Determine conditions for deep cratering under rocket plume–regolith interaction

Determine the specific plume and soil conditions under which deep cratering occurs during rocket exhaust impingement on lunar regolith, to assess the risk that larger lunar landers could excavate deep craters.

Background

The paper distinguishes surface erosion from deep cratering mechanisms (e.g., bearing capacity failure, diffused gas eruption, diffusion-driven shearing, and diffused gas explosive erosion). While Apollo landings generally did not exhibit deep cratering due to soil strength and low permeability, abrupt shallow blasts were observed late in descent, suggesting that under certain conditions deeper excavation could occur.

The authors explicitly state that the combination of plume properties and soil characteristics that would trigger deep cratering remains unknown, and warn that larger landers might be capable of forming deep craters. Identifying this regime is critical for mission planning, landing site protection, and infrastructure safety on the Moon.