研究者詳細 - 趙　孟佑

論文 - 趙　孟佑

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350-V Photovoltaic Power Generation in Low Earth Orbit（共著）査読有り

Mengu Cho, Hirokazu Masui, Shunsuke Iwai, Tatsuya Yoke, Kazuhiro Toyoda

Journal of Spacecraft and Rockets 51 379 - 381 2014年05月

Characterization Experiments of Secondary Arcs on Solar Arrays: Secondary Arc Physical Parameters（共著）査読有り

Hirokazu Masui, Takayuki Ose, Tomoki Kitamura, Kazuhiro Toyoda, Mengu Cho

Journal of Spacecraft and Rockets 51 ( 3 ) 922 - 930 2014年05月

Thermal Vacuum Test Results for Virtex-5 FPGA Based Multi-core On-Board Computer（共著）査読有り

Mohamed Mahmoud Ibrahim, Kenichi Asami, Mengu Cho

IEEE AeroSpace 2014 2014年03月

Effects of Ultraviolet Irradiation and Atomic Oxygen Erosion on Total Electron Emission Yield of Polyimide（共著）査読有り

J. Wu, A. Miyahara, A. R. Khan, M. Iwata, K. Toyoda, M. Cho, X. Q. Zheng

IEEE Transactions on Plasma Science 42 ( 1 ) 191 - 198 2014年02月

Charging and Arcing Test on Semi-conductive Coated Solar Coupon Panel（共著）査読有り

Akitoshi Takahashi, Minoru Iwata, Ryo Muraguchi, Mengu Cho

IEEE Transactions on Plasma Science 42 ( ２ ) 384 - 390 2014年02月

Space education and outreach using a digi-singer on-board a nano-satellite 査読有り

Nakano T., Shimizu T., Chen D., Almubarak H., Cho M.

Proceedings of the International Astronautical Congress, IAC 12 8510 - 8513 2014年01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）

Copyright 2014 by Ms. Tae Nakano. Published by the IAF. Currently, there is no education curriculum that teaches space development or utilisation in Japanese elementary or junior high schools. The early education is vital for such young students to get an interest for future carrier. The aim of this project is to provide an opportunity to understand space related industries. The Kyushu Institute of Technology (Kyutech) has conducted an educational program for students in elementary and junior high schools in collaboration with a local science museum with support from the Japanese Ministry of Education since 2009. In this program, the children experience a part of satellite development together with university students and receive Morse beacon sent from the nano-satellite HORYU-II using a handy receiver and a handmade Yagi antenna. Such signal can be easily acquired without special equipment, but requires special training or a computer program to decode the signal, and hence this is not so appealing to the children. HORYU-IV is a high voltage experiment nano-satellite (30cm cubic, < 10kg mass) under development at Kyutech and to be launched in FY2015. HORYU-IV payload includes Yamaha's eVOCALOID (TM) LSI as an on-board vocal synthesiser, namely digi-singer. Thanks to it, children could experience space not only in science classes, but also in classes of music, art, or physical education. Audio from the digi-singer is not only used for school education, but also for events and creative activities such as a dancing event and illustration, and can attract people who have no special interest in space technologies.

Scopus

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Selection of commercial-off-the-shelf antistatic coating and its applicability for space-use solar arrays 査読有り

Iwata M., Takahashi A., Sakamoto M., Cho M., Muraguchi R.

