Mechanical Characteristics of Lunar Regolith Drilling and Coring and Its Crawling Phenomenon: Analysis and Validation

The collection of lunar regolith with complete stratigraphic information is the key to analyzing the evolution and composition of the moon. To keep each sample’s stratification for further analysis, a sampling method called flexible-tube coring has been adopted for Chinses lunar explorations. Given the uncertain physical properties of lunar regolith, drilling force and core lift force should be adjusted immediately in piercing process. Otherwise, only a small amount of core could be sampled, and overload drilling faults could occur correspondingly. Due to the fact that the cored regolith is inevitably connected to the flexible tube, coring characteristics may have a great influence on both lifting force and sampling quantity. To comprehend the regolith coring characteristics, a flexible-tube coring motion mechanics model was established and verified to acquire the lifting force results accurately. Herein, the judgment conditions for the flexible tube crawling phenomenon are proposed. Finally, the accuracy of the model is verified by comparing it with the Chang’e V telemetry data. This article provides theoretical support for the design and regulation improvement of Chang’e VI drilling and coring in the future.