Study On Life Test Of Pulse Plasma Thruster

As the first electric propulsion device to be successfully applied to space flight,the pulse plasma thruster(PPT)is suitable for precise positioning,attitude control,track correction,resistance compensation and orbital elevation of micro-satellites,because of its advantages of high specific impulse,small volume,light weight,simple structure,flexible control and higher control precision.The life test of PPT is the key link in the engineering application of PPT.It can give the life conclusion of PPT prototype and provide important test data for the failure mechanism of PPT.It has the characteristics of long period,large amount of data and high cost,and the special requirements for the long time automatic monitoring and testing process and data collection are put forward for the life test system.Therefore,this paper systematically studies the related equipment of the PPT life test system,and carries out the corresponding life test research.It has important engineering application value and theoretical significance.In this paper,the requirement analysis of PPT life test is carried out.On the basis of the existing equipment in the laboratory,the structure framework of the PPT life test system is put forward,and a data acquisition system program with the function of real-time data acquisition and storage is designed.An automatic ignition counting device for PPT is developed in this paper.Through the analysis of the output signal of the photoelectric conversion device and counter performance,the parameters matching of the photoelectric conversion device and the counter are realized.The verification research is carried out,which verifies the reliability and applicability of the device.Based on the principle of resistance partial pressure,this paper develops a partial voltage probe to collect the PPT discharge voltage,solves the problem of the voltage mismatch and common mode interference between the voltage measuring probes and the data acquisition card,and uses it to simplify the determination method of the spectral test time datum.Finally,the PPT life test is carried out by using the PPT life test system.The results show that the new phenomenon of PPT ignition success rate is caused by propellant gas storage,and the discharge delay time increases with the number of discharges,which can be used to characterize the stability of discharge.The end of life of the test PPT is caused by the serious carbon deposition of insulating ceramic slices between the discharge channels.