Vierstein said:
Just imagine it gets close to a large object, like another star system, or a large rock, how is it supposed to escape again?
It might crash into it and that would be the end of it but if it doesn't have an atmosphere and it just goes by the surface it will be going too fast to become a satellite, just change directions and end up going to some random angle off again.
You need to study just what it takes to capture an object to be a satellite. If you know the orbital velocity of a planet, multiply it by the square root of two and you know the escape velocity. Now if you want to be captured by a planet you first need to be going slower than escape velocity or its a no go, goodbye planet. So you first need to slow down to less than the escape velocity at whatever altitude you pass by. Then you need to slow down even more by that same factor, square root of two, to be captured. How do you suppose all that is going to happen to a non-powered space probe flying through space? The only possible way would be if the planet had an atmosphere and you use aerobraking but that is not going to happen to a random probe passing at a random altitude and random velocity, most certainly faster than the escape velocity of said planet.
It takes very detailed calculations to safely be captured via aerobraking, there would have to be a computer onboard with sensors like radar or lidar or some such to track the probe every second of the encounter and a means to slow down first to make aerobraking even work.
Then you have to know just how fast you can dip into the atmosphere and just how long to keep from burning up, slowing down a bit after each dip into the atmosphere and so forth.
This is an active system and is used by the space shuttle, Mars probes and such but has to be very carefully planned.
You are not going to even get close to pulling that off by a random dead probe passing by a random planet with or without an atmosphere, which would happen to the Voyagers for literally millions of years anyway. It could probably go a billion years before anything like that would happen.
It's a vast empty space between the stars.