Does physics forbid such a device; a heat destroyer

[mfb]

I am highly confident that human emotions and motivations are of crucial importance for the fate and future of humanity.
I do not want to give any estimate for the influence of humanity on the future of the universe, and I do not even have a measure which would allow this.

I don't want to full into a pedantic cycle of physics nit-picking

Where is the problem with large radiators then? It is just an engineering issue, and it is usually fine to assume that those are solved in science-fiction.

 

[Deeviant]

I am highly confident that human emotions and motivations are of crucial importance for the fate and future of humanity.
I do not want to give any estimate for the influence of humanity on the future of the universe, and I do not even have a measure which would allow this.


Where is the problem with large radiators then? It is just an engineering issue, and it is usually fine to assume that those are solved in science-fiction.

The problem is that it doesn't not accomplish the goals I had in mind(I mainly wanted a device that could absorb and convert latent waste heat).

To give you a better picture of what I am working toward, picture this; In the future of spacecraft warfare, all the scenarios I have come up with is that you are completely out of luck as far as defensive systems go. I see no feasible way to create a star trek style "shield", nor any reasonable way to armor a spaceship that would be in any way capable of standing up to even the weapons we could build now, let alone weapons of the future.

Thus, I see only one defense left: stealth. The hulls would be built for stealth, and one important requirement for that would be that the hull would need to cool, specially so it does NOT emit large amounts of highly detectible EM radiation via black-body. And it must remain cool despite housing a large generator of some type inside it.

If anybody has any crazy ideas for possible defensive systems that physics may allow, I would certainly like to hear it, but I could not even think of a system that could sufficiently protect a ship against a large thermonuclear bomb. There just doesn't seem to be any good physics here to grab on too; magnetic shielding would only work against charge particles and requires too much energy anyways, a simply material based approach seems to fail against the furiosity of possible weapons, mirroring might be effective against one of the most obvious space-based weapons(laser) but would completely defeat the stealth idea and would be completely ineffective against kinetic or other more exotic weapons.

So, I would foresee that a futuristic spaceship intent on warfare would somewhat resemble a submarine, not in shape or operation, but in general philosophy. For this reason I imagine a black EM absorbing hull, some method of dumping heat that doesn't act as a beacon, a inertial/kinetic propulsion system as simple as accelerating masses to significant fractions of light (which happens to double as a weapon system).

I have however, conceptualized a few ideas which do bend the rules a bit. For instance:

"Hawking" generators/weapons: Using some unknown process normal matter is condensed and compressed past it's Schwarzschild radius, creating an non-gravitationally induced black hole. Such a small black hole will then almost immediately evaporate via hawking radiation in the form of EM radiation, funny enough this is also a black-body emission. This would allow one to convert mass directly into energy without an matter/anti-matter reaction. I may be wrong, but I assume it radiates energy equivalent to the starting mass as well as the energy introduced via the compression. Other than the obviously enormous challenge of compressing matter to such a degree, I am reasonably sure this idea is in line with accepted physics. Obviously, this would also serve as a tremendous weapon; perhaps have an anti-matter kicker that provides compression energy then resulting in a center mass finding itself within it's own Schwarzschild radius and almost immediately converting itself into extremely hard EM radiation(the temperature of a 500 metric ton black hole would be 2.454406e^17 K, found with this very nice black hole calc ap http://xaonon.dyndns.org/hawking/). Anti-matter is obviously very powerful itself and extremely possible, but has many problems, which the Hawking devices overcome; there is no ready source of anti-matter so it will never be an energy source but rather a most effective means of story and concentrating energy, and anti-matter explosions are nearly as big as you think they would be since it is very hard to get each atom to combine considering the extremely energetic reactor, in fact most anti-matter would likely be wasted with only a small amount actually being converted.

 

[Drakkith]

Well, you could have all ships come with a cooling system that routes the heat to a specific location where and deposited. The resulting radiation is focused into a collimated beam and emitted in a specific direction. Unless you are in the direct line of this beam then you cannot detect it. I can think of a few situations where it would be useful in the book, such as a "lucky break" in detecting an incoming attack by a patrol that by chance stumbles in line of site of this beam.

For defending against nuclear warheads, a laser of some type, perhaps UV or X-Ray could be used for destruction of the warhead before detonation. A nuke in space must be very very close to damage something, as most things in space are many many kilometers away from each other.

 

[Dale]

I have however, conceptualized a few ideas which do bend the rules a bit. For instance:

"Hawking" generators/weapons:

I don't think this is bending the rules as much as you might think: http://arxiv.org/abs/0908.1803v1

 

[Drakkith]

I don't think this is bending the rules as much as you might think: http://arxiv.org/abs/0908.1803v1

That. Is. Cool.

 

[mfb]

Thus, I see only one defense left: stealth.

In this case, I have bad news for you.

You can direct the radiated heat to some extent, but if the enemy is prepared for that the spaceship cannot really hide.

