Interlune, a Seattle-based firm, says it can harvest helium-3 from the Moon’s regolith in a four-hour process. The Sun’s fusion reactions generate helium-3, which escapes as part of the solar wind. Over billions of years, the wind has bombarded the Moon, where the lack of atmosphere and magnetic field allows the particles to embed in the regolith. Helium-3 concentrations in certain titanium-rich lunar soils range from 10 to 20 parts per billion, higher than on Earth but still low. The isotope is of interest for fusion energy, ultra-cold cooling, medical research, and neutron detection. Several companies, including Interlune, are exploring lunar helium-3 extraction, but the physical feasibility of collecting the particles in such a short timeframe has not been demonstrated. The company plans to test the method on Earth before deploying a lunar extractor, and the outcome will determine whether the approach can be scaled for commercial use.