A Sweeping and Grinding Methods Combined Hybrid Sampler for Asteroid Exploration

Abstract

Successful sampling on the surface of asteroids is difficult because of their weightless environment and unknown material mechanical property. This work presents an asteroid sampler based on sweeping and grinding methods to improve the success rate of sampling. The sampler uses two brushes rotating clockwise and counter-clockwise to collect sample particles on the surface of asteroids. When encountering the hard rock or sample particles with large cohesion, the sampler adopts a drill bit to grind them to loose samples suitable for collecting by the brushes. The interaction between the brushes and the regolith is modeled and the sweeping mechanism is designed. A simple grinding mechanism is also designed. Numerical simulation and prototype experiments, at different parameters including blades number, rotational speed, and feeding speed of the brushes, mechanical property of the sample, and gravity, were conducted for validating the proposed methods. The 280g sampler prototype with 8 blades of brushes could collect about 19g regolith simulant in 25s in earth environment. The drill bits could work together with the brushes to improve the sampling efficiency through DEM simulation in case of large cohesion among sample particles. The sampler will be a good choice for installing into an asteroid rover in exploration.