Radioisotope Power: Historical Review

Abstract

Radioisotope power has enabled such breakthrough space missions as the Pioneer flights to Jupiter, Saturn and beyond; the Voyager flights to Jupiter, Saturn, Uranus, Neptune and into interstellar space; the Apollo lunar surface experiments; the Viking Lander and rover studies of Mars; the Galileo spacecraft that orbited Jupiter; the Ulysses mission that studied the polar regions of the Sun; the Cassini mission that orbited Saturn and the New Horizons mission to Pluto and the Kuiper Belt. Radioisotope heater units have enhanced or enabled a number of scientific missions. Since 1961, the United States has successfully flown 42 radioisotope thermoelectric generators (RTGs) to provide electrical power for 24 space missions as well as hundreds of radioisotope heater units designed to keep spacecraft components warm. The former Soviet Union flew at least 35 nuclear reactors and a handful of radioisotope heater units.