Updated: May 2020
Space exploration missions require safe, reliable, long-lived power systems to provide electricity and heat to spacecraft and their science instruments. One flight-proven source of dependable power is Radioisotope Power Systems (RPS). A type of RPS is a Radioisotope Thermoelectric Generator (RTG) — a space nuclear power system that converts heat into electricity using no moving parts.
The Department of Energy (DOE), in support of NASA, has developed several generations of such space nuclear power systems that can be used to supply electricity — and useful excess heat — for a variety of space exploration missions. The current RPS, called a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), was designed with the flexibility to operate on planetary bodies with atmospheres, such as at Mars, as well as in the vacuum of space. An MMRTG generates about 110 watts of electrical power at launch, an increment of power that can be matched with a variety of potential mission needs. As with prior RPS, ensuring a high degree of safety is also a fundamental consideration.