Many future space power requirements in the low power regime (watts to a few kilowatts) 9 with durations of a few months to years 9 are potentially satisfied by utilization of radioisotope power subsystems. The isotope power subsystems of today , essentially first generation devices, do not provide a direct basis for extrapolation to future performance capabilities. Many development problems must be solved before isotope power subsystems realize their full potential.
The currently operational isotope powered I!SNAP I! units for space application are characterized by high specific weight (l watt/lb), low power output (\u3c=25 watts) , low heat source temperature (~1000°F)^ and low conversion efficiency (\u3c=5%). Future capabilities promise 10 to 20 watts/lb, 2000°C heat source operation ^ and conversion efficiencies approaching 20%. This paper examines the technical advancements necessary to attain these performance capabilities
