Quasisteady Ablative Magnetoplasmadynamic Thruster Performance with Different Propellants

Abstract

This paper discusses quasisteady, ablative, magnetoplasmadynamic (MPD) thruster operation and performance. Quasisteady MPD thrusters operate with instantaneous power levels of a few megawatts during pulses (shots) that last approximately 1 ms. The MPD thruster used during this study consisted of coaxial electrodes with radially positioned bars of propellant that passed through the sidewall of the anode near the cathode tip. Four different polymer propellants were investigated: 1 ) polytetrae uoroethylene (Tee ont), 2) ethylene-tetrae uoroethylene resin (Hye ont), 3) polyethylene, and 4 ) ethylene-chlorotrie uoroethylene resin (Halart). Voltage, current, ablated propellant mass, jet velocity, and impulse bit were measured for e ve different values of energy per shot in the 1666‐ 3000 J range for each propellant. Polyethylene exhibited different electrical behavior (higher discharge voltages and impedances ) compared with the other three propellants that showed the typical features of high-ionization regime operation. Polytetrae uoroethylene provided the highest thrust and thrust-to-power ratio e gures, whereas ethylene-tetrae uoroethylene resin had the lowest values of these parameters. Polyethylene exhibited the highest exhaust velocity.