ADVANCES IN THE COUPLED DYNAMICS OF RIGID BODIES AND GRANULAR MEDIA FOR SMALL BODY CONTACT EXPLORATION

Contact exploration of small celestial bodies represents a major technical challenge in deep space missions and is recognized as a key enabling technology for advancing China’s strategic goals in space. Such missions involve complex and highly dynamic interactions between spacecraft systems and the irregular, particulate surfaces of small bodies. These bodies typically exhibit rubble-pile internal structures, with their surfaces covered by loosely bonded, gravel-sized particles that result in distinct granular behavior and mechanical unpredictability. Under microgravity conditions, the interaction between rigid spacecraft components and the granular regolith demonstrates multi-scale effects, strong nonlinearity, and extreme sensitivity to initial and boundary disturbances. These characteristics significantly complicate the accurate modeling, simulation, and engineering design of contact events. The coupling dynamics between rigid bodies and granular materials exceed the traditional frameworks of rigid body dynamics and continuum mechanics, thereby presenting novel theoretical, computational, and experimental challenges for the field of space dynamics. This paper provides a comprehensive review of both domestic and international missions that have engaged in contact exploration or surface sampling on small celestial bodies. It identifies and distills key mechanical issues arising from the interaction between rigid structures and complex particulate surface layers. This paper also summarizes current modeling approaches used to represent the mechanical properties and dynamic responses of small body surfaces, outlines typical analytical methods for studying rigid body-granular media coupling, and reviews recent research progress in