Technology development issues in space nuclear power for planetary exploration

Abstract

Planning for future planetary exploration missions indicates that there are continuing, long range requirements for nuclear power, and in particular radioisotope-based power sources. In meeting these requirements, there is a need for higher efficiency, lower mass systems. We describe here four technology areas currently under development that address these goals: modular RTG, modular RTG with advanced thermoelectric materials, dynamic isotope power system(DIPS), and the Alkali Metal Thermoelectric Converter(AMTEC). The modular RTG is the next generation improvement in RTG performance, where work is now focussed on development of the multicouple converter technology. If advances are also made in thermoelectric materials, the modular RTG may provide as much as 10 W/kg at 10% efficiency. The DIPS technology, at much higher efficiencies, would enable multikilowatt radioisotope power if reliable, long term, continuous operation under space conditions can be assured. Finally, while static AMTEC devices offer the potential for efficiencies comparable to dynamic systems, this technology is the least mature of those discussed, and will require the demonstration of several component technologies in long life tests.