JSC Mars-1 Martian Regolith Simulant particle-charging experiments in the presence of AC and DC corona fields

The National Aeronautics and Space Administration maintains an ongoing interest in Martian dust particle charging as it impacts future Mars missions. Particle charging can be used in experiments to help gather information about Martian saltation, tribo-electric charging, and discharge. Particle charging and adhesion can also become a nuisance in future Mars missions. In order to collect more information about the extent of dust particle charging at Martian atmospheric pressures, experiments were performed in a 7 Torr environment testing the contact and frictional charging of the Johnson Space Center Mars-1 Martian Regolith Simulant. An apparatus was devised that dropped the simulant down a deflection board whose surfaces were coated with sheets of either polycarbonate (Lexan), flouroplastics (Rulon and Teflon), glass and carbon fiber laminate (G-10), acrylic, or acetate. The particles, under the force of gravity, bounced, rolled, slid, and were deflected until falling into a Faraday cup for charge measurement. Additionally, the particles were allowed to fall through either an AC, +DC, or −DC corona field. The corona fields are intended to test the effects of inundating the simulant with positive and/or negative ions to test the enhancement or suppression of tribo-charging.