or space fighter programs.

An excellent example of this is Fred W. "Bud" Redding's space cruiser or spaceplane, which is being funded by Defense Advanced Research Projects Agency (DARPA) as a research vehicle. The Redding space cruiser is delightfully simple and brings out the machismo in hot fighter pilots. A slender cone about 24 feet long with a base diameter of about five feet, the vehicle is a scaled-up version of the proven Mark 12 Minuteman re-entry vehicle. The aerodynamic characteristics of this shape are very well known and understood. It's a hypersonic and supersonic airframe shape with good lift-to-drag ratio and therefore good maneuverability. And small delta wings, and it becomes highly maneuverable. It's large enough that a single pilot clad in a pressure suit can sit in an unpressurized cockpit in the aft end just ahead of a ring of rocket motors. A hatch that can be opened allows him to stand up in the cockpit to look around. In this "open cockpit" space vehicle, the pilot "owns space" around him.

The nose of the conical spaceplane can be folded back to permit it to become a "pusher" or space tug for shifting larger loads in orbit. With a Centaur underneath it as a lower stage, it is capable of taking its pilot around the Moon and back.

The simplicity of the Redding spaceplane comes from its lack of design compromises. One of the things that makes the space shuttle orbiter so complex is the requirement that it fly well at subsonic, supersonic, and hypersonic speeds. This was a difficult and expensive technological feat requiring many compromises that didn't contribute to low cost and design simplicity. If a spaceplane is designed to fly at only supersonic and hypersonic speeds, it can be greatly simplified. But how can it be landed if it won't fly at subsonic speeds?

The Mark 12 re-entry vehicle is a fine supersonic and hypersonic airframe but a streamlined anvil at subsonic speeds. The Redding spaceplane is the same. But rather than compromise the design by giving it a good subsonic lift-to-drag ratio to permit a horizontal landing, Bud Redding opted to use another simple and straightforward method: a parachute. Not the simple circular parachute used on early Mercury, Gemini, and Apollo space capsules that dropped the capsule into the ocean in an uncontrolled fashion. Instead, Redding suggests the use of the steerable, flyable "parasail" used by thousands of sports parachutists every weekend. Once the spaceplane gets into the atmosphere and its speed slows to subsonic where it becomes a brick, a parasail chute is deployed, allowing the pilot to steer the slender cone to a soft landing inside a fifty-foot circle. It could be landed even on the deck of a ship at sea.

The Redding DARPA spaceplane is almost a technological reality today. But coming down the line very quickly is something the United States Air Force calls the "transatmospheric vehicle" (TAV). This is not a space fighter or a space cruiser. It's conceived as a vehicle larger and more complex than the Redding spaceplane but smaller and simpler than the NASA space shuttle. The TAV would take off horizonally from the runway of any Air Force base, fly into orbit using wings for lift and a combination of turbo-ramjet and rocket engines for propulsion, operate in low Earth orbit, and return at will to land horizonally on the runway of any Air Force base. The TAV may be operation in the 1990s. The Redding spaceplane could be flying in the 1980 decade. Neither of these space fighter-like vehicles will look anything like what anyone thought a space ship would in the annals of science fiction. They won't look like X-wings, Y-wings, TIE fighters. Vipers, Starfighters, or anything else conceived to date in the minds of authors or illustrators. There is one thing for certain: When their appearances become unclassified (like the appearance of the Redding spaceplane already is), artistic interpretations based upon their designs will quickly come to grace not only science fiction book and magazine covers, but also the beautiful full-color institutional ads of aerospace companies—product ads proudly announcing that "HyperTech's Mark Three Solar Powered Laser Gizmoscope was chosen above all others to provide essential on-board services," and numerous backgrounds for national newsmagazine covers.

Beyond the 1999 space fighter, however, the technological crystal ball becomes cloudy. This is not to say that the wildest hallucinations of a Hollywood art director are a better indication of what futuristic space fighters would look like. Probably not, because such concepts are based solely on what looks good and appears to be futuristic. The actual space fighters of the twenty-first century will not only look "right," they will be beautiful in their own way because they'll be designed with a full understanding of the mission requirements of a space fighter based upon realistic military doctrines of space. They will be difficult to operate, dangerous to life and limb, and push human capabilities to their utmost limits just as has every scouting and fighting vehicle (including the horse) throughout history. Far more important in the long run is the inevitable spin-off of space fighter technology into the technology of civilian and commercial spacecraft. Just as the airliners and general aviation aircraft of 1984 use the engines, electronics, aerodynamics, and other technologies pioneered for military aircraft, so the military spacecraft will also contribute toward the accompanying commercial and private use of space. And that possibility is perhaps far more exciting than space fighters themselves. Move over, science fiction. Another of your dreams is about to become reality!

from AFTERWORD: SPACE FIGHERS by G. Harry Stine (1985)

The above was written in 1985. Alas no "space fighters" have made an appearance. And unfortunately with current technological advances, it seems more likely that a space fighter developed today will be an unmanned drone, not a Starfury.

SECTION 1: SPACE FIGHTERS

     Basic Assumptions:
     This paper was written using the following assumptions as a baseline.
     1. Physical laws:
     The laws of physics as we know them still apply. This means that spacecraft move in a Newtonian (or Einsteinian, though this realm is outside the scope of the paper) manner, using reaction drives or other physically-plausible systems (such as solar sails) for propulsion. Thermodynamics dictate that all spacecraft must radiate waste heat, and lasers obey diffraction. The only exception is FTL, which will be included in some scenarios.
     2. Technology:
     The technological background is less constrained. If a system is physically plausible, the engineering details can be ignored, or at most subject to only minor scrutiny. The paper will examine a spectrum of technology backgrounds, but will focus on near to mid-future scenarios, where the general performance and operation of the technology can be predicted with at least a little accuracy. A common term used to describe this era is PMF, which stands for Plausible Mid-Future. This term (coined by Rick Robinson) is difficult to define, but it assumes significant improvements in technologies we have today, such as nuclear-electric drives, fading into those we don’t, such as fusion torches.
     3. Environment:
     This paper will attempt to examine a wide variety of environments in which space combat might occur. However, it will make no attempt to examine all of them, and the scenarios described will conform to several principles.
     First, this is a general theory. Any scenario that is dependent on a one-shot tactic or highly specific circumstance will likely not be included, except during the discussion of the beginnings of space warfare, or to demonstrate why it is impractical in the long run. The recommendations made are not optimal for all circumstances, nor is such a thing possible. They are instead what the author believes would be best for a realistic military based on the likely missions and constraints. Picking highly unlikely and specific sets of circumstances under which they are not optimal is best answered with a quote from the author about one such scenario, posting on the Rocketpunk Manifesto topic Space Warfare XIII: “You need a blockade, a hijacking (innocents aboard a vessel trying to break the blockade), and a high-thrust booster on the hijacked ship. Two stretch the limits of plausibility. The third is ridiculous. Claiming that this justifies humans [onboard warships, see Section 2] is like claiming that because warships sometimes run aground, we should install huge external tires on all of them to help get them off.”
     Second, no attempt will be made to include the effects of aliens or alien technology, because to do so would be sheer uninformed speculation.
     Third, the default scenario, unless otherwise noted, is deep-space combat between two fleets. Other scenarios will be addressed, but will be clearly noted as such.

Space fighters are a controversial topic in hard sci-fi space warfare discussions.  The consensus among the community is that they are not practical in the way they are depicted by Hollywood, nor in most other ways imagined, and that is a view the author shares.  However, this consensus is continually challenged, and the purpose of this section is to collect most of the rebuttals to those objections.

What exactly is a space fighter?  That varies depending on the context of the discussion, but the average person would probably point at an X-wing or TIE fighter.  A 10-20 m long spacecraft with a one or two man crew and a few hours of endurance.  In other words, something much like an atmospheric fighter, but in space.  Others would expand the definition to include any small, low-endurance combat craft, particularly those carried by other vessels.  Some would broaden the definition even more, to the point where it bears no resemblance at all to a classical space fighter.  Many of these proposals for “fighters” suffer problems which render them marginally effective or ineffective, and those that don’t are the ones that bear the least resemblance to the visions of Hollywood.  In the interest of accuracy, any vessel carried and deployed (that is to say, not merely shipped to a destination) by another vessel will be referred to as a parasite, leaving fighter to describe Hollywood-type combat parasites.

The origin of the space fighter is obvious.  It was developed out of an analogy to wet navy combat, specifically the aircraft carrier and its fighters.  Even the serious space warfare community often engages in wet navy analogies, so it appears to make sense to expand it to include carriers and fighters.  This suffers one critical flaw.  Aircraft carriers are effective primarily because aircraft work in a different environment then do ships.  A carrier can stay on station for months, but can only go at around 30 knots, while a fighter can make Mach 2, but only has a few hours endurance.  In space, a fighter will have no environmental advantage over its carrier.  Both obey the same rules, so any advantage must come from size and design.  A much better analogy is that of large and small warships, such as destroyers and Fast Attack Craft.

The naval analogies that underlie the basic concept of the space fighter deserve closer examination.  Before the late 1800s, small craft did not have the ability to threaten larger ones while the larger ship was not at anchor.  This changed with the invention of the torpedo.  For a time, many, most prominently the French Jeune Ecole, believed that the torpedo boat spelled the end of the battleship.  While this obviously did not happen, many navies experimented with various ways to use torpedo boats, including building torpedo boat carriers.  During the Russo-Turkish war of 1877, the Russians converted several vessels to carry torpedo boats, and a torpedo boat operating from the tender Veliky Knyaz Konstantin became the first vessel to sink another with a self-propelled torpedo.  In the 1880s, the Royal Navy built HMS Vulcan, while the French Navy produced Foudre, both cruiser-type vessels, meant to travel with the fleet and deploy 8 or 10 small torpedo boats against the enemy.  Both remained in service for about two decades, before being converted to other roles.  There has been occasional discussion by various powers about building more such ships, including by the US in WWII, but nothing came of it.  In fact, despite the presence of LSDs (Land Ship Dock) in the fleet, including for carrying PT boats to the front lines, there are no records of PT boats being launched into action from LSDs.  The total failure of this idea renders dubious the prospect of a similar vessel in space.

These are the next major issues.  One often-noted advantage is that a fighter only has to carry a few people and a few days’ worth of life support, which gives it superior performance to a larger ship.  This makes sense at first glance, but several factors conspire to defeat it.  First, how much of that performance is really useful?  Second, how does the fighter in question actually kill its target?  Third, how much money is being spent on all of this, anyway?  Fourth, do we need people aboard at all?

Maneuverability is a common explanation for fighters.  The logic is that a ship that has a higher acceleration is better, so cutting out as much dead weight as possible is good.  However, to what extent is this statement true when balanced against other factors.  A fighter by definition is of limited operating endurance.  Most proposals run from hours to a week or two.  Within that time, it must return to its base, generally a carrier, to restock.  A ship’s maneuverability is furthermore defined by two factors, delta-V and acceleration.  While a fighter would have superior acceleration, that must be balanced against its generally more limited delta-V.  

One salient fact to keep in mind is that ships that maneuver in combat using the same drive they cruise under are not maneuverable in combat.  Given the amount of time spent under thrust, generally measured in days if not weeks, ships will be unable to change the tactical geometry in a meaningful way during a few hours, let alone a few minutes.  This does not apply if the ship fights under a different engine then it maneuvers with.  Attack Vector: Tactical uses this approach, with engines having a high-efficiency, low-thrust cruise mode and a high-thrust low-efficiency combat mode.  However, this seems somewhat unlikely given currently foreseeable technology.  Mass-injected fusion drives could work this way (as they do in AV:T), but they are at the limits of the technology under consideration in this paper.

The limited endurance of a fighter presents two problems.  The first is that, as mentioned above, a ship that uses the same, or even a similar (within about an order of magnitude in terms of thrust/delta-V) drive in combat as in cruise will not be able to change the tactical geometry in a meaningful way during combat.  This applies to parasites as well.  The parasite’s cruise drive is that of the carrier, which means that it must have a significantly higher-thrust drive then the carrier does.  However, given that both operate in the same environment, the parasite will likely have to mount an entirely different type of drive.  This is a common fictional explanation, but there is no reason to believe that a small ship will be able to use drives that a larger ship could not also mount.  One could install a chemical or nuclear-thermal engine, which are not likely to be used by interplanetary vessels, but both of those have limited delta-V, which, when combined with the next issue, renders that proposal extremely questionable for deep-space combat.

An interesting solution to the different drive problem is an “antimatter afterburner”.  This involves the use of small amounts of antimatter in a fighter engine of some type as the name implies.  The originator of the idea suggested that expense and danger would prevent similar technology from being used on larger vessels.  The use of antimatter in large quantities removes the idea from the realm of the PMF, and the author believes that danger can be handled with proper engineering.  Expense is an open question, but the other problems with fighters are likely significant enough to torpedo the idea.

A parasite must return to its carrier before its endurance is exhausted.  While that statement is obvious, it places severe limitations on tactical flexibility.  First and foremost, a parasite will need four times its average transit velocity relative to the carrier in delta-V.  To state it another way, a parasite will have an average transit velocity of at best one-fourth of delta-V.  Maneuvering the fighter will reduce the transit velocity available.  If a parasite is using a high-thrust, low-ISP drive, the low delta-V achievable will limit transit velocity, and maximum range from the carrier (assuming the carrier does not accelerate during the mission) can be defined as transit velocity times one-half of endurance.  For any reasonable ranges, endurance will have to be large, or transit velocity very high, implying fusion drives or similar technology, and raising the question of the advantage of fighters over conventional ships again.  

Note that the maximum range for a given endurance and delta-V will only occur when the delta-V used for the outbound and return legs is equal.  Any other distribution will result in a lower average transit velocity, and thus reduced range. This distribution also corresponds to the highest average transit velocity possible for a mission of a given range, which could be of great importance if the fighter is to be recovered and reused during a given battle.  Table 1 shows how the distribution of delta-V affects transit velocity for a given endurance and total transit time for a given range.  Note that these numbers only apply in flat space and if the carrier is not accelerating during the mission.  Because the fighters start at rest relative to the carrier, and must return to it, any velocity the carrier initially possesses is irrelevant.  Flat space should be a reasonable approximation for deep-space engagements, and near-orbital space will be dealt with later.  Also, it is assumed that the burns are short relative to the total transit time, which is a good approximation for most cases, although not necessarily high-end ones.

Table 1
High Leg
Delta-V
Fraction
Low Leg
Delta-V
Fraction
Relative
Total
Time
Transit
Velocity
(Delta-V
fraction)
Relative
Range
0.50.51.00000.251.00
0.60.41.04170.240.96
0.70.31.19050.210.84
0.80.21.56250.160.64
0.90.12.77780.090.36

If the carrier maneuvers during the mission, it sets off a complex interplay of carrier delta-V expenditure, fighter delta-V expenditure, and transit time changes, leaving aside the tactical effects of the carrier’s maneuvers, which fall outside the scope of this section.  In the most extreme case, a fighter might expend its entire transit delta-V in a single burn to intercept the target, and then allow the carrier to match velocities and catch it.  This would require massive delta-V from the carrier, and significant time, particularly if the carrier’s drive is low-thrust.  Also, the tactical and orbital effects are likely to be severe.  A more practical situation might be for the fighters to expend all of their delta-V on the outbound leg, and wait for the carrier to reach them at the target.  This takes less delta-V from the carrier, and significantly less time, but does leave the fighters vulnerable if things go wrong.  Moving the carrier towards the target is also potentially problematic.  If the carrier simply accelerates and decelerates to rest relative to its initial velocity, the transit time is reduced somewhat at a cost in delta-V.  If it does not decelerate, the fighters will have to expend additional delta-V to match velocities.  Likewise, after reaching the target, the fighters could expend all of their delta-V on start of the return leg, and the carrier could match velocities.  The effect of all of these must be evaluated on a case-by-case basis, although the analysis itself is quite simple once the parameters are established.

