Numerical investigation and optimisation of the anchor rod configuration in a drilling anchor for asteroid exploration

Due to the microgravity environment of the asteroid surface, the asteroid probe needs to connect with the asteroid surface by an anchoring device to provide enough anchoring force for in situ exploration. Compared with other anchoring methods, drilling anchors have the advantages of adaptability, reliability, and reusability. The anchor rod is the key component of the drilling anchor, and its configuration directly affects the anchoring performance. A numerical model is established based on cavity expansion theory to investigate the influence of the anchor rod configuration on the anchoring performance. Five kinds of anchor rods with different cross-section shapes are selected to conduct anchoring experiments. The numerical model calculation results are compared with the experimental results to verify the numerical model's accuracy. The anchoring performance of the anchor rod with different cross-sections, rotation angles, axial sections, and torsion angles is analysed. The optimal anchor rod configuration is obtained by optimizing the numerical model. The anchor rod with a rectangular cross-section and axial-section and no torsion has the best anchoring performance. This work provides a new approach to calculate and evaluate the anchoring performance of various anchor rod configurations of anchoring devices during the asteroid exploration process.