 

[Deeviant]

In this case, I have bad news for you.

You can direct the radiated heat to some extent, but if the enemy is prepared for that the spaceship cannot really hide.

That was an interesting page, with a rather large amount of thought placed into it. However, it really seemed like they came up with a conclusion and then filled in the blanks.

Really though, the only point that I agree with is the black-body radiation is going to be a problem, hence the creation of this thread in the first place. One of the points they seem to keep going back to is that a ship has to have some huge drive plume, this is not at all I how I envision my ship, they will accelerate basically by using a mass driver, which doubles as a weapon. Radar could be easily defeated, a telescope would extremely hard pressed to pick up black ship(which could also have technology to light up it's hull to mimic the background stars behind it).

If push comes to shove, I use a black-body pumped laser and lase the energy out into space in such a narrow beam, a detection systems would simply not be useful. (http://www.freepatentsonline.com/3614663.html).Still though, I want my heat destroyer =/

 

[mfb]

(which could also have technology to light up it's hull to mimic the background stars behind it)

If you know the position of the enemy (and therefore the position on the ship you have to light), which is somewhat strange as you try to make ships invisible (and probably not just the own one). As alternative, you could have light emitters everywhere. In addition, you should try to reproduce the spectrum.

Your mass driver can have a high efficiency, sure. The required high acceleration is not trivial, but might be possible. However, the exhaust is not the main point. As soon as your ship has warm parts, it also needs some blackbody radiation.

 

[Plastic]

what is heat?

radiation? -> photoelectricity.
kinetic energy of a large particle? -> you could annihilate that particle with antimatter and harvest the resulting radiation, destroying the 'heat' in the process.

 

[Dale]

The problem is that it doesn't not accomplish the goals I had in mind(I mainly wanted a device that could absorb and convert latent waste heat).

As described, you cannot absorb and convert latent waste heat to work without a cold reservoir, and even then you are limited by Carnot. However, here are three ideas:

1) They have developed a way to greatly expand their effective surface area for radiation. The bigger the surface area the closer to 2.7 K they can radiate with the radiator serving as the cold reservoir. Since it is slightly higher than 2.7 K the blackbody spectrum would be slightly different, so could still be tracked. But it could be made arbitrarily difficult by making it arbitrarily large.

2) They have developed a way to exchange heat directly with deep space at 2.7 K as the cold reservoir. Although there is no known way to do it, it does not violate the second law of thermo (but it might violate some other laws, I am not sure). In principle, there would still be energy leaving the ship, even if it were at 2.7 K, so there may still be a way to track it.

3) Military ships could be equipped with a material of very high specific heat capacity which is actively cooled down to a few μK (requiring substantial work) during "off duty" times. Then during operations that material could be used as the cold reservoir and the hull kept at 2.7 K without radiating. That would limit the time that they could be stealthed by the amount of time that it would take to heat up the material.

 

[rorix_bw]

I see no feasible way to create a star trek style "shield", nor any reasonable way to armor a spaceship that would be in any way capable of standing up to even the weapons we could build now, let alone weapons of the future. I could not even think of a system that could sufficiently protect a ship against a large thermonuclear bomb.

You do it the same way we do it today. Shoot the missile or jam its radar.

I suggest researching modern warfare especially air and sea. This is almost all electronic now (no more dogfights!). We have both hard and soft kill systems in use today, for preventing missile hits. Modern warships are not significantly armoured in way that World War II ships were, or that tanks are.

Hard kill involves shooting the missile. There are a number of systems for this e.g. AEGIS air defence system on the US Navy "Burke" class Destroyers. This was designed for air defence (against missiles and aircraft) but is now being adapted to defend against ballistic missiles (it has hit them in tests: give it a few more years). The premise of the system is that you fit surface-to-air (SAM) missiles to a ship, add a very sophisticated air defence radar, and theoretically (if it all works, and the crew all do their jobs) you can stop missiles and aircraft from reaching you.

I haven't seen any classified data on this but you can assume it *probably* works as follows: It has 90 missile cells. Each cell holds a single long range surface-to-air missile (SAM), or 4 short range ones (the new ESSM 4-packs). It will shoot 2 of the long range missiles at each incoming air target at about >100km range and each missile *probably* hits 0.5 of the time. At about >50km range it will shoot 2 of the short range ones at any "leakers", with almost certainly higher pH. At point blank range it will use a single RAM missile vs any leaker. In tests, RAM has a 0.9 pH.

I don't know what range they are hitting ballistic missiles at. Ask me again in 10 years. Space combat would probably be extending the ranges.

Soft kill can involve electronic jamming (ECM "Electronic Counter Measures"). For example radar "decoys". These rely on the fact that a missile must somehow be able to find its target by itself (unless you want to put a pilot into it) and do this it has a radar. The radar works by giving off signals that bounce back from the target and by detecing the reflected signals, the device locates stuff. By transmitting "false echos" you can confuse a radar.

