Seattle Company Simulates 15,000 Years of Solar Wind in Just 4 Hours

The Sun creates helium-3, a rare isotope of helium, through its nuclear fusion processes. Some of this helium-3 escapes the Sun’s gravity in the solar wind—a continuous stream of charged particles that travels throughout the solar system.

For billions of years, the solar wind has swept across nearby celestial bodies, including the Moon. Unlike Earth, the Moon has no global magnetic field or substantial atmosphere to block these particles, allowing helium-3 ions to reach its surface almost uninterrupted.

Over time, helium-3 has accumulated in the Moon’s soil, known as regolith. The ions penetrate only a short distance into individual grains, but meteorite impacts regularly churn the lunar surface and distribute some of the helium-3 beneath the top layer.

Helium-3 concentrations are extremely low—typically around 10 to 20 parts per billion in titanium-rich lunar soils, which are better at retaining solar-wind ions. Even so, the isotope is far more abundant on the Moon than on Earth, where the atmosphere and magnetic field provide significant protection from the solar wind.

Could helium-3 be mined on the Moon?

The possibility of extracting lunar helium-3 has attracted interest from scientists, engineers, and advocates such as geologist and Apollo 17 astronaut Harrison “Jack” Schmitt. In the long term, helium-3 could potentially be used as a fuel in nuclear fusion reactions. In the near term, however, its more practical applications include cooling materials to ultra-low temperatures, supporting medical and scientific research, and detecting neutrons.

Because helium-3 has valuable applications on Earth, it is considered one of the few lunar resources that could potentially be mined and transported back to our planet for commercial use. Companies such as Seattle-based Interlune are exploring the feasibility of lunar helium-3 mining. Before deploying a full-scale extraction system, researchers must determine whether collecting the isotope from lunar regolith is technically and economically practical.