VASIMR Performance Measurements at Powers Exceeding 50 kW and Lunar Robotic Mission Applications

Abstract

Efficient plasma production and acceleration is observed in a new high power Variable Specific Impulse Magnetoplasma Rocket (VASIMR) experiment, the VX-100, using argon propellant. The Radio Frequency (RF) power exceeds 50 kW. A 100 % propellant utilization is achieved with ion fluxes up to 1.7×10/sec. We measure an ionization cost of 80±10 eV per ion-electron pair. Bulk argon ion flow velocities are measured up to 20 km/s. Thrust values based on plasma exhaust measurements exceed 1 N. A 200 kW superconducting device, the VX-200, and 150 m vacuum facility are described. We outline the operations concept for a solar-electric lunar cargo tug whose performance is extrapolated from the VX-100 experiment results. Due to the 5,000 second specific impulse of the VASIMR engine, the fraction of the initial mass in low Earth orbit (IMLEO) that arrives in low lunar orbit (LLO) is approximately double that of a chemical propulsion system that performs at a specific impulse of only 450 seconds. The effect of space photovoltaic power cost on the economic advantage of the solar-electric system is examined.