Helium-3 mining on the lunar surface

The Moon has accumulated helium-3 from the solar wind because, unlike Earth, it lacks a magnetic field that shields its surface. Advocates argue that this isotope could fuel fusion reactors with fewer safety and waste problems than conventional nuclear energy. Apollo geologist Harrison Schmidt and physicist Gerald Kulcinski have promoted lunar mining; Kulcinski’s team has built a small reactor, but helium-3 fusion has not yet produced more energy than it consumes. Critics question whether the fuel can deliver the promised benefits, and physicist Frank Close has dismissed the idea as “moonshine.”

Despite the technical doubts, lunar resources have helped motivate plans for space exploration. India has expressed interest in lunar mining, and moon-resource use featured in Newt Gingrich’s 2012 presidential campaign. Private companies and Google Lunar X-Prize teams have also considered mining, while Shackleton Energy has proposed extracting lunar water to make propellant for missions across the Solar System. The European Space Agency has explored using the Moon as a base for farther-reaching missions. Helium-3 is more abundant on Jupiter, and extraction there might require less energy, but the planet’s great distance makes it an impractical alternative for now. Whether lunar helium-3 can become a viable energy source remains unresolved.