http://www.denbeste.nu/cd_log_entries/2004/04/SpaceNavies2.shtml
(http://tinyurl.com/2xmzr)
(The article is pasted below as well)
His biggest concern seems to be the matter of heat dissipation, which brought to my mind the scene in Heaven's Reach (I think), where the communication (?) laser is used to cool the ship, which is under attack. It's been 5+ years since I read them, and I don't have the books handy, so forgive me if I'm mis-remembering things.
Anyway, does anyone remember how that laser cooling worked? Is that reality-based, or posited on some nonexistent future technology?
The other thing that caught my attention was the discussion that a charged particle beam would actually have to be two opposite polarity beams in order to keep the ship's overall charge neutral. Why is there not a similar concern inside, say, a CRT? Is it because a CRT isn't a closed system as a space ship would be?
Cheers, -Bryon (Now only 250 posts behind on my list-reading!)
Pasted article: ------------------------------------------------------ Stardate 20040419.1157
(Captain's log): So if the characteristics of ships and weapons (http://www.denbeste.nu/cd_log_entries/2004/04/SpaceNavies.shtml) dictate strategy and tactics used in naval encounters, then what would be the critical characteristics of space warships which would be critical?
It depends entirely on what assumptions you make. In most of science fiction, it's convenient to toss the known laws of physics out the window, to a greater or lesser extent, and once you do that the door is wide open and anything can result. My intent is to try to stay more realistic. So I will assume that space navies would still be bound by such tiresome limitations as conservation of momentum, the theory of relativity, and the laws of thermodynamics. I will assume no major changes in our understanding of the universe. That means no "faster than light" drives, no "space warp" or "inertialess" drives, no "subspace" or "hyperspace", and so on.
I will also try to reasonably extrapolate current day technology, and I won't consider anything unless I either know in general how it can be done or know enough about it to believe that it will become possible. That means no energy shields, no "leap cannon", no "high temperature superconductors", and so on.
Willing suspension of disbelief works really well for fiction, but this is not intended to be fiction, or analysis of fiction. It also isn't intended to be a technologist's wet dream, where anything which doesn't violate the laws of physics is permitted. I intend to write about what I think is possible, plausible, and feasible. [Any given reader may disagree with my judgment. Such readers are invited to write and post their own articles to their own web sites, but are not invited to send them to me.]
I also make one critical political assumption: nuclear weapons won't be used in fleet actions because of a tacit agreement by both sides, driven by a fear of escalation. If two competing powers are technologically capable of creating fleets of warships for space, both will have nuclear weapons, and deterrence will prevent their use.
So what are the consequences of such assumptions? The first is this: no "stealth". If one fleet wishes to close with another fleet in order to engage in battle, the second fleet will have ample warning that it is coming.
The primary way ships will detect other ships will be with infrared sensors. Radar and other kinds of detectors will also be used, but IR is superior. Ships will glow in IR frequencies because they will be using energy, and the Second Law of Thermodynamics will therefore force them to be warm. [Yes, it would not violate the laws of physics for a warship to carry a big tank of liquid helium and to use it to cool its entire outer skin to 4� K, but no one is going to do that. Really. It wouldn't break any law of physics, but it isn't technologically plausible, for a variety of reasons.]
IR detection is superb even here on Earth, but the main problem with it is clutter. The thing you want to track is glowing, but there's a whole lot of other stuff around and behind it which is also glowing. But space is conveniently clear of clutter nearly everywhere. Add to that the fact that IR detection is passive, and IR would be the primary sensors by which warships would watch one another. (Nor would a backdrop help; advanced computers could implement what amounted to stereo vision in IR and detect a glowing object standing in front of another. If you are between me and the Earth, I can still pick you out through parallax.)
IR detection can be foxed, but not in any way which equates to invisibility. Rather, it is subject to what amounts to active jamming. That would mean that the enemy would know something was coming and would know in general the direction it was coming from, but might not be able to identify what it was (or how numerous they were) or to figure out a location accurately enough for a weapons lock.
Defensive IR jamming involves flares; bright spots thrown every which way in hopes of distracting an IR-homing missile. But something launching flares isn't "stealthy", and flares won't confuse humans or do a very good job of disguising an attacking fleet.
For that kind of jamming, ("offensive" jamming, if you will) you use "smoke". It would be a cloud of material thrown out around an attacking fleet which would interfere with and disperse the IR signature of ships within it. The biggest disadvantage of smoke is that it blinds both sides equally, but there are ways to work around that. Unfortunately, both sides can use those ways of working around that.
