Is space warfare really practical except lasers?

 Pages 1 2 3 4 NEXT
 

I started watching Outlaw star today and it made me think about ships shooting each other, or more likely how impractical it is outside fiction. To paraphrase the hitchhickers guide-"space is really big", any kinetic weaponary is absurdly slow compared to the distance between vessels, missiles need to have a nuclear core and engine just to get close to speed of the ships and even then it's too slow, only lasers seems fast enough to be practical (and even that at "short range" of 10000+ miles). The only other weaponary I think of is straight up teleporting a bomb inside the ship.

Your thoughts?

inu-kun:
missiles need to have a nuclear core and engine just to get close to speed of the ships

Er...no they don't, not if they are on fast moving ships themselves until they are fired.

inu-kun:
The only other weaponary I think of is straight up teleporting a bomb inside the ship.

Hey? There is a massive jump between lasers and teleporters (as we think of them). For example, before you work out how to convert matter into energy, send it away and convert it remotely again back into the original object, you'd end up being able to do everything except the last bit.

That is, convert the bomb to energy, send it to the target and just release it. Your bomb is not going to be more powerful than that, because the matter is going to be totally converted to energy, which is as efficient as it gets. Though, if you send anti-matter, you also convert an equivalent amount of matter, I guess.

(You might have teleporters that work in other ways, such as opening a tunnel through the Warp or whatever though)

...

But yeah, in general, space combat would not be like how it is in the movies. If you want to have a movie about stuff which works like WW2 aircraft carrier groups fighting each other, have a movie about WW2 aircraft carrier groups. Hell, why not some alien planet at WW2 ish levels of technology?

thaluikhain:

inu-kun:
missiles need to have a nuclear core and engine just to get close to speed of the ships

Er...no they don't, not if they are on fast moving ships themselves until they are fired.

The science is abit wonky, but if the ship is already on collision course with another ship firing a regular missile will make the missile only fractionally faster (something like, if the ship 0.8c, and the missile is 0.1c it's relative speed is 0.81~ if I remember my physics well), it's fast but involves your ship trying to ram the other ship.

inu-kun:
The science is abit wonky, but if the ship is already on collision course with another ship firing a regular missile will make the missile only fractionally faster (something like, if the ship 0.8c, and the missile is 0.1c it's relative speed is 0.81~ if I remember my physics well), it's fast but involves your ship trying to ram the other ship.

Oh, sure, if you are traveling at close to light speed, you get weird effects like this.

However, once you can propel ships at close to light speed, why not projectiles like bullets? Or the missile itself, give it a boost on the way out, so to speak.

Also, you don't have to try to ram the other ship. You can be going towards it at great speed, but that doesn't have to be directly towards it. And that's assuming travel in s straight line.

I'd recommend looking at this:

http://www.projectrho.com/public_html/rocket/

Lots of good stuff there.

Space warfare isn't only practical, it's more so then on Earth. Think about it, be it against a planet, moon, station or ship, you can use either missiles with more ease then on Earth (no air resistance) and you can just take a piece of mass and slug it towards your target from, frankly, anywhere. And if you use constant acceleration, the potential energy of some of those slugs of mass could be ones that have a discharge that put the Tsar Bomba to shame.

Anyone else thinking 'lasers are overrated, whatever happened to railguns'?

Yeah... railguns are a more practicable choice of primary weapon on space-faring warships. I think (THINK, please note, I don't know) that for the energy input required to fire/operate a railgun, it provides a great deal more destructive power than a laser. Plus, the energy dissipation from a laser means its effective range is kinda crap... or something along those lines...

SckizoBoy:
Anyone else thinking 'lasers are overrated, whatever happened to railguns'?

Yeah... railguns are a more practicable choice of primary weapon on space-faring warships. I think (THINK, please note, I don't know) that for the energy input required to fire/operate a railgun, it provides a great deal more destructive power than a laser. Plus, the energy dissipation from a laser means its effective range is kinda crap... or something along those lines...

This is pretty spot on. Lasers do have their uses, but mainly as defensive weapons for anti-missile use. Railguns all the way. Those things will flatten a planet.

Space warfare will require a lot of mathematics if it ever becomes a thing. The best weapon is something that can travel really fast relative to another object and that will collide with it. If you can get a 2cm cube up to ~2km/s relative to your target, that is going to cause some serious damage, and also be impossible to detect compared to a missile. Basically warfare will be pre-planned and possibly quite covert, it's pretty easy to deny that you used a weapon like that.

Zontar:
Railguns all the way. Those things will flatten a planet.

Er...very big railgun to do that.

Zontar:
Space warfare isn't only practical, it's more so then on Earth. Think about it, be it against a planet, moon, station or ship, you can use either missiles with more ease then on Earth (no air resistance) and you can just take a piece of mass and slug it towards your target from, frankly, anywhere. And if you use constant acceleration, the potential energy of some of those slugs of mass could be ones that have a discharge that put the Tsar Bomba to shame.

Against a planet or moon that can't maneuver, yes. People hit the correct part of Mars with probes every so often.

Against something that doesn't want to be hit, not so much.

(Also, if your ship is powerful enough to conveniently travel between planets, it's powerful enough to make a hell of a mess when it gets there. You don't need any sort of weapon beyond the ship itself).

One serious problem, though, is that there's no horizon and almost nothing to hide behind. Everyone can see you at all times.

SckizoBoy:
Anyone else thinking 'lasers are overrated, whatever happened to railguns'?