An example of such a system is "Nulka". This is a rocket that you launch from a ship, which can hover close to the sea, and gives off signals, making it look, to the small computer and basic radar in a missile, like a ship. Remember that if a missile "misses" it may not be able to turn around and re-attack: Only a small number of modern missiles can turn around for a second go (fuel limit, computer limit, maneuvering limit, G-force breaks the fins off etc) and they can be shot as they turn.

There are also various "ECM" devices that comprise transmitters mounted on the ship itself, that can emit signals, that have the same effect. e.g. "SLQ-32". The large computer on a warship is much smarter than the smaller one on a missile.

More primitive systems used "chaff" which could be described as "reflective confetti" and produced a cloud on the radar that obscured the targets. One even launched a net at the missile (that didn't really work, but in space you might use a gun that shoots a glob of expanding foam or something to catch the missile, then it can have bomb or a TASER or something in the foam cartridge - net projectors certainly have worked in the past). A basic metal grille should stop a missile, if it hits it hard enough to hurt itself ...

Finally, and this sounds crazy, but you also have to locate the target before you can shoot a weapon at it. I don't mean stealth, I mean: Say there's a CVN (aircraft carrier) attacking you, that you want to get rid of. OK, where is it? It's not going to be in sight of the coast as it can strike from over 1,000 kilometers away. (In space, it's painted black and in any case they probably parked it behind the moon and are sending drones out around the moon to attack you. "Behind the moon" is a big place.)

First, your radar and camera satellites don't cover the entire ocean. There are gaps and because their orbits are known, the carrier can sail between them: (no joke, USA used to do this to Russian RORSATS [Radar Ocean Reconnaissance SATellite) but it is harder now with more satellites (a lot harder). However, USA, Russia and China have all demonstrated the abilty to shoot satellites. In space, radar satellites aren't going to be as lopsided as they are on Earth - they will be be just extra spaceships.

Second, the carrier has a sea control zone of several hundred kilometers in any direction created by its air patrols. Your own scouts and satellites entering this zone are certainly going to come under attack well before they cross the "radar horizon" at the point at which they can detect the carrier due to line of sight over the curve of the Earth or in our case "behind the moon". If the scouts have their own radars on, this is even harder as a radar is like a searchlight: The guy you are looking for can detect you very easily by the beam from your searchlight, and will see you before you see him; it's quite easy therefore for him to shoot his rifle at the light then move to a new place - don't stand next to the guy carrying the light - the equivalent to this is a missile that homes in on active radars. There's also missiles that home in on jamming sources - it's a never ending cycle of weapon vs counter-weapon.

Even if your missiles are set for "bearing only launch" with a wide search pattern (Mr Missile, please fly 500 km in direction A then turn on your radar and look for ship targets over 100 meters in length) not only to the missiles themselves also have to survive, and not get their radars turned off, they are as likely to prang an oil tanker as they are the enemy warship. That's probably less likely in space but you never know ... one assumes you will fight for control of planets, and not randomly in deep space.

Finally, if you're in space and using nukes, note that in space, you're going to have land a nuke very close, as there is no atmosphere to create a pressure wave. There's also nothing stopping the other guy using nukes to counter your nukes. He doesn't need to destroy the missile, just damaging its electronic systems is sufficient.

Missiles can evade (modern anti-ship ones do, they are programmed to make radical maneuvers as they near the target to make it harder to hit them) but essentially they have to get within a certain distance of the target so their destination is known, and they do have a big heat source from their engine and a big searchlight on the front called a radar, so they aren't exactly hard to see.

Guns also can be effective against missiles. The reason gun-based defences are being superceeded with electronics and counter-missiles in modern warfare is due to the limited range of guns vs the speed of modern missiles. However, in space with access to lasers and railguns etc, this may be less of a factor. A gigantic "shotgun" may well be able to deal with incoming missiles.

One other thing to consider, you can stick a gun or submunition on a missile. For example a bomb-pumped X-Ray laser. This is supposed to be a nuke that explodes and directs its force forwards via rods that channel the blast; it's sort of a one use laser that doesn't require you to get close to the enemy. Today we have thing like "subroc" which is a missile that launches a torpedo (because the range of a torpedo is limited, and it does not require a separate torpedo system to launch it); many mines also don't explode, but instead launch torpedoes. You could have a single "bus" vehicle that would spit out submunitions - small anti-missile missiles - in the vague direction of any incoming missile.

Some wikis to check out

http://en.wikipedia.org/wiki/Ballistic_missile_defence

http://en.wikipedia.org/wiki/Nulka

http://en.wikipedia.org/wiki/Aegis_Combat_System

http://en.wikipedia.org/wiki/Electronic_countermeasure

http://en.wikipedia.org/wiki/DDG_51

http://en.wikipedia.org/wiki/SLQ-32_Electronic_Warfare_Suite

BTW: I just remembered there have been nuclear tests vs warships. You have to get considerably closer than most people would imagine ... and that's with an atmophere. They have positively pressurised super-structure and decontamination wash-down systems now on warships. I'll to find the results in Google but that is something you may wish to look for.