Transactions of the Japan Society for Aeronautical and Space Sciences 57 ( 3 ) 153 - 159 2014年01月

記述言語：英語掲載種別：研究論文（学術雑誌）

In recent years, the power generation requirement of spacecrafts has increased in order to load them with many mission devices and to extend their lifetime, hence, high voltages are used. However, such high voltages can cause electrostatic discharges on solar arrays, resulting in damage to the solar arrays. Therefore, we use an antistatic coating, which mitigates the surface charging on solar cells, in order to prevent the discharge. It is considered that an antistatic coating can mitigate surface charging and can prevent discharges on solar cells. The purpose of this research is to develop a coating to mitigate the surface charging applicable to geostationary Earth orbit satellites. We selected a candidate coating with the required surface resistivity and vacuum resistance. Furthermore, we selected a commercial-off-the-shelf antistatic coating after considering the experimental results of charging mitigation performance when simulating the charging condition in space. The candidate agent was coated on a conventional solar array coupon panel, and the charging mitigation performance of the latter was evaluated. We have confirmed a dramatic improvement in charging mitigation performance with this coated conventional solar array coupon. © 2014 The Japan Society for Aeronautical and Space Sciences.

DOI： 10.2322/tjsass.57.153

Scopus

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Role of aging on the threshold of electrostatic discharge on solar array coverglass 査読有り

Khan A., Hughes R., Chen Y., Toyoda K., Cho M., Gray A.

Proceedings of the International Astronautical Congress, IAC 11 8036 - 8040 2014年01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）

Copyright © 2014 by the International Astronautical Federation. All rights reserved. Coverglass has been widely used to cover the solar cells of satellite solar arrays. This acts to protect the arrays from damage due to irradiation by UV, protons, electrons, etc. However, charge accumulation due to high-energy proton/electron irradiation or ageing due to thermal cycling may degrade the quality and affect the threshold for electrostatic discharge (ESD) from the coverglass. In order to reveal the effect of aging on the threshold for ESD in an inverted potential gradient (IPG) condition, several coverglass samples (CMG100-AR) produced by Qioptiq Ltd. have been aged by thermal cycling (-160 to +110 C) and high-energy (500 keV) electron beam irradiation. A ground experiment was conducted by placing virgin and exposed (aged) samples in vacuum, irradiating the samples with a beam of energetic electrons to generate an artificial ESD, and measuring the sample's surface potential by a non-contact method before and after the discharge occurred. Statistical analysis and Weibull distribution confirms that the ESD threshold for aged coverglass is higher than that of virgin.

Scopus

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Three hundred fifty volt photovoltaic power generation in low Earth orbit 査読有り

Cho M., Masui H., Iwai S., Yoke T., Toyoda K.

Journal of Spacecraft and Rockets 51 ( 1 ) 379 - 381 2014年01月

記述言語：英語掲載種別：研究論文（学術雑誌）

A nanosatellite, HORYU-II, weighing only 7.1 kg achieved the highest photovoltaic power generation in orbit, at 350V, breaking the previous record from the International Space Station, at 160 V, by more than a factor of two. The satellite uses a permanent magnet and hysteresis dumper to do passive attitude control using the Earth's magnetic field. Using series-connected micro solar cells, the satellite can carry out high-voltage experiments in space. The high-voltage solar array developed for HORYU-II is suitable for other scientific experiments that make use of high voltages, such as electric propulsion, spacecraft charging onboard a micro/nanosatellite. It is free from the electromagnetic noise associated with high-voltage dc/dc converters and robust enough to operate for a short time in orbit.

DOI： 10.2514/1.A32559

Scopus

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Nano-satellite project-based learning for capacity building in basic space technology development 査読有り

Polansky J., Cho M., Balogh W.

Proceedings of the International Astronautical Congress, IAC 12 8398 - 8402 2014年01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）

