記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2019 IAA AOBA VELOX-IV is a 2U-sized CubeSat that has been developed by the Kyushu Institute of Technology and Nanyang Technological University for the technological demonstration of a future lunar mission. Decades ago, Surveyor and Apollo programs reported light scattering observations on the horizon of the Moon; however, only a limited number of investigations were performed after the Apollo program to observe the lunar horizon glow (LHG). It is still unknown what conditions produce the light glow on the horizon of the Moon. The lunar mission of the AOBA VELOX project is planning to send CubeSats to the Moon and to capture images of the LHG on the lunar orbit while determining the conditions that can support light scattering above the lunar horizon. Before the satellites go into the lunar orbit, the necessary technologies must first be confirmed in Earth orbit. AOBA VELOX-IV was launched to low earth orbit via a JAXA Epsilon rocket in 18th January 2019. This paper explains the LHG mission first, and presents an overview of AOBA VELOX-IV, its payloads, technical issues, and the flight model.

DOI： 10.1016/j.actaastro.2019.05.046

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記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2019 IAA A standardized interface for different CubeSat missions is one of the keys to reducing costs and delivery time. A backplane interface approach, proposed by the University of Würzburg in Germany as UWE-3, was implemented in three CubeSat projects at the Kyushu Institute of Technology (Kyutech) to shorten the development and assembly times. The backplane approach also helped to reduce the risk of workmanship errors associated with the harness. However, changes to the proposed standard interface board were necessary in every CubeSat project, to comply with the mission requirements. To obtain more flexibility, especially for data connections, this work introduces a novel idea of a software-configurable bus interface with a backplane board. A Complex Programmable Logic Device (CPLD) was used instead of hardware routing so that we can reconfigure the bus interface by reprogramming the CPLD. The concept was validated by a functional test with a breadboard module. A radiation test verified that the selected CPLD has enough strength to survive total ionization doses of more than 2 years in low Earth orbit. A new backplane board with CPLD has been integrated into the engineering model of the fourth CubeSat project at Kyutech, the BIRDS-3 project, and system level verification has been conducted.

DOI： 10.1016/j.actaastro.2019.04.047

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記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2019 IEEE. There has been a high demand for low-cost thermal vacuum testing facility for Lean satellite (1U CubeSat) program in emerging space economies. Most often, CubeSat testing is performed in a complex and expensive thermal vacuum chamber equipped with for example shroud filled liquid nitrogen (boiling point is-195.7oC) for simulating the cold temperature environment as close to the cold heat sink of outer space in a simulated low pressure (>10-3 Pa) chamber environment. This paper introduces PeTT vacuum chamber as a low cost and easy access testing facility suitable for simulating cold temperature plateaus for performing a functional test of the internal subsystems of Lean satellite (1U CubeSat) functional test. Under ISO 19683: 'Design Qualification and Acceptance Test of Spacecraft and Units', the test requirement for cold temperature plateau is equal to-or more than-15oC. The PeTT vacuum chamber has been developed to achieve ISO 19683 test requirements. The PeTT vacuum chamber consists of a Peltier cooling device integrated inside a vacuum chamber. The Peltier cooling device consists of 4multi-stage Peltier elements sandwiched in-between a copper surface plate and water cooler has a mass of 3.4kg and size 152mm length × 127mm width × 40 mm height. The Peltier cooling device is targeted for performing 1U Cubesat functional test by conduction heat transfer. The Peltier cooling device has a total maximum exchange heat capability of 400W which runs by water cooling system and varying DC power supply. The vacuum chamber has an inner diameter of 55cm equipped with a rotary pump and diffusion pump to achieve a low pressure around 10-4 Pa. The main goal of this paper is to provide low cost and easy access testing technique for space activities in emerging space economies especially universities space research and development laboratories, to build their capacity in the installation and operation of a thermal vacuum testing facility. This paper provides details of the design and development of the PeTT vacuum chamber, cost, and results for testing 1U dummy CubeSat.

DOI： 10.1109/RAST.2019.8767775

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記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2019 COSPAR The charged dust particles can be mobilized electrostatically by the repulsion between the adjacent grains and the surface electric field due to the incoming electron current and the charge accumulation within the micro-cavities. In this study, the experimental results of the initial vertical launching velocities and the maximum dust heights are compared with the estimated values for the lofted spherical dust grains by the patch surface charging equations. Silica particles with the sizes between <6 and 45 µm in radius are loaded on a graphite plate, and they are exposed to the electron beam with 450 eV energy under 4 × 10 −3 Pa vacuum chamber pressure. During the first set of the experiments, the dust samples are tested without an initial compression process and an additional horizontal electric field. Second, the dust samples are compressed by two different weights in order to increase the packing density under approximately 780.7 Pa and 3780 Pa. Finally, the dust grains are placed between the two parallel aluminum plates to apply approximately 2000 V/m and 4800 V/m horizontal electric field. A high-speed camera is used to record the transportation of the dust grains together with a microscopic telescope, and the results point out that the patch surface dust-charging model estimations are in agreement with the first experiments. On the other hand, the dust particles from the compressed samples are lofted with higher velocities than the estimations, and the number of the dust lofting observations decreases significantly, which demonstrates the importance of the micro-cavities and the increased charging requirement to overcome the contact forces. When the horizontal electric field is present, the initial vertical launching velocities are measured to be lower than the other experiments, which can be attributed to the decreased charging requirement for the dust lofting as a result of inter-particle collisions and rolling motion. According to the experimental results, the electrostatic dust transportation can be controlled not only by the ambient plasma and the solar irradiation on the airless planetary bodies, but also by the surface properties such as the contact surfaces between the dust grains, the number of the micro-cavities related to the packing density, and the presence of the horizontal electric field contributing to the external forces by other particle motions.

DOI： 10.1016/j.asr.2019.01.045

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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）

© Published under licence by IOP Publishing Ltd. This paper presents an approach to design a feasible and reliable monopole antennae deployment mechanism for CubeSat applications. Nano-satellite has faced problems in designing antennae deployment system due to space and deployment mechanism constraints. In BIRDS-2 CubeSat, the nichrome wire burning release mechanism was used when activated, it will be heated up and thermally cut through fishing line, allowing the two monopole antennas to be deployed on +Y board and at +Z axis direction of the satellite. These antennae involved amateur radio frequencies in UHF and VHF bands due to its low cost and high accessibility by the end users. The UHF frequency band was used for command uplink, mission, telemetry, and CW beacon downlink whilst the VHF frequency band was used specifically for APRS-DP/S&F-RDC mission for both uplink and downlink. In order to achieve the effectiveness of the BIRDS-2 CubeSat communication system agreed with the link budget estimation, the dimensions of antennae on the CubeSat structure depend on the required gain and operating frequency. The paper discusses detailed results of mechanical and electrical interfaces of the two monopole antennas deployment mechanism with the satellite body and the nichrome wire burning release mechanism analysis. The tests results of the mechanism were analyzed particularly on the deployment time and the nichrome wire temperature differences.

