Improvement of the electron beam (e-beam) lunar dust mitigation technology with varying the beam incident angle

Abstract

Dust hazards are considered to be one of the technical challenges for future lunar exploration. In our past work a new dust mitigation technology was introduced utilizing an electron beam to remove dust particles from various surfaces. This technology was developed based on a patched charge model, which shows that the emission and re-absorption of electron beam induced secondary electrons inside microcavities between dust particles can lead to sufficiently large charges on the dust particles, causing their release from the surface due to strong repulsive forces. In this paper an improvement in the effectiveness of this technology is demonstrated with varying the beam incident angle on dust-covered sample surfaces by rotating the samples relative to the beam. Due to random arrangements of the microcavities, more of them will be exposed to the beam with various incident angles, thereby causing more dust release from the surface. The cleaning performance is tested against three samples: glass, spacesuit, and a photovoltaic (PV) panel. Lunar simulant (<25 μm in diameter) is deposited onto the sample surfaces such that the initial cleanliness of the samples is 0 % (full dust coverage) and 40 %. Varying the beam incident angle shows an overall surface cleanliness increase of 10–20 % in addition to the cleanliness achieved with a fixed beam angle. The ultimate cleanliness reaches 83–92 % for the glass and spacesuit samples. The PV panel coated with MgF2 is shown to be more adhesive to the dust with the maximum cleanliness of 50–63 %.