That actually makes sense if you get rid of the assumption that they were in orbit in the first place. Once you have cheap, powerful thrusters like starwars/st

That actually makes sense if you get rid of the assumption that they were in orbit in the first place. Once you have cheap, powerful thrusters like starwars/startrek has (thrusters that can hold the mass of the whole ship against gravity in any direction, independent of the main engine), it makes little sense to actually bother going into orbit, unless you actually want to turn the thrusters off. Instead, just pick a point on the planet and hover over it. Or pick a circular orbit-like path around the planet for maximum coverage. Just pick whatever position or path through space makes the most strategic sense. If you have a ship operating like this, and it loses power to it's thrusters... then of course it will 'sink' into the nearest planet as gravity suddenly becomes the primary force acting on the ship.