During these periods of "sleep," New Horizons is powered by a single radioisotope thermoelectric generator and USES less power than a pair of 100-watt household light bulbs.

The radioisotope thermoelectric generator which is employed in deep space exploration, converts heat from the natural decay of radioisotope materials into electrical power directly.

This paper retrospects to the developing history and usage status of radioisotope thermoelectric generator (RTG) used in space in the 20th century.