13
$\begingroup$

Assuming spacecraft are using contemporary propulsion technology, and are engaging in a dogfight in outer space (whether they are manned, drone, or autonomous), would the movements of the craft be abrupt and jerky, or smooth and graceful?

$\endgroup$
34
$\begingroup$

To expand on Cort's comment. Propulsion in space is too costly and distances too great for a dogfight to happen. With modern tech, space combat is limited to more of an artillery duel between satellites that are on more or less fixed trajectories. If they start trying to move around too much they are going to just end up falling into the atmosphere or flying out into space. They can also see each other way too clearly to ever survive long enough to get into dogfighting range even if they tried. Your armed satellites may have some maneuvering jets designed to make subtle course corrections for dodging, but high speed evasions would use too much fuel and need too heavy of thrusters to be an effective war doctrine using rocket propulsion.

So to answer your question... they would be "smooth and graceful" in the sense that they will not actually be moving around much to begin with.

Perhaps one day we will have some manner of technology that will make orbital mechanics and rocket equations a moot point in the face of overwhelmingly efficient and powerful propulsion systems. With what we've got today, just getting into a stable orbit is a trick unto itself.

$\endgroup$
  • $\begingroup$ The spacecraft would be moving in the sense that they are orbiting a planet or star. To dodge a projectile you’d only need a tiny amount of fuel, assuming you can detect the projectile early enough. Of course that doesn’t help against smart missiles which can follow your new trajectory/orbit and probably have more delta-v than your spacecraft. $\endgroup$ – Michael Aug 14 at 15:44
  • 1
    $\begingroup$ A key aspect of this is impulse management. If I am in a fighter, going 1 on 1 with another fighter, I use some of my fuel to change my direction (to dodge something), and then use some fuel to move back to my previous velocity (which is the direction I wanted to go), I now am in the same position as before, but I now have less fuel. If I do this too violently, or too often, my opponent merely sits still and waits for me to run low on fuel. Accordingly, there is a great encouragement to use as little impulse as possible when maneuvering. $\endgroup$ – Cort Ammon - Reinstate Monica Aug 14 at 16:18
  • $\begingroup$ This issue arises in jet fighters as well. However, thanks to their air breathing nature and their ability to use the air as an inert mass rather than having to carry your own inert mass like a rocket, jet fighters can recover from a momentum deficit better than a rocket fighter could. $\endgroup$ – Cort Ammon - Reinstate Monica Aug 14 at 16:20
  • 1
    $\begingroup$ @Michael, The projectile that you want to dodge almost certainly is self-propelled. The guy who launched it does not want to compensate for the recoil of a tube-launched weapon. If he's going to make it self-propelled, then he'll probably pay the trivial extra cost to make it self guided as well. In that case, your evasive maneuvers will have to be somewhat more than "subtle." $\endgroup$ – Solomon Slow Aug 14 at 17:13
17
$\begingroup$

The short answer is jerky and abrupt, but the longer answer is far more interesting...

First of all, the preceding answers explain why fighter combat in space is really a bad idea; it's not an efficient use of propellants or fuels, and you're far better off doing what was done in naval warfare; focusing on a smaller number of larger ships with REALLY big, long range, powerful guns. But if you insist on putting fighters up there, the first thing you have to do is get the idea of air combat out of your head; space fighters and dogfights are going to look completely different.

Let's start with the fighters themselves. They are not going to be sleek, aerodynamic craft that bank and turn gracefully; they're going to be spheres.

The reason for this is very simple. In an atmosphere, the air itself gives the plane something to help the craft bank and turn; the wings effectively push air around themselves and shape it with control surfaces to move the plane in a desired direction; it's actually pushing against the air to go where it needs to go. In space you don't have that so every change in velocity (whether it be speed, direction or both) must be done with a maneuvering thrusters. To make your fighter as agile as possible, you want to be able to thrust in almost every direction so that you can react to the combat around you with a minimum of orientation changes (as these also cost fuel) and to do that, you want thrusters pointing out in almost every possible direction. That means a sphere.

Now, it's possible for you to thrust in almost any direction without a sphere if you have a thruster that can turn and spin around you; say 3 thrusters each at 120o from each other on a ring that can rotate and spin around your ship, but in a combat situation do you really want to wait the half second or so for your ring to put the thrusters in the right position? Probably not. So, sphere.

Now, dealing with the maneuvers; because you're not pushing against anything but firing a thruster every time you want to turn, and because you don't want to ramp up the thruster gently (time is not your friend in combat) you're going to have a very abrupt, jerky, but agile turning approach. You'll be able to pull off moves that are simply not possible in a plane, and most banking turns a plane uses will actually be inefficient for this kind of fighter, but you're in a different medium to begin with which is why you need to think in a different way as to how you move about in combat.