Yeah... railguns are a more practicable choice of primary weapon on space-faring warships. I think (THINK, please note, I don't know) that for the energy input required to fire/operate a railgun, it provides a great deal more destructive power than a laser. Plus, the energy dissipation from a laser means its effective range is kinda crap... or something along those lines...

Zontar:

This is pretty spot on. Lasers do have their uses, but mainly as defensive weapons for anti-missile use. Railguns all the way. Those things will flatten a planet.

Not even close.

The problem with space warfare is that everyone can see everyione else from very, very far away. As in, the tiny attitude thrusters on the Space Shuttle can be seen from the Asteroid belt. Any kind of massive nuclear engine will be seen from basically anywhere in the solar system, and a large antimatter rocket could poossibly be seen from the next few star systems over.

If you used a railgun at laser range distances, it can be easily dodged. By the time you get close enough to the enemy to effectively use a railgun, their laser would have torn you apart.

On the other hand, if you could use a railgun to accelerate a number of missiles, probably kinetic or nuclear, to a decent speed, they could quite easily wither didge enough laser to get thouogh, or simply force the enemy lasers into overheating, then getting in and landing a kill-hit.

Otherwise, railguns simply don't fire fast enough to compete with lasers.

inu-kun:
I started watching Outlaw star today and it made me think about ships shooting each other, or more likely how impractical it is outside fiction. To paraphrase the hitchhickers guide-"space is really big", any kinetic weaponary is absurdly slow compared to the distance between vessels, missiles need to have a nuclear core and engine just to get close to speed of the ships and even then it's too slow, only lasers seems fast enough to be practical (and even that at "short range" of 10000+ miles). The only other weaponary I think of is straight up teleporting a bomb inside the ship.

Your thoughts?

It depends.

How many missiles are we thinking? Plain chemical warheads acan get to rather fast speeds, and if firing a load of missiles forces the enemy to retreat, well, that's an effective tactic. You could also use kinetic weapons to force enemy lasers tio waste time and heat-sink on zapping them rather tha you.

Da Orky Man:

Not even close.

The problem with space warfare is that everyone can see everyione else from very, very far away. As in, the tiny attitude thrusters on the Space Shuttle can be seen from the Asteroid belt. Any kind of massive nuclear engine will be seen from basically anywhere in the solar system, and a large antimatter rocket could poossibly be seen from the next few star systems over.

If you used a railgun at laser range distances, it can be easily dodged. By the time you get close enough to the enemy to effectively use a railgun, their laser would have torn you apart.

On the other hand, if you could use a railgun to accelerate a number of missiles, probably kinetic or nuclear, to a decent speed, they could quite easily wither didge enough laser to get thouogh, or simply force the enemy lasers into overheating, then getting in and landing a kill-hit.

Otherwise, railguns simply don't fire fast enough to compete with lasers.

That assumes the use of technology to observe things that is far beyond what is possible at the moment or even within sight though. People say space is empty, but there's plenty of things in our system that a ship could easily hid itself as.

Have a ship running on silent and the universe will just think it's another asteroid not worth paying attention to. Then boom, you have a ship which can use railguns to kill merchant ships just by locating their IFFs, looking which direction they're going in, doing a quick bit of math and then sending a few 6 inch slugs that are too small to track.

Railgun rounds don't need to be tons, just a small round going a few kilometers per second faster then your target relative to it will destroy it.

And a problem with lasers is that, being energy based, it shouldn't be to hard to counter those weapons using either hull plating that will deflect/absorb it, or an artificial magnetic field.

Not hugely practical. Space is really big, it would be entirely possible for entire armadas to miss each other, especially if they were designed to minimize light reflection/emission, which is tech we basically already have. As soon as ships reach your planetary system, you've already lost. If you blow them up, your planet will get wrecked by giant chunks of spaceship. If you don't, they can shoot you to death.

On the other hand, if they actually want something other than to kill you, they can't do much either, for the same reason. Space battle seems to be MAD theory taken to the next level. So I imagine that except when launching gunboat diplomacy against places which don't have space travel yet it would mostly be fought by ground troops, with occasional ship destruction when one moved into an exposed position where it could be harmlessly destroyed.

Zontar:

Da Orky Man:

Not even close.

The problem with space warfare is that everyone can see everyione else from very, very far away. As in, the tiny attitude thrusters on the Space Shuttle can be seen from the Asteroid belt. Any kind of massive nuclear engine will be seen from basically anywhere in the solar system, and a large antimatter rocket could poossibly be seen from the next few star systems over.

If you used a railgun at laser range distances, it can be easily dodged. By the time you get close enough to the enemy to effectively use a railgun, their laser would have torn you apart.

On the other hand, if you could use a railgun to accelerate a number of missiles, probably kinetic or nuclear, to a decent speed, they could quite easily wither didge enough laser to get thouogh, or simply force the enemy lasers into overheating, then getting in and landing a kill-hit.

Otherwise, railguns simply don't fire fast enough to compete with lasers.

That assumes the use of technology to observe things that is far beyond what is possible at the moment or even within sight though. People say space is empty, but there's plenty of things in our system that a ship could easily hid itself as.

Have a ship running on silent and the universe will just think it's another asteroid not worth paying attention to. Then boom, you have a ship which can use railguns to kill merchant ships just by locating their IFFs, looking which direction they're going in, doing a quick bit of math and then sending a few 6 inch slugs that are too small to track.

Railgun rounds don't need to be tons, just a small round going a few kilometers per second faster then your target relative to it will destroy it.

