Stable Robotic Grasp Synthesis on A Spent Rocket Stage for On-Orbit Capturing

This paper describes a novel approach on orbital target capturing of a spent Apogee Kick Motor (AKM), by using robotic finger contact stability analysis similarly to terrestrial robotics. The surface curvature of the nozzle offers a robust candidate contact point. The stability of the grasp is assessed according to the Intrinsic Stiffness Matrix of the grasp and the mass matrix of the target, which are expressed on a common coordinate frame, multiplied, and the minimum eigenvalue of the product serves as a stability criterion. We perform a quantitative analysis to assess the stability over variations of the grasping parameters. We also execute a simulation of a chasing spacecraft equipped with a robot manipulator and gripper, grasping an AKM and pulling it towards its body. The results suggest that the grasp is stable, and the finger displacement from the grasped surface is negligible. The results from this paper can be used to develop autonomous stable grasp planning algorithms for orbital robotics.