DOI： 10.1088/1742-6596/1152/1/012007

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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）

© Published under licence by IOP Publishing Ltd. BIRDS-2, the second generation of the Joint Global Multi-Nation Birds (JGMNB) project is a constellation of 1U CubeSats from Laboratory of Spacecraft Environment Interaction Engineering (LaSEINE), Kyushu Institute of Technology, Japan. The BIRDS-2 project consists of three identical 1U built by a group of students from four nations; Japan, Malaysia, Philippines, and Bhutan. It consists of 6 missions; Camera, Automatic Radio Packet Service-Digipeater (APRS-DP), Store and Forward (S&F), COTS GPS, Anisotropic Magneto Resistance Magnetometer (AMR-MM), and detection of single-event latch-up (SEL). The objective of BIRDS-2 is to provide an opportunity to learn the entire satellite system cycle, to lay down the foundation of the sustainable space program, and to create international networks of the ground station to assist the infant space program of the participating country. A total of 11 members learns the satellite development in a lean concept of 30m radius of the work area. The paper will describe the bus system of the BIRDS-2 CubeSats and the development process throughout the one year and three months of the project timeline. Completion of BIRDS-2 flight models remarks the successful design of the CubeSats bus system and waiting for the launch and deploy from International Space Station (ISS) around 3rd quarter of this year.

DOI： 10.1088/1742-6596/1152/1/012008

Scopus

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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 © 2019 by the International Astronautical Federation (IAF). All rights reserved. The Joint Global Multi-National Birds also known as BIRDS, is a multinational small satellite program led by Kyushu Institute of Technology (Japan). BIRDS program gives opportunity to non-space fairing nations to design, integrate, build, test, launch and operate their nation's first satellite. This paper focuses on BIRDS-3 which is the third batch under BIRDS program. BIRDS-3 is a constellation of three 1U CubeSats belonging to Japan (Uguisu), Nepal (NepaliSat-1: Nepal's first satellite) and Sri Lanka (Raavana-1: Sri Lanka's first satellite). BIRDS-3 has two members (students) from Nepal, three from Japan, and two from Sri Lanka and one from Bhutan. These students have been enrolled in Space Engineering International Course (SEIC) in Kyushu Institute of Technology. External dimensions of one satellite is 113.5mm x 100mm x 100mm and the weight is approximately 1.05kg. This constellation executes four missions: Imaging Mission (CAM), Attitude Determination and Control System mission (ADCS), LoRa Demonstration Mission (LDM), Software Configurable Backplane Board Mission (BPB). The CubeSats were deployed to the orbit on 17th June 2019 from International Space Station (ISS). After deployment CubeSats are being operated through BIRDS ground station network. This paper describes the background, missions, stakeholders and initial operational results after the deployment from International Space Station (ISS).

Scopus

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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 © 2019 by the International Astronautical Federation (IAF). All rights reserved. Operating on the basis that "one cannot learn how to build satellites by reading books", Kyushu Institute of Technology (Kyutech) launched its BIRDS Project in 2015 with Ghana, Bangladesh, Mongolia, Nigeria, and Japan. The main purpose was to help most of them launch their first satellites, and then somehow make satellite development sustainable in their own countries after the return of their students. Subsequently, Kyutech started BIRDS-2 in 2016, BIRDS-3 in 2017, and BIRDS-4 in 2018, involving the nations of Bhutan, Malaysia, Philippines, Nepal, Sri Lanka, and Paraguay. BIRDS-5 will start in October of 2019. In this paper we discuss the various capacity building results in these countries. We believe the seeds have been sown in these countries for sustained national space development via the activities of launching their first satellites - a crucial step. The seven nations who did (or are doing) their first satellites are: (1) Ghana, (2) Bangladesh, (3) Mongolia, (4) Bhutan, (5) Nepal, (6) Sri Lanka, and (7) Paraguay. Every nation participating in BIRDS pays its own way - there are no subsidies from Japan. They end up with their first space borne satellites but much more importantly they have engineers who know how to build a CubeSat.

Scopus

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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 © 2019 by the International Astronautical Federation (IAF). All rights reserved. This paper will describe the progress in the SPATIUM satellite project, developed to do the global three-dimensional ionosphere mapping via CubeSat constellation equipped with an atomic clock and will show the result of the on-orbit operation of about 1 year of the first path-finder satellite SPATIUM-I. The SPATIUM-I satellite, launched in October 2018, validated the key technologies that are based on the clock-signal phase-shift sent from the satellite carried Chip-Scale Atomic Clock (CSAC). The satellite did the on-orbit demonstration of Chip Scale Atomic Clock (CSAC) as well as the evaluation of the signal time delay due to ionosphere and atmosphere. SPATIUM-I satellite on-orbit operation results will be presented. Knowing the precise satellite location and the signal delay from each satellite that transmits the signal with two UHF frequencies, by solving the inverse problem we can derive the ionosphere density and atmosphere water vapor. This data can be used to improve the accuracy of the earth and space weather forecast. This concept will then be implemented for the evaluation of Ionosphere Observation and Ionosphere 3D mapping via SPATIUM-II and SPATIUM-III projects. The SPATIUM project is under development by the Laboratory of Spacecraft Environmental Interaction Engineering (LaSEINE) of Kyushu Institute of Technology in collaboration with Nanyang Technological University, Singapore.

Scopus

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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 © 2018 by the International Astronautical Federation. Many satellites already measured ionosphere density in LEO region and still this information is not enough to create a global 3D ionosphere map. The ionosphere constantly fluctuates in a global scale, which is a complication in the process of its re-creation. To improve and validate ionosphere numerical models, measurements taken by the individual satellite are used. To measure the total electron content (TEC), and have higher spatial and temporal resolution, higher accuracy and lower cost in comparison to Global Navigation Satellite System (GNSS), we propose a CubeSat constellation. With 1000 satellites on the different orbital planes in LEO, we can have spatial resolution of 15 km and a temporal resolution of 30 minutes. And the electron density distribution will be known by the solving the inverse problem from many observation provided by the constellation. The first pathfinder satellite, SPATIUM-I, is under development and will be launched in 2018. SPATIUM-I will validate the key technologies that are based on the clock-signal phase-shift sent from the satellite carried Chip-Scale Atomic Clock (CSAC). The project is under development by the Laboratory of Spacecraft Environmental Interaction Engineering (LaSEINE) of Kyushu Institute of Technology in collaboration with Nanyang Technological University, Singapore. This paper will present the status of SPATIUM-I development and the overview of the follow-on projects, SPATIUM-II and SPATIUM-III.

Scopus

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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）

© 2018 by the International Astronautical Federation (IAF). All rights reserved. Every satellite, regardless of its size, mission, value, capability or any other nature, shall comply with safety requirements. This statement applies even to a 1U or less CubeSat. The recent diversity in the CubeSat launch options, however, has brought complication in satellite design and verification. The safety requirements differ among the launch vehicles. The difference is particularly significant between the rocket launch and the ISS release. Satellite developers need to consider how to adapt their design to various safety requirements and how to verify their compliance from the early stage of satellite development, even before they decide on the launch option. Kyushu Institute of Technology (Kyutech) has operated Centre for Nanosatellite Testing (CeNT) in Laboratory of Spacecraft Environment Interaction Engineering (LaSEINE) since 2010. Those satellites that employed commercial-off-the-shelf (COTS) CubeSat components available on Internet had many safety-related issues to be resolved. Kyutech itself has developed 12 satellites that were launched by rockets or released from ISS and experienced various issues related to safety. The safety issues encountered by various CubeSats for various launch options are reviewed. How they were resolved with are introduced with suggestions on how to minimize the troubles that delay the satellite delivery time.