Copyright ©2014 by the International Astronautical Federation. All rights reserved. In April 2013, Kyushu Institute of Technology (Kyutech) launched a new English-based post-graduate curriculum, the Space Engineering International Course (SEIC). The curriculum is either two years (Masters) or three years (Doctor), and consists of research leading to a Master or Doctor degree, lectures on space engineering, project-based learning (PBL), and on-the-job training in space environment testing. SEIC is open to any student, Japanese or non-Japanese, who registers as a full-time graduate student at the Graduate School of Engineering. PNST (Post-graduate study on Nano-Satellite Technologies) fellows are supported through a United Nations/Japan long-term fellowship programme and comprise the core constituency of non-Japanese students. The PNST fellows are primarily from non-space faring nations and are expected to contribute to indigenous capacity building by bringing the basic space technology development knowledge and skills acquired through their studies at Kyutech back to their home countries or home institutions. The objective of PBL is to perform real-world problem solving to an open-ended question or challenge, for example, nano-satellite mission design that benefits society or developing countries. In this process students learn to apply their technical prowess to a real-world project, enhance systems engineering skills, learn to think as global engineers, and practice inter-cultural communication. Nano-satellite PBL in combination with the other aspects of SEIC is designed to allow students to implement applications-oriented space technology outside of Kyutech upon graduation. This paper details the first year of SEIC and nano-satellite activities at Kyutech, and gives updates of the United Nations/Japan PNST long-term fellowship programme.

Scopus

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Monte Carlo simulation of reliability growth of small-scale satellites through testing 査読有り

Cho M.

Proceedings of the International Astronautical Congress, IAC 9 6762 - 6771 2014年01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）

Copyright © 2014 by the International Astronautical Federation. All rights reserved. There is an increasing demand of small-scale satellite (a micro/nano/pico satellite seeking low-cost and fast- delivery) development worldwide. The advantages of small-scale satellite are low-cost and fast-delivery. But, currently the success rate of small-scale satellite is much lower than traditional satellites. The satellite reliability can be modelled by Weibull statistics. A satellite system goes through a series of tests. The tests may detect various defects in design, material, workmanship, etc. Once a defect is detected, it is corrected and the test resumes or the development process goes back to an earlier phase. The failure rate decreases due to improvement and keeps decreasing as the testing continues until it becomes a steady value indicating the shift to the random failure mode. In the present study, we consider how the reliability is improved by testing. We carry out a Monte Carlo Simulation to simulate the stochastic process where a defect is detected by each test. At each phase of testing, we judge whether a defect is detected or not by a random number. The overall test time is calculated and compared to the final reliability that depends on how many of latent defect remain undetected. The simulation result shows repeating a short cycle of testing is effective to obtain relatively high reliability with less testing time.

Scopus

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Low cost thermal-vacuum system for the development of very small spacecraft 査読有り

Shimizu T., Motohata T., Masui H., Iwata M., Cho M., Finnholm J., Kestila A.

Proceedings of the International Astronautical Congress, IAC 8 5903 - 5906 2014年01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）

Copyright ©2014 by the International Astronautical Federation. All rights reserved. Simulated space environments are necessary for validating the functionality of spacecraft and/or payloads during their development phase. A thermal-vacuum chamber is a key space environment simulator. Conventional chambers provide a high vacuum environment as well as thermal cycle environments that provide conditions similar to those encountered in space. However, even small such chambers are expensive, and are often beyond the budget of a university-based space project. In addition, the need to use liquid nitrogen coolant adds an additional high running cost. For this reason, we developed a small thermal vacuum test facility that costs less than 2000USD and which uses solid-state Peltier heaters/coolers.

Scopus

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In-orbit demonstration of passive electron-emitting film for mitigation of spacecraft charging 査読有り

Tanaka A., Khan A., Iwata M., Toyoda K., Cho M., Tsuruda Y.

Proceedings of the International Astronautical Congress, IAC 11 8041 - 8046 2014年01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）

Satellite is greatly affected by the space environment and one of these effects is satellite charging. A passive electron emitter has been developed for satellite charging mitigation. In 2012, emission of electron from this emitter has been confirmed by a high voltage technology demonstration satellite, 'Horyu-II', made by Kyushu Institute of Technology. However, due to insufficient data and longer time resolution, repeated emission has yet to be confirmed. In order to have more data in the shorter time resolution, this emitter has been mounted on a small satellite, named 'Hodoyoshi-3' and 'Hodoyoshi-4' made by Tokyo University, passing through the aurora zone, similar to 'Horyu-II'. Functioning of this emitter and related circuitry for measuring emission current and surface potential on the flight model (FM) of 'Hodoyoshi-4', ground operation has been confirmed. Sampling rate of emission current measurement of 'Horyu-2' was 4 minutes, whereas for 'Hodoyoshi-4' it is one second only. Therefore, we expect much better and reliable information.

