Proof-of-principle thrust measurement experiments for a partially ionized, electrodeless Magnetic Reconnection Thruster (e-MRT)

To address needs for high-power thrusters with long lifetime suitable for high-speed and deep space missions, we are exploring a new electrodeless Magnetic Reconnection Thruster (e-MRT). This concept will use asymmetric, partially ionized, inductively-driven, Alfvénic magnetic reconnection outflows for thrust. Partial ionization may increase power efficiency while maintaining high thrust via neutral-ion coupling. To test the concept, we have performed island merging experiments on the Magnetic Reconnection Experiment (MRX) to measure the thrust from reconnection outflows under Argon fill pressures ranging from 4 to 20 mTorr. We used Mach probes to measure time-resolved ion flows and an in-vessel flexing beam to measure time-integrated impulse from ion+neutral flows. Measured impulses are tens of μN-s, ranging from 10 to 90 μN-s. Initial results suggest that at low pressures (<12 mTorr), total impulse is highly correlated to ion impulse. At large pressures (>12 mTorr), though thrust from ions decreases, neutrals may provide significant additional thrust, thus increasing total thrust and propellant efficiency. Overall, our findings suggest that reconnection shows promise for application to spacecraft propulsion. Optimization of operation regime and prototyping is necessary to demonstrate the concept's viability.