EDIT: I also remembered the "medium problem". This is "a missile is faster than a sea ship because it moves in the air, and not the sea". But a missile is not significantly faster than an aircraft ... and only recently (e.g. Spearfish @ 70 knots) have torpedoes been faster than ships or submarines.

The Russians actually built a submarine (Akula class - NATO name, Russian "Akula" is a different class) with sufficient speed to outrun the American torpedo of the same period, and the American SR-71 "blackbird" airplane was able to outrun anti-aircraft missiles. The actual missile had similar speed to the plane, but since the missle had to close, if the aircraft saw it and altered course, it would pass behind.

 

[Deeviant]

As described, you cannot absorb and convert latent waste heat to work without a cold reservoir, and even then you are limited by Carnot. However, here are three ideas:

1) They have developed a way to greatly expand their effective surface area for radiation. The bigger the surface area the closer to 2.7 K they can radiate with the radiator serving as the cold reservoir. Since it is slightly higher than 2.7 K the blackbody spectrum would be slightly different, so could still be tracked. But it could be made arbitrarily difficult by making it arbitrarily large.

2) They have developed a way to exchange heat directly with deep space at 2.7 K as the cold reservoir. Although there is no known way to do it, it does not violate the second law of thermo (but it might violate some other laws, I am not sure). In principle, there would still be energy leaving the ship, even if it were at 2.7 K, so there may still be a way to track it.

3) Military ships could be equipped with a material of very high specific heat capacity which is actively cooled down to a few μK (requiring substantial work) during "off duty" times. Then during operations that material could be used as the cold reservoir and the hull kept at 2.7 K without radiating. That would limit the time that they could be stealthed by the amount of time that it would take to heat up the material.

Ok, I think I am still managing to misunderstand you. You say we can not exchange head directly with deep space this day, but my understanding is: it happens for free via black body. The ISS is current exchanging heat directly with deep space right now as we speak, is it not? Or are you taking about some other sort of mechanism, I don't understand what you mean by "is no known way to do it".

@rorix_bw:

I think you are thinking too much in terms of today's battle scenarios. Think of a perfected electro-magnetic slug shooter a future ship may pack; let's say this thing accelerates a slug to 99.99% C. Then let's say it fires a slug at your ship the same instant a photon bounces off the ship and heads your way; the slug would only be a bit behind and that photon hitting your ship would be the first moment you could even possibly realize the ship fired a projectile at you in the first place, let alone avoid it somehow. For all intents and purposes, the thing would be like a laser that shoots bullets. Prototypes for this type of weapon technology exist today, albeit at much slower velocities(although they have to deal with air resistances and a ship obviously would not). And the thing is, I don't even think the future ship would use a railgun but something far worse that we haven't thought up of yet, my point is if beefed up versions of today's technology already defeats any kind of defense I can dream up; then defensive ship technology has only one fallback: stealth.

 

[Dale]

Ok, I think I am still managing to misunderstand you. You say we can not exchange head directly with deep space this day, but my understanding is: it happens by for free via black body. The ISS is current exchanging heat directly with deep space right now as we speak, is it not? Or are you taking about some other sort of mechanism, I don't understand what you mean by "is no known way to do it".

Sorry, I was definitely unclear there. I meant that there is no way that I know of to directly use deep space as a 2.7 K cold reservoir in a heat engine.

 

[Deeviant]

Sorry, I was definitely unclear there. I meant that there is no way that I know of to directly use deep space as a 2.7 K cold reservoir in a heat engine.

I think most space probes use the 2.7 K cold reservoir in a heat engine today. I.E. the voyager probes use a plutonium powered thermopile. Plutonium heats up one side of a peltier device and the other side is cooled via black body directly into space.

 

[rorix_bw]

Gaussian Beam

While composing a reply I was wondering if someone knows: is a gaussian beam the best you can focus a laser to? Can you actaully focus it better than this so it retains its full intensity (same beam width) over a longer distance? Wikipedia isn't clear on this, it only says that some lasers can be gaussian. I know I don't have to link to here, as many guys will know already, but I provide for convenience so you can see what I read, not what the truth is :-)

http://en.wikipedia.org/wiki/Gaussian_beam

 

[rorix_bw]

1) Think of a perfected electro-magnetic slug shooter a future ship may pack; let's say this thing accelerates a slug to 99.99% C.
2) Then let's say it fires a slug at your ship the same instant a photon bounces off the ship and heads your way; the slug would only be a bit behind and that photon hitting your ship would be the first moment you could even possibly realize the ship fired a projectile at you in the first place
3) my point is if beefed up versions of today's technology already defeats any kind of defense I can dream up; then defensive ship technology has only one fallback: stealth

I will address the last point first. You cannot envisage a defence because modern military hardware is complex enough to no longer be obvious to one who has not studied them. Now I am not saying that it must be this way and that modern systems will work in space, but it's clear to me there's large difference between how the average person envisages defences work, and how they actually work.

