Science fiction has portrayed all kinds of space warfare, most based on Earth naval warfare of one time or another. Despite what is out there, I really don’t think we’re going to see the future equivalents of men-of-war going broadside to broadside against each other (Star Wars), or a reenactment of the battle of Midway, with tiny fighters striking at massive carriers (Battlestar Galactica). So what will a battle in space actually look like, and what weapons and defenses will be used. Now in this blog I will be discussing ships and weapons of the far future. I don’t think we will be doing much more than shooting slow missiles and lasers at each other in the near future. So this will consider warfare in an interstellar age with some assumptions. One is that we will still have to obey the laws of physics, though we may be able to circumvent some of their effects, like inertia. And we will not have light amp weapons capable of going faster than light, so I will assume that most battles will take place at slower than light speeds. I have no idea how we will finally get around the light barrier, and if we even can. How we do it will have an effect on how we fight in that other realm, and I will eventually have an entry about those possibilities as well. But for this essay I will concentrate on fighting between slower than light vessels within a solar system, and the possibilities and pitfalls of different weapons systems that might be used.
First, a note on hiding in space. It is really really hard to do. Sure, you may be able to use light bending screens, which we are near to deploying today, to make the ship invisible. They might even be able to absorb radar and lidar and not show up on those systems. But ships with huge drive systems and powerful weapons have to generate a lot of energy, and they will radiate heat like small stars. Unless they have something between them and the enemy like a planet or asteroid they will be detected. I have some ideas on how to circumvent this detection that I will talk about in a future blog.
So let’s talk about beam weapons, starting with the favorite of science fiction that’s being developed for contemporary warfare, the laser. Lasers work by emitting a beam of coherent light, meaning that all the photons are the same wavelength. This wavelength can be visible light, xrays, gamma rays, or any wavelength of the electromagnetic spectrum. On striking the target the photons are converted to heat energy, either melting, burning a hole or causing other mechanical damage, depending on the makeup of the target. On Earth lasers have captured the imagination of the military because they are instantaneous strike weapons, meaning that an almost immeasurable time passes from shot to strike. They cannot be dodged or avoided. In space, over long distances, they are not instantaneous strike weapons. In fact, they take time to traverse long distances, and they tend to spread from thin beams to spotlights over the distance. Lasers travel at the speed of light, 300,000 kilometers a second. Meaning if the target is 300,000 kilometers away the beam takes one second to reach a target that may have moved within that time span. And at longer distances the time is greater. At a light minute, 18 million kilometers, it takes the beam one minute to strike at where the target was one minute ago. With luck the target will still be there. And it will have spread so that it no longer resembles the thin beam it was on leaving the weapon. This doesn’t mean it useless, it can still pump damaging heat into the target. And traveling at light speed it can’t be detected until it actually hits. But over very long distances, say many light minutes, the laser is not a very effective weapon. By spreading the beam or firing multiple beams in a pattern the chance of a hit is increased, but the power of the weapon is attenuated if used in this manner. Another word about lasers. Sometimes they are portrayed as super weapons capable of destroying a good sized asteroid in one flash. Actually saw a movie where a fighter jet with an underwing laser destroyed an asteroid. Look up the energy needed to melt a cubic kilometer of rock, or to burn through a kilometer straight in and your jaw will drop. So I’m afraid that spaceships will be firing on each other for at least a measurable period of time to cut through hull armor, or pump enough heat into the interior to make the inside uncomfortable, then longer to make it unlivable.
Particle beams use the mass of a fast moving beam to impart energy into the target. Charged particle beams tend to spread over distance as the particles push each other away. And antimatter particle beam adds the explosive power of the antimatter to the damage, but have the same problem as the charged matter particle beam, in that the particles are repelling each along the way and the beam spreads. They can also be deflected by a magnetic screen, and the more spread they are the better the deflection. An uncharged particle beam doesn’t suffer from the spread problem and won’t be deflected by magnetic fields, but cannot of course be made of antimatter. And as all particle beams are traveling slower than light, they can bee seen coming in on radar or lidar, giving the target time to dodge. I think they will eventually be more powerful than lasers, able to cause much more damage to an armored hull. But the weaknesses will always be there. Over a long distance they will be seen coming, giving from many seconds to minutes to maneuver out of the way. But close in they could be deadly. Now other beam weapons might be possible, though we don’t know of any other possibilities at this time, with the possible exception of microwaves, which might fit in with the laser catagory. In the next blog I will talk about weapons other than beams.