NASA has issued a solicitation for advanced radioisotope power systems to support lunar exploration, targeting 20% system efficiency and 50–150 We power output for lunar landers and rovers. The initiative, part of broader efforts to establish a sustainable lunar presence. The solicitation, announced on Sept. 8 as part of NASA’s NextSTEP-3 Broad Agency Announcement Appendix A: Lunar Enabling Infrastructure Accelerator, seeks proposals to advance technologies for a lunar base in the Moon’s south pole region. The initiative targets capability gaps, including power generation, oxygen extraction, and producing materials on the Moon required for construction and operations.
NASA’s recent solicitation for lunar radioisotope power systems marks a pivotal step in its strategy to enable long-term human exploration of the Moon. The agency seeks proposals for radioisotope Stirling generators (RSGs) capable of reducing fuel requirements by a factor of three to four compared to current technologies while supporting power outputs of 50–150 We for lunar landers and rovers. The initiative, part of the NextSTEP-3 program, also includes research into vertical solar arrays, oxygen extraction from regolith, in-space advanced manufacturing, and innovative nanomaterials production. NASA is accelerating the development of key technologies and closing critical gaps needed for long-term human exploration at the Moon,
said Greg Stover, director of NASA’s Advanced Research and Technology Division. Partnering with industry will strengthen the U.S. industrial base as we mature the capabilities and infrastructure needed for a sustainable lunar presence.
RSGs: Efficiency, Fuel Flexibility, and Lunar Survival
NASA solicits lunar radioisotope power — ANS / Nuclear
The solicitation emphasizes RSGs as a critical technology for lunar operations, particularly in shadowed regions where solar power is unreliable. These systems, which convert heat from radioactive materials into electricity, must achieve at least 20% efficiency, a specific power of 1 W/kg, and a five-year design life. NASA is open to fuels including americium-241, and encourages designs adaptable to Mars missions with extended lifespans and higher power outputs. The solicitation specifies that RSGs must include a Stirling power convertor, electronic controller, thermal management system, heat source, and potentially dynamic balancer. Prototypes are expected to progress from Technology Readiness Level (TRL)-3 or -4 to TRL-5 or -6. NASA also seeks proposals for systems that could theoretically support 300 We power output and 10-year lifespans, though these extensions are restricted to analytical demonstrations rather than full-scale development.
Stover’s Vision: Lunar Base, Mars Mission, and Industrial Growth
The shift to a surface-based lunar base is central to NASA’s current focus. The agency aims to establish a presence in the Moon’s south pole region, where long nights make solar power less effective, making nuclear an important power option. NASA is accelerating the development of key technologies and closing critical gaps needed for long-term human exploration at the Moon,
Stover said. Partnering with industry will strengthen the U.S. industrial base as we mature the capabilities and infrastructure needed for a sustainable lunar presence.
Broader Implications: From Moon to Mars and Beyond
NASA Calls for Proposals to Accelerate Lunar Surface Technologies
The solicitation aligns with NASA’s broader strategy to leverage in-situ resource utilization, advanced manufacturing, and nanomaterials for sustainable exploration. By prioritizing RSGs, the agency aims to reduce reliance on Earth-based resupply missions and enable operations in extreme environments. The initiative seeks U.S.-led capabilities while maintaining full and open competition among private industry, academic institutions, and not-for-profit entities, as well as international partners participating through U.S.-led teams. NASA may apply insights gained from resulting contracts, such as technical data and demonstration results, to shape future acquisition strategies. The solicitation also emphasizes extensions to Mars applications, including survival in the Mars environment, power output of up to 300 We, and design life up to 10 years, though these are restricted to analytical demonstrations.
Additional Details and Context
The solicitation specifies that RSG designs must be capable of providing survival heat and power for landers and rovers to endure harsh environments, such as permanently shadowed regions. The effort is described as fundamentally a research and development initiative aimed at refining system designs and demonstrating innovative approaches where full system definitions are still evolving.
NASA’s focus on nuclear power reflects its need for reliable energy sources in extreme conditions, complementing other technologies like vertical solar arrays and oxygen extraction from regolith. The agency’s NextSTEP-3 program serves as a critical testing ground for these advancements, with the goal of maturing technologies for lunar and interplanetary missions.
Rob Margetta, Headquarters, Washington, 202-358-0918, [email protected]. To learn more about NextSTEP-3, visit: https://go.nasa.gov/4x20o3t.
