Quantify electrostatic contributions to cohesive energy density during plume–regolith interaction

Ascertain how electrostatic charging from hot, positively charged rocket exhaust plasma modifies the cohesive energy density a of lunar or simulant regolith by obtaining electrostatic measurements under both terrestrial and lunar conditions, in order to refine erosion modeling of the laminar sublayer energy-flux mechanism.

Background

In the proposed erosion model, the denominator includes the cohesive energy density a, which the analysis primarily attributes to van der Waals forces. However, in lunar landings the exhaust plume is a positively charged plasma that could neutralize dipoles and create repulsive monopoles, potentially reducing a and thereby affecting erosion thresholds and rates.

The authors explicitly note that without dedicated electrostatic measurements in both terrestrial and lunar environments, they cannot further quantify this effect. Resolving this uncertainty is necessary to constrain a and improve predictions of erosion onset and magnitude.