Determination of the Dynamic Angle of Repose of Lunar Regolith Simulants

Abstract

The determination of the dynamic angle of repose (DAR) of lunar regolith simulants is essential for modeling material behavior during in situ resource utilization (ISRU) processes and lunar surface operations. This study presents a methodology and dedicated test rig employing digital image processing to measure DAR for seven lunar regolith simulants, representing both Mare and Highland regions. Experiments were conducted under terrestrial gravity at rotational drum speeds of 2, 5, and 10 RPM, with standardized material fill and image capture procedures. For each simulant, lower, higher, and total DAR values were recorded, indicating complex dependencies on particle size distribution, mineralogy, and rotational speed. These measurements provide a critical dataset for numerical model calibration and the simulation of regolith handling systems under lunar conditions. The findings emphasize the necessity of selecting appropriate DAR parameters based on regolith type and operational scale to ensure accurate predictions of granular flow behavior in extraterrestrial environments.