Modeling of Electrostatic and Contact Interaction between Low-Velocity Lunar Dust and Spacecraft

Abstract

The accumulation of highly adhesive dust on spacecraft presents a serious issue to hinder long-term extravehicular activity and the establishment of a permanent station on lunar surface. In contrast to the immediate physical damage caused by hypervelocity (>1.0 km/s) impacts, this adhesion observed at low-velocity (0.01 to 100 m/s) collisions can more unobtrusively and mortally degenerate the performance of equipment. This paper proposes a theoretical model aimed at comprehensively analyzing the dynamics of adhesion and escape phenomena occurring during low-velocity impacts between charged dust particles and spacecrafts enveloped by a plasma sheath. The electrostatic force is modeled using the image multipole method, and contact force is calculated based on the adhesive–elastic–plastic theory. The results reveal that the implementation of a dielectric coating possessing both low permittivity and low interface energy can substantially reduce energy dissipation during collisions. However, the ultimate adhesion on the surface or escape from the sheath for low-velocity charged dust is dominated by the long-range electrostatic interaction rather than short-range contact interaction. Positively charged particles of smaller sizes demonstrate a greater propensity for surface adhesion in comparison to negatively charged particles of larger sizes. Counterintuitively, without additional dust removal techniques, modifying the properties of the dielectric coating does not effectively reduce the accumulation of dust, which can be merely accomplished by decreasing the spacecraft’s potential. The model presented in this study serves as a crucial step toward understanding the mechanism of lunar dust pollution.