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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 © 2018 by the International Astronautical Federation. As a technology demonstration mission of the three-member 1U CubeSat constellation of the joint global multi-nation BIRDS-2 Project, the store-and-forward (S&F) mission aims to demonstrate the potential use of a 1U CubeSat constellation for collecting data from ground sensor terminals deployed in remote or isolated sites. The three CubeSats are the first university CubeSats of Bhutan, Malaysia, and the Philippines. Their onboard S&F payloads collect various sensor data from experimental ground terminals deployed in respective home countries. Although a CubeSat constellation is an attractive platform for the said application - due to its substantially simpler design, lower cost, and faster development time - it also presents many technical challenges such as tight size, power, and communication link budgets. In this paper, first, the design considerations and implementation of our onboard S&F payload are discussed. The said payload operates in the VHF amateur band and consists of mostly very low-cost commercial-of-the-shelf components. Sensor data uplink is done at 1200 bps and gathered data downlink at 9600 bps through the UHF communication subsystem. Then, the investigation and test results are presented, including link budget analysis, communication tests, antenna deployment tests, and space environment tests. Finally, the initial on-orbit performance results within one month of satellites' operation in space are tackled.

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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）

© 2018 by the International Astronautical Federation (IAF). All rights reserved. HORYU-IV is a 30cm cubic satellite with an approximate mass of 11kg. The satellite was successfully launched by a H-IIA rocket to an orbit of 575km altitude with 31ºinclination on February 17, 2016. Since then, HORYU-IV has been conducting various flight experiments related to spacecraft plasma interaction. HORYU-IV implements HORYU-II, the previous satellite operated from 2012 to 2017, high voltage photovoltaic power generation technology and uses it to perform research on discharge phenomena. HORYU-IV's main mission is to acquire an arc current waveform by an onboard oscilloscope and capture its image by a camera triggered by the oscilloscope. In addition, HORYU-IV carries out scientific experiments on arc mitigation high voltage solar array, plasma measurement using a double Langmuir probe, vacuum arc thruster, photoelectron current measurement and polymer material degradation. HORYU-IV captured various discharge waveforms and images in space that can be categorized into several types. Ground experiments were carried out to compare the waveforms between the flight results and the ground results. The Double Langmuir probe was operated in space and its result was compared with the computer simulation results. Photoelectron emission yield was measured for several material for the first time in orbit. The overall results obtained in the past two and a half years from the spacecraft plasma interaction experiments will be presented.

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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）

© 2018 Electromagnetics Academy. All rights reserved. The project SPATIUM (Space Precision Atomic-clock TIming Utility Mission) presents a new technique for ionosphere mapping using a constellation of CubeSats equipped with Chip Scale Atomic Clock (CSAC) to provide real-time three-dimensional mapping of ionosphere plasma density at the altitudes of electron density peak (200 to 400km above the Earth). This paper describes the principle of the ionosphere mapping and total electron content (TEC) determination using satellite signal transmission with a dual-frequency and signal shift determination at the Ground Station using the same referenced CSAC clock. The paper also describes reasons of RF signal delays/shifting due to atmosphere and ionosphere plasma conditions. A 2U CubeSat, SPATIUM-I, is introduced as a platform. The future plans for the project expansion are also given.

DOI： 10.1109/PIERS-FALL.2017.8293237

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記述言語：英語   掲載種別：研究論文（学術雑誌）

© 2016 IAA. A single-event latch-up (SEL) test using a252Cf radioisotope was carried out. The results were compared with those of a proton test and from observation in orbit. A radioisotope can reproduce phenomena observed in orbit that are caused by protons. Considering the inexpensive nature of the252Cf test, it is more suitable for nanosatellites that require low cost and fast delivery. A SEL occurrence rate of a commercial-off-the-shelf microprocessor was derived from the ground test results. The252Cf test provided a SEL rate approximately 1×106times greater than that in orbit. This data can be used to derive the minimum SEL occurrence rate in orbit and help satellite designers to evaluate the risk of SEL and take measures if necessary.

DOI： 10.1016/j.actaastro.2016.05.004

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記述言語：英語   掲載種別：研究論文（学術雑誌）

<p>This paper presents a part of the basic research for establishing the unit Qualification Test (QT) conditions within the framework of an international project to make ISO standard, namely, "Space Systems&mdash;Design Qualification and Acceptance Tests for Small-Scale Satellites and Units Requiring Low Costs and Fast Delivery". A laboratory test is conducted to study how vibration acceleration is distributed in a satellite body, so as to define the unit QT random vibration test level. The range of natural frequency and the amplification of acceleration are identified through statistical analysis of the test results. Finite element analysis is carried out to extend the findings to other structural types of micro/nanosatellites. Three structural types are analyzed, i.e., Yojo han, T-type and Pi-type. Based on the results, a unit QT vibration level that provides the minimum reliability assurance for use in space is proposed.</p>

DOI： 10.2322/tastj.14.Pf_51

CiNii Article

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記述言語：英語   掲載種別：研究論文（学術雑誌）

This paper describes the thermal design method of Horyu-2. Horyu-2 was developed by Kyushu Institute of Technology. The project started in 2010 and Horyu-2 was launched by H-2A of JAXA on May 18 2012. At present, Horyu-2 is carrying out many missions and transferring on-orbit data. Horyu-2 orbits 680 km with sun-synchronous polar orbit. Feature of Horyu-2 are lightweight (7.1kg) and large surface (30cm cube) compared with a conventional cube-sat. Thermal design is needed to keep the temperature within the safe range. We conducted thermal analysis in a step-by-step in each phase. This paper reviews the thermal design processes and discusses on-orbit data acquired after launch.

DOI： 10.2322/jjsass.64.270

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130005249170

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）

Italy   Rome   2015年11月30日  -  2015年12月04日

記述言語：英語   掲載種別：研究論文（学術雑誌）

宇宙空間での高電圧の発電を実証するために開発された「鳳龍弐号」での実験結果を紹介する.鳳龍弐号では太陽電池を使用しての300V以上の発電電圧の実証と放電実験が行われた.この発電電圧は現在の所,宇宙空間で太陽電池が作りだした電圧としては最も高い値である.このような挑戦的な実験が可能となったのは,大学を中心として超小型衛星が盛んに開発されており,宇宙空間を使用しての実験は以前に比べ格段に敷居が下がった為である.超小型衛星を使用することでリスクの高い軌道上実証が可能となり,鳳龍弐号のような高電圧を使用する実験も可能となった.ここでは「鳳龍弐号」の開発や軌道上実験の結果と今後の展開について概説する.

CiNii Article

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記述言語：英語   掲載種別：研究論文（学術雑誌）

記述言語：英語   掲載種別：研究論文（学術雑誌）

この章では宇宙機で発生する放電現象について説明する.宇宙機で発生する放電現象が最も起こりやすい箇所は太陽電池パネルであるために,最初に太陽電池パネルの構造について詳しく述べる.その後,太陽電池パネルでの帯電のメカニズムについて説明し,初期放電発生メカニズムを衛星の軌道高度ごとに分けて説明する.続いて,初期放電により引き起こされる影響のさらに大きな持続放電のメカニズムについて説明する.