And a problem with lasers is that, being energy based, it shouldn't be to hard to counter those weapons using either hull plating that will deflect/absorb it, or an artificial magnetic field.

If you run on silent, as in, no engines, radar, or any kind of active broadcasting, you still have to worry about the massive amount of heat leaking out of your crew compartment. Purely RC/AI ship can get close to the 5K background heat of space, but in no way could a human-piloted craft do that. There is no stealth in space, at least of that kind You cannot 'run on silent' without killing your crew.

Magnetic fields, artificial or otherwise, have no effect of lasers. Literally nothing. They do not affect each other in the slightest. Anything like that is pure fiction. As for armour, once you start doing the maths, there are very, very few materials capable of effectively blocking a decent laser, and they'll only do it for a few seconds. Ablative, if anything, is even worse.

For further reading, I recommend the Atomic Rockets website.

http://www.projectrho.com/public_html/rocket/

Basically, if a decent-sized railgun shell, or enough smaller ones, hit a spaceship, that spaceship is out. Kinetic energy is a harsh mistress. The problem is range. If you fire at a ship motionless relative to you, using a railgun at 5km/s and at a range of, say, 30,000km, it has 3000 seconds when it detects the massive heat from your railgun to dodge. In this time, assuming an acceleration of 1/10th of a gee, or 1m/s, it could accelerate up to 3km/s.

There is no way you are ever going to hit at that range.

However, if it fired back with a 100MJ laser over the same period of time, it would be able to drill though slightly more than 100 meters of steel armour with a 25cm wide hole.(Source: http://panoptesv.com/SciFi/LaserDeathRay/DamageFromLaser.php)

More than enough to make your ship unusable for the foreseeable future. And, of course, they'd be able to hit you from much, much further than that, if with less killing power.

I can certainly see a place for railguns, primarily in the launching of unmanned drones at high velocities and to give missiles a nice boost in speed, but for direct space-to-space attacks, railguns firing unguided kinetic rounds just don't seem up to the challenge.

Da Orky Man:

Zontar:

Da Orky Man:

Not even close.

The problem with space warfare is that everyone can see everyione else from very, very far away. As in, the tiny attitude thrusters on the Space Shuttle can be seen from the Asteroid belt. Any kind of massive nuclear engine will be seen from basically anywhere in the solar system, and a large antimatter rocket could poossibly be seen from the next few star systems over.

If you used a railgun at laser range distances, it can be easily dodged. By the time you get close enough to the enemy to effectively use a railgun, their laser would have torn you apart.

On the other hand, if you could use a railgun to accelerate a number of missiles, probably kinetic or nuclear, to a decent speed, they could quite easily wither didge enough laser to get thouogh, or simply force the enemy lasers into overheating, then getting in and landing a kill-hit.

Otherwise, railguns simply don't fire fast enough to compete with lasers.

That assumes the use of technology to observe things that is far beyond what is possible at the moment or even within sight though. People say space is empty, but there's plenty of things in our system that a ship could easily hid itself as.

Have a ship running on silent and the universe will just think it's another asteroid not worth paying attention to. Then boom, you have a ship which can use railguns to kill merchant ships just by locating their IFFs, looking which direction they're going in, doing a quick bit of math and then sending a few 6 inch slugs that are too small to track.

Railgun rounds don't need to be tons, just a small round going a few kilometers per second faster then your target relative to it will destroy it.

And a problem with lasers is that, being energy based, it shouldn't be to hard to counter those weapons using either hull plating that will deflect/absorb it, or an artificial magnetic field.

If you run on silent, as in, no engines, radar, or any kind of active broadcasting, you still have to worry about the massive amount of heat leaking out of your crew compartment. Purely RC/AI ship can get close to the 5K background heat of space, but in no way could a human-piloted craft do that. There is no stealth in space, at least of that kind You cannot 'run on silent' without killing your crew.

Magnetic fields, artificial or otherwise, have no effect of lasers. Literally nothing. They do not affect each other in the slightest. Anything like that is pure fiction. As for armour, once you start doing the maths, there are very, very few materials capable of effectively blocking a decent laser, and they'll only do it for a few seconds. Ablative, if anything, is even worse.

For further reading, I recommend the Atomic Rockets website.

http://www.projectrho.com/public_html/rocket/

Basically, if a decent-sized railgun shell, or enough smaller ones, hit a spaceship, that spaceship is out. Kinetic energy is a harsh mistress. The problem is range. If you fire at a ship motionless relative to you, using a railgun at 5km/s and at a range of, say, 30,000km, it has 3000 seconds when it detects the massive heat from your railgun to dodge. In this time, assuming an acceleration of 1/10th of a gee, or 1m/s, it could accelerate up to 3km/s.

There is no way you are ever going to hit at that range.

However, if it fired back with a 100MJ laser over the same period of time, it would be able to drill though slightly more than 100 meters of steel armour with a 25cm wide hole.(Source: http://panoptesv.com/SciFi/LaserDeathRay/DamageFromLaser.php)

More than enough to make your ship unusable for the foreseeable future. And, of course, they'd be able to hit you from much, much further than that, if with less killing power.

I can certainly see a place for railguns, primarily in the launching of unmanned drones at high velocities and to give missiles a nice boost in speed, but for direct space-to-space attacks, railguns firing unguided kinetic rounds just don't seem up to the challenge.

What about a 'particle' shield idea (i.e.: using tiny objects to diffuse the focused light beam)? I'm no expert on the subject, of course, but it seems to me that if you had some sort of system meant to scatter light (to the proper extent, of course); lasers would become effectively useless.