Once the fighter has reached the target, it must still kill it.  Plausible space warfare weapons break down into three main categories: beams, projectors, and missiles.  Beams, which include both EM and particle beams, travel at close to the speed of light, but fall off with distance.  Projectors cover any weapon that fires mass at a target, where most of the velocity is imparted by a device on the ship itself.  Cannon, railguns, and coilguns are all examples of this.  Velocities achievable are likely to be limited to less than 100 km/s.  Missiles are any kinetic weapons released from a vessel which gain their velocity from some combination of the velocity of the launching ship and an internal engine.

Beams and cannon are not good candidates for fighter weapons.  Lasers scale significantly with size (see Section 7), which generally means that the vessel with the largest laser wins.  Particle beams and launchers also scale with size, though probably not as strongly, which puts any fighter mounting them at a disadvantage.  That leaves missiles.

Missiles make sense.  Put some missiles on a fighter, send it to within range of the enemy, and shoot them off.  The problem is that, in space, missiles don’t have range.  A missile will likely coast for much of its flight anyway.  There is no reason to use a fighter to launch a missile.  Put on another stage, and remove the fighter entirely.  More of these missiles can be fit into the space formerly occupied by the fighters, which increases firepower, and probably cuts costs in the long run, as a fighter has to decelerate to a stop, then come back, burning remass the whole way, not to mention the cost of support facilities for the fighter.  

But what if money can be saved by using the fighter for all of the missile’s primary delta-V?  The fighter simply tosses them out, leaving them to guide their way in.  This vessel is generally referred to as a Lancer.  The problem is, again, delta-V.  A lancer would have to stop, and return to its carrier after launching the missiles.  It might not have to have four times the projectile velocity in delta-V, as it can return to the carrier at a lower velocity then it launched from, but something on the order of three times launch velocity is probably the minimum practical delta-V.  If the lancer and a self-propelled missile are using broadly similar engines (similar ISP) the lancer would have to have at least three times the fuel fraction for the same impact velocity, if not significantly more.

 

The only situation where this would be a generally viable tactic is if, for some reason, the missile cannot use a drive that is within the same ISP range as the lancer’s, probably for cost reasons.  This might be the case when, say, fusion drives are new.  The cost of the drive is high enough that it is a requirement to reuse it.  Conventional missiles are impractical, because chemfuel simply can’t generate enough delta-V to be viable against fusion-powered vessels.  Thus, a lancer is developed.  This is a fairly specific set of circumstances, and should not be generalized to most situations.

Note that the rejection of beam-armed fighters is based upon the beam weapons in question scaling with size.  If this is not the case, (Dr. Device from Ender’s Game is the only example which springs to mind here, although the description in Ender’s Shadow casts doubt on if this is actually what’s going on) there are advantages to having as many platforms in action as possible, and fighters become an option again.  Another case in which fighters (or combat parasites in general) might become practical, also illustrated by Ender’s Game, involves an interplanetary propulsion system that for some reason cannot be fitted to individual combat craft.  This could be for any number of reasons, including expense, minimum size of the systems, or simple rarity of the drive.  In any of these cases, it would be logical to use parasites to fight, and leaving the drive spacecraft in the role of command ship.

One option for parasites is a type of missile defense drone.  The purpose of this drone is to bypass the armor of incoming missiles.  It is not armed with conventional weapons, but instead contains a pair of linked telescopes.  One of these receives a beam from a larger vessel in the main fleet, while the other redirects it to a missile.  Conventional missiles are only armored on the front, so a laser from beside or behind them would be highly effective.  While this tactic is not impossible to counter, mostly by spreading the armor more evenly across the missile, doing so will reduce the armor thickness or increase the mass, and thus the cost of the missile.  Either means is a win for the defender, which makes this category of parasite potentially quite useful.  One thing should be noted about this type of craft, though.  It operates at short ranges from the fleet, and can use a rather low transit delta-V, which removes a lot of the problems of other parasites.

One common claim for the superiority of fighters is that they are cheaper than an equivalent amount of firepower in larger vessels.  On the surface, this claim is true.  Fighters, not being required to have long-term living quarters and the like, do seem to deliver high firepower per dollar (or credit or yuan or what have you).  The economics become much less robust, however, when the cost of the carrier is factored in.  Before delving into that, a discussion of carriers themselves is in order.

Carriers can be of several different types.  The simplest is to strap parasites to the hull of a ship, and detach them for battle.  This design promises low cost, but limits the utility of fighters, as they likely can’t be rearmed or refueled, and maintenance is very difficult.  More complex designs have specialized docks, which allow easy rearming and refueling, but limit access to the outside of the parasite in question.  This works better with gunboat-type parasites, which have significant capability for independent operation, and should be capable of being serviced from the inside.  They would also provide some living quarters and support for the crew.  The final step is a full carrier with pressurized fighter bays, which is the type usually seen on TV.  These are mass-intensive, but allow classical fighter operations, with external maintenance and the like.  The crews are housed onboard, and all support gear is on the carrier.

The first option is obviously the cheapest, but suffers from the fact that it more resembles the British Catapult-Armed Merchant ships of World War II then a proper carrier.  The fighters are one-use, and probably can’t be maintained terribly well.  While they can be recovered after battle, they are helpless until a tender of some sort is reached.  The second option requires a dedicated ship, but, apart from magazines and remass tanks, is not terribly mass-intensive, and probably no more than 25% of the mass of the carried craft is required in clamps and docking systems and such.  The full carrier is, however, highly mass-intensive.  At best, a ratio of 100% of parasite mass to docking facility mass might be achievable.  However, this is probably optimistic.  All quarters and such must be duplicated, and the bays themselves are going to be large, if mostly empty when unoccupied.  There are actually two options for hangar arrangement.  The first, and most obvious, is to dock each fighter in individual bays, or place a few fighters in each bay.  The alternative involves a large central hangar and the use of airlocks to move fighters in and out.  This approach is probably more efficient in terms of mass, volume, and ease of maintenance, particularly for large numbers of parasites, but will launch and recover its parasites more slowly than if they were in individual bays.

Why is mass so important to determine cost?  It’s not weapons and electronics, which are expensive, is it?  The problem is that for a given vessel performance (delta-V and acceleration), cost will tend to scale with mass.  More mass means bigger fuel tanks, bigger engine, and more structure.  A conventional vessel of the same weapons cost as a carrier and fighters will almost certainly be considerably cheaper overall.  It does not require duplicate engines, duplicate quarters, pressurized fighter bays, extra remass tanks, or any of the other sundries that a fighter squadron would require.  

The actual mechanics of carrier operations is an interesting issue as well.  Numerous different methods for operating small craft off of bigger craft have been proposed, some more viable than others.  For the first two types of carriers, the chosen method of recovery, namely simple docking, is quite obvious.  This is also a potential method for a hangar-type carrier.  In that case, the fighter would probably dock on some form of movable attachment, and then be moved inside.  This attachment could range from a simple extendable arm for a bay-style carrier to a “tractor” for a lock-style carrier.  An alternative is the use of an arm to recover (and launch) fighters.  This draws on the experience with the Candararm on the Space Shuttle and ISS.  The advantage is that it requires less skill on the part of the pilot, and is generally more versatile, as well as potentially simplifying handling.  

One interesting alternative is the use of an actual deck, probably on a lock-style carrier.  This is most useful with aerospace fighters, which have landing gear that might simplify handling and operations.  The biggest problem is that there is no gravity to keep the fighter on the deck, necessitating either some sort of physical hold-down, or the use of magnets to keep the fighter on the deck.  The use of a deck was originally proposed in conjunction with the use of arrestor wires, much like how aircraft are recovered by aircraft carriers.  There are, however, numerous problems with this approach.  The dynamics of recovery are significantly different from those of a naval carrier, mostly due to the fact that the wire must both stop the fighter and hold it on the deck.  Even at the proposed approach speed of somewhere below 1 m/s, there are serious questions about the actual viability of hitting such a small target with a hook without snagging one of the wheels, or bouncing off the deck into space.  More problems would be caused in handling the aircraft on the deck, as the original proposal involved using the wires and a magnetically-attached tractor to move the fighter onto the elevator before strapping it down.  In total, this is not a viable solution to the problem, and would not be seriously considered by any competent aerospace engineer.  A better alternative if a proper deck must be used is based on the Canadian Beartrap system for helicopter recovery.  In this, a cable attaches the fighter to the carrier, and the fighter is simply winched down at low speed.  This is more space-efficient, safer, and easier to implement.  The biggest problem with it, and a serious problem with the wires, is the need to open holes in the heat shield of the fighter.  While the conventional landing gear would indeed need such holes, opening them unnecessarily increases the chances of something going wrong, as does cutting extra holes for the hook or beartrap system.  All in all, it appears that either a probe or an arm system would be the most effective.

The only situation in which a fighter-like vessel would be useful as a major combat craft is during planetary defense.  This scenario plays to the advantage of short-endurance craft (low cost per unit firepower).  However, there is no reason to suppose that conventional fighters will dominate this field.  It is entirely possible that full-sized warships could be constructed with limited endurance specifically for planetary defense missions.  The best analog for these vessels are the coastal defense ships of the first half of the 20th century.  This concept is covered in more detail in Section 6.

The last question is the one that nobody wants to ask.  Do we even need people aboard these things?  As Rick Robinson points out, there are only three missions for space fighters:

  1. Fighting each other, which is not a reason to exist.
  2. Destroying battle stations, which are only vulnerable to fighters for some reason.
  3. “To give prominent roles to young males in their early twenties, so they can display their swagger, coolness, and fast moves on any attractive female of an Interbreedable species.”

To seriously look at this, we first need to establish one principle of spaceflight.  Spacecraft are the ultimate in fly-by-wire controls.  There is no need to have people stuffing photons into the lasers, or laying the coilguns by hand.  There are no stokers throwing uranium into the reactor, and no lookouts in the crow’s nest watching for the enemy.  Almost all roles aboard a ship are those of bridge crew, or maintenance.  Why is this important?  The computer doesn’t care if it gets its orders from onboard control stations or by tight-beam laser from a mothership a light-second away.  This makes automation very easy.  Fighters almost by definition have no maintenance onboard, leaving only the pilot.  But why have a pilot onboard?  He only adds mass, and lots of it.  For a few hours to a day or so, he can probably get by on a ton or two.  After that, habitation demands start to render the “fighter” indistinguishable from a normal ship.  This neglects the added costs of the hab itself.  That mass can be a significant fraction of the total vessel mass, which will either drive up vessel mass and cost for equal performance, or reduce performance.  All of this indicates that any form of fighter, or combat parasite in general, is likely to be unmanned.  

All of the above discusses the usefulness (or lack therof) of fighters to a deep-space fleet engagement, and combat will obviously not be limited to that environment.  Orbital combat is often suggested as an ideal environment for fighters, and on the surface, it has much to recommend it.  The superior acceleration of the fighter allows it to change orbit more quickly than a larger vessel, and the fact that it’s in orbit keeps it close to the carrier.  At the same time, a larger vessel is more vulnerable to surface-based defenses and less maneuverable.  The problem is lack of role.  There is no particular reason that a vessel would need to venture into low orbit for battle.  A laserstar should be able to stay well out of range and fire into low orbit, and the fact that the vessel in question is the attacker allows it to force the faster opponent to give battle.  While some sort of spotting drone might be required, there is no reason for it to be manned or armed.  

The most likely use of manned parasite craft is for carrying people, either for landing or boarding missions.  These are not terribly common during battle, but occur more frequently on patrol missions.  Patrol missions are where parasites are likely to come into their own.  First, patrol is not used to speak of a ship making a loop to check on a colony.  The concept involved is more akin to the Asiatic Stations of the beginning of the 20th century.  The proposed “Patrol Carrier” would be semi-permanently stationed at a potential crisis area, most likely a gas giant, and carry a variety of small craft.  The carrier has the responsibility of dealing with any minor crises in the area, similar to the manner in which carrier battlegroups are deployed by the US today.  The technological imbalance involved makes several things feasible, including lancers.  The lancers operate in a low-threat environment, but might be used regularly.  One problem with lancers that most people miss is the fact that they require frequent use to be cost-effective.  Given the expected rarity of major battles, lancers make little sense for the main fleet.  However, a patrol carrier in an active region would need to make frequent use of them, making them more useful.

An interesting suggestion for such a vessel is to make use of the same drives for both lancers and manned patrol/inspection missions.  This would have advantages in logistics, but might require significant design compromises.  First off, the payload sizes are likely to be somewhat dissimilar.  A manned inspection pod is likely to be somewhere above 10 tons, which is quite large for a typical lancer payload.  It is possible that multiple sizes would be used, but that reduces the logistical advantages.

Another type of fighter that has been suggested is the aerospace fighter.  It, as the name suggests, operates both in the atmosphere and in space.  This is somewhat more plausible, as deep-space craft will almost certainly be incapable of atmospheric flight.  Aerospace fighters can be divided into four categories: dual-role, ground-launch space, space-launch air, and space-drop air.

Dual-role aerospace fighters are designed to fight both in the atmosphere and in space.  This type is actually the classic Hollywood “Space Fighter”, but is extremely unlikely in reality.  Both aircraft and spacecraft suffer significant performance penalties for excess mass.  The requirements of combat in the air and in space are vastly different, which means that the mass penalties pile up quickly.  Add to that the fact that the dual-role has to cross a third environment (atmosphere-to-orbit and back) and the resulting design will be expensive, underperforming, and probably a maintenance nightmare to boot.  There is virtually no commonality between the requirements of the different roles.  The only common weapon would be some form of gun, and a conventional gun is unlikely to be of much use in space due to its low muzzle velocity, while high-velocity guns used in space might well have problems functioning in an atmosphere.  Missiles for the two environments will be completely different (although it might be possible to make a dual-purpose missile at a moderate penalty in size/cost/performance), and the use of lasers on an atmospheric fighter is dubious at best, particularly lasers with sufficient range for space use.  Theoretically, two sets of optics could be used, one for space and the other for atmospheric combat, but mass again dictates against this.  The airframe and atmospheric engine are virtually useless in space, and the fact that it must also have a heat shield and be an SSTO seal the verdict.  The only situation in which one of these might see use would be for overawing primitive natives, particularly those that understand the design tradeoffs involved.

Ground-launched space fighters are entirely different.  As the name suggests, they only fight in space. Besides not having to deal with the mass of the atmospheric combat systems, this has other advantages.  It does not strictly have to be an SSTO, and for very early space combat could be the dominant warcraft.  An example of this would be the Dyna-Soar spaceplane, which was to be launched by a Titan III.  The weapons fit would probably be limited, and on-orbit time minimized, possibly to the point of taking the SpaceShip One approach and not going into orbit at all.  The biggest question for this design is operational.  What advantage does it have over putting another stage on a missile?  Basing is non-trivial unless one accepts the design headaches of VTOL, and there is probably only a small marginal cost savings, easily erased if the opponent destroys the fighter on even a small proportion of missions.  The only advantage the author can think of is the ability to use vacuum-frequency lasers.  Aerodynamic limitations would restrict mirror size, and mass would restrict both that and laser generator mass, which then raises the option of making a bigger ground-based laser instead.

