Experimental Method for Measuring Cohesion of Regolith via Electrostatic Lofting

The hypothesized electrostatic lofting of individual regolith grains on the Moon and asteroids has been investigated extensively in laboratory studies. Cohesion may dominate how regolith behaves on these small, airless bodies, yet the magnitude of this force remains uncertain. We induce the electrostatic detachment of dust as a mechanism to break cohesive bonds between individual zirconia-silica microspheres in order to measure the interparticle cohesive force between them, likely dominated by capillary bridges. A high-speed camera imaged centroid positions of the lofted microspheres over time. Using the centroids from the initial detachment, we numerically calculated initial accelerations to solve for the cohesion that had been restraining the microspheres. Unexpectedly, the electrostatic lofting of clumps of particles was observed and experimental results showed that clumps were a nonnegligible portion of the lofted object population.