An obvious workaround is sensor drones. A fleet in being would be surrounded by a loose shell of small robotic units containing sensors, engines and radio links back to the fleet. When a http://www.denbeste.nu/cd_log_entries/2004/04/SpaceNavies.shtmlsuspicious bogie was noticed, other sensor drones could be sent to check it out. If it's a moving cloud of smoke, sensor drones could penetrate the smoke to see what was inside. And a drone in a smoke cloud likely would detect a ship inside the cloud before the ship detected the drone and took it out.
At best an attacking fleet could try to disguise its characteristics, but could not prevent the defender from knowing that something was coming, and knowing that it was probably hostile, and there's a good chance the defender could learn a lot more than that.
I don't think "stealth" would even be possible for radar. Modern anti-radar "stealth" technology is actually rather specific. The F-117 relies strongly on the shape of thttp://www.denbeste.nu/cd_log_entries/2004/04/SpaceNavies.shtmlhttp://www.denbeste.nu/cd_log_entries/2004/04/SpaceNavies.shtmlhttp://www.denbeste.nu/cd_log_entries/2004/04/SpaceNavies.shtmlhe ship, with its facets reflecting radar away. The B-2 relies extremely heavily on special materials on its skin which absorb specific radar frequencies. In essence, it's painted "black" at those frequencies. (There's much more to it in both cases, but that's the core of each's "stealth".) However, there's no reason to believe that future radar technology could not develop to the point where such limited counter-measures would be useless.
As the wavelengths used for radar become shorter and shorter they are harder and harder to fool. If the transmitted radar blip is a "glissando" or a "chord" instead of a "single note", that makes it even tougher. Add in sophisticated post processing, including doppler analysis and cross-comparison of physically-separated radars (on several ships and/or sensor drones), and operate the radar at near-millimeter wavelengths (say, 100 GHz or higher), and you can pretty much forget about radar "stealth". Active jamming might still be possible, but that isn't stealthy.
It's also possible to listen for other kinds of electromagnetic emissions, but the point is already made, so I won't go into more detail. Nobody will sneak up on a fleet in being in open space with a shell of detection drones except through subterfuge.
Before we go much further, it's important to discuss the implications of the Second Law of Thermodynamics. Warships will be hot and will have to shed a lot of heat in order to avoid destroying themselves.
There are lot of ways of getting rid of waste heat, and convection is by far the easiest and most convenient. It's what cars use, and what nuclear power plants use, and what our bodies use. A fan moves air past the radiator of a car, and since the radiator is warmer than the air, it is cooled and the air is warmed. The cooling tower of a nuclear reactor sheds heat into cold water, boiling it and turning it into water vapor which is dispersed into the atmosphere. Our bodies shed heat in expelled breath, and through our skins into the air, sometimes aided by sweat.
Unfortunately, in space there's no atmosphere to convect heat into, and you have to rely on radiation. After the Shuttle launches and achieves orbit, it has to open its cargo bay doors, and they stay open until just before it returns. That's because the inner surface of the doors are covered with panels which radiate heat away into space. A coolant circulates between those panels and areas in the ship where energy is being used (and therefore where heat is being created). If the cargo doors cannot be opened, the Shuttle has to land again almost immediately.
The Shuttle is not a very energy-intensive system; it powers itself using fuel cells burning hydrogen and oxygen, at power levels of at most a few kilowatts. Active warships will have nuclear power plants similar to but much larger than the ones used in nuclear submarines, and will often operate at multi-megawatt levels, especially while they are using energy weapons. And a lot of the energy systems I will discuss will utilize energy inefficiently, with almost all the energy applied turning into waste heat which must somehow be dealt with.
Nor is this something which can be solved by better design. Even if every energy mechanism on the ship operates near the theoretical limit of efficiency, there will still be a lot of heat generated. It is physically impossible for any device to utilize energy 100% efficiently without producing any waste heat at all. The Second Law of Thermodynamics doesn't permit it. And as a practical matter, human engineering rarely comes even close. In many systems, 30% efficiency is considered superb, and in some systems it can be as bad as a couple of percent. All the rest of the energy becomes waste heat.
Therefore, warships will require large radiators, and since they will potentially have to dissipate megawatts they'll be very hot during intense operations, likely glowing in visible frequencies.
Radiators would obviously be a favored target for enemy attack. A ship which loses its radiators would have to cease operation beyond minimal levels even if it took no other damage, and it would be impossible to disguise or mask the radiators in any way. (If they're covered, they're no longer radiators. They can only work because they're exposed to open space.)
