NASA tests new nuclear fuel that could outlast plutonium in space

NASA is exploring americium-241 as a promising alternative to plutonium-238 for powering long-duration space missions, particularly those venturing far from the Sun where solar energy is insufficient. Traditionally, NASA has relied on plutonium-238 in radioisotope power systems (RPS) for over six decades, but americium-241 offers advantages including a longer half-life (432 years) and potentially easier, more cost-effective production. In collaboration with the University of Leicester, NASA’s Glenn Research Center tested a Stirling generator powered by simulators mimicking americium-241 decay heat. This Stirling convertor features floating pistons without crankshafts or rotating bearings, enabling continuous operation for decades with minimal wear. Notably, the system maintained power output even after one convertor failed, demonstrating robustness crucial for deep-space missions. The successful prototype met performance and efficiency goals, prompting NASA to develop a next-generation testbed with reduced mass, improved fidelity, and readiness for environmental testing