Why the US Is Racing to Build a Nuclear Reactor on the Moon

NASA is fast-tracking a plan to build a nuclear reactor on the moon by 2030 under a new directive from the agency’s interim administrator Sean Duffy.

The plan revives a decades-old dream of scaling up nuclear power in space, a shift that would unlock futuristic possibilities and test legal and regulatory guidelines about the use of extraterrestrial resources and environments.

Duffy, who also serves as President Donald Trump’s secretary of transportation, framed being first to put a reactor on the lunar surface as a must-win contest in a new moon race. “Since March 2024, China and Russia have announced on at least three occasions a joint effort to place a reactor on the Moon by the mid-2030s,” said Duffy in the directive, which is dated July 31.

“The first country to do so could potentially declare a keep-out zone which would significantly inhibit the United States from establishing a planned Artemis presence if not there first,” he added, referring to NASA’s Artemis program, which aims to land humans on the moon in the coming years.

The directive laid out a roadmap to design, launch, and deploy an operational 100-kilowatt reactor to the lunar South Pole within five years that would be built with commercial partners (for comparison, 100-kilowatts could power about 80 American households). While the specs are, well, speculative at this point, 100 kilowatts represents a dramatic power boost compared to the basic nuclear generators that fuel Mars rovers and space probes, which typically operate on just a few hundred watts, equivalent to a toaster or a light bulb.

The implications would be transformative, “not just for the moon, but for the entire solar system,” says Bhavya Lal, who previously served as NASA’s associate administrator for technology, policy, and strategy and acting chief technologist. Placing a nuclear reactor on the moon would allow the space industry to “start designing space systems around what we want to do, not what small amounts of power allow us to do. It’s the same leap that occurred when Earth-based societies moved from candlelight to grid electricity.”

Could NASA Build a Lunar Nuclear Reactor by 2030?

Establishing a nuclear plant on the moon by 2030 won’t be a lay-up, but many experts believe it is within reach.

“Four-and-a-bit years is a very racy timescale” but “the technology is there,” says Simon Middleburgh, a professor in nuclear materials and co-director of the Nuclear Futures Institute at Bangor University in the UK.

The issue up to this point hasn’t necessarily been technological readiness, but a lack of mission demand for off-Earth reactors or political incentives to strongarm their completion. That calculus is now shifting.

“We’ve been investing over 60 years and have spent tens of billions of dollars, and the last time we launched anything was 1965,” says Lal, referring to NASA’s SNAP-10A mission, which was the first nuclear reactor launched to space. “I think the big moment of change was last year, when NASA actually, for the first time in its history ever, selected nuclear power as the primary surface power generation technology for crewed missions to Mars.

“There’s now policy certainty that we didn’t have before,” she adds. “Last but not least, the private sector is not only interested in using space nuclear power, they’re even interested in providing space nuclear power.” Both startups and established aerospace companies like Boeing and Lockheed Martin are researching the use of nuclear power in space. “There’s a lot of puzzle pieces that have come together in a good way, where we can actually move.”

NASA’s Artemis program is supposed to lay the groundwork for a permanent base at the lunar South Pole and pioneer technologies to move on to Mars, though its future is uncertain. Regardless, the energy needs of any crewed missions in exotic environments like the moon, where nights last two weeks and temperatures wildly fluctuate, necessitate steady and abundant power.

“Lunar gravity and thermal swings are brutal,” Lal says. “Daytime temperatures are about 100 degrees Celsius. Nighttime is close to absolute zero. All the electronics must be radiation hardened. Although, I’ll be honest, the biggest risks are not technical. The biggest risk is maintaining that momentum and the mission goal.”

Enter China, which is also planning a moon base at the South Pole. This region is rich in resources and water ice, which makes it an attractive site for exploration and a potential permanent presence, and China is in talks with Russia to partner on building a reactor there by 2035. These developments have galvanized officials at NASA, the Department of Defense, and the Department of Energy to get into the race.

“It could be done, because we do very well here in the US when we have a strong adversary, and we haven’t had one for 40 years,” says Mohamed El-Genk, a professor of nuclear engineering and founding director of the Institute for Space and Nuclear Power Studies at the University of New Mexico. “But a lot of things need to be worked out for that to happen.”

How Would This All Work?

Duffy’s directive included few details about the design or scale of the planned reactor, and it’s anyone’s guess what concepts might emerge in the coming months.

“To further advance US competition and lunar surface leadership under the Artemis campaign, NASA is moving quickly to advance fission surface power development,” said Bethany Stevens, press secretary at NASA Headquarters, in an email to WIRED. “This critical technology will support lunar exploration, provide high-power energy generation on Mars, and strengthen our national security in space. Among efforts to advance development, NASA will designate a new program executive to manage this work, as well as issue a Request for Proposal to industry within 60 days. NASA will release additional details about this proposal in the future.”

