Development of a Microwave Discharge Ion Thruster Using Argon

Abstract

Thrust performances in a microwave discharge ion thruster using argon as the propellant were investigated for possibility of alternative propellant of xenon. First, the ion beam currents using a 10 cm class were measured. The ion beam currents with argon propellant are larger than those with xenon propellant at Pi >24 W in the same configuration. The propellant utilization and ion beam production cost are 0.50 and 440 W/A, respectively at 2.45 GHz microwave input power of 37 W and argon gas flow rate of 2.28 sccm. Next the ion beam currents of 2 cm class ion thruster were measured. The optimum mass flow rate is 0.4 sccm, which is larger than that using xenon. This would be due to the smaller ionization cross section and lighter mass than those of xenon. The propellant utilization efficiency and ion beam production cost are 0.73, 750 W/A, respectively at argon mass flow rate of 0.4 sccm and input power of 16 W. This performance of ion thrusters using argon competes against that using xenon.