But I also suspect that some warships might carry a tank of something like liquid nitrogen, to be used convectively during short periods when ship energy use was extreme. (This would be similar to the water a Harrier carries. When the Harrier goes into "hover" mode, the engine has to be overcranked and water is injected into the input air stream to keep the engine from blowing up. A Harrier usually carries enough water to hover for 90 seconds.)
What weapons can we plausibly postulate? The most obvious is missiles, which would carry conventional warheads of some kind. They would be smart, would carry both passive and active sensors, and could carry any of several kinds of warheads. Generally speaking, I see three kinds of warheads as being the most common.
One kind would get close to an enemy fleet and then generate a high-intensity ElectroMagnetic Pulse in hopes of frying enemy electronics. A second kind would use an advanced form of what are now known as "self-forging weapons", directing an extremely high speed stream of liquid metal directly at a ship with the intention of penetrating the hull and damaging what is inside. A third type would fire shrapnel, and would be designed to be used against the radiators of the target ship. But other kinds of warheads might appear in response to development of specific ship technologies, so this is far from being an exclusive list. (For instance, I can conceive of a missile which ends up firing a solid penetrator at an enemy ship.)
Another obvious weapon is high power lasers, megawatt or more beam power. I do not think they would be useful as offensive weapons against enemy ships. For one thing, it would be nearly impossible to keep a laser beam locked to within a couple of centimeters on an enemy ship's hull so that it had time to burn through. Nonetheless, I think that lasers might be used, as defensive systems against incoming projectiles. But lasers generally are extremely inefficient, and the power of the light beam would only be a small percentage of the total energy used, the rest becoming waste heat in the ship. That places distinct limits on how much they could be used and how powerful the beam could be, and in fact it is highly unlikely that they would approach a megawatt of beam power.
Far more useful would be masers. A MASER is much like a LASER except that it operates at microwave frequencies. Generally they will be more efficient, and they could be effective at much lower power levels because the attack mode would be entirely different. A laser would attempt to damage an enemy by localized heating leading to a burn-through, but a maser attack could be an effective way to disrupt the function of enemy electronics systems, or even to destroy enemy electronics entirely.
As anti-missile weapons, a laser would try to burn a hole through the missile. Ideally it would take out something critical, or would puncture a fuel tank, or would set off the warhead. A maser would transmit a somewhat broader beam and would try to generate intolerable levels of EMI (electromagnetic interference) in the guidance circuitry of the missile.
It's not clear that a maser would really be needed. A big phased-array microwave antenna might well be sufficient, if it was capable of transmitting enough power with fine enough angular control (i.e. fine enough phase-delay control over the transmission elements).
Defending electronics against that kind of induced-EMI attack is called hardening and various approaches are used. Encasing it all in metal enclosures helps a lot (especially if it is mu metal), and there are other things which can be done. But this is a case of non-linear scaling, and it is my opinion that the curves favor interference over hardening when it comes to smaller units like missiles. It doesn't take very much induced noise to really louse up electronics badly, and all hardening technologies only serve to attenuate the interference. (Nor would optical computing really help. It would still use electric signals and would still be vulnerable.)
Thus I think space fleets would carry missiles but would generally not find them useful unless fired in such vast swarms as to overwhelm defensive systems. It would be much preferred to find weapons against which defense was more difficult.
Which is why, oddly enough, I think that there would still be a place for some sort of gun. Some guns might be based on mass accelerators, but that requires a lot of power and generates a lot of heat, and it might well be that guns powered by explosive charges (i.e. cannon) might still have a place. Given no air resistance and no gravity-induced trajectory, a cannon might well not even have to be very large in order to be effective. (And given an effective ambient air pressure of zero, the barrel could be particularly long, increasing the muzzle velocity per unit detonation charge.)
If a gun of some kind fired a "dumb" solid penetrator, there's no obvious defense. There would be no electronics for masers to foul up, and a laser couldn't destroy it during the brief travel time to target, even assuming it could lock onto an object that small.
The big disadvantage is that such a projectile would be relatively slow and unguided, and could easily be detected via IR and radar. (Even if it was guided when launched, it would be unguided after defending masers got done with it.) If the fleets operate at great enough range, a ship targeted by enemy gunfire could move out of the way before the projectile arrived, and in any case targeting would be much more difficult. Thus if some ships in warring spacefleets carried guns, then the fleets would fight at long range in order to nullify enemy guns. If they came too close action would be swift and deadly as the gunships fought it out.
