Patent ID: 8689537

Claim:
A method of operating an electrothermal thruster in the vacuum of space, the electrothermal thruster having: a gaseous propellant tank holding a gaseous propellant at a first pressure, a controlled valve coupled to the gaseous propellant tank for controlling a release of the gaseous propellant from the gaseous propellant tank into a plenum at a second pressure, and at least one microcavity coupled to the plenum, the at least one microcavity having a diameter of about 50-300 microns, the method comprising: heating the gaseous propellant from the plenum into a plasma with a temperature of about 500-4000 K, wherein the heating of the gaseous propellant is achieved by providing a sequence of discharges from an alternating current in communication with a pair of electrodes insulated in a material; supplying a power to the pair of insulated electrodes at a discharge frequency of about 5 to 500 kHz and supplying a voltage at about 1000 V with a discharge current amplitude at about 1 mA; and wherein the temperature of the plasma through the at least one microcavity increases, resulting in an increase in a velocity of the plasma as it discharges out of the at least one microcavity producing thrust, and further resulting in less than 1% ionization of the gaseous propellant from the plenum.