why space fighters would actually be useful

December 30, 2011

Just about every sci-fi movie featuring a battle in the depths of space generally shows large ships engaged in pitched combat sending out a swarm of fighters to deliver surgical blows to their enemies. Big battle ships do make perfect sense. After all, if you’re out to invade other worlds or conducting military patrols in deep space, you need to have enough room to house your crew and store enough supplies to keep said crew healthy and well fed. But when it comes time to actually engage an enemy, what about the fighters? The physics of space flight mean that you can’t simply send something like a plane to dogfight its way to bomb your targets, they will be going far too fast for that. The best they could do is repeated hit and run raids, whizzing past enemy craft to then reverse course back towards their mothership, hoping to pass by the enemy one more time on return. So there have been murmurings by those who want more science in their science fiction that if we ever have any real wars in space, we can forget about the fighters. Instead, we’ll just use small, powerful kinetic missiles.

But before we start redesigning our plans for fleets of battleships meant to project power on an interplanetary scale and nixing research into space-based fighters and bombers, we should consider that the same issues have been encountered on Earth. For decades now, the U.S. had extremely accurate long range missiles that can be launched by a submarine or an aircraft carrier in the rough geographical vicinity of a target. If it weren’t for the treaties and a real risk of nuclear war should someone overreact, ICBMs could be armed with more or less conventional warheads and sent to deliver precise strikes to enemy installations more than half a world away. Why do we even need planes anymore if a missile can get there faster and do about as much damage without any risk to real live pilots, not to mention saving us the cost of building and maintaining new jets and bombers? Well, according to Air Forces around the world, it’s actually more expensive and logistically difficult to simply fire a whole lot of missiles into enemy territory than to send in bombers with a fighter escort during a full blown military campaign, and the reasons why could apply quite well to combat in space.

You see, guided missiles don’t just obliterate their targets and then come back, and the missiles in question here cost millions and millions of dollars to build and maintain. And what if you need to recall a missile in the middle of a mission? You’ll have to blow it up or divert it, losing it in the process. Planes can simply be called back, or rerouted to multiple targets to deliver multiple bombs in a single sortie. Here, missiles are useful for taking out air defenses and radar installations, soften up extremely hard targets, and lay the general paths for bombing raids. After this initial volley, bombers and fighters can rush in to further dismantle enemy targets by dropping ordinance like bunker busters, extremely useful against a hardened installation, but far too heavy to load onto a missile and lob at an opponent. Likewise, in space, small but heavily armed craft which can whizz by enemy battlecruisers, delivering bomb after bomb after bomb after a volley of lasers and KKVs impairs the target’s ability to defend itself from the incoming swarm, can do a lot more damage at a smaller cost than just missiles all by themselves. And when you’re fighting an enemy millions if not billions of miles from home, you really need to try and get the most bang for your buck since a trip to your planet to reload is no trivial task.

So really, far from being a waste of resources, fighters for battleships would actually be a cost-effective way to deliver lots of damage to enemy craft very quickly, and given their small size and high velocity, they wouldn’t be easy to shoot down as they fly back and forth, emptying their weapons bays as soon as their targets are close enough to ensure a direct hit. And nothing says that they would have to be flown by humans, so there wouldn’t have to be any risk associated with being a space fighter pilot. It would be more like flying a drone, if there will even be a need for human drone operators that far in the future. As odd as it sounds because the situation is usually reversed, it’s the movies that have it right about space fighters rather than the scientific skeptics here, at least as far as the rationale for having them is involved. The actual mechanics of their use on the battlefield as they’re portrayed on the silver screen however, well… let’s just say that entire chapters of books have been devoted to explaining just how wrong directors have them, but that’s a different topic.

[ illustration by Kaimiirah ]

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  • EastwoodDC

    There are some other complications you have not considered. May I recommend: http://www.projectrho.com/rocket/spacegunexotic.php#id–Space_Fighters–Efficacy

  • Greg Fish

    Eastwood, you certainly may, but I already see some issues with the conclusions that were made on the page. Allow me to point out a few…

    you needed delta v equal to about four times that of a comparable mass missile that just needs to do a drive-by shooting.

    Just because you’ll expend four times the energy to control a fighter than a missile in a rough estimate, doesn’t make the fighter four times more expensive. Boosting it with a launcher on the carrier already cuts down the energy requirement by 25% and if it then delivers multiple warheads (which now don’t need boosters big enough to reach their targets), then you were far more effective with your fighter than a missile. A bomber like the B2 will need far more fuel than a Tomahawk. But the B2 can destroy more than one target during a single sortie which makes it effective and efficient.

