What would combat in space [I]really[/I] be like?

[Bromley]

As with AndrewL, Peter Hamilton in the Reality Dysfunction goes the route of missiles and counter missiles. Of course, he also has hyperspace, but without that space combat’s going to be really boring (as in Triskadecamus’ example).

[Bromley]

I should have said that his missiles had various warheads, from nuclear/other energy to kinetic (from memory). Also, the effectiveness of these missiles (and the ships) was entirely dependent on their max. acceleration.

[Loopydude]

@Chronos

Bad assumption. In actuality, his turning radius is going to be huge, and his actual direction of motion isn’t going to change by very much. If, for example, the turn takes a second, then he’s going to go approximately 8 kilometers along his path during the turn. And since he’s only going to be changing his direction by a small angle, his turning radius is going to be larger yet.

Also, there’s no such thing as a “minimum speed to stay in orbit”. If you change your speed, either by increasing or decreasing, then you’re just going to go into a different orbit. Now, it may be that your new orbit intersects the surface of the planet you’re orbiting, which will create problems later. But until then, you can still correct your orbit again to put you back to something safe.

And again, all we really care about is relative motions. Suppose we have an astronaut on the Space Shuttle playing with his Star Wars toys. He moves them around in dogfights, and their motion is much the same as if he were playing with them back on Earth, aside from the lack of that pesky gravity. He’s perfectly capable of moving them through all sorts of maneuvers without squishing his arms from the acceleration. But the X-Wing and Tie Fighter toys, like everything else in the Space Shuttle, are actually in orbit. Their motion, given those forces, is no different than it would be if they were outside the Shuttle.

Well, if Luke’s turn amounts to swinging around and slowing down such that the rear of his X-Wing is now pointing in the opposite direction, but his motion relative the planet’s surface is still in the same direction, then effectively he has an opposite orientation, pretty much the same orbit, slightly slower orbital velocity, and Vader whizzes past him at whatever their relative velocity is. Meanwhile Luke is accelerating towards the planet surface, because his change in velocity does not allow him to stay in orbit at that altitude. If he turns around again and speeds up, he can maintain his current altitude; but if he keeps himself pointed in the opposite direction to Vader’s direction of motion, his ground speed is rapidly approaching zero, and he’s going to drop like a rock until his velocity is sufficient to put him in a stable orbit in the opposite direction to Vader. Probably all this isn’t an issue in a craft as nimble as an X-Wing, just as you say.

But I get the sense, based on what I see in the movies, and how the ships move relative to near and far-off objects that are on the screen, that Luke doesn’t just execute a turn by decreasing his relative velocity and orientation slightly; he really is turning around, relative to the planet, Death Star, big-ass star cruiser, or whatever. Maybe I’m wrong about this, but it looks to me like he’s flying at the Death Star major fast, goes into the trench, misses, whips around, and blasts away from the Death Star, again major fast, only to then hurl around and go for another run. That says to me his maneuvers have involved completely reversing his velocity relative to the Death Star, in this instance, and that’s one hell of a change in velocity, by the looks of things. I figure he’s moving at what must be, given the size of the Death Star, say, many thousands of km/h. And those dramatic turns only take a couple seconds to complete. At 8300m/s, assuming no change in total velocity during the turn (of course the x and y components of his V vector change dramatically), a generous ten-second circular turn traces an arc 8.3 km long. This gives a turning radius of about 2.64 km. He’s still feeling over 2600 gees, and that’s gotta hurt. Even if he’s only changing velocity by a tenth that amount, he’s still feeling some serious force. Granted, maybe it wouldn’t be lethal, but he’d be out cold, probably, and would have burst capillaries all over the place, so he’d look like hell and have blood in his eyeballs, etc.

But I’ll stand corrected if my assumtions about his changes in relative velocity aren’t correct. If his real changes in overall velocity are small, as Chronos and Dancing fool suggest, my objections have no real basis.