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/110010016667

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）

Japan   Kobe   2015年07月  -  2015年07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）

Japan   Kobe   2015年07月  -  2015年07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）

Japan   Kobe   2015年07月  -  2015年07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）

Japan   Kobe   2015年07月  -  2015年07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）

Japan   Kobe   2015年07月  -  2015年07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）

Japan   Kobw   2015年07月  -  2015年07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）

Japan   Kobe   2015年07月  -  2015年07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）

Turkey   Istanbul   2015年06月  -  2015年06月

DOI： 10.1109/RAST.2015.7208447

Scopus

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）

Turkey   Istanbul   2015年06月  -  2015年06月

DOI： 10.1109/RAST.2015.7208450

Scopus

記述言語：日本語   掲載種別：研究論文（学術雑誌）

CiNii Article

記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.2514/1.A33007

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）

本講座では宇宙機で発生する放電現象についてこれまで述べた.宇宙工学の分野の中でも非常に狭い領域のトピックを取り扱った.しかし,宇宙機の電源システムに直接影響を与える,非常に重要な分野であることは理解頂けたと思う.以下に本講座の総括と今後の展望を述べる.

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/110010016774

記述言語：英語   掲載種別：研究論文（学術雑誌）

Development of small satellites (50kg or less) is undergoing all over the world. Regardless its size, any satellite has to be tested for space environment. Various environment tests, such as vibration, vacuum, low and high temperature are necessary. Especially, shock test is one of the most difficult tests. The shock test needs to satisfy the SRS (shock response spectrum) requirement imposed by the launcher. If the SRS obtained in the test does not exceed the SRS requirement level, the test is invalid. At the same time, the SRS level as low as possible while satisfying the requirement is desired to protect the satellite from the overstress. SRS obtained by an air-gun type shock machine was analyzed using a commercial finite element code (LS-DYNA) to investigate the SRS at low frequencies, 100 to 300Hz, which is very difficult to control in the actual test. The analysis showed that controlling the friction of the slide table is effective to change the slope of SRS at the low frequencies. The lower the friction, the higher slope of SRS is obtained.

DOI： 10.2322/jjsass.63.117

その他リンク： http://ci.nii.ac.jp/naid/130005072535

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）

Canada   Toronto   2014年09月  -  2014年09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）

Canada   Toronto   2014年09月  -  2014年09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）

Canada   Toronto   2014年09月  -  2014年09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）

USA   Cleveland   2014年07月  -  2014年07月

DOI： 10.2514/6.2014-3420

Scopus

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）

USA   Pasadena   2014年06月  -  2014年06月

記述言語：英語   掲載種別：研究論文（学術雑誌）

USA   Pasadena   2014年06月  -  2014年06月

記述言語：英語   掲載種別：研究論文（学術雑誌）

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）

Noordwijkerhout   Netherlands   2014年04月  -  2014年04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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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 (252Cf) 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 18thMay 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 (10thSeptember, 2014), SEL was occurred 5 times on the H8/36057 on board Horyu-2. By using the252Cf 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 by252Cf using as a radiation source.

Scopus

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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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記述言語：英語   掲載種別：研究論文（学術雑誌）

This paper presents the basic research for establishing the qualification test (QT) level a unit has to pass to be sold as a product for space usage. A laboratory test campaign was conducted to study how the mechanical stresses distribute within a satellite body so as to define the unit QT level. We carried out random vibration tests using two types 50cm/50kg class satellites and measured the distribution of acceleration inside the satellites. The research focuses on the provision of the physical basis of the test conditions to be defined in the new standard. We tried to identify the range of natural frequency and amplification of acceleration in various launching environment through statistical analysis of the test results. The detailed test procedure, analysis method and primary results are herein reported.

DOI： 10.2322/tastj.12.Pf_1

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130003395430

記述言語：英語   掲載種別：研究論文（学術雑誌）

The space solar power system (SSPS) transfers enormous amounts of electrical energy through microwaves. When high-power microwaves are irradiated from an antenna in a LEO plasma environment, there is a concern about discharge caused by interaction between the plasma and the microwaves. There has been no experimental observation of such an interaction phenomenon. Verification experiments are essential for SSPS to become a reality. We examine whether discharge or related phenomena occur or not on patch antennas under various conditions in the laboratory. We verify the hypothesis of discharge inception that the discharge is caused by multipactoring and breakdown of the outgas product. We compute the minimum electric field for the discharge inception.

DOI： 10.2322/tastj.12.11

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130003395403

記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.2322/tastj.12.Pf_39

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130005109519

記述言語：英語   掲載種別：研究論文（学術雑誌）

The Kyutech (Kyushu Institute of Technology) Satellite Project developed a high-voltage demonstration satellite called "Horyu-II" between 2010 and 2012. Horyu-II is a nanosatellite 350 mm x 310 mm x 315 mm (X*Y*Z) in size, with a mass of only 7.1 kg. This satellite was launched on May 18, 2012 as a piggy-back payload of the 21st H-IIA launch. Its missions are the demonstration of high-voltage technology in orbit, mitigation of electrostatic discharge (ESD), and so on. In this paper, we describe the design of the power system and its verification through various ground tests. The power system is equipped with a thin-film double-junction GaAs solar cell, with an efficiency of 20%, as the primary power source for the first time in orbit. The satellite also carries Ni-MH batteries for power storage. The power system architecture was simplified as much as possible with failure prevention mechanisms, such as over-current protection and various switches related to safety and debris mitigation. We present the analysis of the telemetry data obtained after the launch and validate the effectiveness of the design and verification processes.

DOI： 10.2322/tastj.12.Tf_49

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130004699597

記述言語：英語   掲載種別：研究論文（学術雑誌）

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）

Students of Kyushu Institute of Technology successfully developed a 7kg nanosatellite, HORYU-II. The satellite was tested extensively at Center for Nanosatellite Testing. There are many lessons learned through its designing, development, testing and operation to be shared among the university satellite community. Since 2013, the university will launch a new post-graduate program, Space Engineering International Course, where Japanese and foreign students learn the basic space technology through hands-on experience gained by participating in a satellite project utilizing space engineering research infrastructure within the campus. The program is also carried out as United Nations/Japan long term fellowship programme to assist capacity building of basic space technology in countries that have little experience in satellite development. Selected students will be awarded Japanese government scholarship. This paper describes the space engineering education at Kyushu Institute of Technology. © 2013 IEEE.

DOI： 10.1109/RAST.2013.6581159

Scopus

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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）

The High Voltage Technology Demonstration Satellite named HORYU-II is a nano-satellite (30cm cubic shape, 7kg) successfully developed by students at Kyushu Institute of Technology. The main purpose of this satellite is orbital demonstration of the feasibility the forthcoming space high voltage technologies. The International Space Station (ISS) generates the highest voltage, 160V, among all of the current active space systems. HORYU-II aims at being the world's first satellite to generate a voltage of 300V by using solar array, which is significantly higher voltage than the one generated on board the ISS. However, due to the generation of the high voltage, Electrostatic Discharges (ESDs) are more likely to occur. Therefore, HORYU-II also aims at performing a demonstration of ESD mitigation technology. HORYU-II was launched by a H-2A rocket on May 18, 2012. HORYU-II is functioning normally and data from orbit have recently been recorded and data analysis is under way. Results of the analysis will be presented in detail at the conference. © 2013 by Kyushu Institute of Technology.

