Investigation on the ultimate uplift capacity for asteroid exploration in drilling anchoring process: Numerical modelling and DEM simulation

Due to the microgravity environment on the asteroid surface, the asteroid probe can not stay on the asteroid surface for a long time for in situ exploration. Therefore, an anchoring device is required to provide enough ultimate uplift capacity to hold the asteroid probe on the asteroid's surface. In this work, based on the circular arc failure surface hypothesis, a numerical model is proposed to predict the ultimate uplift capacity of the anchor rod of the anchoring devices during the anchoring process. The discrete element method (DEM) simulation is adopted to calculate the ultimate uplift capacity and analyze the geomaterial behavior. To accurately simulate material properties, the parameters of three typical geomaterials are calibrated by the calibration tests. The anchoring experiment verifies the DEM simulation results, and the error between the anchoring experiment results and DEM simulation results is less than 14%. The distribution of loaded particle forces in the geomaterials under various anchoring angles(30°–60°) and the anchoring depths(20 mm–40 mm) in the simulation are compared and analyzed. Compared with the DEM simulation results, the ultimate uplift capacity's numerical model prediction results have an error of 5%. This work provides a new approach to predict the ultimate uplift capacity of the anchor rod of the anchoring devices during the asteroid exploration process.