A long time ago in a galaxy far, far away, George Lucas added Space Fighters to the standard arsenal of SF warfare tropes. For Hollywood it was love at first flight, partly for the cool special effects, partly for the reason I gave
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SFConsim-l the consensus has been trying to stuff the things back in the toy box for the last eight years … but no one listens to us.
Lucas did not invent space fighters, of course. I don't specifically recall any in the SF I read growing up, but I vividly remember one in an animated series I used to watch in grade school. (That was also a long, long time ago, and alas I have no idea what show it was.) Space fighters didn't really catch on till Lucas, though — the clearest evidence being that Trek had nothing of the sort.
So ... what exactly is a space fighter, and what does SFConsim-l have against them? If Star Wars, Battlestar Galactica, and Babylon 5 are anything to go by, a space fighter is exactly what you would imagine: the spacegoing equivalent of a DeHavilland DH-4 or an F-16. It is a small spacecraft, about the size — and, oddly, roughly the shape — of a present-day fighter jet. It has a single pilot or at most a two-man crew, strapped into a cockpit with minimal habitability, clearly intended for short missions of only a day or so at most. We see them whooshing and gyrating across the screen, zapping away at each other. Now and then they also destroy the odd stray Death Star, which with typical bad-guy carelessness is designed to obliterate whole planets but cannot defend itself effectively against killer gnats.
(Credit to Babylon 5: not only did its Starfuries have less overt similarity to atmospheric jet fighters, they sometimes even maneuvered like spacecraft instead of airplanes — an all but unique Hollywood tribute to Sir Isaac Newton.)
So what, you may ask, do some of us have against space fighters? The atmospheric kind have been with us for more than 90 years — a shade longer than tanks — so they're no passing fad. What works in one environment, however, isn't automatically suited to a very different one, and fighter planes don't fight in space any more than tanks do. (Yes, the same false-analogy critique can be laid against the analogy of space warcraft to naval ships — but that's an issue for another post.)
Space, first of all, is the same environment for small ships and big ones alike. This immediately knocks the stuffing out of the implicit contrast between small, fast fighters and big, slow space dreadnoughts. Fighter planes are airplanes; battleships are ships: They operate in two entirely different fluid mediums with very different properties. Battleships can't fly, and fighter jets can't cut power and drift while making repairs. There's no such essential difference between space fighters and larger ships — and no inherent reason for the fighter to be faster or more maneuverable.
"Fast" is in fact a bit of a slippery concept when it comes to spacecraft. Speed in space is all relative to begin with; the more useful measure for a spaceship is delta v, "change in velocity" — especially, how much you can change your velocity before you run out of gas. For any given propulsion technology, the way to get more delta v isn't a more powerful engine but a bigger fuel tank. What a powerful engine does give you is higher acceleration — so you can achieve any given delta v more quickly.
"Bigger fuel tank" and "more powerful engine" are also relative — to the size of the ship, more specifically its mass, since that's what you've got to push around. They are also contradictory in a sense — a big propellant supply means more the engine has to push around, so it is hard to get both sprightly maneuver performance (high acceleration) and extended maneuver capability (ample delta v) in the same ship.
Which does suggest that a small, somewhat fighter-like spacecraft, designed for tactical operations with limited endurance, could be a good deal handier than big ships designed for long voyages. The short-range tactical ship — presumably transported to the battle zone by a "carrier," or operating from a nearby base — can carry a smaller and lighter fuel load relative to its size. It doesn't need the supplies, provisions, and life support of long-voyage ships — not even a proper zero-g toilet, let alone bunkrooms and a galley. (Also no crew of techs to keep it running: just a pilot.) The mass saved by leaving all of this out translates directly into higher acceleration: in tactical terms a more agile, "faster" ship.
So isn't this our fighter, even if it doesn't look much like the Star Wars kind?
If it's going to be a useful fighter, however, it should probably have an armament. It can't carry a very heavy one, or you lose the maneuver performance that is the fighter's reason for being. Nor can it carry much armor or other protection, for the same reason. Whatever armament and protection it does carry, however, should be sufficient to fight its enemy counterparts. If successful it destroys them or chases them off, after which it can attack bigger, slower enemy ships ... how?
Broadly speaking, space warcraft in SF use two kinds of weapons. The more familiar are beam weapons — once called ray guns; now usually imagined as lasers or something similar. The hitch here is that our small fighter can't carry a very big one, especially since the weapon needs a power supply. Big, sluggish ships, by virtue of being big and sluggish, can carry a much heavier armament — heavy enough to zap a swarm of fighters out of the sky before the fighters can do much more than scratch the big ship's paint.
Yes, the fighter is fast and maneuverable — but not faster than a laser beam. Nor is there much chance of jinking around to dodging one, at least at any range much less than Earth-Moon distance. Light travels that distance in one and a quarter seconds. Aiming is limited by the round trip (because the gunner depends on light, or a radar beam, etc., to see the target), so at Earth-Moon distance our fighter has two and a half seconds to dodge. That might be enough. But at a tenth of Earth-Moon distance — a piddly 40,000 kilometers — the fighter only has a quarter-second of dodge time.
Dodging "bullets" that come at the speed of light is no way to live long and prosper. So if fortune favors the big battalions, combat between laser-armed warcraft favors big ships that can lay down powerful zaps. Maneuver hardly enters into it.
