The SNAP-27 Radioisotope Thermoelectric Generator (RTG) converted the heat energy from radioactive decay to electrical energy. Five such RTGs provided electric power for the Apollo Lunar Surface Experiment Packages (ALSEP) left on the Moon by Apollos 12, 14, 15, 16 and 17. These stations transmitted information about moonquakes and meteor impacts, lunar magnetic and gravitational fields, the Moon's internal temperature, and the Moon's atmosphere for several years after the missions. After ten years, a SNAP-27 still produces more than 90% of its initial output of 70 Watts.
A.3.2 Electrical Power System
The electrical power system (fig. A-2) provides the power for operation of the experiment packages. The primary electrical energy is developed by thermoelectric action with thermal energy supplied by a radioisotope source. The expected output is a constant 16 volts. The elctrical power system consists of a radioisotope thermoelectric generator, fuel capsule assembly, power conditioning unit, and fuel cask. The radioisotope thermoelectric generator is a cylindrical case with eight heat rejection fins on the exterior and an interior thermopile to receive the fuel capsule. The fuel capsule is a thin-walled cylindrical structure containing the radioisotope fuel, plutonium 238. The power conditioning unit contains the dc voltage converters, shunt
regulators, filters, and amplifiers required to convert and regulate the power. The graphite fuel cask, a cylindrical structure with a threaded cover, was used to transport the fuel capsule from the earth to the moon.
Apollo-12 Mission Reort.
Прил.A3 "EXPERIMENT EQUIPMENT"