Sean Duffy, the acting administrator of Nasa and the US Transportation Secretary, has asked Nasa to accelerate efforts to place a nuclear reactor on the moon by 2030. Photo / Michael Craig
Accelerated plans announced by Nasa this month for the United States to put a nuclear reactor on the moon ahead of its geopolitical rivals would break new ground - not just on the lunar surface, but in the realm of space law.
The vastness of space is governed by long-standing legal frameworks, parts of which have yet to be tested.
Nasa’s efforts in that realm raise thorny questions around those rules, and the possibility for conflict as countries vie for a stepping stone on the path to Mars and beyond, some experts say.
Earlier this month, Sean Duffy, the acting administrator of Nasa and the US Transportation Secretary, asked Nasa to accelerate efforts to place a nuclear reactor on the moon by 2030.
The reactor technology will “support a future lunar economy, high power energy generation on Mars, and to strengthen our national security in space”, Duffy wrote in a directive first reported by Politico.
The Nasa chief cited growing pressure from China and Russia as a reason for urgency on the project. Since 2024, both countries have repeatedly affirmed their plan to jointly install a reactor on the moon by the mid-2030s.
In his directive, Duffy wrote that the first country to place a nuclear energy source on the moon “could declare a keep-out zone”.
Although placing a nuclear reactor on the moon is not a new concept or a shocking leap for Nasa - and the request for proposals calls for the construction of a rather small reactor - Duffy’s framing of the move as relating to geopolitics and control raised questions among legal experts.
“There’s a certain part of the moon that everyone knows is the best,” Duffy said in a news conference . “We want to get there first and claim that for America.”
US lunar activity is largely governed by the Outer Space Treaty, a legally binding agreement signed by all major moon faring nations in 1967, and the Artemis Accords, a set of non-binding principles designed to guide civil space exploration launched in 2020. China and Russia are not signatories to the latter.
Michelle Hanlon, the executive director for the Centre for Air and Space Law at the University of Mississippi, said that certain clauses of the Outer Space Treaty have unintentionally created a first mover advantage for placing an energy source on the moon.
Article 9 of the Outer Space Treaty says that nations have to conduct activities with “due regard” for the activities of others, she said, adding that Article 12 outlines the need for a state to ask permission to work in an area where another nation has an installation.
“Whoever gets there first has this implicit greater right to exclude than anybody else,” Hanlon said. “This raises a question of what exactly ‘due regard’ means.”
Neither the treaty nor the accords mention a “keep-out zone”. In fact, the treaty prohibits all nations from claiming territory on the moon or any celestial bodies.
The accords outline a “safety zone” - areas where nations can conduct space operations with the assurance that their personnel and equipment will be safe from other nations. The size, scope and duration of the safety zones are left vague, however.
“The only practical and legal provision is that if you land on a particular spot, then the Russians or whomever else would not be entitled to land so closely as to prevent an actual operating risk,” said Frans von der Dunk, a professor of space law at the University of Nebraska at Lincoln.
If a nation claims more than a few kilometres as a “safety zone”, other countries might begin to suspect that they aren’t motivated by a desire for security but are instead using it as a “sort of veiled approach to say everyone keeps out”, said von der Dunk.
He added that it is too early to assess the proper size of a lunar safety zone, given how little is known about Nasa’s plans.
The intention of the Outer Space Treaty, according to Erika Nesvold, an astrophysicist and author of Off-Earth: Ethical Questions and Quandaries for Living in Outer Space, was to prevent misunderstandings and conflicts and accidents - not to help people “looking to get a foothold for their nation’s government or profit for their companies”.
China is committed to “the peaceful use of outer space”, said Liu Pengyu, a spokesman for China’s Embassy in Washington. “China has no intention to engage in a space race, nor do we seek so-called edge in outer space.”
Duffy’s team forwarded the Washington Post’s request for comment to Nasa, which said in a statement that the nuclear reactor plans are meant to “further advance US competition and lunar surface leadership”.
Bethany Stevens, a spokeswoman for the agency, said Nasa would share additional details about the plans in the future.
Nasa has been eyeing areas around the moon’s southern pole for science and exploration.
There, the sun hovers below or just above the horizon in some parts, with looming mountains casting long shadows over the surface.
Deep craters are expected to hold frozen water, an extremely valuable commodity in space.
In his Wednesday news conference, Duffy pointed to the availability of ice and sunlight as motivating the push to “claim” space on the moon.
Even in sunlit regions of the South Pole area, solar panels would provide energy for only half the month because a night on the moon lasts roughly two weeks.
Hanlon said that finding a non-solar source of energy for rovers or even an eventual permanent human presence on the moon would be “the right next step” for long-term lunar exploration efforts.
“We can’t ship propane to the moon for energy,” she said.
Though few details exist about the aim of the project, the request for proposals issued by Duffy calls on commercial companies to outline plans to build a reactor that could generate at least 100 kilowatts of power.
“That’s the same amount of energy a 2000-square foot (185sqm) home uses every 3½ days,” Duffy said, describing the project’s scale. “We are not talking about massive technology.”
A 100 kW is a unit of power, not a unit of total energy.
“A typical household might use a little over a kilowatt of power, so 100 kW is enough for say, 80 homes or so on average,” said Edwin Lyman, a physicist and the director of nuclear power safety at the Union of Concerned Scientists, a non-profit science advocacy organisation in Washington.
Space experts are concerned that the urgency surrounding Artemis, Nasa’s return-to-the-moon programme, is papering over a range of lunar legal issues.
Nesvold, the astrophysicist, said there are concerns that racing to the moon could lead to a “gold rush” mentality, conflicts over access to lunar resources, environmental losses and labour exploitation that would especially stem from the involvement of profit-motivated private companies mining on the moon.
Lyman, said “undue speed is not a friend of nuclear power development”, adding that rushing the process could result in “safety incidents and reliability issues”.
Lyman also raised questions about what might be done with radioactive waste on the moon.
“That type of waste could persist for hundreds of years,” Lyman said. “It’s going to be a mess frankly.”