Along with just about every other deep-space probe, and the recent Mars rovers. RTGs just give so much more power per pound in the outer solar system. True rea

Along with just about every other deep-space probe, and the recent Mars rovers. RTGs just give so much more power per pound in the outer solar system. True reactors - not just RTGs - are a bit less common, but have a long history of use in the USSR's radar reconnaissance satellites. (The US only ever launched one, SNAP-10A [0]. The USSR launched more than 30) 0: https://en.wikipedia.org/wiki/SNAP-10A https://en.wikipedia.org/wiki/SNAP-10A