The Pournelle novel The Gripping Hand, sequel to Mote in God’s Eye, has two long sequences of ship-to-ship beam and missile warfare at interplanetary distances taking in to account the effects of relativity and the finite speed of light. Quite fascinating.
Contemporary space warfare is still in its infancy. As someone who makes remote sensing equipment (“scanners,” so to speak), we get approached often by military types. They’re concentrating now on using space mostly as a high ground for observation and communications. And each side hopes to monopolize it. Failing that, then the goal is to deny their opponent critical resources at critical times.
Both dominance and denial are achieved rather easily at this time. Space is such a hostile environment to begin with, it’s expensive enough to make something just tough enough to deal with the environment. Adding extra ruggedness just costs too much. More rugged means more heavy. More heavy means bigger rocket. Bigger rocket means exponentially larger costs…
So, ruggedness isn’t currently a requirement for most space systems. Therefore most of the satellites and all of the manned space vehicles are particularly vulnerable to a number of hazards.
Kinetic kill strategies are the easiest, but you have to trade off against two outcomes, neither of which are desireable: 1) The accuracy necessary to strike your target is incredibly high, and 2) too much debris in orbit makes space unsurvivable by your own spacecraft. You can use the shotgun effect to increase your chances of a kill, but then you’ve made a huge, dangerous mess.
One good role for kinetic weapons, though, is space-to-ground. You’ve heard of “Brilliant Pebbles” or some such? Basically, take a cheap steel rod, put some control fins on the back and a guidance system on the front, just enough to give it a couple meters or so accuracy, send it down on a target from on high, and BOOM. The reentry velocity gives the steel rod enough kinetic energy to mimic the effects of a bomb.
Then there are EMP weapons. These are liable to make the best ship-to-ship weapons in the near term, since semiconductors are so susceptible to electromagnetic pulses. There are two ways to generate them: with the interruption of a large current through a fat coil of wire, or with the detonation of a nuke. We know how to do both very well. And the former is easy to do in space.
Finally, solid state lasers are advancing every day, and the current problems are more engineering than science: scaling the lasing medium, dumping heat, ruggedization, etc. So soon, we will be seeing field and airborne testing of solid state lasers and you can safely bet there will be a test in space before long.
I doubt sincerely we will see anything resembling manned ship-to-ship combat of the Star Trek or B5 flavors for a long time to come. Not until space colonization has taken more than a tenuous start, and people start having fights over the mineral or logistic value of space real estate…
Space Debris and Shielding
Solid State Lasers