Cohesion matters on small bodies, but can current numerical models actually handle it?
– Recent missions reveal asteroid surfaces far weaker than expected (like cappuccino foam). Hayabusa2 SCI experiment (Ryugu) and DART (Dimorphos) produced larger crater/more ejecta than predicted.
– The gap: The low-gravity low-strength environment is very difficult to reproduce on Earth.
Shock-physics codes (iSALE, Bern SPH, SWIFT, pkdgrav3) offer a powerful way to model this regime. But they need to be systematically validated in the low-cohesion, low-gravity regime of small bodies. Benchmarking is needed before these models can address key mission questions.
The Objectives are
- Validate codes against reduced-gravity granular-flow (rotating-tumbler) experiments.
- Validate against laboratory impact-cratering experiments.
- Benchmark the continuum codes against each other in mission-relevant micro-gravity regimes.
- Compare continuum (SPH) and discrete (DEM) approaches to map where each applies.
- Publish open community reference benchmarks: specifications, reference solutions and analysis tools.