US, Russia and China race to put nuclear reactors on the moon

The United States, Russia and China are racing to build nuclear reactors on the moon, as scientists warn about the possible risk of a radioactive mishap. The reactors could revolutionise lunar exploration, providing energy for bases and mining — but the risks of contamination remain.

In January, NASA, the US space agency, announced plans to develop a nuclear reactor on the moon by the end of 2030. Russia, working with China, aims to do the same by 2036 as the countries strive to advance space exploration.

The reactors will be needed to power the mining of frozen water trapped deep in the moon's craters, which scientists believe could supply drinking water, air and rocket fuel for future bases. The reactors would also provide power for the lunar bases themselves.

The US has said NASA's Lunar Reactor 1 would produce 20 kilowatts of electricity, creating enough power to run on its own for five years without maintenance.

NASA's reactor is designed to be compact, weighing under 6,000kg (13,200 lbs), and will fit inside a rocket compartment measuring 3.7 metres (12 feet) long by 5.5 metres (18 ft) wide.

Russia is also building a nuclear reactor, which is expected to produce 10 kilowatts. The reactor, called Selena, will be able to run for a decade without maintenance. It is expected to be ready to power a Chinese-led moon base by about 2036.

The Selena reactor is expected to be even lighter than NASA's, weighing about 1,100 to 1,300kg (2,400 to 2,800 lbs), allowing for an easier and softer landing on the lunar surface.

This would not be the first time nuclear reactors have been placed in space. The Soviet Union launched more than 30 nuclear fission reactors into Earth's orbit between the late 1960s and the 1980s to power spy satellites during the Cold War. The small, 1,000kg (2,200 lbs) reactors powered radar-tracking spy satellites, using heat from splitting uranium atoms to generate 3 to 5 kilowatts of electricity. They are no longer operational, and no other country has sent nuclear reactors into space.

The US has spent $20bn on advanced space nuclear programmes over the past 70 years, but has never successfully launched a nuclear reactor into space since an experiment in 1965. That experiment, carried out to see whether nuclear energy could power a satellite, worked at first but accidentally shut down after just 43 days because a non-nuclear electrical part of the satellite broke down. It is still floating in space today. Previous US attempts to develop nuclear projects have stalled due to shifting budget priorities.

Scientists will first have to build a reactor on Earth, which will then be transported to the moon using a robotic spacecraft that fires rocket engines for a slow and gentle touchdown. Both the US and Russia say they would keep their reactors switched off until they reach the moon, keeping radioactive risk at a minimum until the last step.

Once set up on the moon, the reactors would be designed to run without maintenance for years, supplying power to bases engaged in mining on the lunar surface.

The US, China and Russia all want to build bases near the moon's south pole, close to the known sources of water ice. The ice sits in permanently shadowed craters, where sunlight has not reached for millions of years.

As well as powering the moon bases, the reactors would supply enough power for mining. So far, the three countries want to mine for frozen water which, once released, could be used to support life at bases where people could live and conduct research. Tech billionaire Elon Musk has also said he wants to extract minerals such as aluminium, titanium and silicon, which are required for manufacturing satellites.

Solar power for such endeavours would be limited, as the sun shines on any one spot on the moon only half the time, so solar panels would go dark for about two weeks every month. Simon Middleburgh, director of Bangor University's Nuclear Futures Institute (NFI), told Al Jazeera that solar power is too limited to provide the steady flow of energy a moon base would need, while batteries and diesel are too costly, because everything has to be launched from Earth.

Nuclear energy is the “obvious choice”, Middleburgh said, adding that it must be used “responsibly”. He said it is likely that three or four reactors working together would be required to provide sufficient energy for mining lunar ice as well as supporting a moon base.

In a December 2025 executive order, US President Donald Trump ordered NASA to build a lunar reactor ready to launch by 2030. Chinese President Xi Jinping and Russian President Vladimir Putin have revealed similar plans. In August this year, Sean Duffy, the US transportation secretary, said the US is in a “race to the moon, in a race with China”.

Middleburgh said the 2030 deadline is likely for building the reactor itself, but the harder part will be landing on the moon and safely setting up the system. “The biggest challenge isn't really the nuclear technology at all; it is the regulation for launch, the availability of a launch platform itself, and the landing and setting up the system on the lunar surface ready for it to be operated sustainably and safely,” he said.

The race to the moon also comes amid growing military competition beyond Earth. In September, the US announced it had deployed weapons into orbit, which officials said would be used to defend US forces. While the US did not provide details about these “weapons”, experts say they are likely to be space-based communications jammers rather than kinetic weapons that launch strikes. The announcement raised concerns about the use of space for military purposes, including the potential targeting of satellites that provide GPS, communications and intelligence.

The risks are real. In 1978, a Soviet satellite carrying a reactor, Kosmos 954, scattered radioactive material across nearly 124,300 square kilometres (48,000 sq miles) of northern Canada. The accident forced an expensive military cleanup of the highly radioactive fragments and microscopic particles. On the moon, Middleburgh says, any contaminated area would be “extremely localised” if there were a similar accident.

Legally, no one owns the moon. The 1967 Outer Space Treaty bans countries from “claiming” the moon or any part of it, though they retain ownership of the equipment they send there. The treaty does not ban nuclear power in space. Antonino Salmeri, director of the Lunar Policy Platform, a nonprofit, told Al Jazeera that a reactor can be lawful if it follows the treaty's principles, including peaceful use and avoiding harmful contamination.

Norbert Schorghofer, a senior scientist at the Planetary Science Institute in Arizona, US, told Al Jazeera that all signatories “have the right to mine the lunar surface as long as it is for peaceful purposes”. Whichever country's reactor reaches the “best” water ice first could declare a “safety zone”, which would not be a land claim but could operate like one. Salmeri said declaring one creates no territorial rights, but a reactor shuts others out anyway, because nobody wants to enter a radioactive area.

A Lunar Policy Platform report released last month points to another problem: who is responsible if something goes wrong? The report says existing liability rules have not been designed to regulate the use of long-term hazardous equipment on another celestial body.