Lunar Source of ³He for Commercial Fusion Power

An analysis of astrophysical information indicates that the solar wind has deposited an abundant, easily extractable source of ³He onto the surface of the moon. Apollo lunar samples indicate that the moon's surface soil contains ∼10⁹ kg of ³He. If this amount of ³He were to be used in a 50% efficient D-³He fusion reactor, it would provide 10⁷ GW(electric)-yr of electrical power. The energy required to extract ³He from the lunar regolith and transport it to earth is calculated to be ∼2400 GJ/kg. Since the D-³He reaction produces 6 × 10⁵ GJ of energy per kilogram of ³He, the energy payback ratio is ∼250. Implications for the commercialization of D-³He fusion reactors and for the development of fusion power are discussed.