PARAMETERS OF THE ST-40M HALL THRUSTER WITH INCREASED POWER DISCHARGE SUPPLY

Abstract


 
 
 Abstract. The article presents the results of experimental investigation of the ST-40M Hall thruster modification developed by the Space Electric Thruster Systems (SETS). The thruster used a new filament hollow cathode with an emitting insert made of lanthanum hexaboride (LaB6). The use of a new hollow cathode made it possible to study the thruster’s parameters in the discharge power range of 300 – 550 W. The investigation was carried out using a stabilized voltage supply as a discharge power supply. As a result of experimental investigation, the current-voltage characteristics of the discharge in the accelerating channel of the thruster were obtained at fixed values of the anode’s mass flow rate of the working gas - xenon. The experimental dependences of thrust on the anode’s mass flow rate of the working substance and the discharge voltage, as well as the dependences of the specific impulse and thruster efficiency on the discharge voltage, are obtained. Experimental studies have shown that with a change in the discharge voltage in the range of 250 – 400 V and a change in the mass flow rate of the working gas in the range of 0.9 – 2.2 mg/s, the thruster provides a thrust value of 12 – 33 mN, a specific impulse value of 1200 – 1800 s, and the maximum value of the anode’s efficiency is 48 – 52%. The article also contains oscillogramsillustratingtherepeatedprocessofthethrusterstarting. Experimentalinvestigationofthemodified thruster ST-40M with the new hexaboride hollow cathode showed a significant improvement in thruster parameters compared to the prototype parameter before modification. In the process of experimental investigation, it was found that in some modes of the thruster operation, significant fluctuations in the discharge current occur, which led to a significant decreasing in the thruster parameters. For a more accurate clarification of the nature and parameters of the discharge current oscillations, it is necessary to conduct additional studies. The obtained experimental parameters of the modified ST-40M thruster made it possible to determine the values of its optimal parameters for various space missions.