NASA remotely reprogramming Voyager 1 also means that aliens can reprogram all of our satellites.
This is assuming that they would know and understand the code. Also, that nothing is encrypted but I guess encryption can be broken.
I would doubt they would have encrypted anything on the probe back in 1977 when it launched.
The ultimate security by obscurity. Do you have a 30m antenna? Can you point it exactly at the space ship with almost no error? Do you know what it’s code and protocols are? OK, please reprogram Voyager
OP says reprogram all of the satellites. So I would assume that would include the modern ones with encryption as well.
I cannot confirm or deny any such arrangement exists with an existing alien species.
I would guess not. Any authentication scheme would just be another risk point to not be able to talk to the thing from earth.
But I’m just guessing.