No one seems to have mentioned two of the most important physical constraints on spaceship combat: Light-lag (or how hard your target needs to change course to avoid your lasers) and sensor precision (or how big a telescope you need to aim your weapons precisely enough).

Light-lag: Over large distances, the time it takes for light to travel from the target to your eye or sensors is significant. The Moon is just over a light-second away from Earth, the Sun is just under 500 light-seconds away and Jupiter is more half a light-hour away at its closest. If your target is not accelerating (or is accelerating predictably, such as in an orbit or executing a constant thrust in a fixed direction) this is not a problem: if you know how fast your weapon's projectile (or laser beam) will travel you can work out how long it will take to reach your target and can also predict where your target will be, simply adjust your aim to compensate and physics should work out the rest. But if your target decides to adopt a random walk strategy, performing regular but randomly orientated thrusts the problem becomes much harder, with a randomly accelerating target you can only guess where the target might be and thus you're limited to either taking a lucky shot and hoping, or firing enough projectiles to fill a target-zone such that you hit them no matter how they've accelerated. Eventually you wind up with a balancing act between your ability to fire a large number of projectiles over an area, and the target's ability to thrust hard and often enough to make the zone you have to fill unfeasible. It follows that the smaller and further away a target is, the less hard or often it needs to randomly thrust to create an unfeasibly large target-zone.

Sensor precision: An object reflecting or radiating enough light can be detected by a sufficiently sensitive sensor no matter how small or distant it might be. However when it comes to determining the precise location of the target you still need sufficient angular resolution on your sensors to ensure that your target and your projectile actually strike. Wikipedia has a fairly good article on angular resolution but it can be boiled down to this: At small angles, the size of lens (or interferometric baseline) required by your sensors to precisely resolve a target (or target area) of fixed size is proportional to the distance to the target, proportional to the wavelength of light used by the sensors and inversely proportional to the target's size. For example: to resolve a target or target area with a precision of 100 metres at a distance of one light second requires a telescope (or sensor array) just over 2 metres across (using yellow light), but to resolve a target with a precision of 10 metres at one light-second or a target 100 metres at ten light seconds would require a sensor array 20 metres across. It follows that the smaller a target is or the further away it is, the larger a sensor array you need to achieve the same precision.

Whether or not a zero-gravity combat which involves two opponents firing relativistic chunks of tungsten or laser bursts at each other is feasible would come down to how large the opponents are, how far apart they are, how big a sensor array each of them has and how quickly and for how long each of them can move. For ships sufficiently large and slow, long range combat is totally feasible; for smaller, faster ships the prospects of hitting each other with simple unguided projectiles becomes infeasible at longer ranges. Factors like stealth, surprise, guided weapons, exploding warheads and decoys add a few layers of complexity to this but yeah I think to some extent space combat is totally possible.

Edith The Hutt:
No one seems to have mentioned two of the most important physical constraints on spaceship combat: Light-lag (or how hard your target needs to change course to avoid your lasers) and sensor precision (or how big a telescope you need to aim your weapons precisely enough).

Light-lag: Over large distances, the time it takes for light to travel from the target to your eye or sensors is significant. The Moon is just over a light-second away from Earth, the Sun is just under 500 light-seconds away and Jupiter is more half a light-hour away at its closest. If your target is not accelerating (or is accelerating predictably, such as in an orbit or executing a constant thrust in a fixed direction) this is not a problem: if you know how fast your weapon's projectile (or laser beam) will travel you can work out how long it will take to reach your target and can also predict where your target will be, simply adjust your aim to compensate and physics should work out the rest. But if your target decides to adopt a random walk strategy, performing regular but randomly orientated thrusts the problem becomes much harder, with a randomly accelerating target you can only guess where the target might be and thus you're limited to either taking a lucky shot and hoping, or firing enough projectiles to fill a target-zone such that you hit them no matter how they've accelerated. Eventually you wind up with a balancing act between your ability to fire a large number of projectiles over an area, and the target's ability to thrust hard and often enough to make the zone you have to fill unfeasible. It follows that the smaller and further away a target is, the less hard or often it needs to randomly thrust to create an unfeasibly large target-zone.

Sensor precision: An object reflecting or radiating enough light can be detected by a sufficiently sensitive sensor no matter how small or distant it might be. However when it comes to determining the precise location of the target you still need sufficient angular resolution on your sensors to ensure that your target and your projectile actually strike. Wikipedia has a fairly good article on angular resolution but it can be boiled down to this: At small angles, the size of lens (or interferometric baseline) required by your sensors to precisely resolve a target (or target area) of fixed size is proportional to the distance to the target, proportional to the wavelength of light used by the sensors and inversely proportional to the target's size. For example: to resolve a target or target area with a precision of 100 metres at a distance of one light second requires a telescope (or sensor array) just over 2 metres across (using yellow light), but to resolve a target with a precision of 10 metres at one light-second or a target 100 metres at ten light seconds would require a sensor array 20 metres across. It follows that the smaller a target is or the further away it is, the larger a sensor array you need to achieve the same precision.

Whether or not a zero-gravity combat which involves two opponents firing relativistic chunks of tungsten or laser bursts at each other is feasible would come down to how large the opponents are, how far apart they are, how big a sensor array each of them has and how quickly and for how long each of them can move. For ships sufficiently large and slow, long range combat is totally feasible; for smaller, faster ships the prospects of hitting each other with simple unguided projectiles becomes infeasible at longer ranges. Factors like stealth, surprise, guided weapons, exploding warheads and decoys add a few layers of complexity to this but yeah I think to some extent space combat is totally possible.

