This invention relates to a thruster apparatus applicable to the environment of a space vehicle or satellite and operable for positioning such vehicle or satellite in the proper orbital location. The device utilizes a unique configuration of passageways to convey the propellant to a location adjacent an electrical arc forming device. The propellant, heated thereby, then travels out a nozzle section of the thruster to thereby produce thrust. If desired, an external heater may be provided to preheat the thruster to thereby contribute to greater efficiency in the use of propellant. Further, if desired, the thruster may include an accelerator extension.