Microwave Electrothermal Thrusters (MET) offer a high specific impulse and significant lifetime increases when compared to Resistojets and Arcjets. The technology scales up and down to suit a range of satellite platform sizes. It is also propellant agnostic and compatible with a range of gases, as well as water and ammonia.

The system.

The MET systems under development at URA Thrusters allow for operation at a wide range of input powers and mass flow rates, leading to a corresponding wide range of specific impulse and thrusts. We are designing our systems to be compatible with the following propellants:

  • Water.
  • Ammonia.
  • Argon.
  • Xenon.
  • Krypton.
  • Carbon Dioxide.

The MET thruster also consists of the following systems:

  1. Thruster head.
  2. RF and Power Processing Unit.
  3. Propellant Management System.
  4. Propellant Tank.

Each system is fully tailorable to customer requirements, leading to the most optimised thruster possible.

Discover MET Microwave Electrothermal Thrusters (MET) developed by URA Thrusters


Microwave Electrothermal Thrusters create free-floating plasma discharge in a cylindrical cavity resonator, efficiently heating a wide range of propellants while providing a high thrust to power ratio. Choice of propellant enables a wide range of specific impulse / TTPR combinations to be used, with lighter propellants such as water offering high Isp performance, and xenon high thrust.

The frequency of operation can also be varied, leading to thrusters able to operate at high power (>1 kW), all the way down to very low power (<30 W). We have been primarily focusing on developments at the mid power range and with focus on water as the propellant.

Key advantages.

  1. Cathodeless propulsion enabling long lifetimes.
  2. High thrust capabilities.
  3. High efficiency of heating.
  4. Scalable from low to high powers, and tuneable in performance from propellant choice.
  5. High specific impulse.
Discover MET Microwave Electrothermal Thrusters (MET) developed by URA Thrusters


Thruster Head Thrust (mN) Isp (s) Power (W) Propellant Market Entry
AQUAMET 30 – 150 500 – 1000 < 1000 H2O 2024/25
NMET 30 – 150 500 – 1000 < 1000 NH3
COMET 30 – 150 500 – 1000 < 1000 CO2
XMET 200 – 300 100 – 500 < 1000 Xenon
KMET 200 – 300 100 – 500 < 1000 Krypton


Staab, D., et al. "XMET: Design and early Testing of a Xenon Microwave Electrothermal Thruster." 36th International Electric Propulsion Conference Vienna. Vol. 405. 2019.

Staab, Daniel, et al. "X) MET: design and test of microwave electrothermal thrusters with argon and xenon." (2021).

Staab, Daniel, et al. "XMET: A Xenon Electrothermal Thruster using additive manufacturing." (2018).