Scopus

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記述言語：日本語   掲載種別：研究論文（学術雑誌）

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）

USA   Grapevine   2013年01月07日  -  2013年01月10日

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）

The HORYU-II nanosatellite was launched as a secondary payload on-board an H-IIA rocket on May 18, 2012 (UTC). The spacecraft was completely developed by students from Kyushu Institute of Technology starting from 2010. HORYU-II operated normally from orbit injection until June 5 when anomalies were observed in the housekeeping data. By June 30, 2012, only call signs were received. Fortunately, the satellite was able to reset and operate in steady mode, even though the battery state dropped to about 10%. This paper presents HORYU-II anomaly investigation results and the lessons learned. We carried out Fault Tree Analysis (FTA) to determine failure root cause. Among the phenomena observed were: irregular housekeeping data, unresponsive Telecommands from the ground station, communication limited to call signs, and low residual battery quantity after recovery. After ground-based assessment of the spare bus system, we concluded that the anomaly cause was radiation effect on the On-Board Computer (OBC) system. Single Event Latch-up (SEL) occurrence caused over current of the Micro Controller Unit (MCU). We underestimated the radiation effect. We contrived overcurrent protection for the OBC circuit but we did not measure over current flow on the subsystem when SEL occurs. The communication system is independent of the MCU and can continuously send call signs. For this reason, we were able to receive call signs and trace the satellite even when the OBC MCU stopped operating. The power system was designed to restart when battery charge reached 0% and this was confirmed from ground testing. Copyright© (2013) by the International Astronautical Federation.

Scopus

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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）

© Springer-Verlag Berlin Heidelberg 2013. Since material surfaces on the outside of spacecraft are exposed directly to the space environment, material having high tolerance to atomic oxygen, ultraviolet rays and radiation are preferred for long time spacecraft operation. In order to examine the influence of atomic oxygen (AO) on space grade materials, an atomic oxygen simulation chamber was developed. A system was developed that generates AO using a laser detonation method. A CO2gas laser (5 J) irradiates the oxygen gas in a vacuum chamber (2 MPa) to dissociate the molecular oxygen into atomic. The velocity of AO can be controlled based on the timing between the laser and the gas pulse valve that injects oxygen gas into the chamber. The AO velocity generated by this system is measured using a QMASS (Quadruple Mass Spectrometer) and found to be 8 km/s. It was necessary to measure the AO flux distribution in the chamber at the location where the material samples are exposed to AO. The AO flux distribution was evaluated by measuring the mass gain on a QCM (QuartzCrystal Micro-balance) coated with a silver film upon exposure to the AO.

DOI： 10.1007/978-3-642-30229-9_56

Scopus

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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）

The World's largest spacecraft bus voltage is the International Space Station (ISS) with a bias voltage of 160V. We have investigated a power bus able to handle higher voltage than the ISS. Electro-static discharges (ESDs) are more likely to occur when a satellite generates power at a high voltage rather than low voltage in low Earth orbit (LEO). However, high voltage generation is essential for building large space systems. Therefore, Kyushu Institute of Technology (Kyutech) is developing a high voltage generation technology that could counteract ESDs. This could be considered as a key technology for next generation spacecraft. Nano-satellites are useful and less risky tools for technology demonstration since they are faster and less expensive to develop than large satellites. Therefore, we focused on nano-satellite development to demonstrate Kyutech's advanced high voltage generation technology. All of the on-orbit high voltage tests have been demonstrated by using a DC/DC converter to adapt the high voltage generated by the solar array. This was a World premiere as no high voltage tests had previously been performed in space using solar arrays. To demonstrate the feasibility of on-orbit high voltage generation, we developed a High Voltage Technology Demonstration Satellite named HORYU-2. The mission consisted of 300V generation without causing arcing, and contribution to the practical development of 1MW class spacecraft. On May 18, 2012, HORYU-2 was launched by the H-2A rocket number 21. HORYU-2 has been operated from Kyutech's ground station, and HORYU-2's orbit was confirmed and the mission successful. For the first time in the World, 350V have been generated on-orbit without arc creation. Using two specially designed solar arrays arcing was mitigated. Regarding the sub-missions, ELF was proven to work well on-orbit, Trek measurements are currently under investigation, the SCAMP camera successfully imaged Earth, and the debris sensor has not yet detected debris impact. During the conference, we will present all mission analysis in further detail. Copyright ©2013 by the International Astronautical Federation.

Scopus

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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 Solar Power System (SSPS) transfers enormous amount of electrical energy through microwave. Flight demonstration onboard a small satellite in Low Earth Orbit (LEO) is now under consideration. When a high power microwave is irradiated from antenna in LEO plasma environment, there is a concern about discharge caused by interaction between the plasma and the microwave. There has been no experimental observation on such interaction phenomenon. Verification experiment is essential for SSPS to become a reality. We have set-up an experimental system that can simulate the radiation of high power microwave under dense plasma in a vacuum chamber. A RF plasma source was installed to the chamber that we filled with Argon plasma environment of density from 1011 to 10 m' with 4eV to 6eV temperature under a back pressure of 2.6x10" Pa. A patch antenna made of Glass epoxy substrate was installed inside the chamber. The antenna was connected to a magnetron that could produce 5.8GHz microwave. We monitored the antenna surface temperature, the radiated and reflected power, the chamber pressure and others while we injected the microwave to the antenna up to 45W. We examined whether discharge or related phenomena occur or not on the patch antennas for various conditions to verify the hypothesis of discharge inception that discharge is caused by multi-pactoring and breakdown of the outgas product. Copyright © (2012) by the International Astronautical Federation.

Scopus

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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 cubic nano-satellite with a length of 30 cm, named HORYU-II, was developed at Kyushu Institute of Technology in Japan. HORYU-II is a demonstration satellite for high voltage technology and its two main advantages are its low cost and short time development. HORYU-II's main mission is to demonstrate the possible generation of 300V on-orbit by using spherical solar cells connected in series. This mission can be considered as the first high voltage technology demonstration in the world. To control arcing under negative 300V in space plasma, ETFE (ethylene tetra flouro ethylene) cover and semi-conductive coated solar array efficiency will be demonstrated. Along with this, charging mitigation of spacecraft by using electron emitting film, operation of commercial-off-the-shelf (COT) surface potentiometer will also be demonstrated. HORYU-II was launched by a H-IIA rocket on May 18, 2012. We have been acquiring on-orbit data and monitoring the satellite conditions. HORYU-II succeeded in generating the highest 300V photovoltaic voltage in space for the first time in the world. However, many problems were found during data collection. In this paper, the result of HORYU-II's missions is described.

Scopus

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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）

High Voltage Technology Demonstration Satellite HORYU-II is a Nano-Satellite (30cm cubic shape, 7kg) being developed by the students in Kyushu Institute of Technology. One of the objectives of this satellite is orbital demonstration of forthcoming space high-voltage technologies. The satellite with the highest voltage generation in Low Earth Orbit has been ISS, generating 160V. On orbit, especially LEO, high-voltage (over about 200V) generally induces electro-static discharges (ESD). HORYU-II is aimed to demonstrate new designs of solar array that can generate power, free of ESD, by producing 300V via a specially designed solar array itself, not via a conventional DC/DC converter. If successful, HORYU-II will become the first spacecraft in the world that achieved 300V photovoltaic power generation in space. Copyright © 2012 by the American Institute of Aeronautics and Astronautics, Inc.

