The Technology of Discovery

2The History of the United States’s Flight and Terrestrial RTGs

Andrew J. Zillmer

Idaho National Laboratory, Idaho Falls, Idaho

Space nuclear power systems have their origins in works by Arthur C. Clarke and studies for surveillance and navigation satellites produced after World War II. The processing of materials for the building of atomic bombs led to a number of radioisotopes being available, which in turn increased the number of radioisotopes available for alternative civilian and defense purposes.[1] The Systems for Nuclear Auxiliary Power (SNAP) program consolidated several of the Atomic Energy Commission’s (AEC) reactor and radioisotope programs in the mid‐1950s. RPS models were identified by the odd numbers in their designations and reactor systems with even numbers.

2.1 Flight RTGS

2.1.1 SNAP Flight Program

Initial requirements for SNAP systems came from Project Feedback, a Rand Corporation study, that originated in 1946 to evaluate the feasibility of artificial satellites. Initial power requirements were at least 1 kW_e of power with a closed cycle power plant operating between 422 °C (900 °F) and 704 °C (1300 °F). The original SNAP‐1 and 2 systems used similar mercury Rankine dynamic power conversion technologies, and the SNAP‐1 series of power systems included RTGs.[2]

2.1.1.1 SNAP‐3

The SNAP‐3 system was the first Radioisotope Thermoelectric Generator (RTG) deployed under the SNAP program. It used a static thermoelectric converter developed by 3M. The Martin ...