@inproceedings{oai:jaxa.repo.nii.ac.jp:00008155,
 author = {Emmanuel, Amorim and Cho, Mengu and Emmanuel, Amorim and Cho, Mengu},
 book = {第22回宇宙エネルギーシンポジウム　平成14年度, The 22nd ISAS Space Energy Symposium March 12, 2003},
 month = {May},
 note = {During its lifetime, satellites on a geostationary orbit (GEO) are charged by particles of the magnetosphere (mainly electrons) and dielectrics are differentially charged to a point where a spontaneous discharge may occur. This is a phenomenon called electrostatic discharge (ESD): the charges accumulated by the satellite are dissipated rapidly by an electron emission from the satellite to another part of the satellite (phenomenon called flashover) or to the space environment (called blow-off discharge). The current magnitude depends on the dielectric and satellite size. The electrostatic discharges create a plasma medium and emit light. The damages produced are usually temporary anomalies producing limited disturbances and no permanent damage to the corrupted systems. However permanent damages were observed recently on several satellites. These damages are believed to be produced by secondary arcs triggered by primary electrostatic discharges localized in the vicinity of available energy. These secondary arcs occur particularly on solar arrays between two adjacent solar cells having a differential voltage between them. Protective dielectric cover glasses subjected to alternative charging and discharging by the space environment typically cover the solar cells. These covers are believed to be the site of primary ESD and in some cases this ESD can switch to a secondary arc. Such phenomena have been identified as the most likely cause for the partial power losses of two GEO satellites in 1998. The failures were well correlated with charging environments and occurred in the midnight dawn sector were surface charging is known to take place during sub-storms. This paper reports on experimental investigation of electrostatic discharges and secondary arcs produced in laboratory. An electrical circuit was used in order to simulate the real accumulated charges and a real solar array circuit. The external capacitance value was of particular attention. This capacitance represents the charges accumulated by the satellite and by the cover glasses around the cell where the discharge takes place. The evolution of the discharge current was measured, and an emission spectroscopic study in the discharge zone was made. Finally the location of the discharge was investigated in real time. About 1,000 electrostatic discharges were obtained. The external capacitance values were 0.42, 1, 12.8, 50.8 and 100 nF. Depending on this value, the blow-off current varied between 1 to 70 amperes. The lifetime varied also from several microseconds to several ten microseconds. A total of 36 clearly identified secondary arcs were obtained on both the solar cells and the copper samples. One sustained arc (i.e. the power supply to end the secondary arc had to be shut down.) has been obtained on the solar cell sample. This sustained arc produced big damage: the resistance between the solar cell and the metallic plate (local ground) was as low as 5 ohms showing that this kind of phenomenon can trigger power losses in the real solar array panels. For the other secondary arcs the lifetime was between 10 and 1,500 microseconds. Spectra obtained on the solar cell samples and copper samples allowed identification of spectral lines. In the case of the solar cells, lines emitted by silver, silicon, hydrogen atoms and the C2 molecule are clearly identified. The silver and silicon lines clearly show that there is vaporization of the solar cells. The energy dissipated during a secondary arc is high enough to produce damages. The lines emitted by hydrogen probably come from gas desorption and from the water molecule dissociation. The molecular bands emitted by the carbon molecule can come from the insulator film vaporization. On the spectra obtained on the copper samples, copper, hydrogen and C2 molecule lines have been identified. Copper lines show that the metallic plates are partially vaporized, 資料番号: AA0045915005},
 pages = {21--25},
 publisher = {宇宙科学研究所, The Institute of Space and Astronautical Science (ISAS)},
 title = {Spectroscopic study of secondary arcs on satellite solar arrays},
 year = {2003}
}