This might be a slightly mad idea/question, but would it be possible/feasible to use a catapult type station to 'throw' ships and probes /.../
Didn't NASA once play with this thought?
I remember watching an animation on TV where this kind of system was installed in orbit around Earth and the moon.
Yeah, the problem with the idea is that the rotating station (called a "skyhook" or some other variation) is effectively a giant flywheel that functions as a momentum bank. The problem with this idea is, every joule of energy you impart on a ship is energy the rotating station looses; you'd have to build up that energy by sending something of similar mass or similar velocity to be captured by it or else it will eventually spin down.
Well, the heat buildup is manageable in an atmosphere OR in space, and in the latter environment it's only dangerous to the driver's components and systems, but there are ways around that too.I suggest the trebuchet design as an alternative to mass drivers, since I'm under the impression that mass drivers suffer from massive heat build up, even when used in atmospheres, so I could imagine that such a heat build up in void vacuum could be highly dangerous.
The real problem with mass drivers is that they're huge, expensive, and you can only use them to send payloads into a pre-determined orbit. Nobody's going to do that until the parameters of those orbits are already mapped out; basically it's the high speed rail of space exploration.