For point (1), I see you changed to "impulseguns" from nuclear missiles? Well at least we're helping :-)

Thinking laterally (or again copying from modern design) you do not have to absorb the full energy of a projectile to stop it.

Whatever you make the projectile out of, someone can make armour out of, and it will most likely cause both to shatter on impact - in general, you need to be harder than something to survive striking it. Now you need to decouple the armour from the vehicle so you don't have to eat the added momentum of the surviving parts of the projectile that don't bounce off your (obviously curved) armour due to hitting at an angle.

In space we can launch a plate of armour metal, and drift along behind it. Get a drone to drive it perhaps (or maybe you can use a collapsible bracket or electromagnet). This de-coupling should provide protection against the initial salvo. You might get fragments depending on the angles of the hit and the angle your armour plate is at, but that's why you have a second layer of armour. (This system of 2 plates with a gap, with the outer plate shattering hard rounds, resembles some types of modern tank armour - the spaceship difference is that we don't need to attach the inner plate to the outer plate, so we have no momentum transferred on a hit)

As for point (2) I regard a faster than light detection system as cheating in the scenario you defined. The earliest you can fire is when you receive a reflection - with perfect "optics" both ships can in theory simultaneously detect each other and shoot at the same time. (Unless one side is invisible, which is already how it works today if the sides are mismatched).

You're going to have decide what your space combat ranges are and how fast a ship can maneuver. I am assuming no human crew on the combat units (because sci-fi, and the next generation of fighter planes built here on Earth will be pilotless) so the 9G acceleration limit on consciousness isn't relevant. (Maybe just a few techs and leaders in a command unit, everything else is robot)

If you're fighting at close ranges you need to explain how you got there past all the robofighters and missiles. If you're fighting at long ranges you probably aren't using a gun. Earth to Moon is 0.04 light seconds? Probably no chance of target dodging there, but how big is the ship and even a laser will gradually diffuse? (actually that's an interesting question ... i will pose separately)

The defence there is the same as it probably always will be, use decoys, maneuver erratically and use stealth. With so little time to identify and get a shot off, and such tiny targets, something like coming in with the sun behind you in a cloud of (mirrored?) drones might actually work. Decoys sound stupid but they do work. Really they're just another form of camoflauge, which is just another form of stealth. It's way of saying "I am not here" or "congratulations, you have more targets than guns. how lucky are you?"

Anyway stuff to think about. No-one can predict the future of spacewar but you should at least read up on current systems, since otherwise your book is going to be World War II in space.

 

[Dale]

I think most space probes use the 2.7 K cold reservoir in a heat engine today. I.E. the voyager probes use a plutonium powered thermopile. Plutonium heats up one side of a peltier device and the other side is cooled via black body directly into space.

The cold side of the junction is warmer than 2.7 K.

 

[Deeviant]

I will address the last point first. You cannot envisage a defence because modern military hardware is complex enough to no longer be obvious to one who has not studied them. Now I am not saying that it must be this way and that modern systems will work in space, but it's clear to me there's large difference between how the average person envisages defences work, and how they actually work.

For point (1), I see you changed to "impulseguns" from nuclear missiles? Well at least we're helping :-)

Thinking laterally (or again copying from modern design) you do not have to absorb the full energy of a projectile to stop it.

Whatever you make the projectile out of, someone can make armour out of, and it will most likely cause both to shatter on impact - in general, you need to be harder than something to survive striking it. Now you need to decouple the armour from the vehicle so you don't have to eat the added momentum of the surviving parts of the projectile that don't bounce off your (obviously curved) armour due to hitting at an angle.

In space we can launch a plate of armour metal, and drift along behind it. Get a drone to drive it perhaps (or maybe you can use a collapsible bracket or electromagnet). This de-coupling should provide protection against the initial salvo. You might get fragments depending on the angles of the hit and the angle your armour plate is at, but that's why you have a second layer of armour. (This system of 2 plates with a gap, with the outer plate shattering hard rounds, resembles some types of modern tank armour - the spaceship difference is that we don't need to attach the inner plate to the outer plate, so we have no momentum transferred on a hit)

As for point (2) I regard a faster than light detection system as cheating in the scenario you defined. The earliest you can fire is when you receive a reflection - with perfect "optics" both ships can in theory simultaneously detect each other and shoot at the same time. (Unless one side is invisible, which is already how it works today if the sides are mismatched).

