Electrostatic Beneficiation of Lunar Regolith: Applications in In Situ Resource Utilization

Abstract

Returning to the Moon, or going further afield such as to Mars, presents enormous challenges in sustaining life for extended periods of time far beyond the few days the astronauts experienced on the Moon during the Apollo missions. A stay on Mars is envisioned to last several months, and it would be cost prohibitive to take all the requirements for such a stay from Earth. Therefore, future exploration missions will be required to be self-sufficient and use the resources available at the mission site to sustain human occupation. Such an exercise is currently the focus of intense research at National Aeronautics and Space Administration under the in situ resource utilization program. As well as the oxygen and water necessary for human life, resources for providing building materials for habitats, radiation protection, and landing/launch pads are required. All these materials can be provided by the regolith present on the surface because it contains sufficient minerals and metals oxides to meet the requirements. However, before processing, it would be cost effective if the regolith could be enriched in the mineral(s) of interest. This can be achieved by electrostatic beneficiation, in which tribocharged mineral particles are separated out, and the feedstock is enriched or depleted as required. The results of electrostatic beneficiation of lunar simulants and actual Apollo regolith in a high lunar vacuum are reported, in which various degrees of efficient particle separation and mineral enrichment up to a few hundred percent were achieved.