Radioistope Power Systems (RPS) and Pu-238

The recent shipment of heat source plutonium-238 from the U.S. Department of Energy’s (DOE’s) Oak Ridge National Laboratory to its Los Alamos National Laboratory is a critical step toward fueling planned NASA missions with radioisotope power systems.

This shipment of 0.5 kilograms (a little over 1 pound) of new heat source plutonium oxide is the largest since the domestic restart of plutonium-238 production over a decade ago. It marks a significant milestone toward achieving the constant rate production average target of 1.5 kilograms per year by 2026.

Radioisotope power systems, or RPS, enable exploration of some of the deepest, darkest, and most distant destinations in the solar system and beyond. RPS use the natural decay of the radioisotope plutonium-238 to provide heat to a spacecraft in the form of a Light Weight Radioisotope Heater Unit (LWRHU), or heat and electricity in the form of a system such as the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG).