| Electric Propulsion (EP) has many advantages of high specific impulse, long lifetime, high controlling precision. It can perform many kinds of space mission. After fifty years developed, it had been more and more applications on spacecrafts. Microwave Plasma Thruster (MPT) is a new type of electro-thermal thruster. On the base of success of ground principle prototype, MPT has been researched through theory and testing under the vacuum condition. The vacuum experimental system of MPT has been established, the characteristics of startup and. steady working under vacuum condition have been researched, and application of MPT on geosynchronous (GEO) satellite was probed. They are summed up as follows:1. The vacuum experimental system of MPT has been designed, manufactured, mounted, and debugged, which is made up of vacuum subsystem, measurement and control subsystem of virtual instrument, subsystem of small thrust measurement, subsystem of propellant storage and supplying, and prototypes of MPT. The author presided over the setup of vacuum subsystem and debugging of the all vacuum experimental system, and toke part in building of other subsystems. The system can steadily and reliably work, whose working pressure is froml.OPa to lO.OPa. The automatization, communication, and digital of vacuum experiment have basically been realized, which provide well guarantee for investigation of MPT under the vacuum condition.2. Basing on the tests of MPT, the characteristics of reliably start up and steadily work for MPT under vacuum condition have been researched for the first time in China. At same time the performance of MPT have been estimated. The parameters of input power and reflect of microwave (Pin and Pref), pressure of resonant cavity (Pres), flowrate (qm), vacuum degree (Pv), thrust (F), temperature at wall of nozzle (Tw) have been measured during the testing. The reasons and law, which effect startup and steady work of MPT, have been researched. Testing research specifies that MPT can reliably start up for Ar, He, N2, H2, and Air under the vacuum condition, and that ignition is easiest with Ar, than with N2, and most difficult with He. With the incident power increasing, startup becomes more and more easy. At a certain range of vacuum pressure, startup is easiest. The optimum Specific Power (SP) of Ar is 4.0 MJ/kg, and that of He is 30 MJ/kg. At designed state, the specific impulse and efficiency are 5758.3 m/s and 55.4% at 100W incident power, 6107.6m/s, 57.1% at 1000 W incident power with He respectively. During longtime firing, parameters of Pin, qm, F, pres are steady with He and Ar.3. Optimization of system and mission based on genetic algorithm (GA) about GEO satellite using MPT has been probed after analysis of orbit dynamics, and building of mathematic model about GEO satellite platform and each subsystem. This optimization application is a general way for using other EP carrying out OT and NSSK of the GEO satellite. The results illustrate that MPT propulsion system can be used to OT and NSSK of the GEO satellite. It appears to be a veryattractive option to drastically increase payload mass and brings in numerous commercial profit.When the burning arc is 600 , the time of Orbit Transfer is 165 days with four 1000W MPTs to carryout orbit transfer. The mass of payload increases 86%, which means the number of transponder on satellite increasing from 24 to 44 with four 1000W MPT to carrying out orbit transfer and four 100W MPT performing NSSK during the period of 8 years lifetime.The research indicates that MPT shows many advantages, such as moderate specific impulse,high efficiency, long lifetime, low plume contamination, simple structure, low weight, and so on. Comparing with other EP, MPT has particular advantages to perform OT and NSSK of GEO satellite. It has a potential prospect of application in the future. For example, it can be used to drag make-up and solar pressure cancellation of low orbit spacecraft, formation flying and precise positioning of small satellite, repos...
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