Unfortunately, it is not practical to "fill the sky with projectiles" in order to make a long range attack which is impossible to dodge. For instance, some future equivalent of a Claymore Mine might throw out a huge number of projectiles, but they would also be small and slow and less dangerous. The same argument applies to any sort of rapid fire gun. This tactic might not be totally useless but it will not dominate.
The only real way that could be done is with a futuristic equivalent of what was once known as a "fire ship". One of the things the English did against the Spanish Armada in one harbor was to set fire to some ships and send them in under sail without crew (or only minimal crew) to try to crash into Spanish ships. By so doing, the English hoped to get the Spanish to come out for a fight.
A futuristic fire ship would essentially be a monumentally huge missile. The size of a ship, under robotic control, it would rush the enemy and then detonate, spraying an immense amount of shrapnel towards the enemy. But it would have to survive long enough to detonate, which means it might well have a mechanical clock as a backup detonator, just in case all its electronics got knocked out by enemy EMPs or masers.
The big disadvantage of guns (and missiles) is that they use physical projectiles. The ship has to carry them in order to expend them, and weight will always be a premium. I intend to discuss the entire issue of weight later, because it is a major factor in ship design, but for the moment just accept this: weight is bad. If possible, a ship would rather rely on energy weapons if such weapons could be effective.
A high-powered maser might well be able to affect the electronics on an enemy ship, too, and if so that would be the preferred attack. But there's another kind of energy weapon which might turn out to be very useful: charged particle beams.
This would be a particle accelerator of some kind, but not like a research accelerator. The critical characteristic would be current, not voltage; the number of particles, not the energy each carried (and the speed at which it was moving). In terms of a weapon, there's no great advantage in reaching relativistic velocities, but it is essential that the beam be strong.
If I fire a beam of electrons at someone else, it means I'm changing my own charge. Electric charge is one of the more interesting phenomena in the universe because it's one of the few things which is absolute, not relative, and one of the few things which seems to be absolutely conserved. As I fire electrons at an enemy, my ship will become positively charged, and that makes it harder and harder to accelerate the electrons. It's also a real risk later because my ship is now a massively-charged capacitor just waiting to suck electrons from something else when I get close enough.
Basically, it can't be ignored. Like heat, it's something that has to be dealt with. That's why I think that if particle accelerators were used, they'd be used in matched pairs. A ship would carry two, one of which fired electrons and the other of which fired positive ions of some kind, most likely protons (i.e. ionized hydrogen atoms). The ship would monitor its own absolute charge and control the current on the two beams as necessary to keep its own charge near zero.
If you hypothesize a pair of kilo-Ampere beams with particle velocities 5% of C, in parallel a couple of meters apart, then the effect on a metal-hulled ship would be most impressive.
First, this would generate hard X-rays on the inside of the target hull. Depending on the specs of the beams and the thickness of the hull, the resulting radiation levels might well be fatal to humans in a very short time, or could doom them to slow death in hours or days. Such X-rays would also be very unkind to electronics.
Second, beams with such power levels would cause heating of the metal and might be able to burn through given time.
Third, there would be a huge induced current flow between the two impact points, causing further heating.
Fourth, that current flow is going to generate monumentally large amounts of electromagnetic interference inside the ship, which will be radiated inside by the hull itself. It's hard to see how even hardened electronics could continue to operate.
The problem, of course, is aiming. If you're shooting at a ship which is a hundred kilometers away, it's going to be damned hard to score with this kind of beam unless you sweep with it. The question would be how long such a beam-pair would have to be on an enemy ship in order to eliminate it from combat. And the longer the range, the more the beams will spread and the more they'll bend towards one another, because that's how charged particles act. There would definitely be a limit to effective range for this kind of weapon.
Such a beam weapon would also require huge amounts of power and would convert little of that into energy in the beam. The rest would become local heat, and the limiting factor on operation of a weapon of this kind would be how fast you could dump that heat, or otherwise deal with it. That might well make it very difficult to sweep with the beams, if they could only be operated for brief periods, after which the ship would have to wait to cool. (Which is why a ship might carry some quantity of liquid nitrogen or the equivalent.)
Other issues remaining to be dealt with are communications, human crew sizes, propulsion, and the overall question of tradeoffs and mass allocation in ship design. That comes in the next article.
Update: As to the "swarms of missiles overwhelming defenses", it occurs to me that there's a countermeasure. A missile designed to generate an EMP could be used against an incoming missile swarm, and if everything went according to plan would knock out the guidance electronics of nearly every incoming missile in the swarm.
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