Are there rules for this? I doubt it, but asking can't hurt.

Also, targeting personal scale targets from orbit, or very high altitude? Just have the target roll athletics or pilot to dodge the splash or in the interest of not splatting them just narrate the strikes and have them miss?

On the other end of the spectrum, and probably more appropriate, hitting a grounded Victory II with turbolasers from orbit. Would there be any change from it being stationary in space?

(For context, it's been heavily damaged in a recent battle and was forced to land for repairs with no nearby friendly bases to jump to. I'm planning on it taking at least a month if not several before it's ready to jump back to friendly space, but if enemy battleships track it down before then I may need to know this.)

Technically it would work just like anything else. You'd determine the Sil of the target and roll to hit. A city might be Sil 8+, a district 6-7ish, a skyscraper or shopping center 5ish, Home or small Warehouse 4ish, small home 3ish, Shed 2, Person 1, squirrel 0.

Typically (to avoid some DERP) you'd probably have the ship target a large area to generate more favorable dice pools, with the actual on the ground results being more environmental effects than resolved attacks. You know, apply various setbacks, upgrades, terrain checks, and Triumph/Despair narrations relating to what amounts to a massive artillery strike. Though you could do something like assign a district or city a building count, average HT, and average Armor rating and run it like attacking a minion group if you wanted a way to really show how much damage is taking place.

Targeting individuals would get silly though as the difficulty gets so high the ship would be straining systems to get the firing solution so the generated Threat would become hilarious. Though if you did succeed in hitting a person with a turbolaser the +50 crit option would certainly be in order.

Grounded ships would be targeted as normal.