You're going to have decide what your space combat ranges are and how fast a ship can maneuver. I am assuming no human crew on the combat units (because sci-fi, and the next generation of fighter planes built here on Earth will be pilotless) so the 9G acceleration limit on consciousness isn't relevant. (Maybe just a few techs and leaders in a command unit, everything else is robot)

If you're fighting at close ranges you need to explain how you got there past all the robofighters and missiles. If you're fighting at long ranges you probably aren't using a gun. Earth to Moon is 0.04 light seconds? Probably no chance of target dodging there, but how big is the ship and even a laser will gradually diffuse? (actually that's an interesting question ... i will pose separately)

The defence there is the same as it probably always will be, use decoys, maneuver erratically and use stealth. With so little time to identify and get a shot off, and such tiny targets, something like coming in with the sun behind you in a cloud of (mirrored?) drones might actually work. Decoys sound stupid but they do work. Really they're just another form of camoflauge, which is just another form of stealth. It's way of saying "I am not here" or "congratulations, you have more targets than guns. how lucky are you?"

Anyway stuff to think about. No-one can predict the future of spacewar but you should at least read up on current systems, since otherwise your book is going to be World War II in space.

To be honest, I'm really not picking up what you're putting down. There is no material that can successful absorb the energy of a .99 C projectile of any significant mass, and your idea of some sort of "decoupled" armor is laughable, you'd have to know where I am in order to put it "in line" with my attack vector; I already said I'm focused on stealth. To put it into perspective, a 1 kilogram projectile traveling at .99 C represents 10.52 MEGATONS of energy, there is NO material conceivable that will be able to withstand that much energy.

It's strange that you basically said I was wrong, then agreed with me; "The defence there is the same as it probably always will be, use decoys, maneuver erratically and use stealth". Maneuverability isn't going to happen, it takes too much energy and mass for a ship of any decent size to rapidly change velocity, decoys are only useful AFTER you have been discovered else you will just give away your general position, that leaves one thing: stealth. As for you WWII in space, that is exactly what I foresee; a scenario similar to WWII submarine warefare.

 

[Drakkith]

To be honest, I'm really not picking up what you're putting down. There is no material that can successful absorb the energy of a .99 C projectile of any significant mass, and your idea of some sort of "decoupled" armor is laughable, you'd have to know where I am in order to put it "in line" with my attack vector; I already said I'm focused on stealth. To put it into perspective, a 1 kilogram projectile traveling at .99 C represents 10.52 MEGATONS of energy, there is NO material conceivable that will be able to withstand that much energy.

Perhaps, but there is no way to accelerate a 1 kg mass to 0.9999c using a single launcher either. It require extremely hard acceleration for a very long period of time to get up to speed using a propulsion system. It takes the LHC almost an hour to accelerate protons up to their top speed, and this is using multiple stages of circular accelerators that are kilometers long, and you're talking about something many orders of magnitude larger. It isn't feasible at all.

 

[mfb]

Well, the LHC needs ~30min because the bending magnets have to be ramped up. Acceleration itself could be done within milliseconds. You will not see bending magnets at the acceleration of macroscopic objects.
However, large objects have serious issues with the maximal acceleration. Acceleration to relativistic velocities within reasonable length (not several million kilometers) is impossible today, and this is not just an engineering issue.

 

[rorix_bw]

There is no material that can successful absorb the energy of a .99 C projectile of any significant mass ... To put it into perspective, a 1 kilogram projectile traveling at .99 C represents 10.52 MEGATONS of energy, there is NO material conceivable that will be able to withstand that much energy.

I said you don't have to absorb all of it. If it breaks up when it hits something floating in space (not attached to your ship) made of the same material as it, it doesn't matter as much.

Your idea of some sort of "decoupled" armor is laughable, you'd have to know where I am in order to put it "in line" with my attack vector;

Put it all around like a cage. I found some photos down the bottom of the modern version of this. It is not decoupled from the vehicle but that is the tech advancement I was proposing for "space wars". A little drone computer to control a bunch of metal plates with engines. Or you can electromagnet them? BTW I know this doesn't stop hard rounds (it's for RPG and other "plasma jet" weapons - don't know if a physict would call it a plasma, but it is a jet of hot, vapourised metal), but that's the not point: the point is "it's a cage" and it's a cage because they can't predict which side will get shot at.

http://farm1.static.flickr.com/137/407807009_84d10d122f.jpg
http://media.defenseindustrydaily.com/images/LAND_RG-31_LROD_Armor_lg.jpg

It's strange that you basically said I was wrong, then agreed with me; "The defence there is the same as it probably always will be, use decoys, maneuver erratically and use stealth".

No you said stealth was the ONLY defence. That's not identical to what I said.

As for you WWII in space, that is exactly what I foresee; a scenario similar to WWII submarine warefare.

Getting off topic here, but I don't agree there either: WW2 submarines preferred to attack while surfaced and in most cases weren't able to fight a warship - they were typically sent after mechants instead.

