JSC Mars-1 Martian Regolith simulant particle charging experiments in a low pressure environment

NASA has a keen interest in Martian dust particle charging as it impacts future Mars missions. The particle charging can be used in experiments to help gather information about atmospheric electrostatics, saltation, and tribo-electric charging. Additionally, the charging could also be a nuisance for equipment because of the potential hazard of electrostatic adhesion and discharge. In order to gather more information about the nature of particle charging at Martian atmospheric pressures, experiments were performed in a 7 Torr environment testing the contact and frictional charging of the JSC Mars-1 Martian Regolith simulant. An apparatus was devised that dropped the simulant down a deflection board whose surfaces were coated with various materials of interest. The particles were illuminated by a UV source as they fell. The UV illumination was added to consider whether the surface states of the particles would be augmented to permit greater tribo-charging. The charged particles would then exit the board into a Faraday cup to measure the amount of charge accumulated using an electrometer. The materials used on the deflection board surfaces included copper, glass and acetate. The UV source did not significantly alter the experimental outcomes.