50 Years of Nuclear-Powered Spacecrafts

Here are a couple of good articles to learn more about how nuclear fuel is used for space missions and its history: http://www.space.com/12118-space-nuclear-power-50-years-transit-4a.html ..., see also: http://www.space.com/13709-plutonium-shortage-nasa-planetary-science-future.html ...."Plutonium-238, which is different than the type of plutonium used in nuclear weapons, emits heat that is converted into electricity. The material has been particularly useful on missions that venture into the outer solar system, where the scant sunlight cannot effectively be harnessed using solar panels."