 

[Deeviant]

Perhaps, but there is no way to accelerate a 1 kg mass to 0.9999c using a single launcher either. It require extremely hard acceleration for a very long period of time to get up to speed using a propulsion system. It takes the LHC almost an hour to accelerate protons up to their top speed, and this is using multiple stages of circular accelerators that are kilometers long, and you're talking about something many orders of magnitude larger. It isn't feasible at all.

To be honest, an engineering problem is exactly what it is. Given a few thousand years, I think it would be foolish to say that any complex engineering problem could not be solved. In the end though, it doesn't matter. It could simply be a gamma laser. Anything armoring that would defend against a laser, would make it less stealthy. The bottle line is a ship is going to have to contend with relativistic weaponry.

I said you don't have to absorb all of it. If it breaks up when it hits something floating in space (not attached to your ship) made of the same material as it, it doesn't matter as much.

Put it all around like a cage. I found some photos down the bottom of the modern version of this. It is not decoupled from the vehicle but that is the tech advancement I was proposing for "space wars". A little drone computer to control a bunch of metal plates with engines. Or you can electromagnet them? BTW I know this doesn't stop hard rounds (it's for RPG and other "plasma jet" weapons - don't know if a physict would call it a plasma, but it is a jet of hot, vapourised metal), but that's the not point: the point is "it's a cage" and it's a cage because they can't predict which side will get shot at.

As I already said, the amount of energy released by a host of possible future space weapons is far too great for a material based armor approach. Stealth IS the only defense.

 

[Drakkith]

To be honest, an engineering problem is exactly what it is. Given a few thousand years, I think it would be foolish to say that any complex engineering problem could not be solved.

An engineering problem? It is FAR more than that. To be honest I don't see any point to this thread any more. You have your answers to your initial question and most of the thread has simply been argument on non-existent weaponry and defensive measures. I don't see it going anywhere else so I am done.

 

[Aero51]

In response to the origonal post, you can actually use targeted sound waves to heat small areas to very high temperatures. This is currently being researched as a method to destroy tumors in "hard to reach" locations.

 

[Deeviant]

An engineering problem? It is FAR more than that. To be honest I don't see any point to this thread any more. You have your answers to your initial question and most of the thread has simply been argument on non-existent weaponry and defensive measures. I don't see it going anywhere else so I am done.

Right, because we have never heard of a laser before, that's totally crazy. And it would be foolish to even think a few thousand years of human advancement could yield a serviceable relativistic mass-driver, which funny enough is just about lowest tech "high-tech" weapon in common sci-fi use.

Perhaps you just don't like that fact I don't agree with you. Anyways, the thread will end when the responses do. As far as the point of the thread it is obviously useful for me to discuss these things with others and experience different viewpoints, even if I do not agree with all of them, this is how learning works.

 

[mfb]

If weapons are just an engineering problem (they are not*), what is different in defense?

*relativistic mass-drivers are somewhere between "limit of physics" and "limits of engineering". For electrostatic acceleration, you hit the physical limit of electric arcs quite soon. Pure magnetic acceleration hits similar limits in field strength and gradient. Electromagnetic interaction similar to railguns might achieve higher accelerations, but you need a direct contact between projectile and the gun, which gives serious issues with relativistic velocity. In addition, I think you will need superconductors to get a reasonable current density in the projectile. This limits the allowed temperature of the contact. It is an engineering issue, but a serious one as you have physical limits everywhere and you have to go around them.
1000km^2 of solar cells? Engineering problem. Disassembly of a planet? Engineering problem. Relativistic mass-driver? Problematic.

 

[Dale]

Yes, but the standard in hard sci-fi is just that it not violate any known physical laws. Anything else, including things between the limit of physics and the limits of engineering, is considered fair game. So a relativistic mass driver would be appropriate provided merely that conservation of energy and momentum is not violated.

However, I agree in principle with the "what is different in defense" premise. Stealth would certainly be an important defense, but not the only one.

 

[rorix_bw]

As I already said, the amount of energy released by a host of possible future space weapons is far too great for a material based armor approach. Stealth IS the only defense.

I disagree for a number of reasons, many already stated.

Now what about over-penetration?

What happens if you shoot a car with a really big, slug firing weapon, like a tank gun?

That should annihilate the car, right?

Well no. Slugs are not explosive. It will strilke the window, or door, pass straight through the car, and go out the other side. The window is weak enough that it won't be able to receive more energy from the bullet than is required to break the glass. I wouldn't like to be sitting in that car, but many of the occupants will survive the broken window glass and the vehicle will probably still be drivable.

Hunters know this too: over-penetration of targets is a consideration.

So if you're using a solid round, your target must have sufficient mass to convert its energy. For example if you instead hit a tank with that, instead of a car, it would indeed "stop" the bullet, and the impact of the bullet could physically explode the tank. (So you have 2 ammo types: explosive for unarmoured targets, and slugs for armoured).