    … put in the life support compartment, and the payload mass, and it gets even worse; rocket performance is the red queen’s race, and you rapidly hit declining efficiencies.

    This implies that fighters and bombers in space must be manned. They don’t. Hell, we are making manned fighters and bombers optional right here on Earth. In space, we’d be relying strictly on drones rather than housing an extra 20 to 50 crewmembers which would be very expensive and totally unnecessary.

    In terms of pure offensive firepower, there is little you can do with a fighter that a cruise missile can’t do better in a space game context.

    To call this metric simplistic would be a very serious understatement. Again, consider the role of the B2 bomber. If we simply thought about the firepower rather than logistics then there’s no need for a bomber. We’d just fire the warheads it delivers without it. Yet the bomber gives you far more flexibility in delivering these warheads. I dedicated one full quarter of the post in explaining hit it would work in space and why. Maybe you want to address that rather than just throw out a link which seems to be written by someone with a very good idea of motion in space but not even a cursory one of aerial combat.

  • We use bombers (and drones increasingly) because we have the following constraints:

    1) Horizon distance. You can’t reliably see things on the ground in Kandahar from Nevada without having a drone overhead to look at things.
    2) Ambiguous, cluttered targets.

    Note that when we have to hit things that don’t move relative to background clutter – like buildings and aircraft carriers on the open ocean- we use TLAMs.

    Remove either of these constraints and the cruise missile wins out, repeatedly. Note that both of those constraints apply to attacking the ground from space!

    When you’re attacking the Stellari Mortis*, it is highly unlikely that the target you’re going to be blowing up can be plausibly explained as a baby food factory or a wedding reception.

    Let’s look at the 4x delta v regime issue next.

    4x delta v isn’t simply 4x the fuel – it’s more like 4x log-n the fuel based on your iSP.

    Your fighter/bomber has to do the following:

    1) Accelerate torwards the target.
    2) Match velocities with the target to the point where ‘human input’ in the targeting equation matters – if your bomber is doing a crossing vector on the target at a Rate of Closure of 5-15 km/sec the window in which your human input matters is going to be vanishingly small. Note that matching velocities with your target to the point where merely human reaction speeds and judgement can matter means your ‘bomber’ is a much slower object in the sky relative to the target, and much easier to shoot down. On the flip side, if you’re coming in behind a spread of higher velocity projectiles….you may be considered too low of a threat target to shoot at.
    3) Decelerate after overflying the target.
    4) Thrust on a vector where it can be recovered.

    Now, there is a place in this for a recoverable first stage.

    Lots of drives get very low thrust but very good ISp – if you make a first stage that has an ion drive that accelerates the missile payload towards the target, detaches it, flips over and accelerates back to the carrier, it can be an effective range extender, but it’s not the same thing as a fighter or bomber. It’s a recoverable first stage. :)

    Another thing that makes “fighters” viable is low total engine power plant constraints.

    AV:T (pardon me for shilling!) had a doctrinal change happen when total engine energy constraints went up.

    We use a mostly magical fusion torch for AV:T purposes. It gives noncombat thrusts in the regime of 4-6 milligees in noncombat mode, and in combat mode, we measure thrust in increments of 125 milligees – 8 of these is a full G.

    Because of how kinetic weapons work in AV:T, anything that can’t at least do a combat thrust of about 500 milligees requires extensive point defense. It’s a sitting duck. We also use solid fuel booster rockets for missiles because of logistics – vacuum welding, long cruises, and maintaining cryogenic oxidizers and/or hypergolic fuel mixes with 19 year old spacers do not make for happy happy captains. (Even solid fuel boosters have a shelf life, shown in game.)

    This is a fairly ‘artificial’ constraint – it’s there to keep rocket thrusts high enough to overtake a typical target in game, while being short enough duration and low enough total delta-v to make it possible to evade them if you’re willing to spend the fuel and can thrust perpendicular to their axis of closure. It’s also meant to keep games from devolving down to “missile launches at ranges which make maneuver pointless” – it’s justifiable in terms of technological assumptions and physics – the boosters require about a 20% improvement in ISp over current technology to get the performance parameters we use.

    When total engine output is smaller, the ships have to be smaller to get thrust that allows them to course correct and dodge missiles. This leads, naturally, to a gunboat tender and gunboat arrangement. As drive technology allows ships to sustain higher thrusts and evade missiles, frigates become more survivable…but there is still a doctrinal set that uses large numbers of gunboats thrusting in, launching missiles, pivoting 120 degrees away and thrusting like mad to avoid overflying the target in case the missile strike doesn’t kill it off.

