Research on a rotary-percussive coring drill for lunar exploration

China is launching the Chang'e project to send automated machine for acquiring the lunar soil and returning to the earth. Thus, we are trying to develop a kind of effective mechanism for the exploration mission of lunar soil coring. This paper presents a rotary-percussive coring drill which is a novel scheme for the deep surface soil acquirement. Two degrees of freedom are included in the proposed drill mechanism. Specifically-designed drill unit including auger and drill bit is employed to finish the coring of the simulant of lunar regolith. We have proposed a novel coring concept named soft-bag coring. Since there is no relative motion between the soft-bag and the cut soil core, the soft-bag method may keep the original stratification of lunar soil. A test-bed has been developed to conduct experimental tests under different drilling parameters and circumstances. The related drilling parameters such as rotary speed, penetration ratio, and percussive frequency are adjusted to adapt to different situations in the experiments. The experimental results indicate that the specifically considered drill mechanism with soft-bag inside can get high coring ratio and excellent stratification of the soil.