Radioisotope Thermoelectric Space Power Supplies

The weight and efficiency of radioisotope thermoelectric space power supplies, using Plutonium-238, Curium-244 and Strontium-90 fuels, lead telluride and silicon germanium alloy thermoelectric systems, and ranging in power output from 30 to 300 electrical watts are presented. It is shown that there is a definite radiator temperature for which generator weight is minimum and that this temperature varies with fuel, thermoelectric conversion system and power level. In addition, the various factors governing the selection of a particular radioisotope power supply for a given mission are discussed.