Somewhere on the Moon’s south pole, in a permanently shadowed crater where temperatures plunge below minus 280 degrees Fahrenheit, NASA wants to switch on a nuclear reactor before the decade is out. Not a radioisotope battery like the ones that have powered Mars rovers, but a full fission reactor: a self-contained power plant capable of splitting uranium atoms and generating enough electricity to run habitats, science labs, and oxygen-extraction equipment through the punishing 14-day lunar night that solar panels cannot survive.
The effort is called the Fission Surface Power (FSP) program, and as of spring 2026, it represents one of the most ambitious pieces of hardware in NASA’s Artemis architecture. If it works, it will be the first nuclear power plant ever operated on another world.
The partnership and what it has produced so far
NASA and the U.S. Department of Energy formally partnered to develop a lunar fission reactor, with DOE supplying reactor expertise through Idaho National Laboratory and NASA handling mission integration, landing, and surface operations. The agencies set an explicit goal: deliver a working reactor to the lunar surface by 2030, according to NASA’s joint announcement.
The program has already moved through an initial concept phase. In 2022, NASA and DOE selected three industry teams to develop competing reactor designs, each receiving approximately $5 million through Idaho National Laboratory. The awardees were Lockheed Martin, Westinghouse, and IX, a joint venture between Intuitive Machines and X-energy. All three concepts targeted a 40-kilowatt-electric (kWe) class system designed to operate autonomously on the lunar surface for at least 10 years.
Forty kilowatts of continuous electric power is modest by terrestrial standards, roughly enough to sustain 33 average American households, but on the Moon it would be transformative. Current lunar surface missions rely on solar arrays and batteries that go dark for two weeks every lunar cycle. A fission reactor would deliver steady, round-the-clock power regardless of sunlight, enabling sustained human presence rather than brief visits.
KRUSTY: the ground test that proved the physics
The technical foundation for the FSP program traces back to a ground experiment with a memorable acronym. KRUSTY, short for Kilopower Reactor Using Stirling Technology, ran at the Nevada National Security Site in 2018. Engineers built a small uranium-fueled reactor, brought it to full power, and demonstrated that it could regulate itself without human intervention, even when they deliberately simulated hardware failures.
KRUSTY produced roughly one kilowatt of electric power. A Department of Energy technical report documented the test data, and peer-reviewed results were published in the journal Nuclear Technology, confirming that the reactor physics, fuel behavior, and Stirling power-conversion cycle all performed as modeled. Scaling from one kilowatt to 40 or more is a substantial engineering leap, but it builds on validated science rather than an unproven concept.
The 40 kWe vs. 100 kWe question
Perhaps the most consequential unresolved question in the program is how powerful the flight reactor will actually be. The 2022 concept awards targeted 40 kWe. But NASA’s Glenn Research Center, which manages the FSP acquisition, later published a request for industry feedback describing a requirement of at least 100 kWe using a closed Brayton cycle for power conversion.
The gap between those two numbers is not trivial. A 100-kWe reactor could anchor a large outpost with multiple habitats, support industrial-scale oxygen extraction from lunar regolith, and power rovers and construction equipment simultaneously. A 40-kWe unit would serve a smaller crew with tighter energy margins and fewer concurrent operations. Higher power also means more mass devoted to radiator panels, radiation shielding, and structural supports, all of which complicate launch and landing logistics.
As of spring 2026, NASA and DOE have not released a public trade study showing how they plan to resolve this tension. The evolution from a 40-kWe baseline toward consideration of a 100-kWe system suggests the agencies are trying to match the reactor’s capability to expanding Artemis surface plans, but it also signals that the final design has not been locked down.
Schedule pressure and procurement delays
Glenn Research Center’s planning documents have indicated an intent to place the reactor on the Moon by the first quarter of fiscal year 2030, which corresponds to October through December 2029. That leaves roughly three and a half years from early 2026 to complete final design, fabricate reactor hardware, qualify the system through ground testing, integrate it with a lunar lander, launch it, and land it safely.
