Physical Phenomena of Electric Thrusters in Space

A joint study among Japan，Russia and USA was carried out in order to understand physical phenomena on electric thrusters in space。Direct-current(DC)arcjet thrusters，magnetoplasmadynamic(MPD)thrusters，ablative pulsed plasma thrusters，ion thrusters and Hall thrusters were investigated.Physical plasma properties，such as electron temperature and electron number density，in their thrusters were measured by means of electrostatic probe method and spectroscopic technique，and plasma features and acceleration processes were examined.In Japan，the Institute of Space and Astronautical Science is promoting the sample and return space mission from an asteroid，the MUSES-C，which is scheduled to be launched in 2002 and to bring back some specimens to the Earth in 2006 from an extra-terrestrial object。In the MUSES-C mission，the cathode-less microwave discharge ion thruster system is ready as a primary propulsion in the interplanetary space。The 400W microwave discharge ion thruster was studied to improve the thrust performance。30-cm-diam.Ring-cusped，20-cm-diam.Microwave discharge and C I D260 ii D2-propellant ion thrusters，0.3-1kW DC arcjet thrusters，10-100kW steady-state and 1kW quasi-steady MPD thrusters，0.5-5kW Hall thrusters，and their plasma plumes-spacecraft interactions were investigated aiming at applications to practical near-earth and interplanetary missions.Non-propulsive applications of electric thrusters to material processing were also conducted.

A joint study among Japan, Russia and USA was carried out in order to understand physical phenomena on electric thrusters in space. Direct-current (DC) arcjet thrusters, magnetoplasmadynamic (MPD) thrusters, ablative pulsed plasma thrusters, ion thrusters and Hall thrusters were investigated. Physical plasma properties, such as electron temperature and electron number density, in their thrusters were measured by means of electrostatic probe method and spectroscopic technique, and plasma features and acceleration processes were examined. In Japan, the Institute of Space and Astronautical Science is promoting the sample and return space mission from an asteroid, the MUSES-C, which is scheduled to be launched in 2002 and to bring back some specimens to the Earth in 2006 from an extra-terrestrial object. In the MUSES-C mission, the cathode-less microwave discharge ion thruster system is ready as a primary propulsion in the interplanetary space. The 400 W microwave discharge ion thruster was studied to improve the thrust performance. 30-cm-diam. ring-cusped, 20-cm-diam. microwave discharge and CィイD260ィエD2-propellant ion thrusters, 0.3-1kW DC arcjet thrusters, 10-100kW steady-state and 1kW quasi-steady MPD thrusters, 0.5-5kW Hall thrusters, and their plasma plumes-spacecraft interactions were investigated aiming at applications to practical near-earth and interplanetary missions. Non-propulsive applications of electric thrusters to material processing were also conducted.