Review of research and development on the microwave electrothermal thruster

The microwave electrothermal thruster shows promise for spacecraft propulsion and maneuvering. It promises advantages over other electrothermal thrusters in the areas of operating life, efficiency, and propellant selection. In the microwave thermal thruster, the electric power is first converted to microwave-frequency radiation. In a specially designed microwave cavity system, the electromagnetic energy of the radiation is transferred to the electrons in a plasma sustained in the working fluid. The resulting high-energy electrons transfer their energy to the atoms and molecules of the working fluid by collisions. The heated working fluid expands through a nozzle to generate thrust. Estimated performance efficiencies are reported and compared with other electrothermal systems.