The timeline is tight by any measure. Idaho National Laboratory’s own milestone tracker shows that requests for proposals have experienced delays, and NASA’s solicitation timeline has been updated more than once. For comparison, the KRUSTY ground test took several years from concept to execution, and it did not need to survive a rocket launch, operate in a vacuum, or reject waste heat on an airless surface with temperature swings exceeding 500 degrees Fahrenheit.
Budget visibility adds another layer of uncertainty. The three initial concept awards totaled roughly $15 million combined, a modest investment for a program that must ultimately design, build, test, launch, and land a nuclear reactor on another celestial body. No detailed post-concept budget breakdown from NASA or DOE has appeared in publicly available documents. Without that information, it is difficult to assess whether the 2030 target is fully funded or whether it depends on future congressional appropriations that have not yet been secured.
Fuel, regulation, and the HALEU bottleneck
Building a space-rated fission reactor requires high-assay low-enriched uranium (HALEU) fuel, a specialized material enriched to between 5 and 20 percent uranium-235. Domestic HALEU supply has been a recognized bottleneck across the U.S. advanced nuclear sector, not just for space applications. DOE has been working to expand production capacity, but whether enough HALEU will be available on the FSP program’s timeline is an open question that procurement documents have not publicly addressed.
Regulatory hurdles add further complexity. Launching a nuclear reactor requires compliance with federal guidelines governing the use of radioactive materials in space, including detailed safety analyses of launch-failure and atmospheric-reentry scenarios. Operating one on the Moon raises questions about radiation shielding for nearby astronauts, thermal management in a vacuum, and long-term waste handling. The program’s public documents have not yet detailed how these challenges will be resolved at the flight-system level, such as how much shielding mass will be allocated versus relying on physical distance between the reactor and crew habitats.
Geopolitical context: China’s parallel effort
NASA is not pursuing lunar nuclear power in isolation. China’s space agency has publicly discussed plans to deploy a nuclear reactor on the Moon as part of its International Lunar Research Station program, with timelines that overlap NASA’s 2030 target. The parallel efforts add a competitive dimension to what is already a technically demanding program, and they help explain why both NASA and DOE have framed the FSP project not only as a science and exploration initiative but also as a national security priority.
A White House executive order directing interagency coordination to accelerate advanced nuclear reactor technologies has reinforced that framing. NASA’s FSP program claims alignment with the order, though the directive itself does not contain specific funding commitments or schedule mandates for the lunar reactor. It signals political support without guaranteeing programmatic execution.
What the reactor still needs to prove
The foundational physics behind the FSP program are solid. KRUSTY demonstrated that a small fission reactor can self-regulate and produce electricity as designed. The institutional machinery for building a flight system is in motion: concept studies are complete, procurement planning is underway at Glenn Research Center, and three credible industry teams have already produced competing designs.
But the distance between a one-kilowatt ground demonstration and a 40-to-100-kilowatt autonomous power plant on the lunar surface is enormous. The program must still finalize its power class, secure sustained funding, navigate HALEU supply constraints, clear nuclear launch-safety reviews, and integrate the reactor with a lander and surface infrastructure that are themselves still under development. NASA has not fully described the power distribution architecture, such as whether the reactor will feed a centralized grid connecting multiple habitats or primarily support a single base, and those choices will ripple through cable routing, fault protection, redundancy, and maintenance planning.
If the pieces come together, the FSP program will mark a turning point not just for lunar exploration but for humanity’s ability to sustain itself beyond Earth. A reliable, long-duration power source is the single most enabling technology for a permanent Moon base, and eventually for crewed missions to Mars, where solar intensity drops and dust storms can black out panels for weeks. The reactor that NASA and DOE are trying to build is, in that sense, less a piece of Artemis hardware than a proof of concept for living on other worlds. Whether it lands on the Moon by 2030 will depend on decisions, dollars, and documents that have not yet materialized.
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*This article was researched with the help of AI, with human editors creating the final content.
