Formation Of Compact Aggregate Piles On A Surface Through Horizontal Energy Dissipation

Accumulation of dust on the Lunar and Martian surfaces plays a critical role in both surface evolution and human exploration efforts, limiting equipment lifetimes and obscuring optical surfaces. Yet, the underlying physics of surface soiling is still poorly understood. Recent laboratory experiments reveal that particles impacting a surface with impact velocities ranging from 65.5 to 115 $cm/s$ under vacuum conditions assemble into Compact Aggregate Piles (CAPs) \cite{Griffin2025CAPs} . This analysis of particle charging and material adhesion found that the adhesion force dominates the clustering process, although electrostatic forces may begin to alter particle trajectories as impact energies are reduced through bouncing. The present study explores whether CAPs can form in the complete absence of charge. Using a Monte-Carlo framework informed by experimentally determined impact energy and angle distributions, particle deposition is simulated based solely on rolling and adhesion physics to produce CAP formation. Horizontal energy dissipation is found to be a sufficient driver of initial CAP formation, indicating that such structures may form even in environments where charge accumulation is minimal. As such, these results provide new insights important to both space exploration on the Lunar and Martian surface and current particle adhesion challenges faced by surface exploration systems.