What is a Radioisotope Thermoelectric Generator?
A radioisotope thermoelectric generator (RTG) is an electric power source which uses the heat produced by radioactive decay. Radioisotope thermal generators are not nuclear reactors and do not use nuclear fission or fusion for energy, although they are still highly radioactive. Radioisotope thermal generators are used when other power sources are too expensive or impractical, such as on spacecraft and automated beacons and radar systems. A radioisotope thermal generator contains a quantity, often several pounds (kilograms) or more, of highly radioactive material. The radioactive material must produce enough heat to provide significant amounts of electricity; at the same time, it must not decay so quickly that the radioisotope thermal generator is useless after a few years. Plutonium-238 is the most common isotope used for radioisotope thermal generators, although strontium-90 and others have been utilized in the past. Plutonium-238 is expensive to produce, but it gives off low-penetrat
