1 MicroVacuum Arc Thruster Design for a CubeSat Class Satellite

This paper describes the University of Illinois 2-cube CubeSat (10 x 10 x 20 cm) designed for April 2003 launch. The Illinois Observing NanoSatellite (ION) includes a scientific mission to view the airglow layer of the atmosphere and a CMOS camera for space and Earth photography. ION will also be used as a test bed to demonstrate a number of technologies including an active 3-axis attitude control system, with a new propulsion system used for both attitude control as well as orbital maneuvers. The new vacuum arc thruster (VAT) propulsion system produces ion velocities of up to 30,000 m/s, driven mostly by local pressure gradients. A 12 V inductive energy storage circuit is used to provide the initial breakdown and to sustain the plasma. Four thruster heads can be controlled individually to produce arc pulses with adjustable pulse width and repetition rate. Size and mass have been driven by the CubeSat requirements and amount to 4 x 4 x 4 cm and 150 g, respectively. Thrust to power ratios are expected to be ≈10µN/W. The individual impulse will be close to 1µN-s/pulse. Challenges to the design and integration of the VAT into a CubeSat size satellite are presented. On board diagnostics and methods used to verify operation of the VAT are discussed