Dust mitigation technology for lunar exploration utilizing an electron beam

Abstract

Dust mobilized on the lunar surface due to natural processes and/or human activities can readily stick to spacesuits, optical devices, and mechanical components, for example. This may lead to dust hazards that have been considered as one of the technical challenges for future lunar exploration. Several dust mitigation technologies have been investigated over the past years. Here we present a new method utilizing an electron beam to shed dust off of surfaces. Recent studies on electrostatic dust lofting have shown that the emission and absorption of secondary electrons or photoelectrons inside microcavities forming between dust particles can cause the buildup of substantial negative charges on the surrounding particles. The subsequent repulsive forces between these particles can cause their release from the surface. Fine-sized lunar simulant particles (JSC-1A, <25 μm in diameter) are used in our experiments. The cleaning performance is tested against the electron beam energy and current density, the surface material, as well as thickness of the initial dust layer. It is shown that the overall cleanliness can reach 75–85% on the timescale of ~100 s with the optimized electron beam parameters (~230 eV and minimum current density between 1.5 and 3 μA/cm2), depending on the thickness of the initial dust layer. The maximum cleanliness is found to be similar between a spacesuit sample and a glass surface. Future work will be focused on removal of the last layer of dust particles and an alternative method using ultraviolet (UV) light.