Combustion Enhanced Electric Propulsion

ABSTRACT: Orbital transfer missions require a demanding combination of lightweight, flexible operation and high Thrust-to-Power (greater than 120 mN/kW) electric propulsion. Adding Neutral Entrainment (NE) to a pulsed electromagnetic thruster has the potential to dramatically increases the total Thrust-to-Power by decreasing effective plasma frozen flow and ionization losses. It also enables a new class of thrusters, so-called Combustion Enhanced Electric Propulsion. In Combustion Enhanced EP a lightweight propellant in burned in a micro mono-propellant thruster within an EP system. That decomposed, hot, neutral gas is then entrained in a 5-15 kW class NE thruster. This coaxial combination of thrusters decreases overall system mass and complexity, while simultaneously increasing performance. By harnessing the momentum and chemical energy of the mono-propellant and entraining it in a plasma stream, T/P can be increased at all operational exhaust velocities. The following Phase I study will develop a series of system and thermo-chemical models to optimize total efficiency, T/P, and system flexibility. An experimental program will address the thermal and engineering challenges of a Combustion Enhanced Electric Propulsion system. BENEFIT: By utilizing Combustion Enhanced Electric Propulsion with an electromagnetic thruster, lightweight mono-propellants can be used from 200-2000 s specific impulse. This thruster system will greater than 100 mN/kW and operate over 50% efficiency from 500 to 2000 s. Additionally, this system should be lightweight (less than 1 kW/kg). These combined abilities yield a thruster system that has numerous mission benefits and, thus, commercial benefits. A 3-15 kW system operating on a green mono-propellant would enable wide-ranging multi-mode orbital transfer missions. For non-DOD missions, the ability to efficiently use In-Situ Resources has tremendous benefits to interplanetary missions.