High power theta-pinch propulsion for piloted deep space exploration

Abstract

The piloted deep space exploration missions envisioned by the NASA Human Exploration and Development of Space initiative will require the development of advanced electric propulsion systems capable of providing high specific impulse for extended periods of operation. Current electric propulsion thrusters are well suited for orbit maneuvering and robotic exploration, but at present they cannot provide the combination of specific impulse, lifetime, and efficiency required for piloted deep space missions. The theta-pinch thruster concept is a high power plasma rocket that can potentially meet these future deep space propulsion requirements. Efficient, partial preionization of a gas propellant followed by rapid adiabatic magnetic compression is used to generate, heat, and expel a high velocity, high density plasma to provide thrust. The concept is electrodeless, and radial compression of the plasma by the magnetic field of the discharge coil mitigates material erosion to ensure long thruster life. Because the heated plasma is free to flow along axial magnetic field lines during compression, a magnetic mirror located at the entrance to the discharge chamber is used to direct the plasma flow out of the thruster. The thrust and specific impulse of the engine can be tailored for a given mission scenario through the selection of propellant species, mass flow rate, compression coil discharge current, and/or the compression coil repetition rate, making this a unique and versatile electric propulsion system.