Performance Characterization of Simulated Regoliths and Space Debris to Investigate the In-Situ Resource Utilization Capabilities of a Pulsed Plasma Thruster System

Abstract

A coaxial pulsed plasma thruster operating at 18 Joules per pulse was discharged over lunar regolith simulant, silica powder, powdered aluminum, and solid Polytetrafluoroethylene to evaluate their potential as minimally refined in-situ propellant resources on other planets or moons for electric propulsion. All the propellants ablated and their plumes were examined using high-speed imaging, spectroscopy, and a double Langmuir probe. Silica produced a greater spectral intensity than lunar regolith. Imaging revealed that micron sized radiating particles are ejected from the anode, cathode, and propellant surfaces with speeds of up to 60 m/s. The double Langmuir probe revealed that in-situ propellants may produce peak charge densities similar to PTFE. Slower populations of charged particles were observed after the initial discharge only in the powdered propellants. The probe also revealed a lower bound to the plasma exit velocity of 6.3 km/s for aluminum, 19.3 km/s for lunar simulant, 17.8 km/s for silicon dioxide, and 20.39 km/s for PTFE.