DOI： 10.2514/6.2012-719

Scopus

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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）

Japan   Nagoya   2012年10月  -  2012年10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）

Italy   Naples   2012年10月  -  2012年10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）

Japan   Nagoya   2012年10月  -  2012年10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）

Japan   Nagoya   2012年10月  -  2012年10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）

Italy   Naples   2012年10月  -  2012年10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）

Japan   Nagoya   2012年10月  -  2012年10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）

Japan   Nagoya   2012年10月  -  2012年10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）

Japan   Nagoya   2012年10月  -  2012年10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）

USA   Utah   2012年08月  -  2012年08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）

Japan   Kitakyushu   2012年05月  -  2012年05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）

Japan   Kitakshu   2012年05月  -  2012年05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）

Japan   Kitakyushu   2012年05月  -  2012年05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）

Japan   Kitakyushu   2012年05月  -  2012年05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）

Japan   Kitakyushu   2012年05月  -  2012年05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）

Japan   Kitakyushu   2012年05月  -  2012年05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）

Japan   Kitakyushu   2012年05月  -  2012年05月

記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.1109/TPS.2012.2187074

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.1109/TPS.2011.2179813

Scopus

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.1109/TPS.2011.2176754

Scopus

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）

There is a lot of debris in space. There are currently about 15,000 individual pieces of space debris that can be observed from the earth, with a likely even greater number existing with a size less than 10cm, the limiting size of earth-based observations. Fears exist that as space debris continues to increase, the Kessler Syndrome will occur, eventually preventing any form of spaceflight. The purpose of this research is to remove the debris to prevent such a situation from happening. For the first time, it is proposed to bias voltage on net electrodes, as the space debris will be charged by the plasma interaction. The charged debris will then be slowed by the electric field surrounding the net electrodes, causing the debris to re-enter the atmosphere. In this research, a 100μm copper powder is used, followed by 2mm Ellenpall. This presentation addresses how much the debris is charged and how far the debris is shifted by the electric field.

DOI： 10.2322/tastj.10.Tr_47

CiNii Article

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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）

DOI： 10.14822/kjsass.59.691_238

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/110008711708

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）

Laboratory of Spacecraft Environment Interaction Engineering (LaSEINE) in Kyushu Institute of Technology in researching spacecraft charging and arcing, space debris and small satellite. Laboratory of Spacecraft Environment Interaction Engineering has test facilities specialized space environment and provides the education for the space environment. In particular to spacecraft charging and arcing, the solar array panel made in Japan and abroad were tested. The laboratory is one of the world's leading authorities on spacecraft charging and arcing. Recently, the environment test facilities for a small satellite are developed. These facilities can provide most of test environments required small satellites. In this presentation, our past results and future plan will be reported.

DOI： 10.1299/jsmesec.2010.19._B3-1_

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/110008743760

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 lead to arcing and a loss of electricity generation capability in solar panels or even loss of a satellite. The charging problem may be further aggravated by atomic oxygen (AO) exposure in Low Earth orbits, which modifies the surface of materials like polyimide, Teflon, anti-reflective coatings, cover glass etc, used on satellite surfaces, affecting materials properties, such as resistivity, secondary electron emissivity and photo emission, which govern the charging behavior. These properties are crucial input parameters for spacecraft charging analysis. To study the AO exposure effect on charging governing properties, an atomic oxygen exposure facility based on laser detonation of oxygen was built. The facility produces AO with a peak velocity value around 10-12km/s and a higher flux than that existing in orbit. After exposing the polyimide test material to the equivalent of 10 years of AO fluence at an altitude of 700-800 km, surface charging properties like surface resistivity and volume resistivity were measured. The measurement was performed in a vacuum using the charge storage decay method at room temperature, which is considered the most appropriate for measuring resistivity for space applications. The results show that the surface resistivity increases and the volume resistivity remains almost the same for the AO exposure fluence of 5.4&times;10¹⁸ atoms cm^-2.

DOI： 10.2322/tastj.9.1

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130000450582

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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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.

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

DOI： 10.2514/1.49571

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）

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）

The recent trend of satellite manufacturing is to increase its communication capacity, multi-purpose mission payload, electric power and lifetime. A short-circuit due to discharge on the solar array of the satellite hampers its target by causing serious problems, such as, lowering of power generation that ultimately halts the operation of solar array. In this paper, we have investigated possible mitigation methods against short-circuit due to discharge on solar array by applying coating and by changing the shape of Room Temperature Vulcanization: Silicon adhesive (RTV). The electrostatic discharge is mitigated by obtaining the event of secondary arc generated on each condition.

DOI： 10.2322/tastj.8.Pr_2_19

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130001080207

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 this paper, we report about the test results on coupons made for Working Group 1(WG1), which was established to make a Japanese guideline for spacecraft charging design. In particular, the test for a sustained arc was conducted. The sustained arc is one of problem in present satellites. Laboratory tests were carried out with an external circuit simulating a spacecraft power system. The solar array coupon panels simulating the hot and return ends of a string circuit were tested under various combinations of string voltage and string current. We revealed that the threshold conditions for sustained arc were different in string voltage. We show the rating sheet of threshold for sustained arc. Copyright © 2009 by the American Institute of Aeronautics and Astronautics, Inc.

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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 debris is a space object which is not useful and can cause accident in space. Space debris is moving with high speed with average velocity of 10km/s, which can cause damages to the spacecraft and the astronaut operating outside satellite. The method of removing the debris is demanded for our safety operation in space. In this paper, a debris removal method was proposed for small diameter less than 1mm. This method utilizes the interaction between the electrode biased in positive and space ambient plasma in LEO. Copyright © 2009 by the American Institute of Aeronautics and Astronautics, Inc.

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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）

It was verified that the copper powder is charged negatively using plasma. We analyzed the negative charging of the particle in an electron sheath in plasma. It was confirmed that copper powder is charged negatively in electron sheath making by net biased positively. Further, it was also confirmed that negatively charged copper powder is dragged by electrostatic force.

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記述言語：英語   掲載種別：研究論文（学術雑誌）

記述言語：英語   掲載種別：研究論文（学術雑誌）

A solar array electrostatic discharge ground test is necessary to assure spacecraft reliability in orbit. Laboratory experiments were carried out to characterize an electrostatic discharge current waveform with different background pressures and charging environments to identify the importance of the test setup. The waveform strongly depended on the background pressure. This difference can affect the result of the solar cell degradation test. However, in the case of the secondary arc test, the difference of the primary arc current waveform did not affect the duration of the secondary arc. The current available from a power supply mostly determined the duration of the secondary, irrespective of the test environment. Methods to control the primary arc current supplied by an external capacitance are proposed. Copyright © 2009 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

DOI： 10.2514/1.41696

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記述言語：英語   掲載種別：研究論文（学術雑誌）

記述言語：英語   掲載種別：研究論文（学術雑誌）

In the present paper, we propose a method to assess the risk of a secondary arc on a solar array in orbit based on statistical theory. Ground experiments have been carried out to investigate the statistics of temporary-sustained-arc duration. We have found that secondary-arc duration can be modeled as a combination of multiple Poisson distributions. Once we know the formula of the Poisson distribution, we can easily calculate the probability of a secondary arc lasting longer than an acceptable l imit. The quantity of secondary-arc- duration data needed to define the Poisson distribution formula has been discussed. Assuming that thousands or tens of thousands of primary arcs occur in orbit, if the average duration of secondary arcs in the test is less than 5% of the acceptable limit for secondary-arc duration, we can greatly reduce the number of experimental trials to 10 or less in most cases. © 2008 by the American Institute of Aeronautics and Astronautics, Inc.