Space-launch air fighters are the opposite of ground-launches.  They have the advantage over dual-roles of not needing space combat capability, and would in fact probably be designed with the minimum possible space operational capability in mind, only barely getting into orbit after a mission, and relying on the carrier for pickup.  This would of course restrict their use when the opponent still has significant orbital defense capability due to the risk to the carriers.  However, the need to have SSTO capability would still place them at a significant disadvantage compared to conventional atmospheric fighters.  The question again is operational.  It has been suggested that this type of fighter could be used to destroy heavily-defended targets during a planetary invasion.  The author is skeptical of that for a variety of reasons.  To begin with, kinetic bombardment should be more than adequate for almost any target.  The author cannot see any situation in which an airstrike is superior to a kinetic bombardment for a given target.  If for some reason, an airstrike is an absolute necessity, cruise missiles are a far better option.  While they might cost more than a fighter’s payload, they are expendable and do not face the design constraints of having to return to orbit.  Secondly, defending against an in-atmosphere assault is quite easy.  The fighters entering the atmosphere are vulnerable to ABM-type defenses (discussed in Section 4).  These weapons will probably have ranges on the order of 1000 km, giving the opponent plenty of warning, or inflicting heavy casualties on the attackers.  Not only that, the fighters are in fact more vulnerable than kinetics because they must be almost at rest at the end of atmospheric entry, instead of trying to maintain speed.  After reaching the lower atmosphere, fighters are vulnerable to the diverse array of anti-air weapons that have been developed, many of which are quite cheap compared to spacecraft and planetary defenses.  Thirdly, the cost of the fighters is likely to be quite high, as is attrition.  None of the points above suggest that losses per mission will be low, but low losses are required for the reusability touted by proponents of this concept to give significant savings.  The added vulnerability of the fighter returning to orbit is another significant problem.  The defender will keep shooting if for no other reason than to prevent it being sent back tomorrow.  The only situation in which this concept would be practical is one of overwhelming technological advantage, which is mostly outside the scope of this paper.

In fairness, it would be a fairly trivial matter to equip a missile-armed space-launched air fighter to serve as a dual-role fighter.  While the missiles would have to be different, only minor changes would be required to the rest of the vessel.  The problem is that the air mission mass would be a significant penalty, and the expense of the fighters, not to mention the general lack of utility of fighters in orbital combat, renders operational use of the concept dubious.

The last concept, space-dropped air fighters, is the most practical.  Instead of launching a fighter capable of returning to orbit, an invading power fits a more-or-less conventional atmospheric fighter with a heat shield and some modifications to allow air-starting, and drops it into the atmosphere in support of an invasion.  The practicality of planetary invasions aside, the main problems are logistical.  There is only a minor performance penalty, and air cover would be quite useful for a beachhead.  Fuel and (to a lesser extent) ordinance are likely to be the killers here.  A nuclear-powered laser-armed fighter, though a bit far-out, would be the most logical way of solving this problem.  Though undoubtedly more expensive than a conventional fighter, the logistical savings might make up for it.  It is even conceivable that such a craft might be capable of SSTO performance, although the penalties for doing so would be significant.  VTOL offers another option, combined with lots of planning to ensure availability of supplies and weapons.  

Another application of this general concept is expendable drone fighters.  In this case, the fighter is written off after use, but avoids the need to return to orbit.  The practicality of this approach depends on how the debate over manned combat aircraft turns out, a subject which lies outside the scope of this paper.

by Byron Coffey

Culture

Jack Staik has some further observations:

It is true that in a universe governed by hard-headed practicality and realism, a missile bus or an Honorverse-style missile pod would make more sense. However, there is one factor that would allow manned space fighters to proliferate and even prosper - Cultural Bias!

Practical and realistic concerns have often been swept aside in real life by cultural conditioning - look at Japan's centuries of refusal to modernize or adapt until the fact of their utter vulnerability was shoved down their throats by Admiral Perry.

An aristocratic culture with a leaning toward individual heroism (i.e. Arthurian or Samurai theme) would love the idea of manned space-fighters. Noble warriors with the blood of kings firing up their fighters to challenge the Evil Alien Hordes, one man's courage and missiles against the onslaught ... it's a primal image. The fighters themselves would probably be very individualistic, instead of mass-produced identical, to reflect their aristocratic pilot. And since the space-fighter would be the provenance of only the high-caste persons, the cultural conditioning could keep manned space-fighter a viable concept for generations in even a hyper-realistic scenario.

Of course, in time raw practicality will sweep aside the manned space-fighter, much as it did the armored knight on horseback, but the fighters will still be the emblem of a bygone age of chivalry and romance. And a Don Quixote-type character, pulling an ancestor's old space-fighter out of storage, to take up arms against a threat from the heavens, has lots of storytelling potential.

Jack Staik

However, culture only goes so far. Currently (2012) in Afghanistan, the US Air Force is used to attack partisan forces. But more and more the attacks are carried out by remotely piloted drones, not by valiant Top Gun piloted fighter aircraft. The Air Force pilots are quite angry about this. They are angry that their role is shrinking, they are angry that their chances of flying exciting missions grow slim, they are angry that fat-bottomed desk-jockys controlling a drone from an office in New Mexico are called "fighter pilots" just like them, they are just angry. But culture or no, in 2011 the Air Force said it trained more drone pilots than fighter and bomber pilots combined.

A CULTURAL DIVIDE

Until recently, most drone operators were regular Air Force pilots. Now, the service is reaching out to people who've never even flown before. And that has caused friction within the Air Force as it tries to redefine what it means to be a pilot.

"There's a cultural divide," says Kelly, a 46-year-old Air Force reservist from Texas who is now a student at Holloman. Kelly grew up wanting to be a fighter pilot, but his vision is not good enough for that job. But he can fly drones. And he says that irks fighter pilots who see themselves at the top of the Air Force pyramid.

"Part of it is an ego ... I hate to say an ego trip, but it is," he says.

The Air Force has been working to bridge the divide between these two groups of fliers. First off, drone operators are called pilots, and they wear the same green flight suits as fighter pilots, even though they never get in a plane. Their operating stations look like dashboards in a cockpit.

But all of that has made tensions worse. Aaron is another Holloman student. He used to fix military communications equipment; now he's training to operate drones.

"There's still a lot of animosity. You see people in a conventional aircrew that wonder why we get to wear the flight suits even though we don't leave the ground, why do we need flight physicals, why do we get incentive pay — stuff like that," he says.

In 2016 things got worse for human fighter pilots. Researchers developed software that (in computer simulations) reliably defeated human pilots.

BEYOND VIDEO GAMES

Artificial intelligence (AI) developed by a University of Cincinnati doctoral graduate was recently assessed by subject-matter expert and retired United States Air Force Colonel Gene Lee — who holds extensive aerial combat experience as an instructor and Air Battle Manager with considerable fighter aircraft expertise — in a high-fidelity air combat simulator.

The artificial intelligence, dubbed ALPHA, was the victor in that simulated scenario, and according to Lee, is “the most aggressive, responsive, dynamic and credible AI I’ve seen to date.”

Details on ALPHA – a significant breakthrough in the application of what’s called genetic-fuzzy systems are published in the most-recent issue of the Journal of Defense Management, as this application is specifically designed for use with Unmanned Combat Aerial Vehicles (UCAVs) in simulated air-combat missions for research purposes...

High pressure and fast pace: An artificial intelligence sparring partner

ALPHA is currently viewed as a research tool for manned and unmanned teaming in a simulation environment. In its earliest iterations, ALPHA consistently outperformed a baseline computer program previously used by the Air Force Research Lab for research.  In other words, it defeated other AI opponents.

In fact, it was only after early iterations of ALPHA bested other computer program opponents that Lee then took to manual controls against a more mature version of ALPHA last October. Not only was Lee not able to score a kill against ALPHA after repeated attempts, he was shot out of the air every time during protracted engagements in the simulator.

Since that first human vs. ALPHA encounter in the simulator, this AI has repeatedly bested other experts as well, and is even able to win out against these human experts when its (the ALPHA-controlled) aircraft are deliberately handicapped in terms of speed, turning, missile capability and sensors.

Lee, who has been flying in simulators against AI opponents since the early 1980s, said of that first encounter against ALPHA, “I was surprised at how aware and reactive it was. It seemed to be aware of my intentions and reacting instantly to my changes in flight and my missile deployment. It knew how to defeat the shot I was taking. It moved instantly between defensive and offensive actions as needed.”

He added that with most AIs, “an experienced pilot can beat up on it (the AI) if you know what you’re doing. Sure, you might have gotten shot down once in a while by an AI program when you, as a pilot, were trying something new, but, until now, an AI opponent simply could not keep up with anything like the real pressure and pace of combat-like scenarios.”

But, now, it’s been Lee, who has trained with thousands of U.S. Air Force pilots, flown in several fighter aircraft and graduated from the U.S. Fighter Weapons School (the equivalent of earning an advanced degree in air combat tactics and strategy), as well as other pilots who have been feeling pressured by ALPHA.

And, anymore, when Lee flies against ALPHA in hours-long sessions that mimic real missions, “I go home feeling washed out. I’m tired, drained and mentally exhausted. This may be artificial intelligence, but it represents a real challenge.”

An artificial intelligence wingman: How an AI combat role might develop

Explained Ernest, “ALPHA is already a deadly opponent to face in these simulated environments. The goal is to continue developing ALPHA, to push and extend its capabilities, and perform additional testing against other trained pilots. Fidelity also needs to be increased, which will come in the form of even more realistic aerodynamic and sensor models. ALPHA is fully able to accommodate these additions, and we at Psibernetix look forward to continuing development."

In the long term, teaming artificial intelligence with U.S. air capabilities will represent a revolutionary leap. Air combat as it is performed today by human pilots is a highly dynamic application of aerospace physics, skill, art, and intuition to maneuver a fighter aircraft and missiles against adversaries, all moving at very high speeds. After all, today’s fighters close in on each other at speeds in excess of 1,500 miles per hour while flying at altitudes above 40,000 feet. Microseconds matter, and the cost for a mistake is very high.

Eventually, ALPHA aims to lessen the likelihood of mistakes since its operations already occur significantly faster than do those of other language-based consumer product programming. In fact, ALPHA can take in the entirety of sensor data, organize it, create a complete mapping of a combat scenario and make or change combat decisions for a flight of four fighter aircraft in less than a millisecond. Basically, the AI is so fast that it could consider and coordinate the best tactical plan and precise responses, within a dynamic environment, over 250 times faster than ALPHA’s human opponents could blink.

So it’s likely that future air combat, requiring reaction times that surpass human capabilities, will integrate AI wingmen – Unmanned Combat Aerial Vehicles (UCAVs) – capable of performing air combat and teamed with manned aircraft wherein an onboard battle management system would be able to process situational awareness, determine reactions, select tactics, manage weapons use and more. So, AI like ALPHA could simultaneously evade dozens of hostile missiles, take accurate shots at multiple targets, coordinate actions of squad mates, and record and learn from observations of enemy tactics and capabilities.

UC’s Cohen added, “ALPHA would be an extremely easy AI to cooperate with and have as a teammate. ALPHA could continuously determine the optimal ways to perform tasks commanded by its manned wingman, as well as provide tactical and situational advice to the rest of its flight.”

A programming victory: Low computing power, high-performance results

It would normally be expected that an artificial intelligence with the learning and performance capabilities of ALPHA, applicable to incredibly complex problems, would require a super computer in order to operate.

However, ALPHA and its algorithms require no more than the computing power available in a low-budget PC in order to run in real time and quickly react and respond to uncertainty and random events or scenarios.

According to a lead engineer for autonomy at AFRL, "ALPHA shows incredible potential, with a combination of high performance and low computational cost that is a critical enabling capability for complex coordinated operations by teams of unmanned aircraft."

(ed note: for the software details, refer to the report)

Efficacy

But if you want cold, hard, unglamorous reality, Ken Burnside has plenty of it for you:

The other deciding factor is this: A "fighter" needs to be recovered (ed note: Otherwise it is some kind of manned kamikaze missile).

That means you need delta v to get to the objective, then delta v to cancel out your inbound vector, then delta v to get to a rendezvous point, plus delta v for maneuvering in the thick of things.

A rough estimate was that you needed delta v equal to about four times that of a comparable mass missile that just needs to do a drive-by shooting.

Four times the delta v means that your fuel fraction just went up by a factor of something around four (depends on your Isp).

Now put in the life support compartment, and the payload mass, and it gets even worse; rocket performance is the red queen's race, and you rapidly hit declining efficiencies.

If you could build a TLAM that had the operational range of an F-18, you could probably get more of them packed onto a comparable size ship than a comparable mass of F-18s.

TLAMs require lots of data on the target and the terrain and have to fly "over the horizon". A lot of opposition to the TLAM was that it took away the offensive strike mission from carrier aviation.

In space, there's no horizon to hide behind.

Ken Burnside

On a later occasion, in a discussion on space combat game design, Mr. Burnside went into more detail:

The basic argument for fighters is that people think they're fun and cool.

The basic argument against fighters is horizon distance.

Fighters make sense in surface naval operations because a fighter can go to places where the carrier or cruiser can't. The fighter can also go to places where the big ships can't see, because of the curvature of the earth.

Unfortunately, there's no horizon for targets to hide behind in space. Even if you have something short of everyone sees everyone, it's hard(er) to justify fighters seeing things their carriers can't, just because carriers can carry bigger sensors, and space is a very sensor friendly environment.

Fighters do make sense in an orbital reference frame context, where, well, curvature of the earth matters, and where going into atmosphere matters. But this turns fighter carriers into "brown water" vessels that work in the tide pools of planetary gravity wells, which isn't the role you see them doing in fiction, which tends to take WWII carrier ops or modern USN carrier ops and apply an SFnal veneer.

Note that that's all mission specific, and only mildly tech related.

What do fighters do better than, or exclusively related to, larger ships? Answer this, and you get a reason for fighters in a setting.

In terms of pure offensive firepower, there's very little you can do with a fighter that a cruise missile can't do better in a space game context.

Of course, the best reason to have fighters is because they make your game more funnerer. But it does kind of help to figure out what mission they're doing.

Ken Burnside
WHAT ABOUT THE BIOLOGY OF SPACE BATTLES?

An interesting discussion of the physics of space battles brings up a lot of good points — those science-fantasy movies with spaceships flitting about ignore a lot of basic physics. Star Wars was basically WWI biplanes whirling around at speeds under 60kph, which is kind of ridiculous. But fun.

This article points out that that’s not how things would play out if ever there were a real space battle. The ships would have to obey physics and orbital mechanics, and there would be a priority on speed and acceleration and rapid maneuvers; also, explosions are kind of useless in a vacuum. So he talks about using big gyroscopes to whip mostly spherical ships around, and they’d be zooming about in complex spirals to take advantage of gravity wells.

But then he talks about crews.

I’m assuming that we’d have some intrepid members of the United Earth Space Force crewing these combat vessels. Or, at least, crewing some of them – robotic drone fighters would be a tremendous boon to space soldiers, but the communication lag between planets and vessels in orbit would make the split-second judgments of humans necessary at times.

Nah, I don’t believe it. In space battles, you’re talking about tremendous velocities, where maneuvers would slam the pilots with huge g forces. Even our atmosphere-bound fighter aircraft have problems with the limitations of the human body. How can you equip your Star Destroyer with massive gyroscopes that can flip it end over end in seconds, and not realize that using it would snap necks and turn your crew into bloody slime splattered over their cockpits?