Scopus

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ISO standard draft "design qualification and acceptance tests of small-scale satellites and units seeking low-cost and fast-delivery" 査読有り

Cho M.

Proceedings of the International Astronautical Congress, IAC 6 3966 - 3970 2014年01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）

Copyright © 2014 by MENGU CHO. There is an increasing demand of small-scale (small/micro/nano/pico) satellite development and utilization worldwide. The low success rate of small-scale satellites, however, may jeopardize their commercial use. A certain set of tests is necessary to improve their reliability to an acceptance level suitable for commercial investment. At the same time, applying the same test requirements and methods as those applied to traditional large/medium satellites will nullify the low-cost and fast-delivery advantages possessed by small-scale satellites. A new international standard has been developed and proposed to ISO/TC20/SC14. The standard describes test requirements and test methods to qualify the design and manufacturing methods of small-scale satellites and their units, and to accept the final products. Their mass and size is, but not limited to, typically less than 50kg and 50cm, respectively. The standard places emphasis on achieving reliability against infant mortality after the launch while maintaining low-cost and fast-delivery. Since 2011, an international collaborative effort has been carried out to develop the standard draft. The standard draft is currently registered as ISO/CDC-19683. This paper introduces the content of the standard draft.

Scopus

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Challenges and opportunities of UNISEC-Global 査読有り

Kawashima R., Mengu C., Ibrahim M.

Proceedings of the International Astronautical Congress, IAC 12 8472 - 8476 2014年01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）

Copyright ©2014 by the International Astronautical Federation. All rights reserved. The Global University Space Engineering Consortium (UNISEC-Global) has been established in November 2013 with "VISION 2020-100" that aims to create a world where university students can participate in practical space projects in more than 100 countries by the end of 2020. Recently, the number of universities and countries/regions are getting interested in participating in the UNISEC activities. In this paper, the background, vision, mission, structure, implementation, local chapter and status-quo of the UNISE-Global are introduced firstly, and then merits and difficulties in establishing local chapters are described, followed by discussion on challenges and opportunities of the UNISEC-Global.

Scopus

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Basic research on radiation tests suitable for nano-satellites 査読有り

Tomioka T., Masui H., Cho M., Takamiya K.

Proceedings of the International Astronautical Congress, IAC 11 8048 - 8051 2014年01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）

In recent years, many nano-satellites are being developed in universities and private enterprises due to low cost and short development period. Therefore, commercial off the selves (COTS) ICs are often used in the nano-satellite projects. However, COTS ICs are not designed for space usages. It may breakdown due to strong radiation dose in the space. Therefore, radiation durability test should be performed before the satellite launch. Generally speaking, in the space radiation damage is mainly due to protons. To perform the radiation test, an accelerator is required that is expensive and needs long preparation time. Acquiring this type of test facility is against the concept of nano-satellite concept: 'Low cost and Fast delivery'. The purpose of this research is to establish a suitable radiation testing method and evaluate it as a standard for nano-satellites. It has been focused on Californium-252 ( 252 Cf) as an alternative source radiation that is a radioisotope emits heavy ions continuously. In this research, the bombardment target is a microprocessor (H8/36057) used in Horyu-2, a 30cm cubic nano-satellite developed by Kyushu Institute of Technology, Japan. Horyu-2 was launched on 18 th May 2012. One of the main abnormal phenomena observed on board microprocessor was caused by radiation and that was Single-Event-Latchup (SEL). When proton like particle strikes on a semiconductor surface, many charges are generated, named as SEL, which generates over-current in the IC and causes failure. Up to now (10 th September, 2014), SEL was occurred 5 times on the H8/36057 on board Horyu-2. By using the 252 Cf radiation system on H8/36057 microprocessor, similar situation was simulated to reveal the radiation effect on Horyu-2. First, SEL occurrence probability was calculated when single particle struck on the IC surface followed by proton flux with LET. Finally, on orbit SEL occurrence cross-section was calculated. Thus on orbit radiation resistance on microprocessor (H8/36057) can be estimated by 252 Cf using as a radiation source.

