As part of its nuclear fusion processes, the Sun produces helium-3, an isotope that escapes as solar wind and bombards the Moon. Lacking a magnetic field or atmosphere, the lunar surface has accumulated helium-3 in its regolith, with concentrations of 10 to 20 parts per billion in titanium-rich soils. These levels are far higher than on Earth, which is shielded from the solar wind.

Helium-3 has long fascinated scientists and engineers, notably geologist and Apollo 17 astronaut Harrison "Jack" Schmitt. Long-term, it could provide fusion energy; near-term uses include cooling materials, medical research, and neutron detection. This makes it one of the only known lunar materials that could be mined and returned to Earth for profit.

A handful of companies, including Seattle-based Interlune, are interested in mining helium-3 on the Moon. But before a full-scale extractor can be sent, someone must determine whether this is physically practical. Interlune aims to test this by simulating 15,000 years of solar wind exposure in just four hours.