2018.B.2.1. Micro-Cathode Arc Thrusters for CubeSat propulsion

Author(s)

Michael Keidar (1)

The George Washington University, United States of America

Session

B.2

Keywords

Micropropulsion, electric propulsion, plasma

Abstract

The George Washington University (GWU) has developed a CubeSat-class thruster called the Micro-Cathode Arc Thruster (CAT). The CAT is a high Isp (2000-3500s), solid metal fueled, low average power (0.1 W-5 W) 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 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.

The basic system has been previously flown on the United States’ Naval Academy BRICSat‑P mission, scheduled to be launched aboard BRICSat-D in 2018. The system will be used for detumbling purposes only. Thruster subsystem was developed for the BRICSat-P which was launched in May of 2015. Some data has been downloaded from the satellite, and it shows that the satellite has successfully operated the propulsion system. The propulsion system was able to reduce initial tumbling from an estimated 30 º/s to within 1.5 º/s after 48 hours. The micro-Cathode Arc Thruster’s attitude control system (µCAT) is currently in TRL-6 and was launched on CANYVAL-X mission in January 2018. This mission, comprised of two satellites called Tom and Jerry, is intended to test a virtual space telescope designed to study the sun. To align the optical system, one of the satellites is equipped with both reaction wheels and four µCAT thrusters, which will provide propulsive attitude control and desaturation of the reaction wheels.