Well, we have done at least one Earth gravity assist with a nuclear payload in the past. There also was some criticism about it back then: http://en.wikipedia.o

Well, we have done at least one Earth gravity assist with a nuclear payload in the past. There also was some criticism about it back then: http://en.wikipedia.org/wiki/Cassini%E2%80%93Huygens#Plutonium_power_source http://en.wikipedia.org/wiki/Cassini%E2%80%93Huygens#Plutoni...