NASA has been using nuclear powered probes for 50 years. It is called a redioisotope thermoelectric generator (RTG). https://www.space.com/13709-plutonium-sho

NASA has been using nuclear powered probes for 50 years. It is called a redioisotope thermoelectric generator (RTG). https://www.space.com/13709-plutonium-shortage-nasa-planetary-science-future.html https://www.space.com/13709-plutonium-shortage-nasa-planetar... Unfortunately, there is a shortage of plutonium-238 to run these RTGs (see above story). I guess that will get resolved somehow. The current Mars Curiosity rover is powered by an RTG. Since this is the first flying (post-landing of course) probe I suppose it will be the first nuclear powered flight of a planetary probe.