Design and demonstration of micro-scale vacuum cathode arc thruster with inductive energy storage circuit

This study focused on the development of a vacuum cathode arc thruster (VAT), particularly on its design, manufacturing process, and demonstration. Characteristically, the proposed thruster does not require any additional propellant feeding system as the cathode electrode is simultaneously used as a propellant. In the ignition system, tiny spots are coated on the cathode surface to induce plasma flow. Such a setup has the advantages of simplicity, low price, small size, and low weight and is suitable for microsatellites. Moreover, a “trigger-less” method with an inductor storage power system was used for generating the pulsed plasma. This discharge method can significantly reduce input power. Thrust is mainly caused by high exhaust velocities of metal ions in the plasma flow, making ion density, ion velocity, and ion charge influential parameters. A battery was used instead of a power supply system to reduce the energy consumption of the entire VAT processing unit. The energy required for a single pulse was estimated to be 0.266 J, by measuring the change between the discharge current and the voltage. The ion current was measured using an ion detector and was 3.55 A, and the ion velocity was 23150 m/s. In the theoretical analysis, the VAT prototype proposed in this study achieved a single impulse of 4.31 μNs, a specific impulse of 1571 s, and a thrust efficiency of approximately 12.5%.