Radioisotope thermoelectric generator
A radioisotope thermoelectric generator ( RTG , RITEG ) is an electrical generator It is an electrical generator that uses an array of thermocouples to convert the heat released by the decay of a suitable radioactive material into electricity by the Seebeck effect . RTGs have been used as power sources in satellites , space probes , and uncrewed remote facilities such as a series of lighthouses built by the former Soviet Union inside the Arctic Circle . RTGs are usually the most desirable power source for unmaintained situations that need a few hundred watts (or less) of power for durations too long for fuel cells , batteries, or generators to provide economically, and in places where solar cells are not practical. Safe use of RTGs requires containment of the radioisotopes long after the productive life of the un...