DOI： 10.2514/1.37798

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記述言語：英語   掲載種別：研究論文（学術雑誌）

記述言語：英語   掲載種別：研究論文（学術雑誌）

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 the power level of Geostationary satellites increases, discharge phenomena on solar array are becoming serious threat to safe operation. Arcs on solar array can short-circuit the satellite circuit, decrease the satellite power, and then cause the satellite permanent failure. To prevent the failure caused by charging and arcing, it is necessary to investigate the mechanism of satellite charging and arcing phenomenon. The purpose of this paper is to investigate the occurrence condition of a secondary arc by measuring arc plasma characteristics in ground test. We measured the arc plasma temperature and identified the materials emitted using spectrometer at arbitrary time during arc occurring. We investigated the difference of secondary arcs occurrence condition during secondary arcs. From the spectroscopic measurement results, we found that it was necessary for shifting to the secondary arc that the metallic vapor same as the cathode material was emitted. In case of primary arc (PA) dimension changes, the probability of secondary arc and TSA occurrence became high. And plasma temperature was not affected by PA dimension, however the metallic vapor emission of silver was greatly affected. Thus, secondary arc occurrence greatly depends on metallic vapor emission from cathode.

DOI： 10.2322/tstj.7.Pr_2_41

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130000151973

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）

High-efficiency triple-junction (TJ) solar cells with monolithic diodes (MD) are being used for recent spacecraft solar arrays. Because the cell-to-cell inter-connector is usually connected on the MD pad, studying the effects of electrostatic discharge (ESD) on MD is necessary. Laboratory testing of two types of MD functions revealed that the weaker design was damaged by an energy discharge of 0.8J. With an external circuit simulating flight solar array, however, discharge as large as 9.3J didn't destroy the solar cell. Based on the test results, it was concluded that MD solar cells have sufficient resistance against ESD in orbit.

DOI： 10.2322/tstj.7.11

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/130000151792

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 in LEO sweep through a rarefied atmosphere composed primarily of atomic oxygen. Even though the densities are low at these altitudes, the spacecraft surface can experience relatively high incident flux (1019 to 1021 m-2 s-1) of energetic (5 eV translational energy) oxygen atom because of high orbital velocities (8kms -1). Most hydrocarbon polymer and active metals are highly reactive towards the atomic oxygen which affects their chemical, electrical, optical and mechanical properties. We are in the process of designing a facility to simulate the space environment of atomic oxygen. Our aim is to simulate the quick degradation of materials and study the secondary electron emission co-efficient, bulk conductivity and photoelectron emission of degraded materials as they play an important role in discharging and arching phenomenon observed on surface of solar panel. We get high velocity of oxygen in an evacuated hypersonic nozzle. The oxygen is broken down in atomic oxygen using high power C02 laser. The energy of the atomic oxygen is measured using TOF QMAS technique. The flux of oxygen atom is measured using Quartz Crystal Microbalance (QCM). The O- atom source is used to irradiate the sample material used in spacecraft surface.

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記述言語：英語   掲載種別：研究論文（学術雑誌）

An electrostatic discharge test was carried out on a solar array paddle (SAP) for the Greenhouse gases Observing SATellite (GOSAT) on a simulated polar Earth orbit (PEO) environment. To simulate the spacecraft charging conditions in a PEO with an auroral band, when electrons with higher energy than LEO plasma flow to the Earth, three conditions of dielectric charging can be considered on each side of the SAP. At first, the threshold voltage differences of discharge inception were measured experimentally using solar array coupons simulating both the beginning and the end of life under six charging conditions. Next, the Multiutility Spacecraft Charging Analysis Tool was employed to analyze the spacecraft surface potential and the time needed for charging. From the threshold value and the charging analysis, the probability and the number of discharges were estimated in each charging condition during a lifetime of the GOSAT. Finally, the performance of the coupons against discharges was evaluated for each charging condition. All coupons had no sustained arc during these tests; however, there was some electrical degradation of the solar cell. The power degradation during the lifetime of the GOSAT was estimated from these results, and the design of the solar array coupon was confirmed to satisfy the power demand even if the estimated number of discharges occurs in the lifetime. © 2008 IEEE.

DOI： 10.1109/TPS.2008.2002823

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記述言語：英語   掲載種別：研究論文（学術雑誌）

An international project has started to establish an International organization for standardization standard for the electrostatic discharge (ESD) on the solar array panel. For the ESD ground test of satellite solar panel, it is important to understand the characteristics of a primary arc discharge. A solar array coupon made of triple-junction cells is used to understand the primary arc characteristics. In particular, the experiment focuses on the measurement of the propagation speed of plasma generated by the primary arc. The plasma propagation is analyzed using images captured by a high-speed video camera and an image intensified camera. The plasma propagation speed derived from discharge images decreases in proportion to the inverse of the square root of time. The arc current waveform assuming the decreasing speed agreed with the experiment waveform very well. © 2008 IEEE.

DOI： 10.1109/TPS.2008.2003191

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

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）

Secondary arc on satellite solar array is sometimes fatal to spacecraft operation by damaging insulation of solar array string circuit. A proper ground test method is necessary to correctly assess the risk of secondary arc from the probability of occurrence in orbit. Ground experiments are carried out to investigate the statistics of temporary sustained arc duration. It is found that the secondary arc duration can be modeled as a combination of multiple Poisson distributions. Once we know the formula of the Poisson distribution, we can easily calculate the probability of secondary arc lasting longer than an acceptable limit, drastically reducing the testing cost. The number of secondary arc duration data to define the Poisson distribution formula is also discussed. Copyright © 2008 by the American Institute of Aeronautics and Astronautics, Inc.

DOI： 10.2514/6.2008-455

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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）

Electrostatic discharge (ESD) occurs on the solar array due to space plasma interaction. It is considered that solar cell suffers degradation of electric performance, once ESD occurs at the solar cell edge. In order to study the degradation of solar cell electrical performance, we performed ESD tests on Si solar cell in a vacuum chamber. After the ESD tests the solar cell maximum power decreased. We found the damage on surface electrode in the vicinity of ESD spot. Infrared emission due to current leak was found at the spot. The solar cell degraded due to the leak resistance produced by ESD.

DOI： 10.2322/jjsass.55.590

CiNii Article

その他リンク： https://ci.nii.ac.jp/naid/10021152715

記述言語：英語   掲載種別：研究論文（学術雑誌）

The effects of magnetic field configuration on thrust performance in a miniature microwave discharge ion thruster were investigated in order to improve thrust performance. First, the extracted ion beam current was measured for various levels of strength of the magnetic field. It was found that there is an optimum magnitude of the magnetic field. That this is due to the tradeoff between magnetic mirror confinement and microwave-plasma coupling was confirmed by measurement of the ion saturation current into the antenna of the ion thruster. The ion saturation current was found to decrease with an increase in magnetic field strength, due to the improvement in magnetic mirror confinement. The estimated electron temperature also decreases with an increase in magnetic field strength. This result shows that the increase in magnetic field strength leads to a decrease in microwave-plasma coupling. Next, the ion beam current for three magnetic field shapes was measured by changing the length of the central yoke. The results show that the optimum magnetic field shape depends on the mass flow rate because of the tradeoff between magnetic confinement and ionization probability. For the configurations tested, the 3 mm length central yoke is optimal for low mass flow, whereas 7 mm is the best for high mass flow. Overall, the extracted ion beam current is 21.4 mA, at a xenon mass flow rate of 0.036 mg/s, beam voltage of 1500 V, and incident microwave power of 16 W. © 2007 American Institute of Physics.

