Design of the UWE-4 Picosatellite Orbit Control System using Vacuum-Arc-Thrusters

Abstract

An orbit control system has been designed for 1U CubeSats capable of main- taining spacecraft formation after deployment from a common launcher. This system is implemented in the UWE-4 CubeSat. Four thrusters are placed on one side of the CubeSat frame to achieve both two axis attitude control and orbit control. The propulsion system is based on vacuum-arc-thrusters. Thruster scalability allows to miniaturize and integrate it with the spacecraft structure. The small size of the power processing unit with volume and mass of less than 130 cm 3 and 150 g respectively is made possible due to the low voltage operation (25 V) and the simplicity of the ignition process. A legacy spacecraft bus with a proven attitude determination system is used with minimal modifications. Measurements of the ion current using multiple probes show that the thrust is directed, with a plume half angle of � 45 deg. Time averaged thrust to power ratio is approximately 1.5 µN/W.