US-based Intuitive Machines has been granted a $8.2m contract extension from the US Air Force Research Laboratory’s Space Vehicles Directorate (AFRL/RV) to develop next-generation nuclear power systems for spacecraft and lunar infrastructure. The Space Vehicles Directorate is the US Air Force’s centre of excellence for space research. The funding will be used to accelerate readiness of compact nuclear power conversion technology to overcome solar power limitations and enable lengthier missions.
The award follows $9.5m under a previous AFRL programme to develop compact nuclear power systems for space applications. That included the design of a Stirling-based power conversion system which transforms heat from a radioisotope source into electricity. It culminated in a successful Preliminary Design Review by Intuitive Machines in September. The new funding will enable Intuitive Machines to begin preparing the system for flight, marking a critical step toward demonstrating space-based nuclear power in orbit.
Intuitive Machines is a diversified space technology, infrastructure, and services company. In 2024, it soft-landed the Company’s Nova-C class lunar lander on the Moon, returning the US to the lunar surface for the first time since 1972. In 2025, Intuitive Machines returned to the lunar south pole with a second lander. The Company’s products and services focus on three pillars of space commercialisation: Delivery Services, Data Transmission Services, and Infrastructure as a Service. The company has a joint venture, XI, with sister company X-energy.
Intuitive Machines believes demand is growing for reliable, scalable energy systems like Stirling engines which offer continuous power and heat in a much smaller package to support spacecraft and planetary surface missions. Intuitive Machines is meeting that demand by building reliable, scalable energy systems that may power spacecraft and planetary surface missions beyond solar powered limitations.
“This award moves us from design to flight hardware, which is a critical step toward proving that compact nuclear power systems can survive and perform in space,” said Dr Tim Crain, co-founder and Chief Growth Officer for Intuitive Machines. “Because Intuitive Machines is vertically integrated across space data, infrastructure, and delivery services, we can rapidly innovate across the entire mission lifecycle and deliver compact, high-performance technologies and scalable solutions required for sustained operations in space.”
The Stirling Technology spAce Research experimenT (START) is a flight experiment designed to demonstrate Stirling power conversion technology in space. While onboard the International Space Station (ISS) National Laboratory, the Stirling system will be exposed to conditions that cause conventional power systems to degrade more quickly, limiting their operational lifespan and cutting missions short.
By flying the Stirling technology on the ISS National Lab, Intuitive Machines intends to raise the nuclear power technology system’s readiness level from prototype to space-flown, which is a critical step toward commercial, civil, and national security space flight-ready acceptance. The Stirling technology is designed to support critical mission needs by delivering compact, continuous power in space.
These capabilities are essential for enabling stealth spacecraft operations in national security missions, ensuring generators remain functional during prolonged darkness and extreme cold, and powering Position, Navigation, and Timing (PNT) beacons with long-duration nuclear energy to support sustained lunar navigation. In addition, Intuitive Machines has been studying high powered nuclear fission-based systems under contract to the Department of Energy with funding provided by NASA’s Fission Surface Power project.
“We believe the progress under the AFRL programme strengthens our position for future nuclear power programs including NASA’s FSP initiative,” said Crain. “Maturing dynamic power conversion and control technologies that scale is how we evolve from a lunar delivery to a commercial infrastructure service provider on the Moon.”
