Magnetrons are the vacuum tubes inside the ovens that generate microwaves.
The inexpensive tubes worked, and the result is a cheaper, safer design for spacecraft propulsion. Micci's microwave propulsion system for positioning and maneuvering satellites requires 50 percent less fuel than today's chemical propellant variety. The fuel savings could be applied to adding payload, reducing launch cost, or extending the satellite's life span. Funding for testing in space is the main hurdle now, says Micci. The aerospace industry is very conservative.