The United States Office of Science and Technology Policy has published an ambitious roadmap calling for nuclear fission reactors to be deployed both in Earth orbit and on the surface of the Moon by 2031, marking a significant escalation in Washington's push to establish nuclear power as a cornerstone of future space infrastructure.
The White House's science and technology advisory body has laid out plans that would see operational nuclear fission reactors in space within five years, a timeline that experts in the field are likely to greet with a mixture of excitement and scepticism.
The policy document identifies roles for both government agencies and private industry in achieving the goal, which encompasses reactors placed in Earth orbit as well as units designed to operate on the lunar surface. The Moon-based reactors would be intended to provide sustained power for future crewed installations, while orbital systems could serve satellite operations or deep-space mission support.
Nuclear fission power has long been considered a critical enabling technology for sustained human presence beyond Earth. Unlike solar panels, which lose effectiveness with distance from the Sun and are vulnerable to dust accumulation on lunar and Martian surfaces, compact fission reactors can provide reliable, high-density power in almost any environment.
NASA and the Department of Energy have been developing the Fission Surface Power project for several years, with Lockheed Martin, IX (a joint venture of Intuitive Machines and X-Energy), and Westinghouse among the contractors previously awarded concept contracts. The new policy directive appears to sharpen the timeline and broaden the scope of those efforts.
The 2031 deadline is aggressive by the standards of space nuclear development. Previous US space nuclear programs, including the Kilopower reactor demonstration completed in 2018, took years of careful ground testing before any hardware approached readiness for spaceflight qualification. Moving from kilowatt-scale demonstrations to flight-ready systems capable of supporting lunar outposts represents a substantial engineering and regulatory challenge.
International interest in space nuclear power is also growing. Russia has operated nuclear-powered satellites for decades, and China has publicly outlined plans for nuclear-powered spacecraft. The US directive reflects, in part, a recognition that space power infrastructure is becoming a domain of strategic competition.
The policy document's publication does not itself allocate funding, and observers note that Congressional appropriations will ultimately determine whether the ambitions outlined by OSTP translate into hardware in orbit by the end of the decade.
Analysis
Why This Matters
- Nuclear power in space would fundamentally change the calculus for sustained lunar and deep-space operations, enabling crewed outposts and high-power scientific instruments that solar arrays alone cannot support.
- The 2031 timeline, if met, would place the US ahead of China in deploying operational space fission systems — a significant milestone in the growing competition for influence beyond Earth orbit.
- Success or failure will depend heavily on Congressional funding decisions and whether regulatory frameworks for launching nuclear material can be updated quickly enough to match the policy ambition.
Background
The United States last operated a nuclear fission reactor in space in 1965 with the SNAP-10A mission, which ran for 43 days before being shut down remotely. Since then, US space missions have relied on radioisotope thermoelectric generators (RTGs) — passive decay-heat devices used on missions like Voyager and Curiosity — rather than active fission systems.
NASA and the Department of Energy revived serious fission surface power research in the 2000s and again more substantively in the late 2010s. The Kilopower project, which produced a working 1-kilowatt reactor prototype tested in Nevada in 2018, demonstrated that compact space fission was technically achievable. However, scaling to the tens of kilowatts needed for a meaningful lunar outpost remains a significant step.
The current administration has shown consistent interest in accelerating space nuclear programs, framing them as both a national security priority and a prerequisite for the Artemis program's long-term lunar ambitions. The new OSTP document is the most explicit policy statement yet about expected timelines and stakeholder responsibilities.
Key Perspectives
NASA and Department of Energy: Both agencies have been working toward space fission capability and are likely to welcome clearer policy direction, though internal timelines had previously been more conservative than 2031 for operational deployment.
Private industry (Lockheed Martin, Westinghouse, X-Energy): Contractors who have already received development funding stand to benefit significantly from an accelerated program, though they will also face pressure to compress development and testing schedules that normally span a decade or more.
Critics and independent space engineers: Some experts argue the five-year timeline is unrealistic given the need for extensive ground testing, launch safety approvals from bodies including the FAA and NASA's own planetary protection offices, and the complexity of operating reactors in the lunar environment. There are also concerns that rushing nuclear hardware could increase the risk of launch accidents.
What to Watch
- The FY2027 federal budget request, which will indicate whether OSTP's ambitions are backed by meaningful appropriations for NASA and DoE space nuclear programs.
- Progress on the Fission Surface Power project's engineering development phase, including whether any contractor reaches a flight-system preliminary design review before 2028.
- Any international agreements or tensions around the use of nuclear power sources in cislunar space, an area not fully addressed by existing outer space treaties.