Development of a High-Reliability Vacuum Arc Thruster System

Current vacuum arc thruster systems show insufficient reliability in the low-power operation mode, which is required for CubeSat propulsion systems. Typically, the failure of the whole thruster system is caused by the failure of the arc ignition system. The reasons for this are deposition of a conducting coating on the insulator surface and geometry changes of the cathode. In this work, a highly reliable vacuum arc thruster system for electric propulsion of small satellite systems (for example, CubeSats) is presented. It is able to reach more than 10 million pulses while keeping the trigger voltage below 3 kV, which is one order of magnitude higher than those of previously published results. The system includes a novel thruster head design in combination with a newly developed power supply system. It was tested with a variable pulse frequency from 1 to 5 Hz. The thruster uses a single titanium cathode in combination with a dual-anode design and can be easily extended with a magnetic nozzle. The combination of the geometry and the power supply creates a system that deals with the aforementioned failure mechanisms. Several long-term tests were performed to demonstrate the system’s functionality. Moreover, erosion measurements and a failure analysis were conducted.