Production of Lunar Helium-3 Energy Resources

Harrison H. Schmitt
University of Wisconsin-Madison, Albuquerque, NM

Production of helium-3 from the lunar regolith will require a permanent base of operations on the Moon even with automation of various mining, processing and refining activities. Many aspects of lunar operations will be similar to those encountered by terrestrial mining activities. Material mined would be conveyed into a miner-processor, probably by bucket wheel excavation. Fragments greater than ~100 µm (~fifty percent by mass) would be rejected to the side with the remaining fine material moved into a volatile extraction unit. Agitation can release possibly a third or more of the volatile resources.

The undisturbed concentration of helium-3 in the sampled regolith at the Apollo 11 site is about 20 ppb. Ore grades in the polar regions may be several times higher based on measured hydrogen. Each 100 kg of helium-3, that needed to fuel a 1000 MWe fusion power plant, requires processing about 2km2 of lunar regolith to a depth of 3m each year. For operations involving 13, 20 day-months and 20 hour-days, this translates to mining about 1900 tonnes per hour.

Estimates of annual recurring costs per 100 kg of helium-3 require assumptions on development and operating capital, the numbers of direct and support personnel, quantities of imported support materials and consumables, necessary Earth-based operational support, and required fees, insurance and other direct costs. Analysis of recurring costs for helium-3 production units suggest that those costs would approach breakeven relative to steam coal prices of ~$2.50/million BTUs after ten to fifteen production units were in place.