I was actually thinking about this while I was getting lunch. Excellent points. So, conceivably, would that mean that space combat (at least at its outset) would be far closer to conventional naval battle (just with an added dimension?)

senordesol:

Da Orky Man:

Zontar:

That assumes the use of technology to observe things that is far beyond what is possible at the moment or even within sight though. People say space is empty, but there's plenty of things in our system that a ship could easily hid itself as.

Have a ship running on silent and the universe will just think it's another asteroid not worth paying attention to. Then boom, you have a ship which can use railguns to kill merchant ships just by locating their IFFs, looking which direction they're going in, doing a quick bit of math and then sending a few 6 inch slugs that are too small to track.

Railgun rounds don't need to be tons, just a small round going a few kilometers per second faster then your target relative to it will destroy it.

And a problem with lasers is that, being energy based, it shouldn't be to hard to counter those weapons using either hull plating that will deflect/absorb it, or an artificial magnetic field.

If you run on silent, as in, no engines, radar, or any kind of active broadcasting, you still have to worry about the massive amount of heat leaking out of your crew compartment. Purely RC/AI ship can get close to the 5K background heat of space, but in no way could a human-piloted craft do that. There is no stealth in space, at least of that kind You cannot 'run on silent' without killing your crew.

Magnetic fields, artificial or otherwise, have no effect of lasers. Literally nothing. They do not affect each other in the slightest. Anything like that is pure fiction. As for armour, once you start doing the maths, there are very, very few materials capable of effectively blocking a decent laser, and they'll only do it for a few seconds. Ablative, if anything, is even worse.

For further reading, I recommend the Atomic Rockets website.

http://www.projectrho.com/public_html/rocket/

Basically, if a decent-sized railgun shell, or enough smaller ones, hit a spaceship, that spaceship is out. Kinetic energy is a harsh mistress. The problem is range. If you fire at a ship motionless relative to you, using a railgun at 5km/s and at a range of, say, 30,000km, it has 3000 seconds when it detects the massive heat from your railgun to dodge. In this time, assuming an acceleration of 1/10th of a gee, or 1m/s, it could accelerate up to 3km/s.

There is no way you are ever going to hit at that range.

However, if it fired back with a 100MJ laser over the same period of time, it would be able to drill though slightly more than 100 meters of steel armour with a 25cm wide hole.(Source: http://panoptesv.com/SciFi/LaserDeathRay/DamageFromLaser.php)

More than enough to make your ship unusable for the foreseeable future. And, of course, they'd be able to hit you from much, much further than that, if with less killing power.

I can certainly see a place for railguns, primarily in the launching of unmanned drones at high velocities and to give missiles a nice boost in speed, but for direct space-to-space attacks, railguns firing unguided kinetic rounds just don't seem up to the challenge.

What about a 'particle' shield idea (i.e.: using tiny objects to diffuse the focused light beam)? I'm no expert on the subject, of course, but it seems to me that if you had some sort of system meant to scatter light (to the proper extent, of course); lasers would become effectively useless.

The problem with that kind of technique is that the individual flakes of material will extremely quickly, iwthin nanoseconds, start to ablate. Now, rather than having your particle shield block the laser, you have a sort of shotgun effect as those flakes start impacting your hull at quite some speed, whereupon the laser starts doing it's thing.

One possible way to protect against lasers is to have layered hull, probably both made of carbon composite. In-between these layers you have your ship's supply of water. When the laser inevitably cuts through the first layer, it encounters the water. If you can keep up a current in the water, more of it will keep getting in the way, massively degrading the performance of the laser on the second layer.

I was actually thinking about this while I was getting lunch. Excellent points. So, conceivably, would that mean that space combat (at least at its outset) would be far closer to conventional naval battle (just with an added dimension?)

I'm not sure I know enough about naval warfare to answer that.[1] The situation I envision is a couple of ships using shooting dumb projectiles[2] at each other while maneuvering. Each ship has a sensor array[3] and an engine thrusting hard in a random direction every so often. At some point one of these ships will be close enough to reliably hit the other one with a deadly projectile, exactly how close this is depends on the size, thrust, array size and endurance of each ship. At long ranges things like decoys, guided missiles and stealth are more useful, at shorter ranges you pretty much want to be firing your railguns on full auto while your ship dances.

Or at least that's how I envision it. I'll post a few worked examples below to demonstrate.

[1] I almost certainly don't know enough about space science either but somehow I find that easier to bluff
[2] Either solid kinetic projectiles fitted with last minute guidance or an explosive warhead to give them a bigger kill radius or a laser, which is totally a photon-based projectile for these purposes
[3] Probably consisting of a couple of space telescopes on long struts to give a large enough interferometric baseline to resolve the heat signature of the other ship well enough to hit

Da Orky Man:

The problem with that kind of technique is that the individual flakes of material will extremely quickly, iwthin nanoseconds, start to ablate. Now, rather than having your particle shield block the laser, you have a sort of shotgun effect as those flakes start impacting your hull at quite some speed, whereupon the laser starts doing it's thing.

One possible way to protect against lasers is to have layered hull, probably both made of carbon composite. In-between these layers you have your ship's supply of water. When the laser inevitably cuts through the first layer, it encounters the water. If you can keep up a current in the water, more of it will keep getting in the way, massively degrading the performance of the laser on the second layer.

What if you were able to suspend these flakes in some sort of field? Since the laser will have no kinetic energy, if you were somehow able to maintain your field do you think such a technique would still be effective?

