Whay would real-life war spacecraft look like?

[Treldon]

First of all, warfare in space is too costly an idea.

If we are talking about a war between (super)nations on Earth, it is a lot easier and cost efficient to get over it out on the ground

And if it is interstellar, then why bother attacking someone else lightyears away? For resources? You can probably find more in unpopulated systems. Space is big

However, should it happen, it would probably be a combination of small drones and large carriers/stations, with kinetic/particle/laser weapons - whichever has better 'cost to bang' ratio at the time

[RainDreamer]

I don't think it is in the interest of any nation in earth to conduct war in space. The kessler effect from all that debris left behind moving at orbital speed would prevent any kind of subsequent space travel in the future for all sides, and war would just have to continue on the ground in the end. Interplanetary war, however, might be different. I imagine there would be little spacecraft-to-spacecraft battles due to difficulty of detecting and catching up with spacecraft moving in space as a lot of people has already mentioned. It would just be mostly spacecraft dropping things (likely huge kinetic payload like an asteroid or an artificial one, which is both hard to destroy when intercepted, and the fragments when destroyed still pose a threat) from orbit to hit planetary targets. And due to the speed involved, neither side will have complete protection from the other's attack. In between two balanced powers, this would just result in mutually assured destruction, like with nuclear weapons today. Whichever side can afford to lose more would be the one that "wins".

[KerikBalm]

Buy what plant would you produce "soft" X-Ray not in laboratory quantities but in megawatts?

...

If they had any idea of producing "soft" X-Ray of megawatt range, they of course would tell the world about this. But as we can presume, they had none.

Free Electron Lasers.

http://en.wikipedia.org/wiki/Free-electron_laser#Military

FEL technology is being evaluated by the US Navy as a candidate for an antiaircraft and missile directed-energy weapon. The Thomas Jefferson National Accelerator Facility's FEL has demonstrated over 14 kW power output.[27] Compact multi-megawatt class FEL weapons are undergoing research.[28] On June 9, 2009 the Office of Naval Research announced it had awarded Raytheon a contract to develop a 100 kW experimental FEL.[29] On March 18, 2010 Boeing Directed Energy Systems announced the completion of an initial design for U.S. Naval use.[30] A prototype FEL system was demonstrated, with a full-power prototype scheduled by 2018.

http://en.wikipedia.org/wiki/Free-electron_laser#X-ray_laser_without_mirrors

Besides, we never had to limit this to current technology, did we?

http://iopscience.iop.org/0953-4075/46/16/164003/pdf/0953-4075_46_16_164003.pdf

The pulse energy was between 2 to 6 Megajoules, which if it was over the length of a second, would be 2-6 megawatts of output... but it was over the length of 5-500 femto seconds, which means the power output in watts for the short length of the pulse... was .... quite high.

*edit* assuming the longest duration of 500 femtoseconds, but also the highest energy output... that would be a 12 exa-watt laser pulse, thats 12,000 peta watts, thats a minimum of 12,000,000 tera watts, thats 12,000,000,000 gigawatts, 12,000,000,000,000 megawatts of power output during the pulse.

Granted, you'd need to get that engergy into the Gigajoules, not Megajoules, to get the type of ranges I've been talking about in this thread....

So far, these things are so big, that they'd have to be "installations", not ship mounted.

So sort of a death star, or some base on the moon/an asteroid, etc.

It remains to be seen how compact they can be made. Given the military is making prototype ADS FEL lasers it suggests they've been able to reduce the technology to a semi-practical scale. The first hard X ray laser was made in 2009, and was just a modification of the old SLAC.

http://home.slac.stanford.edu/pressreleases/2009/20090421.htm

Obviously if the defenders have this... well, your spacewarcraft is going to have to deal with such weapons.

Also of note, is that this would allow direct planet to planet shots.

Earth's atmosphere would protect us... but Mars'?

Asteroid colonies?

Edited November 25, 2014 by KerikBalm

[NASAFanboy]

Why not just use a suborbital missile?

Because this vision of space combat sastifies the fantasies of scifi-geeks. Otherwise in a serious note, no reason to do much beyond on enemy satellites ASAT missiles that are fired from fighter jets in the atmosphere, which also has the same capability. The USAF ASAT missile is fired from a F-15, so we do have that capability.

[Kryten]

Only practical for low orbits, the Chinese ground-mobile system has demonstrated flight to near-GEO.

[Nibb31]

Yeah, but it takes enough time to reach GEO for the target to evade the manoeuvre. It also takes perfect planning to reach a GEO target with a suborbital missile, and the rocket would have to be pretty big, so the launch would be triggering all the cold-war ICBM monitoring systems.

[Kryten]

If you make a target in GEO evade, you've neutralised it.

[Bill Phil]

If you make a target in GEO evade, you've neutralised it.

