Description: The Electrodeless Lorentz Force Thruster (ELF-160A) has the ability to efficiently ionize and electromagnetically accelerate a variety of propellants over a broad range of specific impulses from 1,000-6,000 seconds. The ELF-160A thruster creates a high-density, magnetized plasmoid known as a Field Reversed Configuration (FRC) employing a Rotating Magnetic Field (RMF). The RMF driven azimuthal currents, coupled with the enhanced axial magnetic field gradient produced by the FRC inside the flux preserving conical thruster, produce a large axial JxBr force that accelerates the plasmoid to high velocity. The ELF-160A is completely electrodeless, the propellant is magnetically isolated from the thruster body, quasi-neutral, and there is zero contact between high temperature propellant and the thruster. Combined with a high ionization efficiency and rapid formation and ejection sequence, the ELF can operate on any gaseous propellant, and do so with a very long lifetime and with low thruster specific mass. The AFOSR-funded 200 kW ELF thruster was designed and testing using Nitrogen, pure Oxygen, and Xenon as its primary propellants and demonstrated no life limiting or erosion issues. The NASA developed 1kW class ElectroMagnetic Plasmoid Thruster (EMPT) demonstrated steady operation on a variety of propellant with over 100 Hrs of operation. The focus of this proposal is to take the results from the ELF and EMPT programs and develop a new 30 kW-class thruster that is capable of long duration operation on any gaseous propellant. Phase I will develop the new systems required to transition this technology to a 30 kW, thermally stable, high temperature thruster and PPU system.

Benefits: The ability to capitalize on In Situ Resource Utilization for electric propulsion on next generation Exploration class missions has dramatic implications for mission success, scale, and cost. Electric propulsion enables the ability to perform Martian and NEO cargo and science missions at high specific impulse and therefore high payload fraction. At higher powers, EP enables rapid orbital transfer and reduced cost manned interplanetary missions. The ability to use Martian, Lunar, and NEO resources for return propellants and multiple mission profiles will reduce the required launch mass and propellant exponentially. The Adaptive Plasmoid Ejector is also lighter, highly scalable in both power and specific impulse, and can be tested at full power in existing facilities. The ELF-160A technology enables ISRU in-space propulsion from 10 kW – 10 MW at 2000-6000 seconds Isp on Any available propellant and has the potential to open up the solar system to low-cost interplanetary travel.

Modern lightweight solar panel technology, such as the DARPA FAST program, has created a unique need for lightweight, efficient, and highly variable power electric propulsion. The related ELF thruster technology is being developed by a DARPA SBIR to meet those needs. And while those programs are developing related pulsed power technologies they are focused entirely on Xenon propellants in order to maximize Thrust-to-Power. However, the ability to use complex propellants such as Air, Nitrogen, or Hydrazine would allow a dramatic shift in the capabilities of DOD spacecraft. An EP system operating at high specific impulse on Hydrazine could be retasked indefinitely between station keeping and rapid orbital maneuvers using a single propellant. Additionally, the ability to use ambient atmospheric gases would enable highly-eccentric orbits that use ambient Air for orbit raising and drag reduction for very low orbits. The ELF-160A thruster has definite payoffs for long-term military missions.