I also don’t buy the stuff about needing the “split-second judgments of humans”. Human brains are slow. It takes us milliseconds to seconds to just absorb simple sensory output — we’re operating with a built-in lag that we don’t notice because your consciousness can’t notice that something already happened until your consciousness notices. So if the outcome of your battle depends on things only happening fast enough for human brains to process them, you’ll be dead when the ruthless cybernetic death machine swivels 10 times faster than a gooey animal body can handle, and decides to fire in microseconds, long before you perceive the new situation.

If our technology ever gets to the point where space battles can become a reality, it will also have reached a point where humans are no longer able to compete on the battle field.

From WHAT ABOUT THE BIOLOGY OF SPACE BATTLES? by P. Z. Myers (2016)

Role

Given the popularity of space fighters in such mass media shows as Star Wars, Battlestar Galactica, Buck Rogers in the 25th Century, Babylon 5, and others, they obviously appeal to people. I'm in the minority, but I think they are missing the point. Here's my reasoning:

It seems to me that the space fighter is nothing more that people taking a dramatic and comfortable metaphor (sea-going aircraft carriers and combat fighter aircraft) and transporting it intact into the outer space environment. But if you think about it, interplanetary combat is highly unlikely to be like anything that has occurred before.

Imagine a speculative fiction writer back in the Victorian era, such as Jules Verne. Say they wanted to write a novel about the far future, when heavier than air flight had been invented, and the age of Aerial Combat had arrived.

They might take the dramatic and comfortable metaphor of sea-going frigates and battleships and transporting it intact into the aerial environment. Held aloft by dozens of helicopter blades, the battleships of the air would ponderously maneuver, trying to "cross the T" with the enemy aerial dreadnoughts.

See how silly it sounds? Well, combat spacecraft behaving like fighter aircraft is just as silly. In both cases a metaphor is being forced into a situation where it does not work.

In reality, when the Wright brothers invented heavier-than-air flight and Fokker Triplanes started dog-fighting Sopwith Camels, it was totally unlike anything that had occurred before. Biplanes never ever tried to cross the T, and a sea-going battleship had never ever performed an Immelmann turn.

Therefore, by analogy, when interplanetary combat arrives, it too will be totally unlike anything that has occurred before.

As Ken Burnside puts it:

On the other hand - Winch's analogy to victorian era fiction about flying dreadnoughts and the "Who the hell thought of an Immelmann turn?" question sort of underscores why I want to model how space combat works using known physics as a gameable experience.

It won't be WWII in space. It won't be the Iraq war in space, it won't be subs in the North Atlantic in space. It will be its own unique thing.

To figure out what that unique thing is, you need to understand the environment of space, how it differs from a planetary environment, and once you have those differences modeled, you need to work out the tactics for this new environment, much the same way WWI biplane pilots had to work out the tactics of air to air combat.

Now, it's certain that I've got things wrong with the Attack Vector: Tactical model. When they get pointed out, I fix them. On the other hand, to the best of my knowledge and belief, it's the first serious attempt at trying to model what the tactical environment looks like.

World War II/Battleships/Fighters in space is about as likely to be an accurate model of space combat as, modeling jet air-to-air combat with pike square formations. Attack Vector: Tactical is probably akin to saying that jet fighters behave like World War I biplanes, only faster. It's still likely wrong, but it's probably much LESS wrong.

Ken Burnside

In Fiction

COMMON DENOMINATOR

Night Killer II was not a beautiful vessel. Satarii fighters are sleek, polished for planetary re-entry, but a space-based interceptor need not be aesthetic. Had I attempted to land on Lot I would have reached the surface in ashes. Night Killer carried her missiles outside the hull in two cylindrical bundles. Radar sweeps and communication aerials were all exposed. Her drive was set on un-streamlined pylons spaced about her stern while the cockpit glass bulged beyond the curvature of her skin, ostensibly for wider vision with less distortion; the effect on the casual observer was that of a mutated hornet's head. And added to this were bundles of thrusters placed strategically about the hull to aid maneuvering. But regardless of her ungainliness, she remained an effective fighting unit, equal and in some ways more than equal to the darting black war craft of the Satarii.

From COMMON DENOMINATOR by David Lewis (1972)
RUN TO THE STARS

"Pursuit fighters," I told the Ship. "Easily fast enough to catch one of our boats, if they can do it within their limited range. It's limited because they're the only kind of craft designed for dogfight tactics.

They're just enormous multidirectional motors in a spheroid hull with one pilot in the centre and a few missile tubes scattered between the motor vents. Fast maneuvering in space means killing momentum one way as well as building it up in another, so there's murderous acceleration and deceleration every few seconds, with the motor blasting in all directions, eating up hydrogen and putting incredible stress on the pilots. Even with all the aids — liquid suspension cocoons, special suits, body reinforcement, field-shields, the lot — it takes years of training to stand it for more than a few minutes at a time.

The American call fighter pilots Globetrotters, for some old game where you had to bounce a ball all the time. I've been in a fighter simulator once — I came out black and blue, and they say the real thing's worse.

And that's our hope — that Liang can hold them off, make them maneuver so much they'll have to give up, or just outrun them. That's what he's trying to do now, but he's got to be careful. They mustn't box him in and stop him maneuvering, that'd let them swarm over him like hornets, killing the boat or crippling it till the gunships catch up —"

From RUN TO THE STARS by Michael Scott Rohan (1982)

Alien Technology

This section has been moved here.

Plasma Weapons

Silly as they are, plasma weapons are a popular SF concept that just won't go away. They are encountered in such diverse places as the original Star Trek TV series, the Traveler role playing game, and the Babylon 5 TV series. They play the role of a futuristic flame-thrower.

Their main draw-back is that they won't work.

Plasma is the so-called "fourth state of matter", and is basically hot air. That is, it is a gas heated to temperatures comparable to the interior of a star or the center of a thermonuclear explosion so that all the atoms are ionized. Unfortunately, according to the virial theorem, the plasma wants to equalize its internal pressure with the external, i.e., it wants to expand into a diffuse cloud of nothing.

Dr. Rodolphe D'Inca is a physicist and researcher of fusion energy at the Max Planck Institute for Plasma Physics. He was kind enough to answer a few questions on the topic for me. Looking at the concept, it was his understanding that a plasma weapon is a gun that ejects a ball of plasma, a plasmoid, at high velocity to destroy the target through kinetic impact.

I asked him if the plasma would expand and dissipate its energy due to Coulomb repulsion, the same problem suffered by charged particle beams. Rodolphe explained:

Most plasmas are neutral: you have a Debye shielding where the cloud of electrons screen the effect of the ions: above a given length called the Debye length, the plasma can be considered neutral. So unlike a charged beam, the Coulomb repulsion doesn't play a role. That's why plasmas a relatively insensitive to electrical fields except for the boundary layer (which is of course of one Debye-length thick).

The Debye length is about 10-4 meters for a Tokamak fusion container (0.1 millimeters) down to about 10-11 meters for solar core plasma (0.01 nanometers). Which means if your plasmoid is larger than a speck of dust you do not have to worry about Coulomb repulsion.

I asked him about Ideal gas laws. Since the plasmoid was basically a hot gas in a vacuum, would it expand and dissipate its energy like, well, a hot gas in a vacuum. Rodolphe explained that yes indeed, due to the virial theorem a plasmoid with no external forces would expand at the Alfven velocity or the ion acoustic velocity due to internal plasma (fluid) and magnetic (electromagnetic) pressures. The Alfven velocity depends upon things like magnetic field strength and total mass density of the charged plasma particles, it is typically something like 500 km/s to 5000 km/s.. This means that after the plasmoid travels for one second, its diameter will be approximately five thousand kilometers, i.e., it has dissipated into nothing.

Well, you might ask, what about adding some external forces to prevent this? Sorry. If you use matter, you are basically trying to make an armored shell capable of containing a thermonuclear explosion in its interior, and having it somehow break apart when it hits its target. This is more or less impossible. And if it was somehow possible using some kind of handwavium, there is nothing preventing your opponents from armoring their combat spacecraft with the exact same thing. It would be much simpler to just use a missile with a thermonuclear warhead.

And if you try to use energy, in the form of a magnetic field or something, you have the same problems. Plus the new problem of somehow making a self-sustaining magnetic ball powerful enough to contain a thermonuclear explosion.

Rodolphe did note that things were different if you were shooting plasmoids inside an atmosphere. In the lab next to his office they are trying to create ball-lightning (page is in German, use Google Translate).

Finally I asked him if the thermal glare from the hot, brightly energetic gas would interfere with tracking your target. Rodolphe explained:

Aiming at the target through a plasmoid shouldn't be too difficult: it will have an average thermal signature which can easily be discriminated from the target.

Dr. Rodolphe D'Inca

He went on to say:

Plasmoids are a very interesting topic and we see that the question of the plasma weapon is not as trivial as expected. I was thinking of two other examples relating plasmas and kinetic energy: the nozzle of the VASIMR engine where you have a magnetic detachment and conversion of plasma pressure into kinetic energy. And the laser-ablation propulsion where a plasma is created at the back of a capsule and, through its expansion, exerts a force on the capsule.

Dr. Rodolphe D'Inca

So there you have it.

For further analysis of the worthlessness of plasma weapons with a focus on Star Wars and Star Trek, I refer you to Stardestroyer.net.

And please note that the jet from a Casaba Howitzer, while it is a plasma, it is not a plasmoid. In any event, it is a very short-ranged weapon.

Nanotechnology

Nanotechnology (and it's extension nanorobotics) is the concept of molecule sized machine. The idea is attributed to Richard Feynman and it was popularized by K. Eric Drexler. It didn't take long before military researchers and science fiction writers started to speculate about weaponizing the stuff. A good science fiction novel on the subject is Wil McCarthy's Bloom.

There are many ways nanotechnology could do awful things to a military target. One of the first hypothetical applications of nanotechnology was in the manufacturing field. Molecular robots would break down chunks of various raw materials and assemble something (like, say, an aircraft), atom by atom. Naturally this could be dangerous if the nanobots landed on something besides raw materials (like, say, an enemy aircraft). However, since they are doing this atom by atom, it would take thousands of years for some nanobots to construct something (and the same thousands of years to deconstruct the source of raw materials).

But using nanobots for manufacturing suddenly becomes scary indeed if you make the little monsters into self-replicating machines (AKA a "Von Neumann universal constructor") in an attempt to reduce the thousands of years to something more reasonable. Suddenly you are facing the horror of wildfire plague spreading with the power of exponential growth. This could happen by accident, with a mutation in the nanobots causing them to devour everything in sight. Drexler called this the dreaded "gray goo" scenario. Or it could happen on purpose, weaponizing the nanobots.

Drexler is now of the opinion that nanobots for manufacturing can be done without risking gray goo. And Robert A. Freitas Jr. did some analysis that suggest that even if some nanotech started creating gray goo, it would be detectable early enough for countermeasures to deal with the problem.

What about nanobot gray goo weapons? Anthony Jackson thinks that free nanotech that operates on a time frame that's tactically relevant is in the realm of cinema, not science. And in any event, nanobots will likely be shattered by impacting the target at relative velocities higher than 3 km/s, which makes delivery very difficult. Rick Robinson is of the opinion that once you take into account the slow rate of gray goo production and the fragility of the nanobots, it would be more cost effective to just smash the target with an inert projectile. Jason Patten agrees that nanobots will be slow, due to the fact that they will not be very heat tolerant (a robot made out of only a few molecules will be shaken into bits by mild amounts of heat), and dissipating the heat energy of tearing down and rebuilding on the atomic level will be quite difficult if the heat is generated too fast.

Other weaponized applications of nanotechnology will probably be antipersonnel, not antispacecraft. They will probably take the form of incredibly deadly chemical weapons, or artificial diseases.

Some terminology: according to Chris Phoenix, "paste" is non-replicating nano-assemblers while "goo" is replicating nano-assemblers. Paste is safe, but is slow acting and limited to the number of nano-assemblers present. Goo is dangerous, but is fast acting and potentially unlimited in numbers.

"Gray or Grey goo" is accidentally created destructive nano-assemblers. "Red goo" is deliberately created destructive nano-assemblers. "Khaki goo" is military weaponized red goo. "Blue goo" is composed of "police" nanobots, it combats destructive type goos. "Green goo" is a type of red goo which controls human population growth, generally by sterilizing people. "LOR goo" (Lake Ocean River) nano-assemblers designed to remove pollution and harvest valuable elements from water, it could mutate into golden goo. "Golden goo" are out-of-control nanobots which were designed to extract gold from seawater but won't stop (the "Sorcerer's Apprentice" scenario). "Pink goo" is a humorous reference to human beings.

ACE Paste (Atmospheric Carbon Extractor) designed to absorb excess greenhouse gasses and covert them into diamonds or something useful. Garden Paste is a "utility fog" of various nanobots which helps your garden grow (manages soil density and composition for each plant type, controls insects, creates shade, store sunlight for overcast days, etc.) LOR paste: paste version of LOR goo. Medic Paste is a paste of nanobots that heals wounds, assists in diagnosis, and does medical telemetry to monitor the patient's health.

Malignancy

MOST SECRET (ULTRAVIOLET) / EYES ONLY UNGUENT SANCTION

NEED-TO-KNOW ABSOLUTE
HARD COPY ONLY/NO TRANSMISSION
ORIGINATOR-CONTROLLED DISSEMINATION
TRACKED-COPY DOCUMENT
NOCONTRACT
NOFORN
SPECIAL SECURITY PROCEDURE BASILISK FIDELIS

Proceed (+/-)? +

EXECUTION:

STRATEGIC ACTION MESSAGE ONLY
IMPERIAL SECURITY EXECUTIVE ONLY
FIFTH DIRECTORATE VETO
X-THREAT ONLY

SUMMARY:

[SSP image elided from file]

The Existential Threats Primary Working Group has maintained in secure storage a number of sub-black level threats, and has access to two black-level threats, of type BURNING ZEPHYR – i.e., unlimited autonomous nanoscale replicators (“gray goo”).

Case UNGUENT SANCTION represents an extremal response case to physically manifested excessionary-level existential threats. It is hoped that, in such cases, the deployment of an existing sub-black level or black-level existential counterthreat may ideally destroy or subsume the excessionary-level threat, replacing it with one already considered manageable, or in lesser cases, at least delay the excessionary-level threat while more sophisticated countermeasures can be developed.

Note that as an extremal response case, deployment of CASE UNGUENT SANCTION requires consensus approval of the Imperial Security Executive, subject to override veto by vote of the Fifth Directorate overwatch.

WARNING:

Communicating ANY PART of this NTK-A document to ANY SOPHONT other than those with preexisting originator-issued clearance, INCLUDING ITS EXISTENCE, is considered an alpha-level security breach and will be met with the most severe sanctions available, up to and including permanent erasure.

Proceed (+/-)?

From Malignancy by Alistair Young (2015)

Hafnium Bomb

Consider an electron buzzing around an atomic nucleus. If it is as close as it can get to the nucleus (i.e., it is in the lowest unoccupied energy band structure) it is in its base energy state. This means it is "at rest", or at least as close as an electron gets to being at rest.

Anyway, if the electron absorbs some energy, from a photon or something, it can no longer occupy the base energy state. It has to rise to a higher energy state. In scientific terms, the electron has become "excited." This is not a stable situation, eventually the electron spits out the extra energy (generally in the form of a photon) and falls back into its base energy state.

