Vibration conveyance of lunar regolith in lunar environment

Abstract

The compatibility of the vibration conveyance system for lunar regolith in the lunar environment was investigated to realize reliable and efficient in-situ resource utilization (ISRU) for long-term and large-scale crewed lunar exploration. Because the dynamics of particles in this system depend on gravitational acceleration and air drag, the effects of gravity and the viscosity of air were determined using numerical calculations based on a single-particle model and modified distinct element method (DEM). The adequacy of numerical methods was confirmed by comparing the numerical calculations with the experimental results obtained in the Earth environment. It was deduced that lunar gravity displayed improved conveyance performance compared to that on Earth. However, at an extremely low acceleration of gravity, particles are not efficiently conveyed because of poor transfer of lateral driving force to particles. Therefore, the vibration conveyance system is valid on Moon and Mars and does not work on asteroids where the acceleration of gravity is extremely low. In contrast, air drag scarcely affects the conveyance performance on Earth, and the performance is slightly improved on the vacuum Moon. Considering the effects of gravity and air drag, the conveyance performance on the Moon was estimated to be approximately 1.4 times better than that on Earth.