You're assuming that satellites are exterritorial. They aren't, they're ab initio the launching state's property and responsibility, barring other agreements to transfer them - and getting one out into a "legal void" isn't going to be trivial.
That said, they don't have to grab the satellite. They have to grab you. Computer vandalism/sabotage/... laws in a lot of legal systems already apply to the controlling people in their home location regardless of the physical location/origin of the computer activity. Your controlling the computer/satellite/botnet/... is the illegal act, not the network packets leaving those systems.
They'll have to identify you first though, which might give some legal shielding.