Nuclear physicists immediately wondered if the protons and neutrons in the atomic nucleus could also become excited. As it turns out, indeed they could. When a nucleon becomes excited, the nucleus becomes a nuclear isomer.

Most nuclear isomers decay back into the base state in a fraction of a second. However, one or two can stay excited for years. Tantalum's isomer Ta-180m has a half-life of 1015 years, which is much longer than the age of the universe. But then there is Hafnium's isomer hafnium-178m2, which has a half-life of 31 years.

Storing Energy

By now you are thinking "So what?"

Well consider this. Excited electrons contain the energy of chemical reactions. For example: a stick of dynamite. Excited nucleons contain the energy of nuclear reactions. For example: a nuclear weapon. Not so boring now, are they?

So converting ordinary hafnium into hafnium-178m2 would be the equivalent of revving up a rechargeable battery with nuclear energy.

One gram of pure hafnium-178m2 (the same mass as a paperclip) contains about 1330 megajoules of energy. This is the equivalent of 317 kilograms of TNT, about the same as the warhead on a Tomahawk cruise missile (TLAM-C). Now you know why people started to talk about a "nuclear hand grenade." (as Alan Bellows puts it: "the most appealing aspect of isomer triggering was its potential to shoehorn yet more death and destruction into convenient 'fun size' packages")

There was also speculation about using hafnium-178m2 as a power source. A suggested application was a nuclear isomer powered airplane. The popular term was "quantum nucleonic reactor".

What was even better is the fact that the energy emerges not as visible light photons, not as ultraviolet photons, not even as x-ray photons. This stuff spits out freaking gamma rays! In other words, it just might be the key to constructing a gamma-ray laser.

The US military was also interested in the fact that hafnium-178m2 could be used to circumvent the Nuclear Non-Proliferation Treaty. Tremendous energy release, intense gamma rays, but it ain't a nuke.

The Problem

The trouble is that it is a worthless weapon if it takes thirty one years for half of the energy to slowly leak out. For a weapon you want it all to burst forth instantly. Therein lies the rub, nobody knew how.

That is where the controversy started.

Enter Dr. Carl B. Collins of the university of Texas. He figured that hafnium-178m2 could be triggered to release its energy by irradiating it with carefully tuned x-rays. The process is called induced gamma emission.

In January of 1999, Dr. Collins lead a team to explore this possibility. They put a tiny smear of hafnium-178m2 on the top of a styrofoam coffee cup, and used a scavenged dental x-ray machine to bombard the sample. After several weeks, the team studied the results. They concluded that there was a teeny-tiny increase in gamma rays measured in the data, which they interpreted as proof positive that they had succeeded. Or at least opened the possibility that there might be some magic frequency which would make the hafnium-178m2 create the desired explosion.

As always in science, if one has extraordinary claims, one had better have extraordinary evidence. And the sad fact of the matter is that Dr. Collins' evidence was pretty pathetic. Many scientists were uncomfortable with his outlandish claims and his experiment's large margin for error. Indeed, his findings were somewhat at odds with the laws of physics given that nuclei are thought to be practically unaffected by electromagnetic radiation.

The US military didn't want to provide funding to a crack-pot, but didn't want to miss out on nuclear hand grenades either. So they asked the Jason Defense Advisory Group (a panel established in 1960 to advise the government in matters of scientific controversy) to make an assessment. The Jasons concluded that the results fell into the former category: the data did not prove that induced gamma emission had occured, and even if it had a successful triggering event would not start the necessary chain reaction due to energy dissipation.

Meanwhile the Argonne National Laboratory used their own powerful x-ray machine in an attempt to reproduce Dr. Collins results. They failed: no induced gamma emission was recorded. Dr. Collins said it must be because your machine is too powerful. The skeptical Argonne scientists tried again using Dr. Collins' specifications. Still nothing was seen. Collins again ascribed the problem to experimental minutia, but by now the Argonne scientists had better things to do with their time.

Dr. Collins' work is more or less totally discounted nowadays, but there is a small group of true believers that still dreams of nuclear hand grenades.

Meson Accelerator

In the science fiction role-playing game Traveller, the most potent starship weapon of all is the dreaded Meson Accelerator (MA). Before MA technology is developed, warship designs have lots of armor to protect them from hostile missile, laser, and particle beam weapon fire. After MA, warship designs omit armor in favor of more weapons, because armor is utterly worthless against MA fire. There is also a tendency to make lots of small warships instead a few large ones, in the pious hope this will prolong the life of your fleet. Or at least prolong it longer than the life of the enemy fleet.

As with all powerful Traveller starship weapons, MA are typically installed as a "spinal mount". MA are also marvelous as a planetary defense weapon. You can put MAs several kilometers below the planetary surface and still shoot at hostile orbiting spacecraft. The spacecraft will not be able to shoot through several kilometers of solid rock (unless they too are armed with MAs).

Later a star nation can develop the technology for the meson screen, which renders MA powerless (much like Kryptonite's all-or-nothing effect on Superman). Then warship design goes back to normal, except all designs must include a meson screen.

Why are meson accelerators so deadly? Because their method of action is so sneaky.


Some background. Nuclear physicists love to play with atom-smashers, particle accelerators, cyclotrons, and the like. These create subatomic particles (i.e., the component particles that atoms are made out of) and make them move really really fast in beam form. Yes, if you weaponize this, you have a particle beam weapon. Anyway, some kinds of particles are unstable, they have a short life-span. After a few nanoseconds they decay into other particles, radiation, or both.

Einstein's relativity, besides forbidding faster-than-light starships, also says that at speeds close to that of light, time will slow down. At about 90% the speed of light (0.9 c), the slowdown is about 2 (called the "gamma factor"). So if a particle has a life-span of 10 nanoseconds when sitting still (relative to you), when the particle is travelling at 0.9 c (relative to you) you will time it as having a life span of 20 nanoseconds or twice what it should be. At 0.95 c the life span will be 30 nanoseconds, at 0.98 c it will be 50 nanoseconds, and so on (see table here). This is yet another bit of weirdness from the screwy world of Einstein's relativity. Thanks, Albert.

Now in physics 101, you'll learn that distance equals rate times time. Our particle moving at 0.9 c has a rate of 269,813,212 meters per second. It has a time (life-span) of 20 nanoseconds or 0.00000002 seconds. Multiplying will show you that the particle will move a distance of about 5.396 meters before it decays. At 0.95 c, it will move 8.544 meters. At 0.98 c it will move 14.690 meters.

Your eyes are probably glazing over by now. The point is by altering the speed of the particle you alter the point in space where it decays.


So how do we weaponize this? Say we have a particle that easily passes through most matter in general (and starship armor in particular) but will eventually decay into a spray of deadly radiation. You aim your particle accelerator at the enemy starship, calculate the range between the accelerator and the enemy, then adjust the speed of the particles such that the point where they decay into deadly radiation is inside the center of the enemy starship. It is like teleporting a burst of radiation into the enemy ship's guts.

Now you see why the meson accelerator is so deadly.

Why the "meson" in "meson accelerator"? Because the people who wrote the Traveller RPG figured that the particle called the neutral pi-meson (pions) would work. They have a mean lifetime of 0.000000084 nanoseconds, and decay into a splendidly nasty spray of gamma rays, electrons and antimatter electrons.


Unfortunately, the meson accelerator shares the same problem with plasma weapons: they won't work. Anthony Jackson points out:

  • Pions are stopped by armor (because they are affected by the strong nuclear force)
  • Pions do not have a life span of exactly 0.000000084 nanoseconds. That is the half life. This means along the entire beam pions are decaying, by the time you reach 0.000000084 nanoseconds half of the pions in the beam have decayed. So there is not a pin-point dot where the pions decay, it is a gradual decay along the whole beam.
  • If you can accelerate pions to such high velocities that the "decay point" is in a ship several million meters away, the particles will have so much energy that you don't have to use pions. At that energy, a beam of garden variety electrons will instantly vaporize any armor that is made out of matter. The gamma factor will be about 1016. This means every single one of the zillions of subatomic pions will have a blast energy of 2.16 × 105 joules. That's right, each single subatomic particle will have the energy of an antipersonnel land mine.

In defense of the authors of Traveller, much of this nuclear science had not been discovered at the time Traveller was written. Later version of the Traveller game try to retcon this by saying the meson accelerator was invented by George Meson, and it actually works by some hand-waving way, and has nothing to do with pions at all.

To amplify what Anthony said:

Pions interact via the nuclear forces. A beam of pions traveling through a material will have a chance of hitting an atomic nucleus. A nucleus has an effective cross sectional "size" of about 1 × 10-30 m2 for high energy particles. A cubic meter of solid or liquid matter with atoms spaced about 0.1 nm apart (a typical atomic spacing) will contain 1 × 1030 nuclei. The total combined cross sectional "area" for the beam to interact with is thus about 1 × 10-30 m2/nucleus * 1 × 1030 nuclei = 1 m2 — the same cross sectional area as our cubic meter of matter. Thus, a beam of particles interacting only via nuclear forces can expect to hit a nucleus after going through about 1 meter of solid or liquid matter (or about 1000 meters of gas at atmospheric density, since gas is about 1000 times less dense). Note that this distance is not affected by relativistic time dilation — there are just as many nuclei in your path no matter how fast you go.

When a pion hits a nucleus at these energies, the nucleus will either have a chip knocked off — a proton, neutron, alpha particle, deuteron, or triton — or shatter into fragments. These nuclear pieces will have considerable energy of their own, hit other nuclei, cause more fragmentation, and so on, while those pieces that are charged will also lose energy to ionization. The pion may or may not be captured when it interacts. If it is not captured, it keeps going (although with less energy) and can knock into more nuclei.

Note that these nuclear interactions are not tunable to some precise distance — they occur throughout the path of the beam as pions and fragments encounter nuclei.

Also, the time to decay is random. A pion might live on average 8.6 × 10-17 seconds in its own rest frame, but this means that half of your pions will have decayed before 8.6 × 10-17 seconds is up, and half are still around. After 17.2 × 10-17 seconds, you still have one quarter of your original number of pions still waiting around to decay, and one-eighth of the pions after 25.8 × 10-17 seconds. If you turn these into a beam of relativistic particles to delay their decay time, you still get them decaying at random all along their beam path, not at one specific point.

Now there is one possible retro-fit justification to this conundrum. At the time Traveler was written, particle physics was still figuring out a lot of the stuff we know about today. Today, meson means a particle composed of a quark and an anti-quark, but back then a meson was a particle with a mass significantly more than an electron but significantly less than a proton or neutron. One of the "mesons" was the "mu-meson," which we now categorize as a sort of heavy electron and not a meson at all. Muons, as they are now called, do not interact via the strong nuclear force but they are charged. Charged particles lose energy at a well defined rate as they go through matter (depending on the particle's charge and speed, the density of the matter, and some details on the chemical and electronic properties of the matter like how hard it is to knock electrons off). Since all the particles in the beam are losing energy at the same rate, they all have nearly the same energy at any point along the beam as they go through matter. In particular, this means they all come to a stop at more or less the same point. If it is a muon, it will decay after it stops into a highly energetic electron plus a couple of neutrinos. The highly energetic electron will dump all its energy into the surrounding material very rapidly. Meanwhile, muons themselves are extremely penetrating — muons from cosmic rays have been known to penetrate not only the entire atmosphere but over a kilometer of rock. By tuning the energy of a beam of muons, and with a good estimate of how thick your target is and a rough idea of its density and composition, you can choose an energy so that all the muons come to a stop in the middle of the target due to ionization losses and then dump a lot of energy there with their decays. You can only do this because muons do not interact via the strong nuclear force, so they do not hit nuclei like mesons or neutrons or protons would — this makes muons far more penetrating.

Alas, muons have a lifetime of about 2 microseconds. If you are tuning the energy to choose how deeply into the target the muons decay, you can't boost the muons up to ultra-relativistic energies to give them enough time dilation to reach distant targets (that would give them so much energy that they would seriously overpenetrate). With a maximum time dilation of maybe 10 for practical purposes, this gives a muon gun a maximum range of around 6 km — less for thinner targets that need lower energy muons if you want the beam to stop in the middle (more precisely, you will have lost half your muons at 6 km with a time dilation of 10 — the beam still goes on a bit further with diminished intensity, but after a few multiples of 6 km, the beam will have been attenuated so much that it will not do anything significant).

Luke Campbell

Strangelet Bomb

Subatomic particles such as protons and neutrons are classified as hadrons. Unlike leptons, hadrons are composed of smaller particles called quarks, you may have heard of them.

Quarks come in six varieties, though pretty much all the matter you have ever come into contact with contained only "up" quarks and "down" quarks. The other varieties are charm, top, bottom, charm, and strange. The other varieties all have more mass than the basic up and down quarks, so other quarks tend to decay into basic quarks.

Strange quarks are only a little bit more massive than up and down quarks. In all known strange-quark containing hadrons, the strange quark quickly decays as expected. But physicists Bodmer and Witten have formulated the Strange Matter Hypothesis, which implies that the decay may not happen if one has a large collection of quarks (a "Strangelet"). The theory predicts that the stable state would be an equal number of up, down, and strange quarks; instead of just up and down quarks. This is due to the Pauli exclusion principle, which I won't bore you with. Whether the Strange Matter Hypothesis is true or not depends upon the surface tension of strange matter. If it is large enough, the hypothesis is true. So far physicists have been unable to determine the value of its surface tension.

"So what?" I hear you grumble irritably. Well, this what:

Strangelets can infect ordinary matter, transforming it into more strangelets.

Does anybody remember the fictional Ice-nine from Kurt Vonnegut's novel Cat's Cradle? Drop a piece of the stuff into the Atlantic and soon all the water on Terra becomes solid and everybody dies. The word you are looking for is "chain-reaction."

If strange matter has a large enough surface tension, a larger collection is more stable than a smaller. In contact with ordinary matter, that matter will move to the more stable energy state, i.e., it will transform into more strange matter. And when matter moves to a more stable state, the excess energy is released (which is basically what powers a nuclear warhead).

Dr. Luke Campbell points out that for a chain reaction, the strangelets have to be negatively charged or neutral. If they are positively charged they will be repelled by positively charged atomic nuclei, and therefore cannot get close enough for infection.

So a speck of strange matter dropped on Terra will gradually consume it, converting it (and everybody living on it) into a hot lump of strange matter.

This is the reason why everybody was screaming about the the Relativistic Heavy Ion Collider (RHIC) experiment at Brookhaven and the Large Hadron Collider (LHC) at CERN. They were afraid one of the experiments would spit out a strangelet with results indistinguishable from a visit by Galactus. Most scientists think the possibility is far fetched, and the fact that you are alive to read these words shows that nothing has happened. So far.

Until the value of strangelet surface tension can be determined, we will not know if strangelet bombs are possible or not. But the idea has already been used in several science fiction stories, so the idea at least is close to being mainstream.

The Burning of Litash (4)

CS Unyielding Order, Litash high orbitals.

“Grid configured.”

“Special package CALYX HOLLOW on the rails, launch when ready.”

“Permissive action set, authentication 0x991AC38575AA0D0E. Admiral, do you wish to deploy the weapon?”

“Deploy it. Right in the starport center, Mr. mor-Calarek.”

“Aye-aye, ma’am. Right in the center.”

