Mechanical behavior of slow intrusion into granular media under microgravity

Abstract

This study focuses on enhancing the design reliability of asteroid lander footpads and sampling mechanisms. It systematically quantifies the constant-velocity intrusion behavior into granular beds under microgravity and identifies key influencing factors. Sensitivity analysis of particle physical parameters based on the discrete element method (DEM) reveals that particle porosity, rolling friction coefficient and elastic modulus are the dominant factors controlling intrusion resistance: a reduction in porosity significantly increases resistance and triggers shear band failure; minor variations in the rolling friction coefficient can cause substantial fluctuations in the average intrusion force; an increase in elastic modulus leads to intensified oscillations in the intrusion resistance. Concurrently, the study establishes a theoretical framework for predicting intrusion resistance and defines the critical size ratio for boundary effects under microgravity conditions. This provides a direct basis for the dimensional design of lander footpads and contact components of sampling mechanisms. The research findings can be applied to optimize the mechanism design and performance prediction for asteroid surface contact missions, effectively reducing mission risk.