Micro-Cathode Arc Thruster for small satellite propulsion

The George Washington University (GWU) has developed a CubeSat-class thruster called the Micro-Cathode Arc Thruster (μ CAT). The μCAT is a high Isp (2000-3500s), solid metal fueled, low average power (<;0.1 W when operating) micro-thruster of small cross section (5 mm), with a mass of less than 200g, and no pressurant tanks. Electric current forms a plasma discharge between a concentric cathode-anode configuration. Thrust is produced through arc discharge, eroding some of the cathode material in uniform manner, to exit at high velocity, during which it is accelerated out the nozzle by a Lorentz force. Thrust can be controlled by varying the frequency of pulses, with a demonstrated range to date of 1-50 Hz, (1 μN-0.05 mN). The μ CAT design achieves uniform electrode erosion, and has demonstrated over two months of continuous operation during trials. The system operates at low voltage, accepting unregulated DC power from the spacecraft bus. The corresponding exhaust plume is 99% percent ionized, with near zero backflux. New ideas for high thrust-to power ratio microthruster will be discussed.