90,000 miles above the surface of Litash, battered in places but still mostly untouched, a near-imperceptible thrum was felt aboard the battlecruiser as one of its axial missile tubes opened and spat out the CALYX HOLLOW package, a tiny cylinder of gray-painted metal. Twin flashes of light, one upon the ship’s hull and one upon the package, marked the invisible beam of a plaser reaching out from the ship and burning off a fragment of the package’s ablative propellant; and at this touch of thrust, it began to accelerate downwards into Litash’s gravity well.

CALYX HOLLOW was a weapon almost trivial in design. No trigger or detonator was needed, and no guidance system fitted. Once it had been launched, the weapons package simply tumbled on a ballistic trajectory into Litash’s atmosphere. A few surviving ground weapons attempted to engage it, without hope of success with the orbital and ground sensor networks both smashed, but even had they been able to target it, it would have made no difference to the outcome, for the best they could achieve would be to fragment the casing early.

But the tough casing remained intact, cloaked in the plasma shock of its uncontrolled reentry, until only a few miles above the planet’s surface the stress of burn-throughs ripped it apart, shattering the delicate containment system within it and exposing its contents to the planet’s air.

Strangelets. Unstable particles, kept artificially intact within the weapon; generated in nature in tiny quantities, harmless due to the speed of their decay. But this was no single strangelet generated by a cosmic-ray impact; within CALYX HOLLOW’s containment was a mass of strangelets calculated to cause immediate prompt criticality. As they spilled into the relatively thick baryonic matter of Litash’s air, they merged with nearby nuclei, catalyzing their immediate collapse into more strangelets, and more, and more…

From the Unyielding Order, light flared over the target, blossoming instantly from a blue-white pinprick to an eye-searing flare hundreds of miles across, driving a visible miles-deep ripple of atmosphere before it, only to crash back into the hollow remaining as the flare itself collapsed – and the display blinked out and filled with sensor failure warnings, while the particle detectors screamed and fell silent as the radiation wavefront swept across them.

Caliéne Sargas’s throaty chuckle filled the silent bridge. “Ha! Well, Cyprium, now we know the damn thing works.”

“Indeed. Although I’m considering passing a note along to the design team about their stand-off range estimates – that was a bit closer than I’d’ve liked.”

“Captain, damage reports as soon as possible, and contact the rest of the squadron for theirs. And have the Surgeon-Lieutenant report to the bridge with his rad-test kits.”

She paused, then added, “And get someone out there in a cutter to find out if the planet’s still there.”

The Burning of Litash (5)

“These images are taken from the records provided by the command vessel of the fleet that carried out ‘Operation Ruby Gauntlet Sable’, the Unyielding Order…”

The ravaged planet hung in the center of the Conclave amphitheater, surface black and charred save for its fiery disfigurement; a crater over a thousand miles wide, filled with a sea of magma welling up through the world’s cracked crust, belching steam into the wracked air at its edge where it intersected the former coast. Newborn volcanoes shouldered their way into the sky at its fringes and along radiating cracks, as the world heaved in the orogenic aftershocks of the detonation.

“These are simply the primary effects of the strangelet bomb deployed by the Empire’s task force. The detonation set the atmosphere of the planet ablaze. Firestorms driven by the pressure wave swept around the world, incinerating not merely everyone who escaped the initial blast, but the entire planetary ecology. The direct radiation and particle showers produced by the bomb have rendered much of the planet radioactive. That alone will render Litash unhabitable for a thousand years.”

~~~

“Ah, ni Korat, sit down. I’m surprised you wanted to be seen meeting at a time like this.”

“We’re already so close to you in the public eye, it’ll hardly matter. And all of us are nervous right now – everyone’s counting on me to find out what’s going on.”

~~~

“Technically, this is not a violation of the Accords as written. Litash was not a signatory to any of the Accords, nor has there been any specific prohibition on the use of strangelet weapons. Litash was a world which supported piracy, slavetaking, and other crimes against Accord members; a general threat to all the Worlds. None of us here would quibble with the right of any Accord member to destroy the Litashian fleet with no quarter given, nor to prosecute general warfare against the Litashian government. But this! This is the destruction of an entire world, its entire population, its entire ecology. This cannot be tolerated by the galactic community, surely. If a smaller polity of the Accord had done this, it would be subject to the most severe censure, and it must therefore be so even if one of the Powers.”

Eldraeverse

Trope-a-Day: Weapon of Mass Destruction

Weapon of Mass Destruction: Per the Ley Accords (i.e., the Laws and Customs of War), in descending order of aargh, you’ve got:

  • Star-Killing Weapons
  • Planet-Killing Weapons
    • large/fast kinetic impacters, including asteroid drops, planet-targeted strangelet bombs, and relativistic k-kill weapons
    • extremely large [strategic-plus] energy-burst weapons, including nucleonic and antimatter warheads
    • self-replicating planetary-scale war machines [berserker probes]
  • Uncontrollable Self-Replicating Infoweapons and Memetic Weapons that affect systems beyond their legitimate targets, propagate themselves widely across the extranet, and lie dormant in archives to come out and kill innocent people ten thousand years later.
  • Ecocidal Weapons
    • merely large [strategic-plus] energy-burst weapons or ongoing bombardments with same
    • general bombardments with small kinetic impactors [smaller asteroid drops, de-orbited satellites/stations, or orbital k-kill systems]
    • uncontrolled self-replicating weapons [autonomous goo, unchained bioweapons, technophages, and clanking replicators]
    • global ecoweapons and phage weapons
    • the use of persistent ecoweapons and bioweapons
    • salting nucleonic weapons [say, cobalt bombs]
    • chemical weapons likely to permanently damage or accumulate in ecosystems

Using any of the first three types anywhere, or the fourth on a garden world, will get your entire polity blasted and governance wiped out even if it takes the use of otherwise prohibited technologies to do it; these are technologies that eliminate habitable worlds – and those are really goddamned expensive – or tend to run beyond any reasonable control. Ergo, they’re the galaxy’s primary do-not-f**k-with list.

Mere tactical-to-strategic nucleonic/antimatter weapons, non-persistent chemical and biological weapons, incendiary weapons, cerebroergetic weapons, and nanoweapons are not covered by this treaty, or considered the equivalent of WMDs. Not enough mass. They’re all fair game.

Ridiculous Handwavium

Tractor Beams

Attractor beams are laser-like beams of energy that pull the target closer to your ship, while pressor beams push the target away. Pressors are also called "repulsors" or "repellors." Often a unit that can emit both attractor beams and pressor beams is called a "tractor" beam (though sometimes that term is just an abbreviation for attractor beam).

These more or less totally science fictional (if you disregard things like using microscopic laser beams as optical tweezers to move microbes around). Tractor Beams are like super-duper electromagnets, but much better. Electromagnets can only attract ferrous objects, while tractor beams can both attract and repel objects made of any material.

Magnets broadcast their attractive effect in all directions. Tractor and pressor beams are beams, any object not actually struck by the beam is unaffected. Electromagnets attraction strength falls off as the 1/r4 inverse square law, while tractor beams tend to have absurdly long ranges (with the exception of the Geegee fields in Poul Anderson's TALES OF THE FLYING MOUNTAINS. They had a range of a few centimeters, so ships had to touch hulls in order to grapple each other).

Young readers may believe that tractor beams were invented by the writers of the original Star Trek (1966). Even younger readers may believe it made its first appearance in the movie Star Wars: A New Hope (1977). I've got news for you, the first example I found was the "Attractive Ray" featured in Edmund Hamilton's Crashing Suns, published in 1928!. "Attractor" and "Pressor" beams appear in E. E. "Doc" Smith's The Skylark of Space (1929). The term "tractor beam" appears to originate in E. E. "Doc" Smith's Spacehounds of IPC (1931).

In James White's novel Star Surgeon (1963) we find a weaponized version of the tractor-pressor beam, the so-called "Rattler." These weapons attract then repel the target at 80 gravities, several times a minute. When used on an entire ship, the hapless crewmembers are shaken like the dried beans in a baby's rattle. If focused down to just affect a small spot on the target's hull, the shear forces can rip the hull like it was wet cardboard. This was also used on C.C. MacApp's nearly forgotten and definitely underrated novel Recall Not Earth.

In the Exordium series by Sherwood Smith and Dave Trowbridge, "ruptors" fire unpolarized gravitons to shake their target to pieces. If you polarize the gravitons you have a tractor beam.

In E. E. "Doc" Smith's Lensman series, tractor beams are used to anchor the inertialess target so it can be damaged by weapon beams (otherwise the weapon beam pushes the intertialess ship away at lightspeed but does not harm it). In response, the enemy developed "tractor beam shears", which were planes of energy capable of "cutting" a tractor beam. Of course if your ship had more tractor beam projector than the target had tractor shears, the target was out of luck.

Doc Smith also implies that if you hit a ship with a attractor and a pressor beam, you can pin the ship at the distance where the force of the two beams balance. He also thinks that you can move the pinned ship laterally left and right by swinging the beam projectors, but that doesn't make sense to me.

Also in Doc Smith's Skylark series, the Osnomian hand guns are very silent, since bullets are propelled not with gunpowder, but by "force-field projection." So logically if one has tractor beams, one also has the equivalent of a railgun or coilgun. In MacApp's Recall Not Earth, tractor beams are used to launch torpedoes out of their tubes.

If you want some nice technobabble, a tractor beam can be hand-waved as a sort of laser using gravitons instead of photons.

GURPS: Lensman

Tractor Beams
     These beams pull their target to the beam generator, and vice versa. They are used for a wide variety of purposes, such as cargo handling, fine maneuvering and grappling in combat.
     The effect of a critical failure on any tractor beam use varies with the use. Most tractor beam mounts are reinforced to support the full weight of the ship under heavy acceleration, so it would be difficult (but hardly impossible) to tear the beam generator out of its mounting. If neither the beaming installation nor the grappled object mount screens, a collision is likely.

Pressor Beams
     Pressor beams (sometimes called repellors) are exactly like tractor beams, except that they work in reverse, pushing instead of pulling, and they cannot be cut. They are the same cost and weight as a tractor.
     Tractors and pressors are an integral part of the Chung (so-called "tensegrity") doctrine of space strategy, used to link massive formations of ships of the line into integral structures.

Tractor Shears
     A tractor shear is a modified pressor that is targeted at the enemy's tractor beam, and sets up an interference pattern which breaks the tractor's grip. The shear does not need to be held on the tractor; even momentary interference is sufficient to cut the beam. The tractor operator may immediately attempt to re-establish a lock, but he must begin anew.

Tractor Zones
     Immediately upon the invention of the tractor shear (above), the scientists of the Patrol began development of the "uncuttable" tractor. What they devised was a biphase version of the meteor screen, a globular shell of force that absorbed all momentum imparted to it and transferred it to the projector and its mounts. While a meteor screen only affects incoming matter, the tractor zone works in both directions.
     The tractor zone is formed uniformly around its generator. All matter contacting its spherical shell of force loses all radial momentum, and stops moving inward or outward. (Any angular momentum remains, and the matter slides around the shell.) Tractor shears, designed to interfere with beams, have no effect on this area of force.
     The target's radial momentum is transferred directly to the mounts of the projector, so those mounts must be constructed to withstand the most violent inert impulses the target can impose, or major damage will result.

From GURPS: Lensman by Sean Barrett (1994)
Rattler 1

By the fourth day the attack showed no signs of diminishing. The rattlers on the outer hull were going almost constantly, their power drain making the lights flicker.

The principle which furnished artificial gravity for the floor and compensated for the killing accelerations used by the ships also lay behind the weapons of both sides — the repulsion screen, originally a meteor protection device, the tractor and pressor beams, and the rattler which was a combination of both. The rattler pushed and pulled — vibrated — depending on how narrowly it was focused, at up to eighty Gs. A push of eighty gravities then a pull of eighty gravities, several times a minute. Naturally it was not always focused accurately on target, both ships were moving and taking counter-measures, but it was still tight enough to tear the plating off a hull or, in the case of a small ship, to shake it until the men inside rattled.

There was no fine diagnostic skill required in the treatment of these rattled men. It was all too plain that they suffered from multiple and complicated fractures, some of them of nearly every bone in their bodies. Many times when he had to cut one of the smashed bodies out of its suit Conway wanted to yell at the men who had brought it in, "What do you expect me to do with this. . ."

But this was alive, and as a doctor he was supposed to do everything possible to make it stay that way.

From Star Surgeon by James White (1963)
Rattler 2

The main screen showed a line of heavy cruisers playing ponderous follow-the-leader along the first section of the incision, rattlers probing deep while their pressers held the edges of the wound apart to allow deeper penetration by the next ship in line. Like all of the Emperor class ships they were capable of delivering a wide variety of frightfulness in very accurately metered doses, from putting a few streets full of rioters to sleep to dispensing atomic annihilation on a continental scale. The Monitor Corps rarely allowed any situation to deteriorate to the point where the use of mass destruction weapons became the only solution, but they kept them as a big and potent stick — like most policemen, the Federation's law-enforcement arm knew that an undrawn baton had better and more long-lasting effects than one that was too busy cracking skulls. But their most effective and versatile close-range weapon — versatile because it served equally well either as a sword or a plowshare — was the rattler.

A development of the artificial gravity system which compensated for the killing accelerations used by Federation spaceships, and of the repulsion screen which gave protection against meteorites or which allowed a vessel with sufficient power reserves to hover above a planetary surface like an old-time dirigible airship, the rattler beam simply pushed and pulled, violently, with a force of up to one hundred Gs, several times a minute.

It was very rarely that the corps were forced to use their rattlers in anger — normally the fire-control officers had to be satisfied with using them to clear and cultivate rough ground for newly established colonies — and for the optimum effect the focus had to be really tight. But even a diffuse beam could be devastating, especially on a small target like a scout ship. Instead of tearing off large sections of hull plating and making metallic mincemeat of the underlying structure, it shook the whole ship until the men inside rattled.

From Major Operation by James White (1971)
Fantasy into Science, or Realizing the Impossible: Tractor Beams

Short of destroying a whole world with planet-breaking weapons, the most action-filled moments in science fiction come when opposing spacecraft clash. As phasers fire and missiles launch, ships frantically maneuver, attack, or spectacularly explode. But sometimes the aim is to capture a spaceship intact, or if she has superior speed, to grab and hold her while battering down her defenses. That is the space version of a fighting technique from the days of wooden sailing ships, which is to pull an enemy ship close and hold her with grappling hooks and ropes, then board her, or pound her into wreckage at point-blank range.

In space, this tactic needs a futuristic version of hooks and ropes – a tractor beam. Like the force of gravity in nature, a tractor beam pulls things toward its source; but in science fiction, it is stronger than ordinary gravity, and unlike gravity, it can be aimed. Tractor beams first showed up in the Buck Rogers stories and the “space operas” of Edward E. “Doc” Smith from the 1920s and 1930s. They still appear in Star Trek, the film District 9 (2009) and other contemporary science fiction.

Gravity may feel all too strong when you are jogging uphill, but technically it is the weakest of the universe’s four fundamental forces (in descending strength, the others are the strong nuclear, electromagnetic, and weak nuclear forces). Gravity’s pull takes on real power only when it arises from a massive object like a planet or a star. The mass of even the biggest spacecraft could not generate enough force to yank in another spacecraft. Going beyond this to create a powerful, directed artificial gravity needs a technology we do not yet have a clue about.

But there is another way to manipulate objects without touching them, using something you would not think has physical impact: light. Light’s intangibility might seem to imply that it cannot affect solid objects. By the weird rules of quantum mechanics, however, light is both an electromagnetic wave and a flock of particles – photons – that carry energy and momentum. As Isaac Newton worked out long ago, a change in momentum produces a force; and so, no differently from baseballs or billiard balls, when photons hit something and thus change their momentum, they exert a small force called radiation pressure.

