Radioisotope Thermoelectric Generators
Made up of three units, these generators function as the main power source. Each unit source consists of an isotopic heat source (Plutonium-238), a thermoelectric converter, a gas pressure venting system, temperature transducers, and a heat rejecting cylindrical container. The power output at the time of launch was 470 watts, however the half-life of plutonium (87.7 years) means that the energy output will decrease over time.