DOI： 10.1063/1.2822456

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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）

Electrostatic discharge on solar array is one of the primary causes of spacecraft anomalies. Such discharges occur due to anomalous surface charging, which means that parts of the dielectric surface on a satellite have different potential from the satellite body potential. Therefore, by preventing to making the potential of the spacecraft negative, we can avoid the discharges on solar array. In this paper, we present the mitigation strategy of spacecraft negative charging via electron emitting film. The electron emission device emits electrons from the spacecraft structure via field emission. The electron emission device prevents the spacecraft potential from falling negative. We have evaluated the mitigation performance of the device and confirmed that the field emission device mitigates the negative charging. Copyright IAF/IAA. All rights reserved.

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記述言語：日本語   掲載種別：研究論文（学術雑誌）

記述言語：英語   掲載種別：研究論文（学術雑誌）

記述言語：日本語   掲載種別：研究論文（学術雑誌）

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）

An electrostatic discharge (ESD) on a solar array causes a serious damage for a satellite. The effective ground test is required to ensure a safety of the satellite. To establish the ground test method, an international project is being proceeding by Japan, Europe and US. In the project three types of test coupons are used for verification of plasma propagation, degradation of cell and occurrence of secondary arc, respectively. This paper introduces ESD test methods, experimental systems and experimental results in Kyushu Institute of Technology of Japan.

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記述言語：英語   掲載種別：研究論文（学術雑誌）

In the MUCES-C mission conducted by JAXA (Japan Aero Exploration Agency), a microwave neutralizer is mounted with a microwave ion engine on the HAYABUSA space probe. The neutralizer consists of an L-shaped antenna to inject microwaves and samarium cobalt magnets to provide ECR (electron cyclotron resonance). Plasma production of a higher density than the cutoff density is expected in the discharge chamber, but the neutralizer is so small that high-precision measurements using a probe are difficult. To clarify the plasma production mechanism in the microwave neutralizer, numerical analysis was conducted using u code coupling PIC (particle-in-cell) method, and a FDTD (finite-difference-time-domain) method. This paper describes effects caused by varying magnetic field configuration and antenna position in the neutralizer. The calculation results show that bringing the antenna closer to the ECR region is effective for plasma production. © 2006 The Japan Society for Aeronautical and Space Sciences.

DOI： 10.2322/tjsass.49.87

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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）

The effect of magnetic field configuration on thrust performance in a 30 W class miniature microwave discharge ion engine was investigated with the objective of improving its thrust performance. The ion beam current with various magnitude of magnetic field was measured, since magnetic confinement and microwave - plasma coupling could be affected by the magnetic field configuration. The ion beam current is increased with the increase in the number of magnets and there is an optimum magnitude of magnetic field. The thrust performance of the miniature microwave discharge ion engine, propellant utilization, and ion beam production cost were 0.67 and 660 W/A, respectively at mass flow rate =0.02 mg/s, and incident microwave power= 8 W.

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記述言語：英語   掲載種別：研究論文（学術雑誌）

Several types of electric propulsions have been developed and used for artificial satellites on geostationary orbit keeping or planetary exploration. A series of small-scale satellites is recently expected to be used instead of traditional large-scale satellites for reducing launch cost and risk. The trend towards needs of small spacecraft requires micro thrusters with high specific impulse. In this study, a micro ion engine utilizing a microwave discharge plasma was fabricated and was tested. This ion engine comprises some components, such as electrostatic grids, antenna, and microwave power supply, which decide its performance. The performance dependence on the components was examined under several experimental conditions. The typical performance parameters of the engine were ion production cost of 770 V, propellant utilization efficiency of 72%, and thrust of 0.66 mN in conditions of input 2.45 GHz microwave power of 8 W and propellant (xenon gas) flow rate of 0.2 sccm with a star type antenna. © 2006 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.vacuum.2006.01.071

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

記述言語：英語   掲載種別：研究論文（学術雑誌）

The effects of antenna configuration on the thrust performance of a 30-W-class miniature microwave discharge ion engine were investigated. The ion beam currents were measured for three different antenna configurations such as disc, star, and cross antennas. The ion beam current of the star antenna was the largest among the three configurations and that of the disc antenna was the smallest. The effect of good coupling with plasma exceeded the effect of large losses on the antenna surface under low mass flow rate with low plasma density. The effect of large losses on the antenna surface also exceeded the effect of good coupling with plasma under high mass flow rate. The results showed that the optimum antenna shape depends on the desired mass flow level due to the tradeoff between microwave plasma coupling efficiency and surface-area recombination. It was also found that the disc antenna was the best at low mass flow rate and the star antenna was the best at high mass flow rate.

DOI： 10.2514/1.18833

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記述言語：英語   掲載種別：研究論文（学術雑誌）

記述言語：英語   掲載種別：研究論文（学術雑誌）

A simulation code has been developed for analyzing plasma behavior and microwave propagation in a microwave ion engine. The code consists of PIC (particle-in-cell) method and FDTD (finite-difference-time-domain) method. In the present study, 10-cm-class microwave ion engine developed by the Japan Aerospace Exploration Agency (JAXA) is adopted as a calculation model. The microwave propagations in the discharge chamber are compared under boundary conditions such as absorption and reflection. In the calculation with plasma, effect of boundary condition on electron energy is investigated. As a result, it is found that increase of electron energy is larger for reflection boundary condition than absorption one. © 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.tsf.2005.08.046

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）

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）

We report here on an optimal configuration of antennas using multi mono-pole systems. In order to optimize the position and length of antenna, the transmission efficiency are analyzed by finite difference time domain (FDTD) method, which is known for its usefulness and simplicity to calculate to electromagnetic field. The relation between the antenna length and transmission efficiency was investigated. First this report shows that experimental data up to now. Then the microwave transmission is calculated by using poynting vector. When transmission value of microwave is calculated, we varied the parameters such as antenna length, yoke length and number of antennas respectively. Finally, we obtain on guiding design principle of ion engines by comparing experimental data and numerical calculation conclusions.

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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）

Study of a small-scale ion engine (diameter of 2.5 cm, input microwave power up to 25 W) utilizing microwave-discharged plasma for space propulsion is reported. The ion extraction tests are conducted under several conditions such as the input microwave power range of 15-25 W, the Ar gas (as propellant) flow rate range of 1.5-3.5 sccm, and two types of antenna shape (L-type or disk antenna). In the tests, ion beam currents and distributions of ion beam current density are measured. As a result, maximum ion current of 8.2 mA is attained at input power of 25 W and Ar gas flow rate of 3.15 sccm with the L-type antenna. Ion production cost and propellant utilization efficiency are estimated from the ion current measurements to examine performances of the thruster. The plasma parameter measurements of electron temperature and density in the plasma source are also carried out. © 2004 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.vacuum.2003.12.066

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