Gas-driven regolith-sampling strategy for exploring micro-gravity asteroids

Small celestial bodies contain abundant scientific information to understand the origin and evolution of the solar system. The acquisition and analysis of regolith sample is the most direct and effective way to explore the geological construction of poorly known asteroids as remnants of earlier existed planetesimals. China is gradually promoting extraterrestrial regolith sampling technology from asteroids or comets nowadays. To obtain surface regolith from ultralow-gravity asteroids, a novel gas-driven regolith-sampling strategy is proposed, and a prototype was designed and fabricated for experimental validation. In this method, an ultrasonic percussive drill with low-reaction force is designed to break surface regolith to fine particles, and sample mobilization and collection is implemented through highly pressurized gas. Fluid-solid coupling simulation was conducted to evaluate regolith-sampling performance under normal- and micro- gravity conditions. Preliminary experiments, both in room and vacuum conditions, showed that the proposed strategy has good geological adaptability and sample-acquiring ability. This method can provide important technical supports for China's forthcoming asteroid-comet regolith-sampling exploration.