Performance Testing of a Resistojet Thruster for Small Satellite Applications.

摘要

Resistojets operating at low power ((carot)lOO W) and using liquid propellants have re-emerged as attractive propulsion options for orbit-raising small satellites deployed at Space Shuttle altitudes (-2OO km). Compared to low power pulsed plasma thrusters (PPT), the resistojet produces two orders of magnitude more thrust (approximately 1.4 mN compared to 140 mN) which is required to overcome drag at solar maximum. The wet mass of both systems is approximately equal although the propellant volume for the PPT is significantly lower since it is stored in solid form. The major disadvantage of the resistojet propulsion system compared to the PPT, is in the complexity added from the propellant tanks. Shuttle integration concerns for the solid TeflonTM propellant of the PPT are minimal or non-existent. Although non-toxic, the water or nitrous oxide propellant of the resistojet requires pressurized tanks and valves which increase safety requirements. To investigate the usefulness of the resistojet for small satellite applications, a series of performance tests have been completed at the AFRL Electric Propulsion Laboratory using the JPL inverted pendulum thrust stand. The tests were conducted for two types of resistojet thrusters developed at the University of Surrey which utilize a packed bed of SiC particles for the heat exchanger. Performance testing eas accomplished at power levels from 0-600 W for five propellants: water, nitrous oxide, water/ methanol, nitrogen, and helium. Two endurance tests were conducted to determine possible failure modes. Performance characterization and thermal models were developed for future design applications of these thrusters. Future USAF and Surrey Satellite Technology, Ltd. (SSTL) missions using these resistojets are also discussed.