The directive echoes the findings of a recent report on space nuclear power, coauthored by Lal and aerospace engineer Roger Myers, which included a “Go Big or Go Home” option to build a 100-kW reactor on the moon by 2030.

This 100-kW design would be “roughly equivalent to sending a couple adult African elephants to the moon with a fold-out umbrella the size of a basketball court, except the elephants produce heat and that umbrella isn’t for shade, it’s for dumping heat into space,” Lal said in a follow-up email to WIRED.

NASA might also draw inspiration from its most recent effort to develop a lunar reactor, known as the Fission Surface Power concept, which was initiated in 2020. The plan was to build a 40-kW reactor that would be deployed autonomously on the lunar surface. While it’s not yet clear which companies will win contracts to build the new 100-kW reactor, the 40-kW precursor involved input from a range of organizations, including Aerojet Rocketdyne, Boeing, and Lockheed Martin from the aerospace sector; nuclear companies BWXT, Westinghouse, and X-Energy; the engineering firm Creare; and the space tech companies Intuitive Machines and Maxar.

The contracted companies for that project were not able to meet the maximum mass requirement of 6 metric tons during the initial concept phase. But the directive from Duffy assumes that the reactor would be delivered by a heavy-class lander that could deliver payloads of up to 15 metric tons.

The 100-kW reactor, uranium fuel, radiators, and other components could be delivered over multiple launches and landings. The site of the plant could be inside a lunar crater or even underground to prevent contamination in the event of an accident.

“The moon presents some serious engineering challenges,” Carlo Giovanni Ferro, an aerospace engineer and researcher at the Polytechnic University of Turin in Italy, said in an email to WIRED. “Without an atmosphere, there’s no convection cooling—you can’t rely on airflow over components like Earth-based systems do—for excess heat rejection.”

Ferro adds that lunar gravity, which is a sixth of Earth’s, would affect fluid dynamics and heat transfer, and that the moon’s regolith—the layer of dust and small rocks that coat the lunar surface—is sticky and electrostatic, and so could interfere with radiators and other components. “It’s likely feasible from a technical standpoint—yet remains highly ambitious,” he says of NASA’s proposed plans.

What Are the Risks and Benefits?

All nuclear technologies demand strict safety restrictions, especially those bound for launches on explosive rockets and landings in alien environments.

“It is very important to have a group of experts sit down and put in the requirements to address all the concerns,” says El-Genk. “The best way is not to give solutions to potential problems, but to ask: Can we avoid potential problems by design?”

To that end, the deployment of a lunar reactor—by NASA, China, or some other entity—will be subject to high regulatory standards at every phase. For example, the uranium fuel is likely to be contained in hardy protective layers in the case of a rocket failure.

“The reason we have regulation is for safety,” Middleburgh says. “We don’t want astronauts running out of a power source. We don’t want them having an accident up there that we can’t recover from. That would be an absolute disaster.

“This will be regulated to the teeth,” he continues. “Who regulates is a question, but regardless, they won’t just start popping things up that haven’t been thought through and demonstrated to be safe there. That would be the end of the program.”

In addition to developing a robust safety strategy, the race to bring nuclear power to the moon will blaze new trails in space law and policy. Whatever nation or entity gets there first will likely establish what the directive calls a “keep-out zone” for safety and security. These zones, which may cover a few square miles, would prevent competitors from entering the same space.

Such activities must cohere with guidelines set by the Outer Space Treaty, which says celestial bodies can only be used for peaceful purposes, and that the exploration and use of outer space shall be carried out for the benefit “of all mankind.”

“I don’t think that there is any violation of any treaties,” Lal says. “It’s more of a functional exclusion that could be because of radiation risks, thermal controls, or accident protocols. It would actually be justified under the Outer Space Treaty Article Nine, as necessary to prevent harmful interference.

“They’re not going to be making any claims of sovereignty,” she adds. “We’re not saying that is some kind of a land grab.”

Space nuclear power has seemingly been on the horizon for generations, but many experts think its moment has finally arrived and that we should strike while the iron (or rather, uranium) is hot. If nuclear reactors take hold in space, it will supercharge the possibilities of exploration and industry.

“When we have that kind of power, we are talking about permanent surface infrastructures on the moon and Mars, lunar mining systems, Martian mining systems to extract oxygen, water, and propellant in actual human habitats—not just for survival, but for livability,” says Lal. “We can do science at scale. We don’t have to miniaturize our instruments so they don’t take too much power, whether it’s radars or seismometers.

“It’s the foundation for opening the solar system,” she adds. “That’s the part that I’m really excited about.”

The first nations to successfully set up a reactor on the moon will have an outsized role in shaping this future—and the likely players are revving up their engines.

“The new space race isn’t about getting to the moon first,” says Ferro. “It’s about who gets to stay.”