1. Spacecraft bus voltage and power 0.1 1 10 2 3 4 1001000 DSCS II RCA SATCOM MILSTAR TDRS SKYLAB SPACE TELESCOPE LEASAT ISS HS702 space factory 、 space hotel Spacecraft power (kW) Bus voltage(V) EOS-AM ETS-8 Before mid-90s After mid-90s After 2010 experimental solar power satellite severe plasma interaction 400V is necessary for next-generation 1MW large space platform after ISS

2. Spacecraft potential in LEO

3. How an arc occur?

4. Charging of coverglass by ions Field intensification at triple junction Field emission of electrons Ionization of desorbed gas Neutralization of coverglass charge Repeated arcing and charging process

5. Sustained arc

6. Test facility

10. GEO Plasma Environment Test Chamber Operational since March 2002 Diameter 60cm, Length 90cm Minimum Pressure 3x10 -7 Torr Equipped with an electron beam gun, a non-contacting surface potential probe, a Kaufman type plasma source, a xy-stage, a low-pressure mercury lamp, halogen heat lamps, a video-image analysis system Electron beam (max30kV) Trek probe X-Y stage controller Trek probe Solar array coupon X-Y stage

11. LEO Plasma Environment Test Chamber Operational since 1998 Diameter 1m, Length 1.2m (excluding sub-chamber) Minimum pressure 1x10 -6 Torr Plasma density 1x10 12 m -3 or above Equipped with an ECR plasma source, a deuterium UV lamp, a mass spectrometer, a x-y stage, a video-image analysis system, a high speed data acquisition system, halogen heat lamps, a spectrum analyzer, a metal-halaide lamp

13. Pressure chamber (1 MPa)  = 600 mm

15. time V fo density temperature density V fo Measurement of gas propertiesMeasurement of flashover voltage Build-up of database

16. Distribution of charge exchange ions and neutralizer electrons near a GEO satellite with an ion thruster Ion densityElectron density

17. Example of three-dimensional simulations x y z  B  v d