Scopus

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Total electron emission yield measurement of insulating materials due to different temperatures 査読有り

Miyahara A., Wu J., Khan A., Toyoda K., Cho M.

Proceedings of the International Astronautical Congress, IAC 8 5867 - 5872 2014年01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）

Copyright © 2014 by KYUSHU INSTITUTE OF TECHNOLOGY. Electron induced secondary electron emission from space insulator is a very important factor in understanding spacecraft charging behaviour. Due to the injection of primary electrons and the emission of secondary electrons in the surface layer of insulator, the target surface will be negatively or positively charged. Additionally, the electron emission yield of the spacecraft surface materials is highly dependent on space environments, such as the temperature variation. In our tests, we chose the polyimide film (Kapton 100H) as the research object, and used a single short, low-density pulsed beam, and also developed a scanning method for the total electron emission yield (TEEY) measurement, which can avoid surface potential influence for insulating materials. Moreover for the TEEY system, we installed a heater for high temperature (around 100°C) and the shroud by using liquid nitrogen for low temperature (around -50°C). Under this experimental situation, TEEY of polyimide films of room, high and low temperature was tested respectively. The conductivity variation of the polyimide film due to the different temperatures was considered to influence TEEY.

Scopus

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Effects of Energetic Electron and Proton Irradiation on Electron Emission Yield of Polyimide Induced by Electron and Photon　掲載年月不明　（共著）査読有り

J. Wu, A. Miyahara, A. R. Khan, M. Iwata, K. Toyoda, M. Cho, X. Q. Zheng

Special Issue of ISTS, Transactions of Japan Society for Aeronautical and Space Science, Aerospace Technology 2014年01月

Evolutionary approach for Space Science Education Development in Africa（共著）査読有り

Muhammad ALKALI, Celina Gana, Danlami Idrisu, Mengu Cho

IOSR Journal of Research & Method in Education (IOSR-JRME) 4 ( 1 ) 22 - 27 2014年01月

UNISECの国際展開 : ビジョン・成果・将来展望(<特集>NPO大学宇宙工学コンソーシアムUNISECの軌跡と展望第2回) 査読有り

川島レイ, 趙孟佑, 宮崎康行, 佐原宏典, 安藤恵美子

日本航空宇宙学会誌 ( 一般社団法人日本航空宇宙学会 ) 62 ( 10 ) 331 - 336 2014年01月

記述言語：日本語掲載種別：研究論文（学術雑誌）

大学宇宙工学コンソーシアム(University Space Engineering Consortium:UNISEC)は10年余にわたる国内高専・大学への実践的宇宙開発の支援を経て,宇宙ハンズオントレーニングの有用性・有効性を確信し,活動を宇宙開発新興国を含む他地域に広げるべく,2011年に国際委員会を組織した.国際向けの活動としては,超小型衛星のミッションアイディア国際コンテスト開催,海外の新興国への衛星開発教育の実践,超小型衛星シンポジウムの事務局運営などがある.UNISECでは,2020年までに100以上の国で大学生が実践的宇宙開発に参加できるような世界を作ろうという「VISION 2020-100」を発表し,世界各地にUNISECのような大学連携組織を作り,それらの組織を横断的につなぐUNISEC-Globalを設立しようという提案を国連の会議等で行い,2013年11月には,第1回UNISEC世界大会(The 1st UNISEC-Global Meeting)を実施し,UNISEC-Globalの設立が宣言された.本稿では,UNISEC国際展開の経緯と成果およびその将来展望,課題について考察する.

DOI： 10.14822/kjsass.62.10_331

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/110009863270

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