WASHINGTON — A new NASA directive to accelerate development of a nuclear reactor for the moon has won a positive reaction from industry, who see the plans as aggressive but achievable.
A directive from NASA Acting Administrator Sean Duffy, dated July 31, instructed NASA offices to move forward with a new development of fission surface power for use on the moon. That directive, first reported by Politico Aug. 4, has not been formally released by the agency.
The memo directs NASA’s Exploration Systems Development Mission Directorate to release a request for proposals (RFP) for a nuclear reactor system within 60 days, selecting two companies six months later for initial studies. The memo gives the option to downselect to a single awardee after the preliminary design review phase.
The program seeks to develop a reactor capable of producing at least 100 kilowatts of power and weigh up to 15 tons. The program’s goal is to have the reactor ready for flight by the end of 2029.
While NASA has not announced formally announced the plan, Duffy did discuss it at an Aug. 5 Department of Transportation press conference about drone regulations in his primary role as secretary of transportation.
“We are in a race with China to the moon, and to have a base on the moon we need energy,” he said. “We’ve spent hundreds of millions of dollars studying if can we do it. We are now going to move beyond studying and we’ve given direction to start deploying our technology to actually make this a reality.”
“This part of the fission technology is critically important to sustain life because solar won’t do it,” he added.
The broad outlines of the directive, including the schedule, power level, number of awards and the use of public-private partnerships through Space Act Agreements, closely parallels one of the options in a report published by the Idaho National Laboratory in July that called for speeding up that space nuclear technology development for power and propulsion. That option, dubbed “Chessmaster’s Gambit,” called for the development of two space nuclear power demonstrations by 2030, each flying a reactor capable of producing between 10 and 100 kilowatts of power.
“We found that if we need to make progress in space nuclear, we need to begin with a small, manageable system on a timeline that keeps stakeholder interest,” Bhavya Lal, former NASA associate administrator for technology, policy and strategy and one of the authors of the study, said at a July 15 Washington Space Business Roundtable event.
“It was very clearly informed by Bhavya Lal’s and Roger Myers’s report,” said Alex Gilbert, vice president of regulation at Zeno Power, a company developing commercial radioisotope power systems, of the NASA directive. “It’s almost like they read their report and decided to implement it.”
Feasibility
Gilbert and others in the space nuclear field see the goals laid out by the new directive as challenging but achievable, provided sufficient resources.
“I think that at this point we can say it’s technically achievable,” he said, citing the progress made on past studies, including of smaller fission surface power systems for the moon as well as the now-canceled DRACO program, a joint effort by NASA and DARPA to test a nuclear thermal propulsion system in space.
One issue he raised is the availability of high-assay low enriched uranium, or HALEU, a fuel for space nuclear reactors. “That’s now something that we’re solving with Department of Energy and the private sector,” he said, so that by 2030 “we’ll have that supply chain in place.”
Space nuclear programs are also benefitting from work done on terrestrial nuclear projects, like small modular reactors. “Until about five years ago, the United States did not have a competitive nuclear industry,” Gilbert said. “We did not have a lot of innovation going on. That has changed decisively.”
“I really think right now we would not have a shot at deploying a space reactor by 2030 if it was not for the terrestrial innovation that’s happening,” he concluded.
Kerry Timmons, who leads strategy and business development at Lockheed Martin for its space nuclear programs, offered a similar assessment.
“I think we’re at a point now where we’ve made a lot of advancements in material development, manufacturing maturity, understanding these higher temperature materials,” she said. “All of those things are getting us to a point now where we’re positioned to have the technology that is ready to integrate into a spacecraft and fly.”
She said past efforts to develop space nuclear reactors were hampered by technological challenges but also policy and programmatic issues. “These programs have tended to be over many years in the past,” she said, making them vulnerable to shifting priorities. “We see a lot of countries putting a lot of things in the press about what they’re planning to do in this area, and I think that’s driving some sense of urgency and desire to prove the American capabilities in this area.”
The timeline in the directive to have a reactor ready to fly before 2030 is “really exciting,” Timmons said. “It creates that sense of urgency” to start work immediately on prototypes to meet that timeline, she noted.
Lockheed has been working on designs for smaller space nuclear reactors, including those up to 40 kilowatts. However, making a 100-kilowatt reactor is not as simple as scaling up a smaller design.
“There is a break point where reactors below 80 kilowatts look one way, and above that look a different way,” she said, based on reactor temperatures and the materials needed to support them.
The directive provided few requirements on the proposed reactor beyond schedule and power. One requirement that was included was the use of a closed Brayton cycle power conversion system.
Timmons noted that the Brayton cycle technology is more efficient at higher power levels than an alternative technology, Stirling cycle. “If I was looking and designing something that I wanted to be extensible to even higher power solutions, then I would start with a Brayton system, knowing that it would be a steppingstone to the next level of power I wanted to go to.”
Workforce, regulations and budgets
One issue Timmons raised is having the workforce available to develop these reactors. “I don’t know that we have all of the people we need, but I think this is the time to start,” she said, noting that Lockheed has partnered with nuclear technology companies like BWXT and SpaceNukes on previous projects to ensure they have the right expertise.
“It really is a big challenge, especially when we’re looking at all of the workforce, all of the supply chains,” said Gilbert. He backed plans in the directive to select two companies for at least initial work on the reactors to promote competition and provide some backup should one falter.
“You want two shots on goal, and that allows some flexibility to maybe choose an incumbent nuclear provider that maybe has a lot of other commitments versus one of these companies that is dedicated to try and do a space reactor,” he said.
Another issue for space nuclear reactors is the regulatory environment. National Security Presidential Memorandum 20, signed by President Trump in his first term in 2019, lays out a performance-based approach to regulating space nuclear power systems, which Gilbert said is a good approach.
“Now the challenge, I think, moving forward, is that we have not yet exercised that,” he said. That includes environmental and launch safety reviews and spaceport operations planning. Experience with launches of radioisotope thermoelectric generators (RTGs), used on a range of NASA science missions over the years, “gets you 70-80% of the way there,” he said, but there will be specific issues with reactors to address.
“From my perspective, it’s understood, but not fully exercised yet,” Timmons said of the regulatory process. “There is a process, and we just would look at that up front to make sure that it met the same timelines as the development of the spacecraft.”
One open question is the cost of developing one or more of these space nuclear reactors. Companies were reticent to offer estimates, citing the sensitivity of such information given an upcoming NASA RFP.
The INL report estimated that each of the two reactors in the Chessmaster’s Gambit option would cost about $1 billion each. A larger reactor capable of 100 to 500 kilowatts of power was studied in a separate option, with an estimated cost of $3 billion.
The NASA directive suggests that the program could tap into a new “Mars Technology” budget line that the agency included in its fiscal year 2026 budget proposal requesting $350 million for it in 2026 and $500 million annually in 2027 and beyond. The budget proposal offered no specifics on how the Mars Technology funding would be spent.
NASA’s Space Technology Mission Directorate has been working on fission surface power, but the memo instructs the directorate to halt any work not directly aligned with the new initiative and direct remaining funding to the upcoming RFP.
Securing funding for this new effort will also require public outreach. “We’re thinking of ways to educate the public on this better, because there’s been some misinformation,” said Timmons.
One person who has endorsed the new initiative is Sen. Mark Kelly (D-Ariz.), a former NASA astronaut. “I know that might sound kind of crazy, but it isn’t,” he said of the plan in a video posted to social media Aug. 5, citing the benefits of having a nuclear power source to support Artemis missions and future exploration.
“So if you think it’s a nutty idea, it’s not,” he concluded. “I think it’s something we all should seriously consider.”