研究者詳細 - 趙　孟佑

論文 - 趙　孟佑

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Guest editorial: Special issue on spacecraft charging technology 2012

Cho M., Cooke D., Ferguson D., Garrett H., Hilgers A., Lai S., Roussel J., Wheelock A.

IEEE Transactions on Plasma Science ( IEEE Transactions on Plasma Science ) 40 ( 2 PART 1 ) 2012年02月

Data analysis of the polar plasma environment for spacecraft charging analysis 査読有り

Cho M., Saito K., Hamanaga T.

62nd International Astronautical Congress 2011, IAC 2011 10 8316 - 8331 2011年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Polar Earth orbit (PEO) is a peculiar orbit where energetic auroral electrons and low-temperature ionospheric plasma coexist. There is a risk of charging and subsequent arcing in PEO. The plasma environment, namely its density and energy, is the crucial parameter for the spacecraft charging analysis. We statistically analyzed the environmental condition in PEO using the data of auroral electrons and thermal ions measured by DMSP (Defense Meteorological Satellite Program) satellites. Probability of a given combination of current densities of auroral electrons and thermal ions has been derived. The energy spectrum of the auroral electrons are also classified into several types and correlation with the thermal ions is analyzed. Combinations of the plasma parameters used by a spacecraft charging simulation software have been identified and database regarding the probability of occurrence of each combination has been formulated.

Scopus

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Evaluation method of solar array panel substrate insulation against sustained arcs 査読有り

Toyoda K., Wada T., Endo T., Cho M., Hoang B., Hsieh T.

3rd AIAA Atmospheric Space Environments Conference 2011年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

A testing method for evaluating the robustness of insulation films against sustained arcs on solar array panels was developed. Metal electrodes were used to simulate solar cells. The gap length between electrodes was controlled. In this paper, five samples with various insulator thicknesses were tested with the testing method. The robustness of the insulation films was evaluated. © 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

Scopus

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Effect of atomic oxygen exposure on resistivity change on spacecraft insulator materials 査読有り

Noor Danish Ahrar Mundari,Arifur Rahman Khan,Masaru Chiga,Teppei Okumura,Hirokazu Masui,Minoru Iwata,Kazuhiro Toyoda,Mengu Cho

Trans. JSASS Aerospace Tech. Japan 9 1 - 8 2011年04月

A Research on Mitigation Method Against Secondary Arcing on Solar Array 査読有り

Tomohiro Wada,Hirokazu Masui,Kazuhiro Toyoda,Mecgu Cho

The Japan Society for Aeronautical and Space Sciences 2011年04月

Initial Operations of Center for Nanosatellite Testing 査読有り

Mengu Cho,Hirokazu Masui,Yasuhiro Akahoshi,Koju Hiraki,Minoru Iwata,Kazuhiro Toyoda,Shinji Hatta

2nd Nano-Satellite Symposium 2011年03月

Development of Thruster using Electric Arc in Plasma Environment for Nano-Satellite 査読有り

Masayoshi Nakamoto,Kazuhiro Toyoda,Mengu Cho

2nd Nano-Satellite Symposium 2011年03月

Development of High Voltage Technology Demonstration Satellite, HORYU-2 査読有り

Hiroki Nishimura,Mengu Cho

2nd Nano-Satellite Symposium 2011年03月

Development of Ground Operation Software for Nano-Satellite HORYU 査読有り

Daiki kubo,Mengu Cho

2nd Nano-Satellite Symposium 2011年03月

Announcing the IEEE Transactions on Plasma Science Special Issue on Spacecraft Charging Technology January 2012

Lai S., Cooke D., Payan D., Hilgers A., Cho M., Garrett H., Ferguson D., Roussel J., Wheelock A.

IEEE Transactions on Plasma Science ( IEEE Transactions on Plasma Science ) 39 ( 1 PART 2 ) 2011年01月

Characterization of solar cell degradation due to electrostatic discharge on multi-junction solar cell 査読有り

Okumura T., Imaizumi M., Toyoda K., Cho M.

Conference Record of the IEEE Photovoltaic Specialists Conference 2599 - 2603 2010年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

A shunt resistance on the solar cell edge which is made by an electrostatic discharge (discharge) causes the degradation of multi-junction solar cell (MJ cell). To prevent the degradation, a trench was formed along the edge of multi-junction solar cell (AD MJ cell). The degradation characterization tests were performed on state-of art MJ cell and AD MJ cell to investigate the effect of trench in plasma environment. © 2010 IEEE.

DOI： 10.1109/PVSC.2010.5614144

Scopus

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Electrostatic discharge test with simulated coverglass flashover for multi-junction GaAs/Ge solar array design 査読有り

Hoang B., Wong F., Funderburk V., Cho M., Toyoda K., Masui H.