That's very true.

In fact:

If you can get a vehicle to evade you into another orbit that it's not planned for, it can no longer perform it's mission. That way it's neutralized. Perhaps that's what space combat will be. Forcing them to leave their target orbit at certain times could change everything about the mission.

Say, if a nuclear-armed craft is on an Earth-Mars transfer, and you rendezvous with it, you can force it off its transfer trajectory significantly. And if you last long enough, the nuke ship will run out if propellant.

Sounds more likely than gun to gun battles.

[elfnet]

A real war in space would be a blood bath for both sides. Not to mention the crap that would rain down to Earth what dosent burn up would impact random locations.

It would be quite the light show at night though I think.

It would never be like a war or battle you will see in say star wars or star trek. We simply cannot control physics to that point yet nor be able to for a very very long time.

As it stands now we are not suppose to arm space. but yeah right. Anyone who believes that the USA or any one else has not put weapons or brought weapons to space needs to wake up from the fantasy.

Weapons? Take a normal firearm. What do you think would happen if you fired a 9mm in zero gravity and zero atmosphere... The recoil would most likely propel you back and probably cause you more damage by hitting something than the other person being shot by the bullet. The shell casing also would be propelled out and have enough velocity and be hot enough to burn into something critical or someone else. Every aspect of a firearm is for its intended use on Earth.

So bring on the laser guns... yeah IF and WHEN they figure out how to shrink a lethal powered laser and its power source into something reasonable then ok sure.

Fact is we cannot get away from our habits on Earth with fossil fuels and BS going on 24/7 so anything like this happening in space is completely irrelevant and a long long way off from happening.

[KerikBalm]

Bill Phil - until they start using nuclear reactors to power space craft, and then they have dV to spare for ion drives and other "electric propulsion" system, or even just NTRs

Elfnet - "the recoil would most likely propel you back and probably cause you more damage by hitting something than the other person being shot by the bullet. The shell casing also would be propelled out and have enough velocity and be hot enough to burn into something critical or someone else. Every aspect of a firearm is"

You've got to be kidding me. The recoil from a 9mm fired in space is not going to be harmful to you.

You think recoil doesn't affect you on Earth? you thin air resistance stops you?

No... its just not that much. It will cause you something like less than 0.01 m/s of a change in velocity.

The casing will only be ejected at a few meters/second at most, and it won't do much burning.

It will still lose heat due to black body radation, and its not all that hot to begin with.

Edited November 25, 2014 by KerikBalm

[Capt. Hunt]

I think that having anything on a predictable orbit would be a bad idea, since all your enemies have to do is place an anti-satellite laser/missile battery along your orbital path. Any space based weapons system would have to have massive amounts of Delta-V so it can constantly change orbits or trajectories.

[Explosionsrule]

Well the reason why fighters would have wings in space is for atmospheric flight. Also wings=more weapons which=explosions

[Bill Phil]

Bill Phil - until they start using nuclear reactors to power space craft, and then they have dV to spare for ion drives and other "electric propulsion" system, or even just NTRs

Elfnet - "the recoil would most likely propel you back and probably cause you more damage by hitting something than the other person being shot by the bullet. The shell casing also would be propelled out and have enough velocity and be hot enough to burn into something critical or someone else. Every aspect of a firearm is"

You've got to be kidding me. The recoil from a 9mm fired in space is not going to be harmful to you.

You think recoil doesn't affect you on Earth? you thin air resistance stops you?

No... its just not that much. It will cause you something like less than 0.01 m/s of a change in velocity.

The casing will only be ejected at a few meters/second at most, and it won't do much burning.

It will still lose heat due to black body radation, and its not all that hot to begin with.

Just because that have high ISPs doesn't mean we can't have the same propulsion system, possibly with a higher mass ratio and thus more deltav.

There is a weapon in development with no casings, actually, caseless ammunition has existed for a while, though that's not what I'm referring to.

If I recall correctly, it's a weapon that's a tube with bullets stacked and it uses electricity to ignite the powder.

[peadar1987]

A Kessler syndrome wouldn't necessarily block off access to space, it would just make certain launch sites unusable. If the battle was fought in equatorial orbit, you would still be able to launch from any other latitude, so long as you inserted into a higher orbit. A polar orbit would form debris in bands which covered all latitudes, which is slightly more problematic, but nothing you couldn't deal with by careful timing.

A Kessler syndrome that neutralises all launch sites, all of the time, is incredibly unlikely.

[Brethern]

If you make a target in GEO evade, you've neutralised it.

What if the ones who put the target in GEO anticipated it having to evade? And prepared things accordingly?

[shynung]

Just because that have high ISPs doesn't mean we can't have the same propulsion system, possibly with a higher mass ratio and thus more deltav.

