Analysis of the lunar regolith sample obstruction in the Chang'E-5 drill and its improvement

The drilling and coring process of the Chang'E-5 mission was terminated at a depth of 1 m due to an extreme lunar regolith profile state. One possible reason for termination was a lunar regolith particle obstructing the sampling entry of the hollow drill tool. This obstruction was caused by particles inside the clearance fit of the coring mechanism. A simulation was carried out using the discrete element method, which verified the particle flow state of the obstruction. A load test-bed was developed to separate the pulling force of the flexible coring tube of the obstruction from the entire drilling and coring process. A sealing device, a sealing ring with a sheath, was designed by isolating the original clearance fit of the coring mechanism toward the obstruction. Based on drilling and coring experiments, the sealing device solved the problem of the high value of the pulling force, which represented good sealing performance and could be used for future planetary penetrating drills like the Chang'E-5 drill.