After being abandoned for decades, the Moon may soon play host to a long-term human presence. Any permanent lunar operation will need a lot of power, and solar might not cut it. That’s why the UK Space Agency has partnered with Rolls-Royce on a new nuclear reactor design. The miniature nuclear reactors could be ready for testing in the next few years, but there are some fundamental design issues to work out first.
The UK Space Agency has announced an initial investment of £2.9 million ($3.5 million) to fund the construction of a test reactor. This follows a £249,000 ($305,000) contract in 2022 that allowed Rolls-Royce to study the concept and do the initial design work. The micro-reactor could generate significant power for a lunar base but might also be useful for nuclear-powered propulsion.
Although solar power is the most common way to power space missions, it’s not always the best way. Some missions have to travel so far away from the sun that they can’t generate much energy, and others are destined to spend time in a dusty environment that could block solar panels. That’s why Curiosity and Perseverance use radioisotope thermoelectric generators (RTGs) for power. However, RTGs aren’t fission reactors. They generate power from heat as the radioactive plutonium decays. Kicking off a fission chain reaction requires careful management.
The company has been light on details but claims the fission reactor is allegedly designed with safety in mind. “Each uranium particle is encapsulated in multiple protective layers that act as a containment system, allowing it to withstand extreme conditions,” Rolls-Royce said earlier this year.
Currently, Rolls-Royce engineers are working on three critical elements of the reactor. They need to determine the best way to generate heat, efficiently transfer it in a vacuum, and then convert it into usable energy. On Earth, nuclear reactors turn water into steam that can spin turbines. The company expects a demo version of the micro-reactor to be ready for delivery to the Moon by 2029. NASA plans to deliver the first modules of the orbiting Lunar Gateway station in 2024 and the final components flying in 2031. With the finished Gateway station, NASA and other space agencies can start planning long-term surface operations that could benefit from the Rolls-Royce reactor.