Key Takeaways & Executive Findings
- •• Thin-walled coring bits outperform conventional thick-walled bits for deep lunar regolith sampling, with Bit D showing optimal performance. • An operational feed-to-rotation ratio (FRR) window of 2.0–2.5 balances drilling load and core recovery rate. • A novel theoretical framework for dynamic drilling load parameters was developed and experimentally validated. • Practical strategies for mitigating drilling-induced disturbances include parameter optimization and bit structural improvements.
Abstract
Acquiring pristine deep lunar regolith cores with appropriate drilling tools is crucial for deciphering the lunar geological history. Conventional thick-walled drill bits are inherently limited in obtaining deep lunar regolith samples, whereas thin-walled coring bits offer a promising solution for lunar deep drilling. To support future lunar deep exploration missions, this study systematically investigates the failure mechanisms of lunar regolith induced by thin-walled drilling tools. Firstly, five thin-walled bit configurations were designed and evaluated based on drilling load, coring efficiency, and disturbance minimization, with Bit D demonstrating optimal overall performance. And the interaction mechanisms between differently configured coring bits and large-particle lunar regolith were elucidated. Coring experiments under critical drilling parameters revealed an operational window for the feed-to-rotation ratio (FRR of 2.0–2.5), effectively balancing drilling load and core recovery rate. Furthermore, a novel theoretical framework was developed to characterize dynamic drilling load parameters, supported by experimental validation. Based on these findings, practical strategies are proposed to mitigate drilling-induced disturbances, including parameter optimization and bit structural improvements. This research could provide valuable insights for designing advanced lunar deep drilling tools and developing drilling procedures.
1. Introduction
Among the celestial bodies in the solar system, the Moon preserves a geological record spanning over 4 billion years, serving as a natural laboratory and the “best specimen” for studying Earth and other planetary bodies [1]. Moreover, the abundant resources contained within the Moon provide an important strategic reserve for the sustainable utilization of earth’s resources [2]. While lunar samples from the surface can provide valuable cross-scale insights into the physical and mechanical properties of the lunar regolith, for instance, Nie et al. [3] had successfully predicted the residual friction angle of lunar regolith based on the Chang’e-5 lunar samples, the extraction and analysis of deep lunar resources hold greater scientific significance for understanding the formation of the Earth-Moon system and the geological evolution of the Moon [4].
Previous missions and scientific researches have demonstrated that hollow, external spiral coring is an effective method for drilling. However, before reaching the deep bedrock of the moon, it is necessary to penetrate the thick surface regolith layer and rubble layer [5]. The conventional coring scheme of continuous drill pipe can no longer meet the needs of deep sampling in the moon. A multi-stage segmented coring drilling approach, as a technical attempt to reach the lunar bedrock, offers significant advantages in terms of drill pipe length and power consumption [6]. With increasing drilling depth, higher demands are placed on the drilling tools, such as cutting efficiency and powder transfer. Thus, developing an optimized lunar coring bit and analyzing its interaction with lunar regolith are critical for future deep drilling missions.
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GAO Zheng, GAO Mingzhong, HAO Haichun, WU Yan, CAO Jinfeng, SUN Qichen, GONG Junshan, ZHOU Lang, ZHOU Xuemin (2025). Investigation into failure mechanisms of lunar regolith simulant under thin-walled drilling tool with critical parameters. SinoTechIntel Verified Research. https://doi.org/10.1016/j.ijmst.2025.05.004
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Frequently Asked Questions
What is the main objective of this study?
The study systematically investigates the failure mechanisms of lunar regolith induced by thin-walled drilling tools to support future lunar deep exploration missions.
Which thin-walled bit configuration performed best?
Bit D demonstrated optimal overall performance based on drilling load, coring efficiency, and disturbance minimization.
What is the recommended feed-to-rotation ratio (FRR) for lunar regolith coring?
An operational window of FRR 2.0–2.5 effectively balances drilling load and core recovery rate.
What practical strategies are proposed to mitigate drilling-induced disturbances?
Strategies include parameter optimization and bit structural improvements.
What is the significance of this research for lunar exploration?
The findings provide valuable insights for designing advanced lunar deep drilling tools and developing drilling procedures.
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