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
- 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.
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.
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
EktB = M * 30073.1 * Rf
EmtB = M * 43.0 * 0.7 * Rf
EmtB = M * 30.1 * Rf
- 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.
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.
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.
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).
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
- 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)
- 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%)
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.
Iain Paterson did some calculations which produced some surprising results.
From The Killing Star by Charles Pelligrino and George Zebrowski (you really should read this book):
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.
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.
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:
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.
Jonathan Cunningham notes that sometimes the opposite is true as well.
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?"
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.
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.
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.
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.
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.
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.
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.
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.
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
0.5 0.5 1.0000 0.25 1.00 0.6 0.4 1.0417 0.24 0.96 0.7 0.3 1.1905 0.21 0.84 0.8 0.2 1.5625 0.16 0.64 0.9 0.1 2.7778 0.09 0.36
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:
- Fighting each other, which is not a reason to exist.
- Destroying battle stations, which are only vulnerable to fighters for some reason.
- “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.
Jack Staik has some further observations:
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.
In 2016 things got worse for human fighter pilots. Researchers developed software that (in computer simulations) reliably defeated human pilots.
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:
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:
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:
He went on to say:
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 (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.
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.
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 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.
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.
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.
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.
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
- 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.
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.
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.
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.
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.
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:
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.
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.
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).
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.
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.
In the wargame by Redmond Simonsen, a top executive of the Ares corporation is assassinated by a sonic pulse over the telephone.