Realistically; for space fighters, you want them to be drones. The G forces and inertial effects on the craft are not going to be friendly to your pilot, who needs to be able to maintain some consistent frame of reference for 'up' and all the accompanying directions. You can't do that in a space fighter because every thrust is going to act on the pilot to reorient his 'down' to align with the thruster just fired. Also, because of the fact that you're moving in a way that planes can't most of the time, your pilot will suffer massive G-forces and won't last long in the cockpit. Further, not having to maintain life support for the pilot means you can make the craft more compact, making it a smaller target while also allowing it to be more nimble. It's basically a weapons platform surrounded by engines all pointing outwards.

The important thing to note is that cars, planes, and even boats can manage their smooth turns because they're all effectively pushing against something; a road, the ocean, or an atmosphere. Your space fighter has nothing to push against, so it must use its engines to do ALL the pushing. Once you get your head around that, smoothing the change in velocity means making the craft inefficient and before long, you're taking the pilot out of the craft for his or her protection more than anything else as you give your craft an edge (hopefully) over the enemy craft.

Put even more simply, if modern drones could be designed to make instant 90o turns in the air, they would be simply because it would give them an edge in combat. Your space fighters CAN be designed to do that, so they will.

$\endgroup$
  • 9
    $\begingroup$ Space fighters designed to make 90<sup>o</sup> turns in space? Not quite. They would need to decelerate almost instantaneous in their forward momentum vector while doing the same in accelerating orthogonally. This exceeds contemporary propulsion technology by orders of magnitude. But given the right propulsion systems, yes they could, though not presently. $\endgroup$ – a4android Aug 14 at 2:10
  • 7
    $\begingroup$ Inertia is a female dog... $\endgroup$ – Ian Kemp Aug 14 at 7:41
  • 8
    $\begingroup$ While I agree with much of your reasoning, I disagree with your conclusion; Modern propulsion technology would struggle to deliver sufficient impulse for the "jerky" movements you suggest, especially without the damping properties of atmosphere. Once you reduce the impulse, your drone manoeuvres with sweeping curves instead - otherwise, it has to slow to a stop, and then set off in the new direction. $\endgroup$ – Chronocidal Aug 14 at 8:32
  • 2
    $\begingroup$ @a4android if you hold the Alt key and type 0176 on the numpad, you get a degree symbol: ° $\endgroup$ – Carl Kevinson Aug 14 at 13:35
  • 3
    $\begingroup$ @IanKemp That would actually be a good name for a female dog. Thanks for the idea! $\endgroup$ – Adrian Hall Aug 14 at 13:41
11
$\begingroup$

There won't be any dogfights in space without the tag.

The reason is that we have been toying with lasers for a long time. The YAL-1 project was cancelled, yes, but it worked kinda well in 2014. If we are going to space, we are going to have better technology. The lack of an atmosphere will also make it much easier to hit stuff with lasers.

YAL-1 could deliver well in the range of 2kWh in 3 to 5 seconds. That is enough to really ruin the day of whomever is in the receiving end - too concentrated and you get holes in our hull, too dispersed and in the very least your instrumentation goes blind.

You just can't compete with lasers. The fastest acceleration we've ever managed for a rocket-powered vessel was with New Horizons. It passed the Moon's orbit within nine hours of its launch. Light, however, is much faster and will cover the same distance in close to 1.3 seconds.

So don't try to enter a dogfight in space - as soon as you are seen, you are toast.

Someone might say "oh come on Renan, this means acceleration will be jerky in order to avoid lasers". The attacker may simply spread the laser wide. As long as you are within the beam you are in trouble, for the same reason that laser pointers are dangerous to aircraft. The laser will not reach you as a small dot. And once you are blind, there isn't much point in doing random maneuvers.