On Earth, the radiation pressure from sunlight is 50 million times weaker than atmospheric pressure, but a laser can intensify the effect to a useful level. In the optical tweezers method, developed at Bell Laboratories in 1986, a focused laser beam suspends small biological objects like bacteria and DNA molecules in mid-air and can be used to manipulate them. On a larger scale, the Sun’s radiation pressure can drive a spacecraft, if the ship is outfitted with a big sail that can capture the push from many photons. In 2010, the IKAROS spacecraft launched by JAXA (Japan Aerospace Exploration Agency) deployed a sail with an area of 200 square meters and headed off toward the planet Venus, accelerated by sunlight.

These applications may not be all that surprising, because it is easy to picture tiny bullets of light pushing an object. But could light possibly attract rather than repel a body, and would that be of any earthly use? To NASA, the answer to both questions is “yes.” The agency envisions “unearthly” uses such as cleaning up the orbital debris ringing our planet and pulling an incoming space rock off course before it hits the Earth; but like those imaginary space battles, these efforts would require strong forces and will happen only in the future if at all.

However, NASA also wants to pull in smaller things like tiny extraterrestrial particles that can carry valuable information. Obtaining such samples is a rapidly growing part of space exploration. NASA’s Stardust space probe, launched in 1999, gathered microscopic dust particles from a comet called Wild 2, and returned them to Earth for analysis in 2006. In 2003, JAXA launched its Hayabusa space craft, which retrieved bits of a small asteroid and brought them back to Earth in 2010. And just this last November, NASA launched its Mars Science Lab with the Curiosity rover, which will scoop up samples of Martian soil and analyze them for signs of life processes.

Using light to attract and manipulate small samples in space or from planets and other bodies would complement and extend these kinds of missions, each of which takes considerable effort and expense. Light-based sample harvesting could maybe be done at a lower cost and could also allow continual monitoring, for instance, of a planetary atmosphere. According to recent research and some older results, there is reason to believe this is not just wishful thinking.

In two separate theoretical papers published last month, a group at the University of Central Florida (Negative Nonconservative Forces: Optical “Tractor Beams” for Arbitrary Objects), and another from the Technical University of Denmark and the National University of Singapore (Single Gradientless Light Beam Drags Particles as Tractor Beams), showed how to make an object move backward along a light beam. The basic idea is deceptively simple; because the incoming photons carry momentum, if you can get some of them to bounce or scatter off the object in the same direction they are traveling – that is, in the area where the object would ordinarily cast a shadow – then to balance out the momentum going forward, the object has to move backward toward the light source. This would require a laser beam with a carefully designed pattern of varying brightness across its diameter, which is not easy to create, and so these ideas have yet to be experimentally tested. But NASA has enough faith in the approach that it started to fund research in optical tractor beams.

One other potential optical method goes back almost 50 years. In 1964, Victor Veselago, of Moscow’s Lebedev Physics Institute, theorized about an optical medium with a negative refractive index. In ordinary media like water or glass, the refractive index is a positive number that determines the speed of light in the medium and also how much a light ray bends or refracts when it enters another medium. Refraction is the reason that a stick partly inserted in water seems to break and bend upward at the water’s surface. But in a medium with a negative refractive index, the stick would display “backward” refraction and seem to bend down.

Negative refractive indices as Veselago envisioned them have been realized in carefully designed, artificially constructed media called metamaterials. In an especially intriguing breakthrough, these ideas also led to the creation of the world’s first true invisibility cloak, made in 2006 by David Smith and his group at Duke University.

Veselago predicted another “backward” result that amounts to a tractor effect, which is that a mirror embedded in a negative index material would be pulled rather than pushed by a light source. In 2009, Henri Lezec, of the U.S. National Institute of Standards and Technology, described how he and Kenneth Chau tested this theory. They fabricated a metamaterial with a negative refractive index in the form of a tiny nanoscale movable lever, and found that it was indeed pulled toward light from a laser. This would seem to be the first observation of light acting as a tractor beam according to Veselago’s theory, but the results do not fit the predicted behavior in detail. The experiment or the theory may be anomalous, and the experimental result remains under study.

If metamaterials display a true tractor effect that would be fascinating, but it would not be exactly what NASA needs to gather up space debris or interesting space dust, nor would it be useful in future space battles. To reel in a particular enemy ship, some unlucky crewmember would first have to don a spacesuit, venture out, and paint the target with negative refraction paint. If that is the case, we might just as well go back to grappling hooks, ropes, and spacesuit-wearing boarding parties armed with cutlasses.

Newton's Laws

In any event, pretty much all of the depictions of tractor beams totally ignore the fact that they must obey Newton's Third Law (i.e., the law of action and reaction). There are only two exceptions I am aware of. One exception is in TOM SWIFT AND THE RACE TO THE MOON, where the intrepid teenage inventor Tom uses his repelatrons for the propulsion system of his amazing spacecraft Challenger. Another is in the wargame Vector 3. In that game, your ship can use tractor beams to impose x, y, and z acceleration vectors on the enemy ship. However, due to Newton, your ship receives the same vectors in the opposite direction (e.g., if you give the enemy a +4 z acceleration, your ship receives a -4 z acceleration). Note that this only works if the two ships are of equal mass.

Anyway, Newtons says that if the starship Enterprise uses a tractor beam to reel in a Klingon battle cruiser, the Enterprise will also move towards the Klingon. Both will move towards the point called the Barycenter of the two ship system. In the same way if the Enterprise pushes away the Klingon, the Enterprise will also be pushed away from the barycenter.

The acceleration each ship will experience towards or away from the barycenter depends upon each ship's mass. Simply put: if ship Alfa has twice the mass of ship Bravo, it will be accelerated half as fast as ship Bravo. If an Imperial Star Destroyer tractors the Tantive IV, it will be accelerated about 1/110th as fast as the Tauntive. And if the Death Star tractors the Millenium Falcon, its acceleration will be so tiny as to be difficult to detect.

The actual equation is from Newton's Second Law:

a = F / m

where:

  • a = ship's acceleration (m/sec)
  • F = tractor beam energy (Newtons)
  • m = ship's mass (kg)

If you want relative acceleration, use 1 for F and measure m in terms of the other ship's mass.

Example

If the ship in question has a mass of 3.5 times the mass of the other ship, it will experience an acceleration of 1 / 3.5 = 0.29 times as much as the other ship. If the ship has a mass of 1/4 times the mass of the other ship, it will experience an acceleration of 1 / (1/4) = 1 / 0.25 = 4 times as much as the other ship.

Calculating Movement

If you want to open up a real can of worms, you can try calculating what happens if the two ships are moving when the tractor beam is turned on. I am not going to try and calculate the minute to minute effects (because it is way above my pay grade) but the final results after the two ships come into contact can be approximated by the mathematics of a completely inelastic collision. This is the equivalent of figuring the trajectory of two balls of clay that collide and stick together. I will show the equations for figuring this in two dimensions, since I am unsure of my ability to expand it to three dimensions.

Given two spacecraft with masss of M1 and M2, velocities of V1 and V2, and vector directions angles of θ1 and θ2; when they are tractor beamed and drawn together into contact, calculate the combined ships velocity Vf and vector angle θf.

Step 1: Calculate each ship's x and y coordinate displacement
  • V1x = V1 * cos(θ1)
  • V1y = V1 * sin(θ1)
  • V2x = V2 * cos(θ2)
  • V2y = V2 * sin(θ2)
Step 2: Calculate each ship's momentum
  • O1 = V1 * M1
  • O2 = V2 * M2
Step 3: Calculate each ship's momentum in the x and y axes
  • O1x = O1 * cos(θ1)
  • O1y = O1 * sin(θ1)
  • O2x = O2 * cos(θ2)
  • O2y = O2 * sin(θ2)
Step 4: Calculate the combined ship's momentum in the x and y axes
  • Ofx = O1x + O2x
  • Ofy = O1y + O2y
Step 5: Calculate the combined ship's mass
  • Mf = M1 + M2
Step 6: Calculate the combined ship's momentum
  • Of = sqrt( Ofx2 * Ofy2 )
Step 7: Calculate combined ships velocity
  • Vf = Of / Mf
Step 8: Calculate combined ships vector angle
  • θf = arc tan( Ofx / Ofy )

Tensegrity

E. E. "Doc" Smith was a big fan of attractor and pressor beams, using them in many of his space operas. For reasons that he did not go into, but which I think had to do with Newton's Laws, he sometimes had fleets use attractors and pressors to turn the entire fleet into one rigid object. I figure this gives the fleet immunity to hostile attractor beams. A solitary enemy ship trying to use an attractor on a rigid multi-ship fleet will be like you having a tug-of-war contest with a caterpillar tractor, with the cable looped through your nipples. The mass difference between the rigid fleet and the single enemy ship will see to that.

Anyway, in my long and misspent youth I was a fan of Doc Smith and a fan of a weird concept called Tensegrity. Tensegrity is where you have compression members (girders) held with tension members (cables) attached to the girder ends. The girders float in the air while not touching each other, held rigidly by the tension of the cables. I realized the two concepts could be combined.

In a tensegrity structure, you replace the girders with pressor beams, and the cables with attractor beams. The ships of the fleet occuply the girder ends. Instant Doc-Smithian rigid fleet! I mentioned this to Sean Barrett and he added it to GURPS: Lensman. It was only a single sentence, but I was tickled pink that it made the cut.

Now actually a tensegrity struture is not absolutely rigid. Under pressure the entire structure regularly contracts then expands. This is called "jitterbugging." This is probably a good thing, since structures that are too rigid tend to shatter instead of flexing a bit.

It is possible to make a minimal tensegrity structure, but this is not a good idea for something going into a combat situation. With a minimal structure, if one single attractor or pressor fails, the entire structure collapses. Best to have some redundant attractors and pressors to allow for combat damage.

Of course in a world without attractors and pressors there is no practical reason to want to make a rigid fleet in the first place. But after all this segment is in the "Ridiculous Handwavium" section.

GURPS: Lensman

Tractors and pressors are an integral part of the Chung (so-called "tensegrity") doctrine of space strategy, used to link massive formations of ships of the line into integral structures.

(ed note: for the record, I read about Doc Smith using tractors and pressors in ship formations in the early 1970s when I was a teenager. I learned about tensegrity in in my college years during the late 1970s, and quickly noticed the possible connection between the two. In 1992 I became aware that Sean Barrett was working on GURPS: Lensman and started corresponding with him to offer my help, since I was sort of a Doc Smith expert. So I gave him the connection. He used it and rewarded me by using my name with it. )

From GURPS: Lensman by Sean Barrett (1993)
Spacehounds of IPC

High in the air, another signal wailed up and down a peculiar scale of sound and the mighty host of vessels formed smoothly into symmetrical groups of seven. Each group then moved with mathematical precision into its allotted position in a complex geometrical formation—a gigantic, seven-ribbed, duplex cone in space. The flagship flew at the apex of this stupendous formation; behind, and protected by, the full power of the other floating citadels of the forty-nine groups of seven.


"All captains, attention!" Finally, in a high latitude, the flagship sent out final instructions. "The Hexans have detected us and our long range observers report that they are coming to meet us in force. We will now go into the whirl, and proceed with the maneuvers exactly as they have been planned. Whirl!"

At the command, each vessel began to pursue a tortuous spiral path. Each group of seven circled slowly about its own axis, as though each structure were attached rigidly to a radius rod, and at the same time spiraled around the line of advance in such fashion that the whole gigantic cone, wide open maw to the fore, seemed to be boring its way through the air.


With the terrific acceleration employed by the Hexan spheres, it was not long until the leading squadron of fighting globes neared the Vorkulian war-cone. This advance guard was composed of the new, high-acceleration vessels. Their crews, with the innate blood-lust and savagery of their breed, had not even entertained the thought of accommodating their swifter pace to that of the main body of the fleet. These vast, slow-moving structures were no more to be feared than those similar ones whose visits they had been repulsing for twenty long Jovian years—by the time the slower spheres could arrive upon the scene there would be nothing left for them to do. Therefore, few in number as were the vessels of the vanguard, they rushed to the attack. In one blinding salvo they launched their supposedly irresistible planes of force—dazzling, scintillating planes under whose fierce power the studying, questing, scouting fortresses previously encountered had fled back southward; cut, beaten, and crippled. These spiraling monsters, however, did not pause or waver in their stolidly ordered motion. As the Hexan planes of force flashed out, the dull green metal walls broke into a sparkling green radiance, against which the Titanic bolts spent themselves in vain. Then there leaped out from the weird brilliance of the walls of the fortresses great shafts of pale green luminescence—tractor ray after gigantic tractor ray, which seized upon the Hexan spheres and drew them ruthlessly into the yawning open end of that gigantic cone.

Then, in each group of seven, similar great streamers of energy reached out from fortress to fortress, until each group was welded into one mighty unit by twenty-one such bands of force. The unit formed, a ray from each of its seven component structures seized upon a designated sphere, and under the combined power of those seven tractors, the luckless globe was literally snapped into the center of mass of the Vorkulian unit. There seven dully gleaming red pressor rays leaped upon it, backed by all the power of seven gigantic fortresses, held rigidly in formation by the unimaginable mass of the structures and by their twenty-one prodigious tractor beams. Under that awful impact, the screens and walls of the Hexan spheres were exactly as effective as so many structures of the most tenuous vapor. The red glare of the vortex of those beams was lightened momentarily by a flash of brighter color, and through the foggy atmosphere there may have flamed briefly a drop or two of metal that was only liquefied. The red and green beams snapped out, the peculiar radiance died from the metal walls, and the gigantic duplex cone of the Vorkuls bored serenely northward—as little marked or affected by the episode as is a darting swift who, having snapped up a chance insect in full flight, darts on.


Onward and upward flashed the gigantic duplex cone, its entire whirling mass laced and latticed together into one mammoth unit by green tractor beams and red pressors. These tension and compression members, of unheard-of power, made of the whole fleet of three hundred forty-three fortresses a single stupendous structure—a structure with all the strength and symmetry of a cantilever truss! Straight through that wall of yellow vibrations the vast truss drove, green walls flaming blue defiance as the absorbers overloaded; its doubly braced tip rearing upward, into and beyond the vertical as it shot through that searing yellow wall. Simultaneously from each heptagon there flamed downward a green shaft of radiance, so that the whole immense circle of the cone's mouth was one solid tractor beam, fastening upon and holding in an unbreakable grip mile upon mile of the Hexan earthworks.

From Spacehounds of IPC by E. E. "Doc" Smith (1931)

Protean Weapons

Protean weapons are ones that can transform from one weapon into another.

The Warbots

The Warbots at Critter's Gateway

ca. 7200

The warbot used at Critter’s Gateway was a very capable little vessel, as much spaceship as groundcraft. The soldier, sitting in lotus, was freed of his helmet. From an amorphoid plate at the top of the warbot, he could extrude a battleraft or a head; from two plates at the side he could extrude any of an arsenal of two hundred weapons. The circuitry of these amorphic devices was mostly magnetic and gravitic domains, which could not be altered by any amount of twisting and contorting, so they could be extruded whenever needed, otherwise remaining placid as a puddle of quicksilver in their storage tanks.

Antares, while again the little empire of space, was also the most powerful, for they had over a million of these things strutting back and forth through space.


