A completely solid-state pulsed plasma thruster for nanosatellites, packaged in a 45x45x25mm form factor with no moving parts and no pressurized propellant.
SSP Vacuum Arc Thruster
A completely solid-state pulsed plasma thruster for nanosatellites, packaged in a 45x45x25mm form factor with no moving parts and no pressurized propellant.
Description
The Solid State Propulsion Vacuum Arc Thruster (VAT) is a solid-state electric propulsion system for CubeSats and small satellites, using vacuum arc thruster technology. The thruster creates pulsed electric arcs between an anode and a solid metal cathode; each arc concentrates into tiny cathode spots that vaporize and ionize the cathode metal into a high-velocity plasma jet, generating thrust to propel the satellite. Because the propellant is an unpressurized, highly dense solid metal (not a pressurized gas or liquid), the entire system has no moving parts -- no propellant lines to jam, no valves to fail, and no tanks to leak -- which the company positions as a significant reliability advantage over conventional chemical and cold-gas propulsion. The solid-metal fuel also allows a very compact, easily transported and integrated form factor. Firing hundreds of thousands of short pulses over several days builds up the same total impulse as firing a chemical rocket engine for several minutes, but without the mass and volume penalty of a chemical system, and the pulsed operation enables micronewton-second accurate impulse-bit control suitable for precision applications such as formation flying and drag makeup. As an example, a 1U CubeSat in a circular 525 km orbit firing the thruster for 1 day at 1 W input power gains a delta-V of 0.7 m/s and about 1.27 km of altitude increase; a week of firing at 1 W increases altitude by roughly 8.35 km, enough to offset a year of atmospheric drag with only a few days of firing at low input power. The thruster requires only 5V and GND for power and two 3V or 5V PWM signals for control. A preliminary high-altitude balloon test conducted with the Secunda Amateur Radio Club (SARC) in 2021 demonstrated the robustness of the solid-state design, with the thruster surviving flight and continuing to operate after recovery. A smaller variant sized for PocketQube platforms is in development. Solid State Propulsion is a South African propulsion startup shipping systems to customers in the US and Europe, and has partnered with the Orbit CubeSat team at the Norwegian University of Science and Technology (NTNU).
Specifications
| Thrust | 200 µN |
|---|---|
| Specific impulse | 700 s |
| Power | 0.25-20 W input power |
| Dimensions | 45 x 45 x 25 mm |
| Supply voltage | 5V and GND for power; 2x PWM control signals at 3V or 5V |
| Propellant | Unpressurized solid metal cathode (vacuum arc, no moving parts) |
| Interface | PocketQube variant in development |