Further meditations on space combat

[Elok]

I'm sorry, AAHZ. Would you prefer we discuss epilepsy-inducing Japanese kids' cartoons with no plot and lousy production values?

[Elok]

I defer to people who actually know the nuts and bolts of physics to answer your question about the fields, Patty. Are you thinking a projected field of some kind, or magnetizing the hull? Or both?

[ZEE]

I'm sorry, AAHZ.

Apology accepted LOL, but i would apologize to AAHZ too if i crossed him so i don't blame you

[DanS]

The ship can't possibly move fast enough to evade attack, and no conceivable armor could stand up to a hunk of metal moving at something like a hundred miles per second

How do you propose to propel an object to that relative velocity? How big and how massive of object are you talking?

It may make sense to have your systems degrade gracefully upon impact rather than to carry around slabs of armor.

[Kuciwalker]

A question on shields specific to rail gun defense.

Since we are using magnetic fields to accelerate projectiles, can we then use magnetic fields to slow them down/deflect them?

As I understand a large electric current is passed through the projectile when firing to allow it to interact with the magnetic fields accelerating it, so I guess you would still need that electric current for a defensive magnetic field to interact with it too. Or in other words a defensive magnetic field wouldn't work. Is this correct?

Consider the scale of the magnetic fields involved and the space over which they are applied. Then consider that you would have to establish a similar field over a broad solid angle in the direction of the projectile, in open space rather than an area enclosed by the specially designed machinery.

[Elok]

It's not a matter of degrading gracefully. A magnetically-propelled hunk of metal of modest size (say, smaller than a human) would impart enough energy that I believe it would vaporize half of a navy battleship, if said ship happened to be floating in space. It's comparable to a nuclear weapon; you shoot the SOB out of the way en route or you're dead. Like I said, no armor could protect against it.

There are a couple of different ideas about mass drivers, but they all involve strong magnets. I favor Gauss cannons myself, but honestly I don't know the theory well enough to argue in favor of one or the other. I just know they're not impossible in space. In atmosphere you can't exceed a given velocity or friction with the air will simply destroy the projectile as soon as it leaves the barrel, producing enough waste heat to likely destroy the launcher as well.

[DanS]

I'm questioning the energy and apparatus it would take to propel even something of modest size to a relative velocity of 100 miles per second.

[Koyaanisqatsi]

The enemy's gate is down.

What ever happened to the movie version of that? I know it was in the works a while ago, but I didn't realize I hadn't heard of it for a while until I read that.

[Patroklos]

Consider the scale of the magnetic fields involved and the space over which they are applied. Then consider that you would have to establish a similar field over a broad solid angle in the direction of the projectile, in open space rather than an area enclosed by the specially designed machinery.

Yeah, I did think think the distance would be prohibitive. If it takes a rail gun to speed it up, it would take similar forces to slow it down. Would it be feasible to create a field to simply push it off course? A degree or two might make all the difference.

[Kuciwalker]

It's not a matter of degrading gracefully. A magnetically-propelled hunk of metal of modest size (say, smaller than a human) would impart enough energy that I believe it would vaporize half of a navy battleship, if said ship happened to be floating in space. It's comparable to a nuclear weapon; you shoot the SOB out of the way en route or you're dead. Like I said, no armor could protect against it.

With sufficiently powerful mass drivers you don't actually impart all of the energy on impact - the 'hunk of metal' flies clean through the other ship causing minimal damage.

[Kuciwalker]

Yeah, I did think think the distance would be prohibitive. If it takes a rail gun to speed it up, it would take similar forces to slow it down. Would it be feasible to create a field to simply push it off course? A degree or two might make all the difference.

It matters how far away that degree or two occurs. The closer in you deflect the shot, the more lateral force you need.

[MikeH]

Mike, are you suggesting remote control or complete automation? The former makes assault impractical; it might take minutes, hours or days for a ship to receive and respond to an order, unless it has a commander on a nearby planet, and there are obvious problems with that requirement.

The latter...hmmm. Would you trust the outcome of battles entirely to computers? I would certainly trust a large amount of it to computers, with a large number of auxiliary ships surrounding one or two inhabited command craft to monitor their behavior/progress. I guess it depends entirely on how sophisticated the AI is.

But it might not be the sort of thing in which you have a choice. You're going to need to move people around space sometime, and those people are going to need a means of defense. The attacking ship might well be a robot, but the defender will generally be human. Unless you posit a kind of agreement that wars be fought entirely by robot proxies, and I can't see that lasting long. In a real war, humans are the real target. A transport bearing a load of soldiers to occupy the enemy colony/base/whatever might have a dozen robotic escorts, but they won't be nearly as tempting a target as that fat, relatively helpless transport. I'm assuming here you're not thinking of robot soldiers to occupy as well. All this automation is efficient, but it might not be as cost-effective as grey matter.

Completely automated. If you need people to live there they can go once you've killed everything.

Bombard the planet with asteroids until you've wiped out all life or something

I think that even in the present day a genuine D-Day style invasion would be doomed to failure. Even more so if tactical nukes are deployed. Even worse in space, the lines of communication are so long and transports would be hugely expensive and massively fragile. There's very little downside to nuking stuff in space, there's no land there to ruin, but the invaders would probably want to preserve something (otherwise they'd have nuked it all from orbit, it's the only way to be sure)

I think you are thinking too much like WW-II in space.

[a.kitman]

i dont think space combat is going to be won by the biggest guns but rather by who is the sneakiest.

[MikeH]

I'm questioning the energy and apparatus it would take to propel even something of modest size to a relative velocity of 100 miles per second.

Just need a small force for a long time, assuming your targets are near a planet use gravity and a small amount of energy for manoeuvring jets.

[Heraclitus]

No. Certainly not until you spell summary correctly, and probably not after that.

Mike, are you suggesting remote control or complete automation? The former makes assault impractical; it might take minutes, hours or days for a ship to receive and respond to an order, unless it has a commander on a nearby planet, and there are obvious problems with that requirement.

The latter...hmmm. Would you trust the outcome of battles entirely to computers? I would certainly trust a large amount of it to computers, with a large number of auxiliary ships surrounding one or two inhabited command craft to monitor their behavior/progress. I guess it depends entirely on how sophisticated the AI is.

But it might not be the sort of thing in which you have a choice. You're going to need to move people around space sometime, and those people are going to need a means of defense. The attacking ship might well be a robot, but the defender will generally be human. Unless you posit a kind of agreement that wars be fought entirely by robot proxies, and I can't see that lasting long. In a real war, humans are the real target. A transport bearing a load of soldiers to occupy the enemy colony/base/whatever might have a dozen robotic escorts, but they won't be nearly as tempting a target as that fat, relatively helpless transport. I'm assuming here you're not thinking of robot soldiers to occupy as well. All this automation is efficient, but it might not be as cost-effective as grey matter.

Still, good point. I guess I'm stuck a little in a Star Trek mindset here.

What about a brain in fancy jar as the middle ground?