Conference Record of the IEEE Photovoltaic Specialists Conference 1118 - 1123 2010年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Space Systems/Loral (SS/L) successfully completed electrostatic discharge (ESD) tests of Multi-junction (MJ) GaAs/Ge solar array design in geosynchronous space environment. This ESD test was based on ISO-11221, Space systems - Space solar panels -Spacecraft Charging Induced Electrostatic Discharge Test Methods. In addition to the ISO reference for the test schematic, SS/L implemented modified test circuitry to better simulate the on-orbit operational conditions of our solar array design. The ESD test circuit also included simulated solar array panel coverglass flashover. The ESD test program utilized a 25-cell coupon that had been subjected to 2,000 thermal cycles caused by earth eclipses in GEO orbit and > 12,000 thermal cycles caused by the shadow of the spacecraft antennas. Other ESD test coupons are 4-cell coupons that, after baseline ESD experiments, can later be subjected to combined space environmental exposures tests. To demonstrate design robustness, we performed ESD tests to voltages and currents that are higher than that of on-orbit solar array operational voltages and currents. This paper discusses the coverglass flashover simulation, ESD test setup, the importance of the electrical test design in simulating the on-orbit operational conditions, and the test results. © 2010 IEEE.

DOI： 10.1109/PVSC.2010.5614721

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Development of Electron-Emitting Film for Spacecraft Charging Mitigation: Environment exposure tests 査読有り

Khan A., Sumida T., Iwata M., Toyoda K., Cho M., Fujita T.

48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition 2010年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Prevention of spacecraft charging and discharging has become increasingly important as GEO satellites employ higher bus voltage. There are numerous mitigation techniques against spacecraft charging including electron emission from the spacecraft chassis. A new electron emission device operating in completely passive manner has been developed which utilizes the field enhancement at the triple junction formed at the interface of metal and insulator exposed to space. It is named as Electron Emitting Film for Spacecraft Charging Mitigation (ELF's CHARM). Micro-etching was applied to polyimide-copper (PI-Cu) laminated film to manufacture a laboratory prototype. ELF utilizes pre-breakdown electron emission current leading to arcing at the triple junction keeping the current at the steady state. The electric field at the triple junction is macroscopically enhanced by charging of the polyimide film and microscopically by dielectric impurity on the copper surface. Theoretical rough estimate gives a current of 100 to 1,000μA. The laboratory experiment confirmed stable current emission from 10 to 100 μA from a sample of several centimeters square for 4 hours. Its robustness against ground handling and in-orbit contamination has already been demonstrated. To prepare for flight demonstration as early as 2011, the research and development have been accelerated. To ensure the endurance, recently 100 accumulated hours emission test and effect of high energy electron and proton and thermal cycling have been investigated on recently developed ELF. Post-emission of this electron emitting film confirms the durability under those harsh environments. Copyright © 2010 by the American Institute of Aeronautics and Astronautics, Inc.

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Preliminary experiments for establishing an ESD ground testing method of solar array 査読有り

Toyoda K., Wada T., Yoke T., Suzuki T., Masui H., Cho M.

48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition 2010年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

ESD ground testing on satellite solar array paddle is performed to mitigate catastrophic accidents. An international standard is desired to perform international satellite business smoothly. A standard has been developed in laboratory of spacecraft environment interactions. The draft has been applied. In this paper, preliminary experiments were performed to improve the testing method. Copyright © 2010 by the American Institute of Aeronautics and Astronautics, Inc.

Scopus

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Understanding the effect of atomic oxygen exposure on surface and volume resistivity change in LEO 査読有り

Mundari N., Khan A., Iwata M., Toyoda K., Cho M.

61st International Astronautical Congress 2010, IAC 2010 12 10018 - 10026 2010年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Spacecraft surface charging can leads to arcing and a loss of electricity generation capability of solar panel or even loss of a satellite. The arcing problem may be further aggravated by the atomic oxygen (AO) exposure in Low Earth orbit, which modify the surface of materials like polyimide, Teflon, anti reflective coating, cover glass etc used on satellite surface affecting materials properties such as resistivity, secondary electron emissivity, photo electron emission which govern the charging behavior. These properties are crucial inputs parameters for spacecraft charging analysis. To study the AO exposure effect on the charging governing properties, an AO exposure facility based on laser detonation of oxygen was built which produce 8-14km atomic oxygen with higher flux than in orbit. After exposing materials to 10years equivalent AO flux at the altitude of 700-800km, surface charging properties like resistivity and secondary electron emission is being measured. Measurement of surface and volume resistivity for AO exposed samples was done for polyimide. The measurement was done using the charge storage decay method at a room temperature, which is considered most appropriate for measuring the resistivity for space application. It was found that the value of surface resistivity increases more than two fold and volume resistivity remains same. Measurement of secondary electron emission characteristics is under progress.