There are technical considerations. For the same thermal power output from a reactor/combustion chamber, one can either get high thrust or high I_SP, but not both. If both is needed, one would increase the reactor/chamber's output, either ruining the mass ratio, or if he added more propellant, maximum acceleration, negating the high thrust capability.

Edited November 26, 2014 by shynung

[Bill Phil]

There are technical considerations. For the same thermal power output from a reactor/combustion chamber, one can either get high thrust or high I_SP, but not both. If both is needed, one would increase the reactor/chamber's output, either ruining the mass ratio, or if he added more propellant, maximum acceleration, negating the high thrust capability.

High thrust isn't entirely necessary on solar system scales.

It will all depend on the craft specifications.

[NERVAfan]

In low Earth orbit, spacecraft will probably be unmanned, like modern spy satellites.

Beyond the Moon, though, I think humans in space probably would be involved somewhere because of signal lag preventing effective remote control and not wanting totally autonomous spacecraft with really powerful weapons. The humans might well be on a mothership a thousand km away controlling drones that do the actual fighting, but they'd be "in the loop", I think.

EDIT: However, by the time there's enough human activity in space to make fighting wars over it worthwhile, the technology will be different enough that the actual design of the ships would be much different from something we'd produce now.

[shynung]

High thrust isn't entirely necessary on solar system scales.

It will all depend on the craft specifications.

In a military situation, high thrust/TWR is a very important consideration. It affects how well a particular spacecraft is able to avoid physical projectiles (anything that isn't a beam weapon). To simplify, the higher Gs the craft can pull, the more likely it is to evade a missile of some sort.

[Bill Phil]

In a military situation, high thrust/TWR is a very important consideration. It affects how well a particular spacecraft is able to avoid physical projectiles (anything that isn't a beam weapon). To simplify, the higher Gs the craft can pull, the more likely it is to evade a missile of some sort.

That's assuming that pieces big enough to be a problem would be untrackable. And if you consider that some kind of armor would be used...

It's much less of a problem than you would think.

[Mitchz95]

I imagine the actual combat ship would be a relatively small, destroyer-type vessel that uses a "carrier" to travel interplanetary distances. The carrier would have everything needed for long-term life support, while the destroyer would be a utilitarian combat vessel with just enough to support the crew for the duration of the engagement (ie, a few days).

[Kryten]

What if the ones who put the target in GEO anticipated it having to evade? And prepared things accordingly?

If you can just as effectively use a moving sat, why use GEO at all?

[kerbiloid]

Free Electron Lasers... FEL technology is being evaluated by the US Navy as a candidate for an antiaircraft and missile directed-energy weapon.

X-ray through the atmosphere?.. Let's await real experiments, not R&D publicity billboards. The weak side of any Xraying is that it is greatly absorbed by air.

(Yes, I understand that you're going to shooting with this through vacuum. But I mean: if they even test this plant, the result could be a little bit disappointing, so looks like this is yet a blueprint & slogans, not a real working technology. )

So far, these things are so big, that they'd have to be "installations"

And probably will stay at this scale.

Edited November 26, 2014 by kerbiloid

[shynung]

That's assuming that pieces big enough to be a problem would be untrackable. And if you consider that some kind of armor would be used...

It's much less of a problem than you would think.

Armor will be designed according to what the spacecraft is supposed to endure, and the rest of the spacecraft will be built around it. Both maximum acceleration, delta-V, and armaments will be considered for the final design, just like today's military jets.

Also, any physical missile fired at a spacecraft doesn't have to be invisible to be problematic. It only needs to chase you around like an attack dog. The purpose of high acceleration capability is to avoid these.

[KerikBalm]

X-ray through the atmosphere?.. Let's await real experiments, not R&D publicity billboards. The weak side of any Xraying is that it is greatly absorbed by air.

(Yes, I understand that you're going to shooting with this through vacuum. But I mean: if they even test this plant, the result could be a little bit disappointing, so looks like this is yet a blueprint & slogans, not a real working technology. )

And probably will stay at this scale.

FEL lasers can produce a large variety of wavelengths, and can easily be tuned to produce different wavelengths.

The military would not be interested in using an FEL to make X rays in the atmosphere.

As far as reducing the size, there are a number of other ways to produce a relativistic electron beam that are much more compact than a linear accelerator like in use at stanford... a dense plasma focus for one.

The Stanford FEL is a retrofit of an existing linear accelerator. It was not designed from the start to be an FEL, nor have they given any consideration to weaponization of it.

But we also have no spacecraft designed for war.

There is nothing inherent in physics that says an X ray laser is impossible (we have them now, even if they are pretty huge)

There is nothing inherent in physics that says you can't focus them (granted, they are approaching the limits)

Thus with sufficient technical development... X ray lasers would become the ultimate spacecraft weapon.