Systems for Nuclear Auxiliary Power

The Systems Nuclear Auxiliary POWER (SNAP) program (also "Space Nuclear Auxiliary Power" program) was a program of experimental radioisotope thermoelectric generators (RTGs) and space nuclear reactors flown during the 1960s by NASA. The SNAP program developed as a result of Project Feedback, a RAND Corporation study of reconnaissance satellites completed in 1954. As some of the proposed satellites had high power demands, some as high as a few kilowatts, the U.S. Atomic Energy Commission (AEC) requested a series of nuclear power-plant studies from industry in 1951.

Source: Wikipedia — Systems for Nuclear Auxiliary Power (CC BY-SA 4.0)