Artillery in Sci-Fi

[Simon_Jester]

Lot of people said lots of things, but I wanted to put this particular bit up before going to bed and I have to go to bed very soon.

...ignoring the fact that any counter orbit weaponary would be essentially artillery.

No, I'm not ignoring that. Effective surface to space weapons MIGHT be useful as surface-to-surface artillery, but that's not the way to bet. Engaging targets in space requires your weapon to meet certain specifications, whether the weapon is a missile, a beam, some kind of 'gun' firing solid projectiles, or anything else. Engaging targets on the ground requires your weapon to meet different specifications. In general, a weapon specialized to meet one role will be more effective within that role than a weapon designed to do two very different things.

For example, a missile designed to be fired from a silo on your planet to blow up a starship in high planetary orbit needs:

1) Very high terminal velocity (otherwise the enemy has lots of time to dodge)
2) Guidance systems that are good at homing in on a single target surrounded by nothingness from a long way away (e.g. passive homing on the enemy's radar signal)
3) Extremely high yield (especially in soft science fiction where ships may shrug off kiloton-range firepower easily).

A missile designed to blow up a formation of ground troops on your own planetary surface needs:
1) Low terminal velocity, so it doesn't burn itself up in atmosphere or overshoot the enemy formation entirely.
2) Guidance systems that are good at picking out a target from a massive, clutter-filled background at short range (e.g. FLIR).
3) Limited yield, so that it can safely be used with minimal collateral damage.

Designing a weapon capable of filling both roles means compromising the ability to fulfill either role well.

You can get into situation where the "fort" is strong enough to withstand bombardment but unable to stop you from landing thus causing land battle to be a nessesity or the fact that something as simple as ECM can give the defenders the ability to hide even large forces from orbital observation.

ECM is not necessarily effective against, say, a person looking out the window of their spaceship with a telescope or a camera... Moreover, why would anyone who fortifies a planet limit themselves to fortifying only one point on that planet? Surely it is more likely that an interlocking grid of defenses would exist, in which case someone somewhere on the planet has to actually hit and engage the fortifications rather than just being able to casually sneak troops anywhere on the planet at will.

bare in mind that wars are most of the time about capturing an objective not indiscrimanate destruction.

But in an interstellar war in a typical SF setting, the objective to be captured may not be on the planet you're fighting over. Maybe you're only fighting over this planet to secure a safe line of supply to another star system. Or worse yet, maybe the goal really IS extermination (xenophobic aliens attacking humans reflexively, or vice versa).

Maybe (as is often the case) the attacking army doesn't care about taking the city intact and just doesn't want a hostile force using it as a base. You never know.

I think that is the point to make it as hard as possible for enemy to land ground forces in the first place. Planetary missile bases and beam weapon batteries would be better investment of resources than large ground armies. Destroying enemy transport ships carrying ground invasion forces with surprise missile or laser attack is much easier than having them land and deploy ground forces causing prolonged and messy battle on the planet.

This is basically my point, yes- that the only class of ground based weapon systems that really do much to protect the defender's land from damage and devastation is weapons that can shoot targets in outer space before they penetrate the atmosphere.

[NecronLord]

Umm, guys talking about ST and planetary defence. Cardassia did have a massive defence network by the end of the war. Such systems were seen in the Battle of Chin'toka:

Clip

Notably, the power generation for the system was on the asteroid-moon that's shown getting blown up at the end there, and they tricked the defense system into firing on its own generator station. But that thing goes up with a considerable bang.

It's notable that the Dominion/Cardassians decided to locate the generator on a moon around Chin'toka, rather than on the surface. I'd say mass planetary defenses for the main star trek races are pretty clearly something that you don't want to be built in your city, given how the power-generator explodes a miles-wide asteroid when it's destroyed.

[Sea Skimmer]

Building ground based defenses is only an advantage if 1) you have a lot of your economic power on the ground and a decent cost to lift the war material into orbit and 2) rock and earth can provide any useful protection. In a lot of sci fi neither of these things is true, at which point you'd actually find it easier and better to build defenses in orbit. Nearly any weapon or sensor meanwhile will work better in orbit then it would from the ground. Rule of thumb is a real life rocket is loosing about 1km/s of delta vee to aerodynamic drag to get from sea level to LEO. That's a serious speed, nearly mach 3 at sea level, and while you might easily build a missile to overcome this, the fact remains the faster you go and the harder you accelerate the worse this drag would become. Meanwhile lasers just hate the whole idea, and particle beams have properties which make them unsuitable for firing from the ground to space, you need different kinds for in the air or in the vacuum.

Now on the other hand if your economy is surface based, which would be strange in any realistic space traveling setting, but is oh so typical of sci fi, and you have shields, then digging in on the surface could make sense. It could also make sense if you have some kind of constraint on building space capable ships or platforms, such as low density power systems (aka realistic ones). Generally though someone who controls orbit should be able to ruin the shit of anyone on the surface. Enough to force them to only defend specific points, at which point the whole concept gets open to question, as the desirability of fighting to the death for a city sewer system will highly depend upon the nature of the war.