Simulation of Nonspherical Asteroid Landers: Contact Modeling and Shape Effects on Bouncing

Abstract

This paper presents a methodology for the fast, parallelized simulation of the bouncing deployment of lander/rover probe to an asteroid or comet. The target asteroid or comet is represented implicitly with a signed distance field, allowing for fast collision detection with high-resolution shape models. The gravity field of the target body is voxelized to make run-time computations efficient. Collisions and contact motion between a probe with arbitrary shape/inertia and the target body are evaluated using a hard-surface contact model with restitution and friction. The shape, gravity, and contact models are well suited for parallel implementation on a high-end graphics processing unit found in modern personal computers, which enables broad but detailed studies with a relatively large amount of simulations. Probe deployment to asteroid Itokawa is simulated to examine the trends in the motion of different probe shapes. Similarly, the effect of variations in the surface interaction coefficients and probe mass distribution are identified. These results are compared and contrasted with previously observed trends in the motion of strictly spherical probes and have implications for the general design of small-body surface exploration probes.