Edith The Hutt:

I was actually thinking about this while I was getting lunch. Excellent points. So, conceivably, would that mean that space combat (at least at its outset) would be far closer to conventional naval battle (just with an added dimension?)

I'm not sure I know enough about naval warfare to answer that.[1] The situation I envision is a couple of ships using shooting dumb projectiles[2] at each other while maneuvering. Each ship has a sensor array[3] and an engine thrusting hard in a random direction every so often. At some point one of these ships will be close enough to reliably hit the other one with a deadly projectile, exactly how close this is depends on the size, thrust, array size and endurance of each ship. At long ranges things like decoys, guided missiles and stealth are more useful, at shorter ranges you pretty much want to be firing your railguns on full auto while your ship dances.

Or at least that's how I envision it. I'll post a few worked examples below to demonstrate.

You keep mentioning telescopes. Would something like LIDAR(sp?) be more effective?

[1] I almost certainly don't know enough about space science either but somehow I find that easier to bluff
[2] Either solid kinetic projectiles fitted with last minute guidance or an explosive warhead to give them a bigger kill radius or a laser, which is totally a photon-based projectile for these purposes
[3] Probably consisting of a couple of space telescopes on long struts to give a large enough interferometric baseline to resolve the heat signature of the other ship well enough to hit

Projectiles may be slow compared to the enormity of space, but do you know what will be even slower: ships. There in lies why space combat is hugely practical, no matter how fast your ship is going, it can't out run a projectile fired from something like a rail gun. Also there is the fact that who ever gains tactical superiority in the space above a planet will find themselves with a massive tactical advantage. They have the option to just rain down destruction from on high like the wrath of god, with no impunity and no recourse. These weapons could bust any bunker on the planet, strike any concentrated military force, and make supply movements impossible. If we were to create some sort of interstellar military, fighting in space isn't just an important phase, it is the most important phase.

Damn, I wish I could find an older video someone did on how they envisioned space combat would happen. Since human brains don't handle sudden changes in inertia too well (the brain sloshes around inside the skull and damages itself), he thought that most of the actual combat would take place between remote-controlled or AI-based fighter units that could be built to withstand all the stresses of changing direction quickly, while the actual humans would be housed within much larger vessels with the best armor and shielding technology could come up with.

Essentially, iirc, space combat would be fought by proxy, almost video-game style.

senordesol:

Da Orky Man:

The problem with that kind of technique is that the individual flakes of material will extremely quickly, iwthin nanoseconds, start to ablate. Now, rather than having your particle shield block the laser, you have a sort of shotgun effect as those flakes start impacting your hull at quite some speed, whereupon the laser starts doing it's thing.

One possible way to protect against lasers is to have layered hull, probably both made of carbon composite. In-between these layers you have your ship's supply of water. When the laser inevitably cuts through the first layer, it encounters the water. If you can keep up a current in the water, more of it will keep getting in the way, massively degrading the performance of the laser on the second layer.

What if you were able to suspend these flakes in some sort of field? Since the laser will have no kinetic energy, if you were somehow able to maintain your field do you think such a technique would still be effective?

The flakes are moved via ablation, not direct transfer of kinetic energy. Essentially, the laser rapidly heats up the section of the flake exposed to the laser. This intense heating means that part of the flake breaks off, like how wood breaks up in a fire. However, since this heating is so incredibly rapid, these parts brake off so fast that they impart significant energy to flake itself, similar to having a small explosion next to it. This would propel the flakes into your ship at a force that magnetic fields cannot maintain on such small objects.

You keep mentioning telescopes. Would something like LIDAR(sp?) be more effective?

This is about where my physics runs out I'm afraid. From my extensive research I believe lidar would probably not help with angular resolution, although it would possibly help with rangefinding (which in itself is pretty useful for narrowing down your target's position and speed) I used telescope as a lazy shorthand for photon sensor, for which lidar would do the job also. It would pretty much ruin all chances of a stealth approach though as lidar involves shining a laser directly at the target, not only giving away your location but also signalling pretty heavily that you're about to attack.

Edith The Hutt:
No one seems to have mentioned two of the most important physical constraints on spaceship combat: Light-lag (or how hard your target needs to change course to avoid your lasers) and sensor precision (or how big a telescope you need to aim your weapons precisely enough).

Light-lag: Over large distances, the time it takes for light to travel from the target to your eye or sensors is significant. The Moon is just over a light-second away from Earth, the Sun is just under 500 light-seconds away and Jupiter is more half a light-hour away at its closest.

choppity chop chop

Sensor precision: An object reflecting or radiating enough light can be detected by a sufficiently sensitive sensor no matter how small or distant it might be.

Snippity snip snip

Both problems are relatively easy to get round with one simple weapon. You fire a homing missile in the general direction of the target. When the missile comes within real time light range and you have a good position fix you set off the warhead which is a nuke powered x-ray laser. The target could not use a nuke powered x-ray laser as a point defence weapon without destroying itself in the process so the missile would have a longer range than any point defence.

Space warfare, in general, isn't practical.

To start with the obvious, it's actually really very hard to move an object into space and the tyranny of the rocket equation is such that there is an absolute limit on how bit something can be if you want to have it leave the earth after being built here. What this means is that, unless some radical new propulsion system is designed and built, any supposed combat is going to take place between relatively small ships if there are to be launched from earth. They will also have other limitations as well as they will, for example, be constructed as lightly as possible all thanks to that damnable rocket equation I mentioned before. What this ultimately means is that any craft launched into space from the Earth is going to be small and fragile and there is little to be done to improve these things without an entirely new paradigm in propulsion (or moving every phase of the construction somewhere with more forgiving gravity).

