Hello again :) My first questions had some wonderful answers, but brought me to the following problem:

Although (in my eyes) really dull, the Cpt. Geary series (the Lost Fleet) tends to depict the relativistic issues with space combat quite well (timescales, speed distortion etc.)

Is there anything I can do to combat these circumstances? Which means I want a kind of atmospheric fighter-dogstyle-combat in space with engagement ranges of several miles (instead of light seconds).

I could just 'make it so'. But I'd like to have a possibility to explain, why my space-combat is not like you would expect. How would I justify something like that?

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    $\begingroup$ Without going to the length of an answer, I'd say that one problem is that a fighter spaceship is just a kind of very expensive rocket that you have to recover. Wherever you can send a fighter spaceship you can send a bunch of rockets with minimal intelligence, eventually with submunitions and stuff... and as braking and reversing is very expensive in space, it's just better to have those smash into targets or just forget if they miss. $\endgroup$ – Duralumin Feb 18 '15 at 16:10

The simple answer is that you can't, but the more complex answer is that if you stretch a few things you might be able to get close.

First lets look at the main "problems". The things that stop space combat being like what you want. These are the main 3, although they are not the only ones but you can follow the same process to isolate the others too if they become a problem.

  1. AI - spaceships would be controlled by computers with superhuman reflexes and g-force tolerance.

  2. Velocity - spaceships have no real maximum speed, instead they have maximum acceleration and can achieve a maximum speed based on that.

  3. Ranges - with no maximum velocity and no air resistance engagement ranges are huge

There are a lot of ways to solve this but the simplest are:

  1. Development of electronic warfare has reached the point that enemy computers beyond a certain complexity can be shut down. It's just not possible to shield them enough to work. Organic brains are resistant and while people have experimented with organic computers to control spaceships they have not managed to get them working yet.

  2. Either accept this as unavoidable, set things in a crowded environment (for example a planetary ring) where there is no space for maximum speed, or have some sort of new drive system. If you had a drive that didn't need reaction mass but which operated on the fabric of space, essentially giving you velocity relative to the nearest gravity well, then you could get spaceships that fly like planes (or even like cars but in 3 dimensions). This is similar to how ships in Eve and Elite: Dangerous work, having a top speed and turning like an airplane.

  3. The crowded environment might explain engagement ranges, if people are hiding in the planets rings, etc. In addition the advanced electronic warfare might make long range engagements very hard. Basically if you are more than a few miles from the target then you just cannot get a reliable weapons lock.

  • $\begingroup$ With such good answers as those two it is hard to choose. But I have to pick yours, because you ability to nail the problems down, so I can invent my own solutions is fantastic! $\endgroup$ – user6415 Jan 12 '15 at 11:00
  • $\begingroup$ - I will have an 'anti-ai' fraction, probably mechanoids themself. This will make autonomous drones very dangerous, so they need to be little more than remote-controlled machines $\endgroup$ – user6415 Jan 12 '15 at 11:00
  • $\begingroup$ - 3. is the best one: I will have nobody (with exceptions) fight in free space, because weapons would just be too deadly there, and there is nothing worth fighting about. Which means all fight fights would be in the inner systems or asteroid belts etc. This weakness can be made into a plot device :) $\endgroup$ – user6415 Jan 12 '15 at 11:01
  • $\begingroup$ In regards to #3, you could also extend the modern-day idea of active protection systems. Softkill measures like stealth, sensor jamming, and decoys could make long-range targeting difficult. Longer ranges would also give more time for hardkill measures, like shooting down enemy missiles. $\endgroup$ – KSmarts Jan 12 '15 at 21:07

I'm a pilot, just arrived in a hostile system. They see me three light minutes away. Why can't they just slag me now? Because I know they're going to try, and while going in the general direction I want I'm accelerating randomly. This means they're going to have to fill the space I could be occupying three minutes from now (when their projectiles arrive) with shots, which is a lot of space if I have decent acceleration and use it randomly.

Note that I have to change the direction of acceleration on timescales shorter than the light travel time, or I'm a sitting duck. This means that as my opponents get closer, the volume of space they have to shoot shrinks (especially if I'm doing anything other than accelerating randomly in different directions every second), and I'm dead.

What if you have an extremely rapid way to move unpredictably? Maybe an FTL technique that never worked out for travel because it only works over 100m, but it's effective for jumping out of the way of projectiles. In that case you're not so much trying to shoot the opponent down directly as you are trying to checkmate them. You want to force them into a situation where there is nowhere to jump to that isn't going to be occupied by weapons fire. And then shoot them, of course.

You'll need something that can sense relativistic slugs incoming and activate this jump extremely rapidly - maybe ships with better computers can dodge faster incoming shots.

This also suggests a superweapon: a 'dark' projectile which is harder/impossible to detect.

  • $\begingroup$ Thanks for the answer again, frodo! As said in my comment, its hard to choose, and your help will probably find you way into my work! Thanks! FTL travel however is limited to jumppoints (intradimensional) by the plot, so the short jump will be hard to incoperate, but ill try, because I like the concept. $\endgroup$ – user6415 Jan 12 '15 at 11:03
  • $\begingroup$ Buckshot at relativistic speed? $\endgroup$ – JDługosz Feb 19 '15 at 17:49

First things first. You aren't going to get anything that looks like WW1+2 dogfighting in space. Atmospheric craft push against the air to turn. That is how they can turn without losing speed. Spacecraft can't do that. If you are traveling 100 km/h in one direction, then you want to travel perpendicularly to your flight path you first have to decelerate until stopped, then accelerate in the direction you wanted to turn. If you don't stop before turning (you can stop your forward momentum while you are turning, if you want - that's no problem) then you won't be traveling 90deg along your original path, you will be flying 45 deg along it.

