Nearly all such satellites would have highly directional antennas, so the aliens would have to be neat earth before they could do that. Voyager is not expecting a command signal from anywhere else but Earth. The signal would have to originate not more than a fraction of a degree from Earth from Voyager’s perspective.
**This also means that aliens can reprogram all of our satellites. **
Yes if they can track them in middle of space.
It’s impressive that we can still send data to the satellite. I mean you need to send the signal to the place where the satellite will be in 24 hours.
Nearly all such satellites would have highly directional antennas, so the aliens would have to be neat earth before they could do that. Voyager is not expecting a command signal from anywhere else but Earth. The signal would have to originate not more than a fraction of a degree from Earth from Voyager’s perspective.
So they just need to go behind it?