And how would you get them out to, and stop at, 550 AU? Voyager 1 and 2 are nuclear powered with RTGs and they are respectively about 150 AU and 125 AU from the sun, and they are going really fast. The Voyager RTGs are also fairly depleted at this point. I’m guessing these spacecraft would need a faster, more efficient mode of propulsion, like a nuclear thruster or ion drive (or Epstein drive?!). One could also get a lot more fuel for the journey if the the probes didn’t have to launch fully fueled from the Earth’s surface.