The United States is racing to build nuclear power reactors for the Moon, with the first system planned for the end of the decade. This would keep astronauts alive through weeks-long lunar nights, as well as powering permanent bases and outposts – and giving Washington an edge over China and Russia in a new space race.
NASA confirmed in a directive signed at the end of July that it will appoint a nuclear power czar and select two commercial proposals for the project within six months.
The aim is a 100-kilowatt reactor, ready to launch by 2029 or 2030. Unlike solar panels, nuclear systems can work around the clock – vital in a place where one night lasts 14 days.
Why nuclear, why now?
The announcement comes as the US prepares for Artemis III – the first planned crewed Moon landing since Apollo, now delayed to 2027.
NASA hopes to build a permanent base near the lunar south pole, but that requires a reliable energy source.
"The sunlight would not be continuous enough to produce the electricity needed for a facility where crews would live," Xavier Pasco, director of the Foundation for Strategic Research, told RFI.
Many analysts therefore see nuclear power as the only practical option. A constant energy supply would allow life-support systems, communications and even mining equipment to run without interruption.
"A nuclear reactor would allow great flexibility of use," explained Paul Wohrer, who leads the space programme at the French Institute of International Relations. He told RFI that such a system would "provide greater electricity availability".
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Investment and delays
NASA has spent around $200 million since 2000 developing compact nuclear systems, although none have yet flown.
In 2023, it funded three contracts worth $five million each, aimed at building units that could generate 40 kilowatts – enough to power 30 households for a decade.
Yet the schedule looks tight. The Artemis III landing has already slipped to 2027 – a date many still doubt is achievable given the planned lander, SpaceX’s Starship, is far from ready.
China, in contrast, is targeting 2030 for its first crewed mission and has been more consistent in meeting deadlines.
“According to all the specialists, 2030 seems extremely optimistic,” Pasco said.
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Technical obstacles
Even if the timeline holds, the challenges are enormous.
"We are starting to talk about SMRs – small modular reactors capable of generating energy in a compact version,"said Pasco.
"But we also have to make sure they work well in extreme temperature conditions and can dissipate heat. There are major questions that are not resolved."
Cooling is one of the toughest challenges. On Earth, nuclear reactors use water for this – but that is not possible on the Moon.
“It will require the development of particular technologies, notably in terms of reactor cooling capacity, since the reactors we know on Earth are cooled with water," Wohrer explained. "But there is no way to circulate water intelligently on the Moon."
There are also questions about transporting uranium and managing nuclear risks in space.
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Race with China
NASA says the project is not just about technology, but geopolitics too.
Its directive notes that 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".
The memo warns that the first nation to place a reactor could "declare a keep-out zone, which would significantly prevent the US from establishing its planned Artemis presence if it is not there first".
"China seems more advanced than Russia in the space field," said Wohrer, adding that human missions to the Moon are "the main priority for NASA in this geopolitical contest between the US and China".
This rivalry is also shaping how NASA presents its plans.
"The interest for its current leadership – which is a political leadership – is of showing that there is momentum and that the agency wants to invest in this programme in a determined and stable manner," Pasco added.
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A long history
Nuclear power in space is not a new idea. Since the 1960s, it has powered probes sent far from the Sun. The US even tested nuclear propulsion rockets.
“They had gone quite far in the tests. There was a model that was almost ready to fly at the time,” said Wohrer.
The Soviet Union has also experimented in the field.
“Spacecraft have already used nuclear technologies, for example for very distant scientific probes. There were even Soviet satellites that used nuclear reactors in space,” Pasco said.
The idea of developing reactors for long missions arrived back on the table in the early 2010s.
At that time NASA began work on a programme called Kilopower, which focused on developing nuclear reactors for lunar missions and possible future missions to Mars.
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International law does not forbid nuclear power in space – a 1992 UN resolution allows it if no other energy source is possible.
The 1967 Outer Space Treaty bans countries from owning the Moon but says they must take the interests of others into account.
In 2020, the United States launched the Artemis Accords, signed by 56 countries including France. They propose “safety zones” on the Moon to prevent interference between missions.
China and Russia, however, refused to sign, and critics argue such zones could be used to block rivals once a country is established.
Partially adapted from this story by RFI's French-language service
