High-fidelity landing simulation of small body landers: Modeling and mass distribution effects on bouncing motion

The surface dynamics of small bodies is a key problem for landing and sample return missions. It is also very meaningful for the research of morphologic evolution of small bodies. However, such surface dynamics problem is so difficult that the high-fidelity simulation of a lander on and above the surface of a small body is still a big challenge. This paper proposes a method to simulate six degrees of freedom motion of arbitrary-shaped landers in the neighborhood of a small body with multi-contact. In detail, the contacts between the lander and the small body are processed by utilizing the Polygonal Contact Model (PCM). Considering the orbital and attitude dynamics, the dynamical model of a lander in six degrees of freedom is constructed over a small body. Some specific issues in the numerical integration are addressed and figured out. Furthermore, two methods are proposed to reduce the computational cost significantly, which make the Monte Carlo simulations feasible. Finally, the effect of the lander mass distribution on its bouncing motion is investigated parametrically to illustrate the effectiveness of the above method.