Mechanical properties of loose soil during dynamic penetration of landing pad under microgravity

The safety of lunar and planetary exploration is contingent upon a preliminary assessment of the interaction between loose soils composed of regolith that covers a celestial surface and the landing gear of spacecraft, which should be designed in accordance with the findings of the assessment. However, given the issues associated with replicating the surface layer of celestial bodies on Earth, the verification of the gear design can be challenging. Conducting a real-size low-gravity test in the design verification process of a large spacecraft remains cumbersome and resource intensive. As such, drawing valuable knowledge from scale model tests is the only available solution. This paper presents the results and findings of a dynamic penetration test conducted on a scaled landing pad under microgravity using a drop tower. The experimental findings demonstrate that the results of the dynamic penetration of the pad into the regolith simulant are not necessarily indicative of the worst-case scenario of low-gravity conditions and that they are equivalent to the results obtained in the gravitational environment of the earth. This finding suggests that design verification may be feasible through tests using a full-scale spacecraft model. • Regolith simulant and silica sand exhibited different dependence on gravity. • Regolith showed gravity-independent features in dynamic penetration tests. • Basis for predicting low-gravity test result with test on ground was obtained. • Equipment for dynamic penetration tests under microgravity was expounded.