This theoretical ship has more problems before it though. It had to use almost all of it's fuel just to get into space leaving it with very little to use to maneuver. This, for the record, is why we have to have heat shields on spacecraft: there isn't enough fuel left to slow down using anything other than a target's atmosphere. Once launched, there is little the vessel could do to radically alter course without resigning itself to doom by some other means than hostile weaponry. You might point to Ion engines but these are rife with problems not the least of which is that they offer very little in the way of acceleration offering only the barest nudge; indeed, the only thing making them attractive is that they could conceivably be run for months on end allowing for huge gains in velocity over time. On top of that you still have the basic problem that space is inconceivably vast which simply means that there is no way you'd engage in battle in the depths of space - you'd be looking for a tiny fraction of a mote of dust in an infinite void that in the very best case is only moving fractionally slower than your own vessel and the odds of successfully intercepting such a vessel are so remote you'd be better off hoping that something terrible happens to the target by chance.

So that means our laughably small ships can't fight in deep space, can't do much in terms of maneuver in an orbit around a planet and are fragile enough that grains of sand could punch through them as though they were constructed of paper but let's presume you still want to have them duke it out over the planet. The question becomes what weapons are practical.

To start, lets consider the laser - in order to be useful as a weapon we need technologies that simply don't exist at the moment but let's assume we solved the problem of powering and firing such a weapon while still being able to make it small and light enough to throw into space. This laser does have an advantage - even though a ship in orbit might be moving exceptionally fast (8+ km/s) a high energy laser moves even faster (by many orders of magnitude) which means if you can see your prospective target and aim the weapon, you have an all but guaranteed hit. Such a weapon does, of course, require a direct line of sight meaning that for nearly half of an orbit a target would be completely impossible to hit. Given all the practical realities of maintaining an orbit, this basically means that ship combat with lasers would either be over in an instant or could be stretched out for weeks or months while the two ships circle the planet waiting for a chance to fire. That seems to be a fairly huge flaw which begs the question of if we can do better.

A pure kinetic kill weapon seems to have value as little energy would be necessary to cause catastrophic damage. Better still, because of the relatively low velocity, such projectiles would be easily affected by gravity thus making it reasonable that you could engage targets beyond line of sight. It still might take days or weeks for your shot to arrive but such things matter surprisingly little as the shot itself could be nearly impossible to track and evade. Thus unless the target maneuvers randomly (which places them at risk of instant laser death) they probably won't evade the projectile unless you simply miss (which, all told, would be phenomenally easy to do).

That leaves one last reasonable option - having your spaceship launch a separate ship that has some power to maneuver on it's own along with some kind of guidance package designed to help it improve accuracy. These devices already exist and are called missiles. The benefit to such systems is that they could easily engage a target anywhere in a similar orbit to your own and thanks to the various miracles of physics and chemistry could be pitifully small by terrestrial standards while still maintaining the ability to cause catastrophic harm. You could conjure a host of warheads from those designed to produce a cloud of micrometeorites for the opposing ship to smash into to something simpler like a vehicle that launches a small dense metal spike at the last moment or simply rams the target by itself.

The advantage of lasers all told is such that any space combat would be designed around simply not being in a position to be shot by a laser - a relatively trivial feat accomplished through simple timing of when you launch the vessel. Projectiles are simple and somewhat more effective but could reasonably be defeated by random maneuver or by having far higher quality detection systems than we currently employ. This leaves the missile as the best option as it combines the ability to engage beyond line of sight with the difficulty of evasion of a laser.

Of course, if you are asking about science fiction spaceships that somehow managed to solve problems like "not being able to go very fast" and "it's really hard to get something into space in the first place), you'll still likely arrive at a similar conclusion. Lasers have advantages, yes, but they likely wouldn't actually come into play except, perhaps, as point defense systems against various projectiles. I doubt there is a non-magical solution to the problem of maneuver in space simply because the cruel reality of physics says trying to radically alter the velocity of a vessel going tremendously fast is going to be very very hard to do.

albino boo:

Edith The Hutt:
No one seems to have mentioned two of the most important physical constraints on spaceship combat: Light-lag (or how hard your target needs to change course to avoid your lasers) and sensor precision (or how big a telescope you need to aim your weapons precisely enough).

Light-lag: Over large distances, the time it takes for light to travel from the target to your eye or sensors is significant. The Moon is just over a light-second away from Earth, the Sun is just under 500 light-seconds away and Jupiter is more half a light-hour away at its closest.

choppity chop chop

Sensor precision: An object reflecting or radiating enough light can be detected by a sufficiently sensitive sensor no matter how small or distant it might be.

Snippity snip snip

Both problems are relatively easy to get round with one simple weapon. You fire a homing missile in the general direction of the target. When the missile comes within real time light range and you have a good position fix you set off the warhead which is a nuke powered x-ray laser. The target could not use a nuke powered x-ray laser as a point defence weapon without destroying itself in the process so the missile would have a longer range than any point defence.

Wait...what?

Hang on lemme see if I got this... there is a laser on the homing missile that fires when it comes into range of its target? I guess that makes sense, but why can't it be destroyed by PDCM? Just because it's nuclear powered doesn't mean destroying it will result in an atomic explosion if it's reactor is breached.

senordesol:

albino boo:

Edith The Hutt:
No one seems to have mentioned two of the most important physical constraints on spaceship combat: Light-lag (or how hard your target needs to change course to avoid your lasers) and sensor precision (or how big a telescope you need to aim your weapons precisely enough).

