Rebound Suppression Mechanisms of Particle-Filled Flexible Shells for Small Body Landings

TL;DR

This study models how particle-filled flexible shells dissipate impact energy to prevent rebound on small bodies, providing insights for designing better landers in low-gravity environments.

Contribution

We develop a detailed computational model of flexible shells with granular fillings, revealing their superior energy dissipation mechanisms compared to rigid shells.

Findings

Flexible shells dissipate over 90% of impact energy.

Particle filling ratio significantly influences energy loss.

Granular beds limit shell deformation during impact.

Abstract

The extremely weak gravity on small bodies makes landers prone to rebound and uncontrolled drift. To mitigate this, the Hayabusa2 mission employed a particle-filled flexible shell, but the coupled dynamics of shell deformation and internal particle dissipation remain unclear. We develop a computational model representing the flexible shell as a spring-mass network and fully resolve particle collisions, friction, and interactions with granular beds. Results show the flexible shell-granule system dissipates over 90 percent of impact energy, far exceeding rigid shells. Energy loss arises from shell-particle coupling, with the particle filling ratio dominating. Impacts on rigid planes produce large shell deformation, while granular beds limit deformation. Scaling and velocity analyses reveal distinct dissipation regimes. These findings clarify energy transfer mechanisms and inform the design of microgravity impact mitigation devices.