$\endgroup$
  • 8
    $\begingroup$ When spread to a ship-sized spot, 2KW beam is not much worse than a spotlight. $\endgroup$ – Alexander Aug 13 at 22:21
  • 3
    $\begingroup$ As a wide beam you'd just drain your power dry, then they see you again and begin proceeding to destroy you. This concept should be more clearly paired with something like missiles or railguns or something; so, you can capitalize on that blindness. Otherwise this is a good answer. $\endgroup$ – Nosajimiki Aug 14 at 1:40
  • 2
    $\begingroup$ I don't want to rain on your parade, but this answer is a good one about possible contemporary weaponry that could be used in space dogfights and not contemporary propulsion technology as asked in the question. $\endgroup$ – a4android Aug 14 at 2:00
  • 2
    $\begingroup$ If anything, lasers would be a good reason for space dogfight because of the inverse square law. To gain a distantly unpleasant output at the target area, your emitter should be within hundreds of meters from the target. $\endgroup$ – mg30rg Aug 14 at 12:20
  • 1
    $\begingroup$ Lasers are too short-ranged for space combat. Taking the YAL-1 as an example, and assuming it becomes harmless at a power density of 1 kW/m^2 (roughly equivalent to sunlight), it will have a range of around 35,000 km, not quite enough to shoot geostationary orbit from low-Earth orbit. $\endgroup$ – Mark Aug 14 at 20:10
4
$\begingroup$

In space, everything is ballistic in nature.

It would be smooth, but not graceful. Both ships would be struggling to stay within their optimum ranges, and out maneuver the tracking speed of the enemy guns.

The whole thing devolves into firing mass drivers at each other from miles (and miles) away, then adjusting position, so that hopefully, the other projectile misses. Most of the time, the ships would be operating at such extreme ranges that the other ship would only be visible on instruments.

Imagine the scenario: Ship fires, several minutes pass. Gunner: "Negative hit sir" Sensors: "Incoming projectile" Captain: "Adjust heading to miss the projectile, re-target and return fire. Someone bring me a hot cup of Earl Grey."

If you have lasers, it's a game of "let's see how long it takes for you to have a hull breach", with both sides firing until either guns blow up, or the other ship does (from miles away, again):

Ship fires, several minutes pass. Gunner: "Their armour is holding, and they are returning fire." Captain: "Maintain fire, and deploy reflective plating. Keep an eye on temps" Ship maintains fire, several more minutes pass. Gunner: "Hullbreach reported by telescopics, and guns are starting to overheat". Captain: "Good, cycle lasers and heatsinks, and find us another target"

Small, maneuverable ships could be used, but not for dog-fighting; they would be used in boarding actions, and as they would see you coming for literally hundreds of miles away, the casualty rate would be horrific(think world war 1 level losses). If you could invent some form of stealth tech, this could make for exciting boarding marine action.

The only way to have dogfights be viable, is for the ships to have reactionless, low inertia drives, which enables fast changes in velocity, with little in the way of G-forces. At this point, the motion of the ships would be erratic, making long range artillery utterly pointless outside bombarding space stations. At this point, the motion of ships would be jerky and erratic, as they try to do the same thing all pilots have since aerial warfare began: getting behind the enemy(where there are typically no guns), and shooting them. This is your basic star wars/battlestar galactica, star trek etc fare.

So, for your world, You have to decide what space combat will be like:

  1. Dogfighting, using "magic" propulsion which also gets rid of G-forces powerful enough to liquefy a man.
  2. Long range artillery duels, using missiles, point defence guns, armour and mass drivers.
  3. Ships with heavy armour on the front. These ships simply ram into the other ships, to cause as much damage as possible. Basically steerable missiles with a crew.
  4. Laser combat. More long range engagements, with each combatant trying to melt through the other ship before the same happens to them.

Basically, unless you use some space magic, space combat is going to be dull, and uneventful, until something actually hits, then everyone dies, as the ship now has a massive hole in it.

$\endgroup$
  • 2
    $\begingroup$ To your 2nd option, I'd like to add that mass drivers would look very odd as they would aim at really weird places, but never right at the target (or leading it), potentially shooting around the earth instead by predicting their path. They'd be really software-focused in their aim. $\endgroup$ – Infrisios Aug 14 at 13:38
  • $\begingroup$ So, ballistic but not balletic then? $\endgroup$ – Alchymist Aug 14 at 13:38
  • $\begingroup$ Indeed. Mass drivers do not make exciting weapons, except when they hit something. The actual use of them is just firing into the black. Indeed. Not balletic at all. $\endgroup$ – Ian Young Aug 14 at 13:43
  • $\begingroup$ Imagine ships that have depleted their ammunition but still have some maneuvering fuel or are still actively acquiring ionization energy from their solar panels. Then it becomes a battle of close-quarters, employing ramming or melee weapons and energy starvation. $\endgroup$ – pygosceles Aug 15 at 17:47
2
$\begingroup$

There's been a few realisic approaches to combat in space in various novels. I liked Niven's one in Protector - the assailant drops a bomb out the back of the ship, and a few days later there's an explosion as the pursuing craft hits it.

But, that's not going to make for good TV!

