DEVELOPMENT OF A HOLLOW CATHODE MICRO-THRUSTER FOR SMALL SATELLITES

摘要

An energy balance approach is used to determine hollow cathode geometries suitable for operation as a low power arcjet for small satellites. Principle mechanisms that govern overall operation of the thruster are reviewed and a basic hollow cathode design process is developed to determine relative operating characteristics to suit resource constraints (<30W, <28V). Hollow cathode operating parameters are shown to be particularly sensitive to orifice geometry, while short orifices (<0.25mm) are best suited to maintaining the discharge voltage within acceptable limits over broader operating ranges. Corresponding orifice diameters should be set to give the required plasma density for sufficient resistive dissipation within the orifice, which thus controls power deposition into the propellant. An engineering model thruster is presented as a basis for expanding low-cost small satellite capabilities and fulfilment of debris mitigation guidelines into the next decade.