1999 Fiscal Year Final Research Report Summary
Research and Development of Ground Simulation Methods for Spacecraft Environment, and Degradation Experiments of Spacecraft Materials
| Project/Area Number |
09555301
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Aerospace engineering
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| Research Institution | Osaka University |
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Principal Investigator |
TAHARA Hirokazu Graduate School of Engineering Science, Osaka University, Associate Professor, 大学院・基礎工学研究科, 助教授 (20207210)
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| Co-Investigator(Kenkyū-buntansha) |
OMAE Nobuo Faculty of Engineering, Kobe University, Professor, 工学部, 教授 (60029345)
TAGAWA Masahito Faculty of Engineering, Kobe University, Associate Professor, 工学部, 助教授 (10216806)
YASUI Toshiaki Graduate School of Engineering Science, Osaka University, Research Associate, 大学院・基礎工学研究科, 助手 (10263229)
SETSUHARA Yuichi Welding Research Institute, Osaka University, Research Associate, 接合科学研究所, 助手 (80236108)
MIYAKE Shoji Welding Research Institute, Osaka University, Professor, 接合科学研究所, 教授 (40029286)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Space Environment / Simulation Experiment / Electric Charging / Plasma Contactor / Ion Sheath / Thermal Control Material / Polyimide / Kapton |
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| Research Abstract |
A ground facility was developed for simulation of material and space plasma interaction and for study of spacecraft charging and discharge phenomena. The plasma simulator consisted of a vacuum tank, two turbo-molecular pumps and an electron cyclotron resonance plasma source of a magnetic-field-expansion plasma accelerator. Oxygen, nitrogen and argon plasma properties were measured. The simulator was found to have a high potential for ground tests. Using the simulator, the structure of an ion sheath created around a high voltage solar array and the degradation of surface materials near the array due to high energy ion bombardment were investigated. A negatively biased plate was exposed to oxygen plasma flow. The ion current and the plasma potential distribution were found to be intensively changed by the biased voltage and the attack angle, particularly a scaling parameter derived from the one-dimensional ion sheath theory. Furthermore, in order to examine the influences of ion bombardment on chemical structures of spacecraft surface materials, polymer films of polyimide BPDA-PDA Kapton, located on the biased plate, were exposed to oxygen plasma flow. The XPS analysis showed that an addition reaction of oxygen atoms or ions at wake condition was negligible compared with that at ram condition because of a smaller ion flux. Consequently, the addition reaction and a desorption of structural components were found to occur by ion bombardment. They are expected to cause the decrease in performance of spacecraft thermal control. Furthermore, in order to understand the relaxation of spacecraft charging by plasma flow, i.e., plasma contactor operation, Kapton and Teflon FEP films negatively charged by exposure to high energy electron beams and metal plates in series with negatively charged condensers were exposed to argon plasma flow. Negative charging was rapidly relaxed, and the attack angle influenced the time variation of the neutralization current.
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