Scopus

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Development and verification of on-orbit demonstration device for Electron-emitting Film (ELF) for spacecraft charging mitigation 査読有り

Sumida T., Shibagaki R., Khan A., Iwata M., Toyoda K., Tomonari S., Cho M.

61st International Astronautical Congress 2010, IAC 2010 12 10011 - 10017 2010年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

As geo-stationary (GEO) satellite bus voltage increased due to the increased size of the satellites, the number of solar array failures due to spacecraft charging increased. We are developing an electron emitter that emits electrons from the conductor by using the enhanced electric field at the triple junction which occurs simultaneously while spacecraft charging. The emitter is composed of an insulator on top of cupper plate. Parts of the cupper plate are exposed through the insulator ensuring the triple junctions that are the source of electron emission. This emitter operates in a completely passive fashion. In this paper, the authors conducted the verification test of this emitter after making a measurement circuitry. This time, the surfaces of the emitters were coated with a special material to enhance the electron emission current. In the ground test, the emitters were biased to a highly negative potential with respect to a vacuum chamber ground and exposed to an electron beam. This leaded the simulation of satellite charging. Then the operation of the measurement system had been checked to confirm the emission as well as surface potential. These results permit this electron emitter to be used in actual space environment.

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Capacity building in basic space technology development through on-the-job training in nano-satellite design, building and testing 査読有り

Cho M., Balogh W.

61st International Astronautical Congress 2010, IAC 2010 2 1710 - 1716 2010年12月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Developing countries that in the past have mostly focused on applications-oriented aspects of space technology are increasingly also interested in building indigenous capacities for basic space technology development. A nano-satellite development program is an ideal first-step to establish such a basic capacity. Experience gained through on-the-job training, going through the complete cycle of designing, building and testing a satellite, is crucial to gain this capacity. To fill that demand there is a need for educational institutions to offer appropriate on-the-job training opportunities. Kyushu Institute of Technology and the United Nations Office for Outer Space Affairs will launch a long-term fellowship programme on nano-satellite technologies for post-graduate level students from developing countries and countries with economies in transition. The first students supported by the fellowship programme are expected to enrol in Kyushu Institute of Technology on October 1st, 2011. The length of the fellowship programme for each student is three years. Students will work in the newly established Centre for Nanosatellite Testing, which can handle a full range of environmental tests required for a 50cm-class nano-satellite. Because all tests can be conducted with the facilities available inside the campus, intensive and efficient cycles of designing, building and testing become possible. This paper describes the details of the fellowship program. Copyright ©2010 by the International Astronautical Federation. All rights reserved.

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Characterization experiments of secondary arcs on solar arrays: Threshold and duration 査読有り

Masui H., Ose T., Kitamura T., Toyoda K., Cho M.

Journal of Spacecraft and Rockets 47 ( 6 ) 966 - 973 2010年11月

記述言語：英語掲載種別：研究論文（学術雑誌）

An electrostatic discharge test performed on a solar array panel is one of the important tests carried out before spacecraft launch to ensure spacecraft reliability in orbit. In this study, the effects of secondary arcs on the solar array, which can cause catastrophic accidents, are considered. The sustained-arc threshold of multijunction and silicon solar arrays was investigated to establish the design guidelines for ensuring the safety of satellite solar arrays. In this experimental study, the string voltage, string current, gap length, and solar-cell type were selected as test parameters. Gap lengths were 0.5, 0.8, 1.0, and 2.0 mm. For 0.5 and 0.8mmof gap length, a permanent sustained arc occurred under the condition of 1.5 A of string current for 50, 70, 90, and 110 V of string voltage. Furthermore, temporary sustained-arc duration exponentially increased with increasing string current. Temporary sustained-arc duration longer than 1 ms can serve as a practical alarm for the imminent permanent sustained-arc inception. © 2010 by the American Institute of Aeronautics and Astronautics, Inc.

DOI： 10.2514/1.49571

Kyutacar

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CAPACITY BUILDING IN BASIC SPACE TECHNOLOGY DEVELOPMENT THROUGH　ON-THE-JOB TRAINING IN NANO-SATELLITE DESIGN, BUILDING AND TESTING 査読有り

M. Cho,W. Balogh

61th International Astronautical Congress 2010年10月

Development and Verification of On-Orbit Demonstration Device for Electron-emitting Film (ELF) for spacecraft charging mitigation 査読有り

Takahiro Sumida,Ryunosuke Shibagaki,Arifur R. Khan,Minoru Iwata,Kazuhiro Toyoda,Setuo Tomonari,Mengu Cho

61th International Astronautical Congress 2010年10月

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