Inline screw feeding vacuum arc thruster

A new type of micropropulsion device for nanosatellite applications is presented-the inline-screwfeeding vacuum-arc thruster (ISF-VAT). This thruster couples a conventional "triggerless" ignition geometry with a feeding mechanism that maintains a steady state discharge performance. The feeding mechanism implements a screwaction on a central cathode rod. At a predetermined rate, a complete and uniform erosion of the cathodes tip is obtained as well as "healing" of the insulator coating. The inline feeding of the cathode forces the arc to emerge on the tip of the cathode, flush with the exit plane of the anode. This enables the plasma plume to efficiently accelerate away from the thruster, eliminating the need for an additional ion acceleration stage. The ISF-VAT feeding mechanism is computer controlled and offers reliable operation of the thruster over a large number of pulses. Characterization of the ISFVAT performance is presented, conducted on an experimental prototype in the Aerospace Plasma Laboratory, Technion. Measurement results of the mass flowrate, electrical parameters of the discharge, and thrust are presented. Using a Ti cathode at a discharge power of 3W, a mass flowrate of approximate to 1.8 x 10(-9) kg/s and a thrust level approximate to 7 mu N were measured. More than 10(6) pulses were demonstrated in a single run, accumulating a total impulse of 0.2 Ns. The thruster prototype dimensions are 15 x 15 x 65 mm(3) and are approximate to 60 g in mass. Published by AIP Publishing.