What would warfare look like on bodies the size of Ganymede to Europa?

Question

As for more specific numbers these bodies are in the range of between the size of 2634.1±0.3km & 1560.8±0.5km in radius. The environmental conditions of them are that of the bodies of that size within the solar system. These being Ganymede, Titan, Mercury, Callisto, Io, & Europa. The Moon is heavily populated & is in a very different situation to the rest of these These bodies haven't been changed from their current environments other than some human colonies & mines. The technology level is near future.

The main thing to be gained is resources, although small amounts of industry exist. The main combatants are large industrial powers with the majority of industry on the moon & earth. Their main concern is still what happens on earth, but they still have separate branches for operating in space. Losing colonies on these planets isn't much of a concern as they are mostly underground & their populations are small. The main goal is securing the ability to mine resources & having a place to dock ships.

What would warfare be like on these bodies under these conditions?

Answer 1

There are three main traits that make these places different warfare-wise: the horizon, the air(or lack thereof), and gravity.

The horizon: on a flat area of Europa you'll get a horizon at around 2 km, depending on how tall you are. This effects all modes of spotting and detection including radar. (Most of these don't have a magnetosphere to bounce radar signals off of.) This gives you shorter notice on surprise attacks and less effective high grounds. Warfare would therefore use them less and focus on the less.

The air: On earth, enemies are alive unless you do something about it. In space, people are dead unless they do something about it. The amount of damage you must inflict to bring people to their knees is far less. (Knock out power, blow the oxygen, one big hole in a hab.) Additionally living is infrastructure heavy, making running an insurgency very difficult. Small loitering drones would also be less practical, because of their constant high fuel consumption. Weapons deploying from orbit would be far more practical, as they wouldn't be slowed down/burned up by the atmosphere. Finally, conventional weapons from earth would get some extra range from the lack of air resistance. (The last three points don't apply to titan.)

Gravity: shooting things into orbit is not generally a war tactic on earth. Because of the low delta-v requirements of orbit on these bodies, that would be very different. Orbital velocity of Europa is just under 1.5 km/s, whish is slower than the muzzle velocity of many current day canons. With the lack of air it is possible to fire unguided projectiles into very low orbits and basically bombard any part of the planetoid with cheap artillery. Additionally, instead of having an air force, you'd probably have some kind of on orbit space force, doing recon, bombing and space-supriority missions.

Answer 2

The answer by thewildnobody gives the best explanation of what would be different. I thought I would try and take those points and synthesise them into a conclusion as to what a war would actually be like:

It would be a cold war

(Pun intended)

The most similar "war" fought in history is the cold war:

• There would be no direct action involving large armies and troops. Too easy to see, and too easy to kill.
• As it is too easy to cause (and hence be hit with) massive damage, belligerents would engage in a lot of spying, posturing, statecraft and diplomacy, before engaging in violence. Any army regulars would be used more as a show of force, rather than actual force itself. Expect lots of indirect warfare such as sabotage using spies, and cyberwarfare aimed at disrupting key infrastructure.
• Armies would probably be small, but arsenals large. Expect regular (mutual) threats of annihilation.
• Any actual "boots on the ground" operations will be small-scale special forces operations. Small teams of highly trained soldiers aiming to infiltrate, cause damage and flee as quick as possible. Knowledge of actions may be disavowed or blamed on 3rd parties.
• Satellites are easy to put up and easy to bring down. Expect them to be used more for temporary recon to support limited special forces missions, launched in the knowledge that they will soon be shot down in retaliation.
• The overall strategy is to get the opponent to waste so much money and manpower defending themselves, and building up their arsenal, that they eventually bankrupt themselves and withdraw, or sue for peace on favourable terms.
• In the event that diplomacy fails, you may end up with an escalating series of strikes that culminates in both sides largely annihilating each other with an overwhelming barrage of long range missiles. High ranking officials may survive in hardened underground bunkers long enough to evacuate after the dust settles.

Answer 3

Given the distance to any likely military manufacturing sites or bases with reinforcements (apart from the Moon), it would seem that one side or the other would end up with orbital superiority for a significant time period - and on relatively small radius bodies even a single spacecraft orbiting would be able to scan and track enemy forces in the open fairly regularly (although it could use thruster mass to try to surprise enemy forces using that regularity as a window to move between areas of cover).

With modern imaging equipment detecting recent changes to a location is easy, so "digging in" or otherwise trying to create hiding/defensive spots artificially is likely to expose rather than conceal, so in terms of moving through uninhabited locations it would mostly be moving from one natural hiding place to another - the shadowed inner rim of craters seems a common choice, although this may depend on the body in question and its surface features.

Depending on how well equipped/supplied the force without orbital supremacy is, one of their key strategic aims would presumably be to attempt to strike at the orbital spacecraft - some equivalent of SAM launchers, although probably single shot disposable fired remotely in some way (timed, remote controlled), as the location is likely to get pummelled shortly after whether it was successful or not.

In terms of the equivalent of urban warfare, this seems to depend on whether the miners are part of a rebel force or the economic "prize" being fought over by the two sides. In such a hostile environment even if they are not being targeted specifically, if there is nearby hostility the civilian casualties could rack up quickly. And it wouldn't be surprising for that to happen seeing as they are the only reason for military interest in the area presumably, whether defending them or trying to capture the mine (destroying it could presumably be done from orbit easily enough).

With the costs/infrastructure involved in delivering and supplying soldiers in such remote locations, it will only involve small elite forces rather than masses of conscripts. And they will be heavily loaded just with survival gear, limited ammo (whether it be bullets or batteries), etc., so the combat will be over quickly, unless the side without orbital supremacy is being secretly helped by the miners - which is going to be difficult to do without being caught.

Landing and recovering troops from these places is also going to be tough on the "invading" side - there are more options landing at least, as while parachutes would only work in some of the examples, in low gravity there would be alternatives such as a disposable jet pack to make a soft landing while allowing the inserting spacecraft to leave before it gets shot down, landing and taking off giving a big time window for it to be intercepted, but it would seem unavoidable if trying to recover troops. The alternative being to send enough spacecraft to take over orbital supremacy from the enemy force, and then send in troops supported by those spacecraft.

In terms of defending the miners, deploying unmanned video look out towers to monitor the approaches (and maybe remote controlled weapons emplacements as well) would be an option, combined with low aspect or even mostly underground bunkers around the perimeter to protect the soldiers against indirect fire during an assault - given the low gravity and in most of the examples lack of atmosphere/wind, such weapons would be very useful, especially with the assistance of a spotter relaying the results to the firer, and the bunkers would have similar weapons to counterattack with, resulting in a fire and move pattern for the attackers, unless they can fire from a naturally defensive location.

Assuming the above the attackers would want to take out the towers with detached units attacking from a different direction from the main thrust of the attack while using indirect fire to open a gap in the defensive perimeter before committing to an assault, allowing the remaining defenders to be flanked or attacked from the rear, possibly using civilian buildings as cover.