There's 2 ways around this.

  1. Work with it. Battlestar Galactica did. You may not be able to turn, but you can rotate and fire behind you while still flying straight. I'm sure you can make interesting and compelling action scenes.
  2. A lot of handwavium. You have a magic drive that makes atmospheric style flight possible outside of an atmosphere. Maybe Einstein was wrong, there is a rest frame, and you can push against it.

Now get over that little 'book-keeping' we get to the interesting bits. How to bring down the range of combat. First we need to look at why the ranges are so long to begin with.

  1. Lasers can go really far without any air to absorb and dissipate them. Projectiles will go forever.
  2. Space is big. If a ship is flying from one star system to another, even at best sublight speeds, it will take years. That is years for the defenders to ready and to take potshots at the invaders. If they are using some sort of jumpgate, it will only take days to get from the outer to the inner system. That's still a long time for defenders to shoot at you.
  3. If you are traveling at best sublight speeds, an engagement in the range several kilometers will be over in femtoseconds. Two ships traveling towards each other at near c are closing at nearly 600,000 kilometers a second. Almost too fast for computers to handle, never mind people. Then after they've passed each other, they need to slow down and turn around, who knows how long that will take. And all one side has to do is not turn around and the other force won't be able to catch them.

You can't have near c travel, combat, and ranges of several kilometers. If you have a laser that shoots several kms, and you and your target are traveling at c, its is little better than not having weapons and just hoping for a collision. Space is that big, several kilometers is that small. If two satellites are in GEO and their orbits differ by a tenth of a degree, they are hundreds of km away from each other.

If you are going to have people flying from one side of a system to the next, and not traveling at near c, you are looking at 50 year time spans.

Your best bet is to find some way of keeping things slow (low orbit speeds) and small (not flying across the whole system to get from point A to B). You can, I'm sure, come up with a lot of ways to do this, but some sort of 'jump' drive is probably easiest. You are in orbit around a planet and you calculate a jump to another planet, and then instantly, or sometime later, you pop out at the calculated position traveling along your same path. Star Wars has this type of drive. Star Trek had something similar that would work. You just 'go to warp'. You aren't a target for days or years while flying where you are going. From the perspective of someone at your final destination, you just appear.


Lets propose a drive system that admittedly has no basis in reality:

It reacts against the basic fabric of the universe. (And I don't believe this goes against Einstein--relativity could be a simplification based on an inadequate observation point.) It creates only a pseudo-velocity--you move but you do not have the kinetic energy associated with that velocity and you will return to your original velocity the instant the drive is shut off. (The Lensman, Starfire and Fifth Imperium universes use a drive of this nature and I'm sure there are more that don't come to mind right now.)

Now lets add another kink to the situation: The maximum attainable velocity is a function of your drive power and the local gravity gradient. Out between the stars you zip along at FTL velocities and combat is effectively impossible due to the difficulty in locating what you want to shoot at. Only when you get deep enough into a gravity well can you bring the enemy to bear. Missiles aren't used because in any reasonable engagement you can't hope to get them through the enemy's point defense. Long range beams aren't an option because the target can jink out of the way.

Thus you end up with all combat being short range beam weapons used in the proximity of a planet.

  • $\begingroup$ That makes me think of a couple of leectures I just saw on youtube. Sean Carroll speaks about possible alternatives to dark matter and dark emergy. The presentation, in both cases, is to show what changing the gravitational field theory would entail. TeVeS (a solution to MOND) introduces a vector field with a spacial direction; the scalar field implies changing Newton's constant. Some technobabble based on that might be what you describe. $\endgroup$ – JDługosz Feb 19 '15 at 17:56

Fight in a gas cloud.

While cosmic gas clouds are still incredibly thin, at relativistic speeds they will anyway cause considerable friction to your space fighter, so I'd expect more or less the same sorts of maneuvers as in air to be possible. It also means that going faster will cost more energy, and that with your drive off, you'll slow down.

It will not bring the scales down, however, but then larger distances are compensated by larger speeds. There's still the problem of space ships being very small compared to the ranges, but this can be ovwercome by just having a tactical display in your ships that shows the ships much enlarged just to help the intuition of the fighter (because, after all, in the actual space you'll not really see the ship with bare eyes), and weapons that actively steer towards the ships close to their way, so that a shot in the approximate direction (just accurate enough to hit the displayed image if it were not controlled). This would also solve the problem that you don't know exactly where the ship will be when the weapon arrives.

Note that on those distances, lasers would not work because you couldn't sufficiently focus them, and even if you could, aiming them at a far target would be too difficult, especially given that in the time it takes the laser to get there, the ship may already have unpredictably moved to a slightly different place. Also, at large enough distances, also the laser will be weakened by the gas cloud, so its effective range would be reduced. So you'd actually fight with some sort of relativistic missiles. Lasers might be useful for fighting against incoming missiles, however, provided you can detect them sufficiently in advance (which, however, is unlikely unless you're currently retreating in relativistic speed, so the relative speed is low).

So in the end, you'd have a fight that effectively looks similar to a fight in an atmosphere, although part of that similarity is through technical means (enlarged displays, self-steering missiles instead of bullets).


Your FTL warp field could be an actual planetary size bubble created by a leading ship and the field could be filled with an aetheric substance that slows down craft inside of it -- and serves as the "atmosphere" by which sublight dogfitting becomes possible.


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