The Quicksilver Kid

ca. 10,000

By the Eodech (10,000 A.D.) arnorphics had developed a warbot made of nothing but amorphoid metals, memory plastics, solid liquids, contact fields and other prodigies of science. Normally a simple near-globe eight feet big, the Quicksilver Kid looked very much like a glob of mercury when in action. Hands, head, battlecraft and whatnot could be extruded from whatever part of the surface area they would seem to be most useful, and the weapons system had an additional development.

Hidden in the block-circuitry of the hull was a memory center containing records of every science applicable to military purposes, as well as a mechanical design center, so that a soldier need merely size up the situation and inform his warbot to create a weapon equal to it, and hammer away. Powered by antimatter breakdown, the warbot had more than enough power to see this done. No longer were warbots shuttled about by other spacecraft, but had a speed of about one light-year per hour to make its rounds.

There were many wars in the Eodechtic centuries, but none of them especially large on the grand scale. But warbots were used in all of them. For example, the Korel Empire Collapse.

The Korel were human adaptations, two feet tall and looking like toy dolls (behaving much like them, too. Korel were well known for their immaturity). They had a little empire flourishing until 10590, when one of their kings went insane on the throne and attacked the Palaric States, which were then growing into importance. The Korel had a few worthy weapons, which aided in their conquering several planets, and then an ally, the Karpo Regime, a race of hideous gray frogs who had been waiting on the sly for some way to build a little empire. As soon as the Korel had done as much as they could, the Karpo turned on them and soon had a very effective little empire, as well as a full-time occupation in scaring the border stars of the Pale (Palaric States).

An approaching fleet of warbots, after having been ordered to sum up the situation, performed a maneuver which was historical because of its originality. A hundred thousand warbots came together and fused their masses into a thousand medium-sized battleships, which attacked the Karpo fleets. The Karpo fired a salvo at them and broke them all into monolithic chunks of wreckage, which they then went in to investigate. Twisted wreckage, once it surrounded the Karpo fleet, suddenly turned quicksilver, returned to a hundred thousand intact warbots, and destroyed forever the Karpo Regime.

The Korel were chastised mildly. One could never expect much from them in the way of wisdom.

From THE WARBOTS written and illustrated by Larry S. Todd (1968)
Crown of Infinity

(ed note: The Star Kings are the descendants of human beings who escaped from Terra before the planet was destroyed by aliens called "The Masters". Hunted for thousands of years, the Star Kings eventually develop technology to fight the Masters on equal terms. Then they discovered the Master's sinister last plan: to breed other ally alien races who have a higher innovative quotent than humans, and use the allies to create weapons superior to the Star Kings.)

But the Star Kings did not blast them (the Masters) with the awesome weapons the TEMS had given. The TEMS—the mere thought of it sent shivers up and down a man’s vertebrae. When they had learned of the last plan of the dead (Master) leader, all Star King minds had joined together, linked through the C-S headgear. If the Masters managed to breed the beings in their specimen vaults, then they did not have even one generation to find a way to victory.

It was a period of total stress that gave them the answer: a Total Environmental and Mental Simulator. A computer that could simulate or duplicate the mental processes of any actual or artificial being, and through simulated total environmental stimuli create a situation of maximum stress upon that entity. An incredible machine, against which Master and ally were powerless. No matter how much in intelligence potential Master or ally had, the TEMS always came up with a simulated being that was superior. It had no limiting factor as do the brains of living creatures. It could always be added to.


(ed note: The evil race of the Shern are invading our universe through a rip in the fabric of space and time which leads to another dimension. The Star Kings englobe the rip with their super-ships. Until...)

A little closer, thought Carruthers, and then we’ll blow the Shern so far Universes will be born, live and die before any of their kind ever come back!

“That ship!” his wife cried.

“Hadley—Soviet Union! Get back! Get back!” But the ship did not get back. It broke formation and left a gaping hole in the once tight-knit shield of the Star Kings for a tenth of a second—a tenth too long. (Hadley is the first Star King coward, fleeing in fear for his life, abandoning his fellows to their fate.)

(ed note: when a Star King ship is destroyed, it sends out a Death Call. This FTL communication can be heard all over the universe. It only contains the name of the ship that died, and the location. All other Star King ships will rush to that spot to avenge the death of one of their own.

The Star Kings name their ships after location on murdered Terra.)

Carruthers screamed. Ships vaporized left and right. Men cursed and died. Up to the muzzles of the Shem weapons the Star Kings had fought. Now they died beneath those muzzles. Carruthers’ mind reeled at the Death Calls sounding like shots from an automatic weapon: the Calais, the Burma Road, the Troy, the Khyber Pass, the Las Vegas, the Houston, the Honduras of Davies, the Wellington, the Paraguay, the Eurasia, the Coney Island

Carruthers had to blank out his mind. He fought his ship and he unleased the TEMS. Working overtime, that dreaded instrument began thinking and building weapons that the Star Kings had always feared. Now fighting for their lives, they unleashed their devil.

The ship rocked and reeled and shivered. Panels flared, only to be replaced by others. Needles broke and were re placed by C-S directed robot units. Leads broke, fused or vaporized. Grimly, desperately, the handful of Star Kings still alive beneath the Shern weapon muzzles fought. They hurled their own awesome bolts of lethal energies and watched the Shern craft recoil under that fire.

They came warping in.

From a hundred far-flung Universes they came. Wherever the rain of Death Calls had carried, they came. Thousands and thousands and thousands, all the Star Kings alive, came warping in, weapons blazing! (this is an archaic use of the term "Universe" to mean "Galaxy")

Carruthers had no time to pause. He worked his weapons, he fought his ship. Globe after globe of the Shem withered and died. Carruthers saw the last globe flee into the dimensional rift. He hurled the Valley Forge into it. The ship hit an edge and stopped violently. He corrected and lashed out at the Shern globes frying to close the rift. Then other Star King ships were blasting their way through, coming to his aid. The Shern globes withdrew. The Star Kings followed.

But then, as if they had set a trap, trillions of Shem globes closed in over the Star Kings. Surely it was the end of the Star Kings. They had at last met their match. But the TEMS had been unleashed. Untouched for generations because of the undreamed of methods of destruction that it could conceive, it was at last put to work.

“Destroy those vessels,” commanded Carruthers and instantly the TEMS was creating and destroying entire systems of logic and mathematics, creating and discarding scores of new sciences. Before the sensory apparatus of the Shem the Star King ships grew in firepower and defensive capabilities. Weapons were loosed that destroyed entire Universes of the Shern dimension.

From CROWN OF INFINITY by John Faucette (1968)
VAST

There are four telescopes mounted on tracks around the ship’s hull. When two or more are fixed on the same object, their optical signals can be combined, creating an effective lens aperture far greater than any individual scope. At least two lenses are continuously fixed on the alien vessel that has hunted Null Boundary for 150 years.

It’s a Chenzeme courser, an automated warship designed by a race that vanished millions of years before the human species even came into existence. It first appeared when Null Boundary was less than fifty years out of Deception Well. Then, it was moving at close to thirty-nine percent lightspeed, on a course that would take it toward the star cluster called the Committee—opposite to Null Boundary’s vector. Nikko watches its fleeting image, wondering if it will manage to get past the defenses of the human settlements there.

Nikko knows little about the Chenzeme, but he knows this much: Their ships are not powered by conventional physics. The old murderers learned to tap the zero point field, that all-pervasive sea of energy where particles and antiparticles engage in a continuous dance of creation and annihilation. It’s a deadly talent. With the zero point field to power their ships and guns, each Chenzeme vessel has far more energy at its command than any human installation. Their gamma ray lasers can burn away the atmosphere of a living world. Nikko has seen it happen.

A twinge of pain, like the tenderness of a half-forgotten wound, warns him away from memories he does not want to awaken. It’s enough to know the Chenzeme will not be beaten until the frontier worlds own the zero point technology too.

Yet even for the old murderers, energy does not flow in infinite quantity. To catch Null Boundary, the courser would need to swing about and accelerate—a huge investment of both time and energy that can gain it only a very tiny prize. So that first time Nikko sees it, he knows it will ignore him to push on toward the inhabited worlds of the Committee. He has no reason to think he will ever see it again. He aims the ship’s prow at the natural navigation beacon of Alpha Cygni, a white-hot giant star that blazes against a background of dark molecular clouds—and he pushes on, in the direction called swan, where the Chenzleme warships seem to originate. He has set out to find their source, and he will not be distracted. Like a tortured man stumbling vengefully toward his tormenters, he has to know why.

A century and a quarter later, the courser reappears in Null Boundarys telescopes, approaching obliquely, far to the stern.

Now it has closed to 21.6 astronomical units—some three billion kilometers behind them. It’s a luminous object agleam with a white light generated by the membrane of philosopher cells that coats its needle-shaped hull.

Human ships and human worlds were not the original targets of the Chenzeme, but their automated ships have proven adaptive. So Nikko has adapted too. He cannot outrun the courser or match its guns, but on Null Boundary’s hull he has grown his own layer of Chenzeme philosopher cells, forever dreaming their simulated strategies of war and conquest.

The cells are an intellectual machine. Not so much a mind, as a billion dedicated minds in competition, gambling their opinions. Approval means more and stronger connections to neighboring cells. Disapproval means an increasing isolation. Links are made and shattered a thousand times a second and long-chain alliances are continuously renegotiated. Consensus is sought but seldom found.

This is the clumsy system that guides the Chenzeme warships. Nikko thinks on it, and he doesn’t know whether to laugh or to weep in terror.

From VAST by Linda Nagata (1998)

Electromag Catalysis Poison

This one is total technobabble nonsense, but it is entertaining.

In James Blish's The Triumph of Time (fourth novel in the Cities in Flight series) the alien empire The Web of Hercules has spread from the Great Globular Cluster in Hercules to conquer the galaxy. They use the Web to destroy planets: beams of heavy nuclei of antimatter send from about one light-year distant. As they hit the planet's atmosphere, they make weird yellow-green glowing patches as they undergo matter-antimatter annihilation and bath the planet in a lethal bombardment of gamma radiation.

They attack the planet He, but the Hevians have a counter weapon.

The Triumph of Time

     “One question at a time,” Miramon said. “Of course we mount weapons. We never talk about them, because there were children on our planet, and still are, the gods receive them. But we had to face the fact that we might some day be invested by a hostile fleet, considering how far afield we were ranging from our home galaxy, and how many stars we were visiting. Thus we provided several means for defense. One of these we meant never to use, but we have just used it now.”
     “And that is?” Hazleton said tensely.
     “We would never have told you, except for the coming end,” Miramon said. “You have praised us as chemists, Mayor Amalfi. We have applied chemistry to physics. We discovered how to poison an electromagnetic field by resonance—the way the process of catalysis is poisoned in chemistry. The poison field propagates itself along a carrier wave, and controlling field, almost any signal which is continuous and conforms to the Faraday equations. Look.”
     He pointed out the window. The light did not seem to have lessened any; but it was now mottled with leprous patches. In a space of seconds, the patches spread and flowed into each other, until the light was now confined to isolated luminous clouds, rapidly being eaten away at the edges, like dead cells being dissolved by the enzymes of decay bacteria.
     When the sky went totally dark, Amalfi could see the hundred streamers of the particle streams pointed inward at He; at least it looked a hundred, though actually he could hardly have seen more than fifteen from any one spot on the planet. And these too were being eaten away, receding into blackness.
     The counters went back to stuttering, but they did not quite stop.
     “What happens when the effect gets back to the ships?” Web asked.
     “It will poison the circuits themselves,” Miramon said.
     “The entities in the ships will suffer total nerve-block. They will die, and so will the ships. Nothing will be left but a hundred hulks.”

     Hazleton turned back to the dosimeters. For a moment, he simply stared at them. Then, to Amalfi’s astonishment, he began to laugh.
     “What’s so funny?” Amalfi growled.
     “See for yourself. If Miramon’s people had ever tangled with the Web in the real world, they would have lost.”
     “Why?”
     “Because,” Hazleton said, wiping his eyes, “while he was beating them off, we all passed the lethal dose of hard radiation. We are all dead as door nails as we sit here!”

From The Triumph of Time by James Blish (1958)

Medusa Weapons

This is totally utterly science fictional with no basis in reality, but it is too amusing not to mention. Remember the Greek myth about the Medusa? Anyone unfortunate enough to look at the Medusa was turned into stone, such was her extreme ugliness. The science fictional version is an image on a monitor or a sound over a headphone that can kill.

The general idea is a person suffering physical or mental damage merely by experiencing what should normally be a benign sensation.

The closest thing to this in the real world are the flashing lights that can trigger a seizure in a person suffering from photosensitive epilepsy. But that is not quite the same thing as a medusa weapon. You may have read about the Denno-Senshi Porygon episode of the TV show Pokémon, where the cartoon flashed the TV screen in such a manner that several viewers had seizures. Mention of such a seizure-inducing flash can be found in the novel and movie of The Andromeda Strain. In 2008 there was a photosensitive epilepsy attack on the on-line forum for the nonprofit Epilepsy Foundation.

Examples

Blit

In the story "Blit" and others by David Langford, some scientist, who should know better, invents a graphic pattern called a "basilisk" that will cause the viewer's brain to lock-up, killing the viewer instantly. It works much like a computer virus, crashing the brain's operatining system.

As the FAQ puts it:

...the human mind as a formal, deterministic computational system -- a system that, as predicted by a variant of Gödel's Theorem in mathematics, can be crashed by thoughts which the mind is physically or logically incapable of thinking. The Logical Imaging Technique presents such a thought in purely visual form as a basilisk image which our optic nerves can't help but accept. The result is disastrous, like a software stealth-virus smuggled into the brain.

David Langford
A Scenario

An atomic rocketship of the valiant Space Patrol fires a warning shot across the bow of the sinister black spaceship belonging to the dreaded Necroscientist of Titan. A signal for parlay is sent, and the foolish Patrol captain accepts a videophone message from the Necroscientist in order to discuss terms. Everybody on the bridge within eyeshot of the videophone monitor keels over dead with the Parrot burned into their visual cortex, as the Necroscientist makes good his escape.

The Cassini Division

In the novel by Ken MacLeod, one of the weapons is the so-called "Langford Visual Hack" (an obvious tip-of-the-hat to David Langford). As a defense, all computer monitors on the ship are designed to contain enough visual static to prevent the visual hack from working.

War Against The Rull

In the novel by A.E. van Vogt, the alien Rull can draw the "lines-that-could-seize-the-minds-of-men". Any human who looks at such a diagram is instantly hypnotized, and will just stand there in a trance.

The Black Cloud

In the novel by Fred Hoyle, a helpful intelligent interstellar nebula attempts to teach a human being its native language with remote controlled audio-visual equipment. This proved to be fatal the the person. The trouble is that humans know to be true too many things that actually are not true. They have to un-learn too much in order to learn the alien language, and the cognitive dissonance is fatal (it causes an inflammation of brain tissue).

Macroscope

In the novel by Piers Anthony scientists discover an alien interstellar broadcast that is sort of a galactic library. Unfortunately for the scientists, the broadcast is overlayed with the "Destroyer Sequence." This is a visual sequence that forces the brain to think certain thoughts it is not able to think, which burns out the brain leaving the hapless victim mentally a vegetable.

Kaleidoscope Century

In the novel by John Barnes, a rogue artificial intelligence can call a person up on a telephone, then use rapidly changing audio signals to reprogram the person's brain, turning them into a brainwashed zombie.

Battlefleet Mars

In the wargame by Redmond Simonsen, a top executive of the Ares corporation is assassinated by a sonic pulse over the telephone.

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