Conceptual Design of Low-Power Vacuum Arc Thruster for CubeSat

Vacuum arc thrusters (VATs) using solid metallic propellants have emerged as promising candidates for CubeSat propulsion due to their structural simplicity, compactness, and minimal power requirements. In this study, a 10 W class low-power VAT with a coaxial configuration was designed for CubeSat platforms. A parametric study was conducted to evaluate the effects of key design parameters on thruster performance. Key parameters included electrode geometry such as tip shape and gap distance, materials of electrodes and insulators, and their respective dimensions. In addition, discharge circuit elements including capacitance, resistance, and inductance were also designed to ensure stable arc discharge and effective power transfer. The designed VAT has an anode with a diameter of approximately 30 mm and a 1 mm gap between the cathode and anode, and was intended to achieve a thrust of ~1.5 µN and a specific impulse of ~1000 s at input power below 10 W. Previous studies have demonstrated that the application of a magnetic nozzle can enhance plasma acceleration and beam collimation in VATs. Accordingly, an axial magnetic field of up to 500 G was considered in the conceptual design with the aim of enhancing thruster performance. In this presentation, the design of the prototype vacuum arc thruster will be introduced in detail.