So what if:

(a) They depressurise the ship before combat, and get into space suits. No "explosions" from explosive decompression and no fires. Yes wearing space suits INSIDE a ship doesn't sound very scifi, but you wanted realism.

(b) The spacecraft is large, but with dispersed components? It might consist of a 100 meter long "ladder frame" with the components placed on the ladder at 10 meter intervals, and (depressurised) living areas between them. No armour at all.

Now any hit from a slug weapon, that did not hit and break the frame, would either only annihilate one module, or pass through the module, depending on the contents of the module. Sure you might a hit a reactor! But the ship has two! And if not a reactor, chances are you drill through an unused crew bunk and nothing else.

At this point you realize that you need explosives or a some kind of shotgun. Then you have to work out how to build a detonator, or a shotgun mechanism that can survive "impulsegun" velocities.

It's really not as simple as you think it is. Also weapons vs defences is a constantly evolving battle and you might be in a situation where you have 2 enemies each with a difference defence, and each requires a different weapon to counter.

Also I still want to know what you're going to do about people floating the armour in a cage around the ship, or people using decoys.

 

[bahamagreen]

Have you not read "The Gods Themselves" (1972) by Isaac Asimov?

You want to employ a mechanism whose conception is yet outside known science, so you need to refer your basis to an interpretation that comes from known science but is not yet known to be true or false.

The arguments against your idea are based on thermodynamics and conservation in a closed system... explore a way to employ the parallel worlds interpretation of QM to override these problems.

Your basis will then have plausible deniability for as long as it takes science to settle on one interpretation of QM...

 

[Deeviant]

Yes, but the standard in hard sci-fi is just that it not violate any known physical laws. Anything else, including things between the limit of physics and the limits of engineering, is considered fair game. So a relativistic mass driver would be appropriate provided merely that conservation of energy and momentum is not violated.

However, I agree in principle with the "what is different in defense" premise. Stealth would certainly be an important defense, but not the only one.

I would love to hear a physics abiding defense against a relativistic projective.

 

[Dale]

I would love to hear a physics abiding defense against a relativistic projective.

I actually don't think that relativistic projectiles would be that effective for the reasons that rorix_bw gave above. Build a ship with redundant systems and fast repair robots; the slug goes right through and you patch the hole.

However, if you want something more exotic, then gravitational lensing could completely protect against all weapons which travel on geodesics. So that would include relativistic projectiles, lasers, and all other beam weapons. You would only be vulnerable to missiles and other self-propelled weapons.

 

[Deeviant]

I actually don't think that relativistic projectiles would be that effective for the reasons that rorix_bw gave above. Build a ship with redundant systems and fast repair robots; the slug goes right through and you patch the hole.

However, if you want something more exotic, then gravitational lensing could completely protect against all weapons which travel on geodesics. So that would include relativistic projectiles, lasers, and all other beam weapons. You would only be vulnerable to missiles and other self-propelled weapons.

A relativistic projectile would initiate a fusion reaction on contact. It would literally hit with the force of a hydrogen bomb...

Your gravitation defense is an interesting angle though. I think the biggest problem I foresee is that most defensive systems seem to amount to a huge amount of of mass (armor/material/gravitation/etc), and in space, acceleration does not come easy(I do not see an inertial-less engine in the future), so the weight would come at a huge cost of energy and the telltale energy emissions. As a somewhat tangential corollary, I see no effective way to protect a planet; a planet is the last place you would want to be in the case of intergalactic war.

 

[Deeviant]

Have you not read "The Gods Themselves" (1972) by Isaac Asimov?

You want to employ a mechanism whose conception is yet outside known science, so you need to refer your basis to an interpretation that comes from known science but is not yet known to be true or false.

The arguments against your idea are based on thermodynamics and conservation in a closed system... explore a way to employ the parallel worlds interpretation of QM to override these problems.

Your basis will then have plausible deniability for as long as it takes science to settle on one interpretation of QM...

I haven't, I'll take a look at The Gods Themselves, thanks.

 

[Dale]

A relativistic projectile would initiate a fusion reaction on contact. It would literally hit with the force of a hydrogen bomb...

Yes, the energy and force is on the order of a nuclear weapon, but the momentum is vastly different. The point is that you are focusing on the former and neglecting the latter, which tends to decrease the effectiveness.

Your gravitation defense is an interesting angle though. I think the biggest problem I foresee is that most defensive systems seem to ...

That is an engineering problem. If future tech can be allowed to solve the engineering problems of offense then "what is different in defense"? Particularly considering that we can already build bunkers to withstand a nuclear attack.

 

[rorix_bw]

Clearly the best solution is not to be stupid enough to start a war in the first place.

edit: I actually think the future of this is a swarm of smaller drone-controlled units that can somehow co-ordinate their actions. I believe it's already a given that "human" pilots are history. This is however not fun to write about.