Light-lag: Over large distances, the time it takes for light to travel from the target to your eye or sensors is significant. The Moon is just over a light-second away from Earth, the Sun is just under 500 light-seconds away and Jupiter is more half a light-hour away at its closest.

choppity chop chop

Sensor precision: An object reflecting or radiating enough light can be detected by a sufficiently sensitive sensor no matter how small or distant it might be.

Snippity snip snip

Both problems are relatively easy to get round with one simple weapon. You fire a homing missile in the general direction of the target. When the missile comes within real time light range and you have a good position fix you set off the warhead which is a nuke powered x-ray laser. The target could not use a nuke powered x-ray laser as a point defence weapon without destroying itself in the process so the missile would have a longer range than any point defence.

Wait...what?

Hang on lemme see if I got this... there is a laser on the homing missile that fires when it comes into range of its target? I guess that makes sense, but why can't it be destroyed by PDCM? Just because it's nuclear powered doesn't mean destroying it will result in an atomic explosion if it's reactor is breached.

Presumably because the missile would be able to fire from further than the countermeasures could reliably detect the projectile. Personally, I'd just go the route of having too many projectiles to defend against as it is simpler to build, deploy and service.

If you're talking about traditional kinetic weapons, sure, they'd be all but useless save for at point blank range in most cases. Of course, you could always just get closer. Just because you've got a square AU's worth of space to play with doesn't mean you have to use it.

Even if that wasn't the case, that doesn't mean they'll disappear though. For instance, have a ship accelerate to 0.99 c while aimed almost directly at your target. Have them fire off a few shots at the right moment and angle. The spare momentum will turn even the smallest of projectiles into devastating armor piercing rounds that the target has no chance to avoid. Of course, this also works the other way around, so one must be careful. If ship sensors are still radiation based, this maneuver is helped by light lag, by traveling at that kind of speed, by the time your enemy can see you, you probably have already fired, and are about to pass them by.

Ooooh. I forgot about Beam Divergance which pretty much screws the intensity of laser weapons at extreme distances. Looks like your best bet might be a very cold, very fast lump of steel after all.

Assuming we could harness the power for it(such as using an anti-matter drive of some sort) kinetic impact weapons would probably be the best bet. Granted it would have to be traveling at an absolutely blistering speed, but if this could be attained then its quite reasonable to expect large coil guns to be an important part of any theoretical warship's arsenal. Though it would be assumed that any space battle would be in relatively close vicinity to some objective such as a planet.

Both problems are relatively easy to get round with one simple weapon. You fire a homing missile in the general direction of the target. When the missile comes within real time light range and you have a good position fix you set off the warhead which is a nuke powered x-ray laser. The target could not use a nuke powered x-ray laser as a point defence weapon without destroying itself in the process so the missile would have a longer range than any point defence.

A high-speed homing missile with a precisely targeted nuclear-detonation powered x-ray laser warhead. There are many words for this kind of weapon, "simple" is not one I'd care to use.

It might be pretty damn effective though.

In regards to light-lag and angular resolution I'd consider this a general case of simply closing range with an enemy vessel before firing a powerful long-range laser at the enemy. Alternatively it's a case of expanding your target zone by several orders of magnitude, you only need to get your missile somewhat close to the target rather than bang-on so you can afford less precision when you initially target and fire.

The problem with the homing missile technique comes in that the target can probably see your missile's course corrections as the missile maneuvers towards the target in mid-flight, allowing the target to deploy counter measures or adjust its course correction to be further from the incoming laser missile. If you only maneuver early and/or late in the flight then you still have to have the initial precision to get you somewhere close so your final course corrections can finish the job. This pretty much negates the advantage of the homing missile part which is that you don't need to have precise aim to begin with.

The x-ray laser part is pretty scary though, a beam of wavelength 0.1 nanometres and width of 30cm would have a beam divergence of about than 2×10-5 arc-seconds, meaning it would only lose half its intensity every ~14 light seconds. Depending how powerful the initial blast that's a hell of range once it reaches it's target.

Yeah, I'm scared of that missile.

senordesol:

Wait...what?

Hang on lemme see if I got this... there is a laser on the homing missile that fires when it comes into range of its target? I guess that makes sense, but why can't it be destroyed by PDCM? Just because it's nuclear powered doesn't mean destroying it will result in an atomic explosion if it's reactor is breached.

The X-ray laser is powered by a nuclear explosion. This was one of the projects from the SDI research from the early 80s. Edward Teller, the creator of the hydrogen bomb, described it as the 3rd generation of nuclear weapons and way of focusing all the energy of a nuclear explosion in one direction. Clearly the energy output from a even a small 20kt device would outrange anything that could be fired from a ship.

SckizoBoy:
Anyone else thinking 'lasers are overrated, whatever happened to railguns'?

Yeah... railguns are a more practicable choice of primary weapon on space-faring warships. I think (THINK, please note, I don't know) that for the energy input required to fire/operate a railgun, it provides a great deal more destructive power than a laser. Plus, the energy dissipation from a laser means its effective range is kinda crap... or something along those lines...

Rail/coilguns would be impractical as well, since the ship it is fired from will experience a force that is equal and opposite to that the slug experiences (newtons laws and all that shit). So when you fire your gun, half the energy will be put into accelerating your ship the opposite way of the slug.

 Pages 1 2 3 4 NEXT

Reply to Thread

This thread is locked