    This could be done even more effectively/efficiently with the ion-drive missile sled described, or having gunboats build up a 30 km/sec closing velocity with cruise mode thrust, and pull the launch and veer.

    The gunboat doctrine for this is ALREADY a “Play it twice, and never speak of it again…” game, because all the interesting decisions are made shortly before the map is set up. Your high speed missiles are either going to obliterate the target, or the target’s going to shred them and take no damage….and nothing you can do, on either side, really changes the effect on game play….so we’re happy to have other reasons that take gunboat/missile spam doctrines off the table, because they’re not terribly fun to play.

    They’re fun to contemplate and go “Ooooooh!” Then you face it, and go “This sucks.” Then you talk your opponent into letting you do it, and your opponent says “This sucks.” and you go back to playing matchups that are fun games of maneuver and tempo and timing and resource management.

    I’ve got constraints that novelists don’t have – I’ve got to make this something that’s fun for both people at the table. And which rewards interesting decisions made after the start of the game.

  • Greg Fish

    Ken, I don’t know why you keep missing the issue of being able to change your mind in mid-attack or deliver repeated shots to an enemy on the same fly-by. Those are not an ability than a TLAM or any other missile has.

    Horizons are not an issue in space, true, but we’re not using fighters and bombers for reconnaissance, we’re using them to attack confirmed targets. Your bit about trying to match your space fighter speeds to those within human reaction time then ignore the notion that human fighter or bomber pilots are fast becoming optional as computers are in a perfect position to completely take over for human pilots in space.

    I’ve written program that solve equations deciding where a certain component should move and how fast and they run in just a few hundred milliseconds. And that’s with an added constrain of an operating system and with the map being read each time. Load a map into an application like that either written in C or an Assembly language running without an OS, or just living on a very fast, dedicated app pool on a powerful server and it can solve complex routing problems up to ten times faster than the blink of an eye.

    Why would I need a human piloting a space fighter or bomber again if I can just use a program like that instead?

  • Paul451

    I suspect the balance between fighters, carriers, missile boats, battleships, and other variants we haven’t thought of, will be driven by the particular balance of technology, propulsion, power, weapons, shields, stealth, etc, at any given moment.

    If you need physical propellant for rockets, then missiles (and missile-boats) will probably dominate. Short range (ten km) lasers, and missiles are sitting ducks, kinetic weapons may be the range weapon of choice, fighters may have a role. Compact propellantless propulsion, sans lasers, and fighters dominate. Stealth returns the horizon problem, perhaps making force-projection of fighters useful again, or swinging things in favour of pseudo-submarines. Force-fields change the game again, FTL yet further.

    Same thing happened on Earth. Battleships dominated while cannons were the weapons of choice. Once range extended over the horizon, and radar improved fire-control, even without carriers and submarines apparently Britain and Germany spent the war afraid of actually sending their battleships into battle.

    Today carriers are probably in the same boat (heh), (or any capital ship) due to the relative cost of carriers versus anti-ship weapons.

    Star Trek got the lack of fighters right for their technology. Their FTL is instant, and ships can manoeuvre in warp, so any sub-light ship can be outrun (or strafed) without being able to respond. And warp sets the minimum size of ships (the 12 “man” Klingon Bird of Prey seems the closest to a fighter, and that has the advantage of sneak attack.) But add a “spool up” time between fixed-minimum-distance “hyperdrive” jumps, and you probably push things back in favour of fighters and carriers.

    Then you’ve got the balance between practical weapons in war, and practical space-navies in peace-time. What you require to protect the borders from barbarians, or impose Imperial will on subject worlds, vs what you need for a head-to-head battle against an enemy empire of similar power. This is something the US faces.

    And throw in a continuous area-affect EMP-type device and steam-punk space battleships rule the skies :)

  • TOM

    Well I think, at very least, fighters are useful for orbital combat, when there are cover, difficult terrain on the surface of the moon, inside an asteroid mine. (It can have giant shafts.)

    Maybe some of theese more difficult mission can even require direct human control.
    /Yes, currently the robots are evolving, but what if future technology will enable to clone natural born pilots, who also good consumers, voters? They would be still aided by AIs./

    About Ken’s arguments : i think, for a slow return of a drone, double amont of fuel is required, and in case of ion, plasma propulsion, propellant isnt the real expensive thing, and it can be reloaded at every celestial body.