Perhaps the next best one is the approach used by Peter Hamilton, his ships get within reasonable distance and fire a huge barrage of missiles at the enemy, who does the same, only many of these missiles are designed to self-destruct in a big old nuclear explosion that will (if they've calculated things right) also destroy the enemy missiles coming at them, a bit like a futuristic version of "missile command". But that's pretty boring too - you may get a very sparkly battle, but its all fought with probabilities.

So maybe the next best is the C J Cherryh approach - your combat vehicle is a small-ish 4-man missile that is dropped near to the target by its carrier (that wisely keeps well out of harms way) and zooms into battle as fast as it can to avoid detection and enemy fire, dropping missiles as it goes that are fired at whatever enemy targets the ship can detect as it passes. Again, its all probabilities but at least this time its people in a ship doing things that make things go bang.

The point of probabilities is that space is very big, so big it makes your walk to the shops seem like peanuts in comparison. So any target will be far, far, far away. that means whatever you shoot at it will probably miss as the target will be somewhere else by the time your munition gets there. (see the Niven bomb I first mentioned). So computers will be tracking what they can passively detect and trying hard to be somewhere that the enemy computer didn't think they'd be when they fired their munitions at them. Payloads don't even have to be explosive - a small lump of metal fired fast enough will destroy any target you care to mention, but you'll be using self-propelled missiles to avoid being pushed away as you fire them.

So your space battles are far more likely to be like submarine warfare today. Lots of nervous waiting to see if there's a sparkly blip of light a few hundred miles away in the darkness, holding your breath to see if the enemy did see you or guessed where you'd be as a small lump of metal comes hurtling at you so fast you can't even see it coming before its ripped you to bits.

So movement: smooth and graceful .. and quiet and stealthy like its tiptoeing through the dark.

$\endgroup$
1
$\begingroup$

Think Alchymist touched on a key point with the ball bearings. The battlefields would remain deadly (and therefore cumulatively deadlier (argh, got be a better way to phrase that)) after the first few explosions and/or shrapnel bursts.

Before long there would be large areas of left over small junk and/or deliberate shrapnel mines where it would be hard to operate in unless you had some sort of massive armor or deflector technology or the ability to somehow phase shift out to other dimensions.

We already have a problem with that now. So the answer to the question would be "neither after the first few encounters because both sides would be denied access"

$\endgroup$
  • 3
    $\begingroup$ Only temporarily though. Nothing stays put in space. You might have temporary, localized areas that become unsafe, especially in gravity wells, but generally speaking your cloud of munitions and debris is going to get more and more diffuse because it's all moving on its own trajectories. Your cloud of dangerous density might persist for hours, maybe days depending on the intensity of the engagement and how quickly things were moving relative to each other, but not much longer than that. $\endgroup$ – Morris The Cat Aug 14 at 15:22
  • $\begingroup$ @Morris The Cat hours maybe days is a long time for something labelled "dogfight". Assuming the OP wanted a battlefield on the same scale of modern air battles we can probably say the debris will clear at the same rate that a craft can traverse the radius of the battlefield. Which, again, would probably be seconds or minutes in something labelled "dogfight". $\endgroup$ – Muuski Aug 15 at 0:03
0
$\begingroup$

With contemporary technology, you really have two choices for stopping your path being purely ballistic. You can expend very large quantities of fuel to change your velocity rapidly (think Saturn V taking off) but you can only do this for a short period of time before you run out, or you can expend smaller quantities of fuel for low acceleration but one you can sustain for longer.

In the first scenario, either you hit the vessel that you are aiming for (with probably catastrophic g forces on both sides) or you get close enough to deliver some other attack. Then you travel past them at speed and probably don't have the fuel to return to the battle. This is similar to a kamikaze attack against a ship rather than a dogfight, or a strafing run if you don't intend to run into the enemy directly.

In the second scenario, you may be able to approach the enemy with a relatively small difference in velocity, allowing you and the enemy to each fire on the other, and maybe even seek to board. This is closer to naval warfare with sail, or even oar-powered vessels.

Neither seems much like a dogfight as you seem to envisage it. Both may be worse than just estimating where the enemy is heading and leaving millions of ball bearings in their path - effectively a mine field.

$\endgroup$
0
$\begingroup$

With known technologies the answer is kind of both, but differing depending on perspective:

  • The accelerations ships would need in order to evade fire at dogfight ranges (which is unrealistic given modern weapons options) would be brutal for the interiors of the ships, any crew, whether on board or operating on remote will have a jerky and chaotic experience of the battle.

  • Due to the fact that 1. only direct counterthrust stops motion in a given direction and 2. that in battle you don't have any maneuvering fuel to spare for course alterations you don't need to make. The actual motions seen from the outside will still be fairly stately.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.