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  2. 船瀬 龍

船瀬 龍

フナセ リュウ  (Ryu Funase)

基本情報

所属
国立研究開発法人宇宙航空研究開発機構 宇宙科学研究所 教授
東京大学 大学院工学系研究科 航空宇宙工学専攻 准教授
学位
博士（工学）(2007年3月 東京大学)
研究者番号
70509819
J-GLOBAL ID
200901051354637504
researchmap会員ID
5000090886

研究キーワード

 11

研究分野

 1

受賞

 4

主要な論文

 115
  • Kenshiro Oguri, Kenta Oshima, Stefano Campagnola, Kota Kakihara, Naoya Ozaki, Nicola Baresi, Yasuhiro Kawakatsu, Ryu Funase
    JOURNAL OF THE ASTRONAUTICAL SCIENCES 67(3) 950-976 2020年1月  査読有り最終著者
    This paper presents the trajectory design for EQUilibriUm Lunar-Earth point 6U Spacecraft (EQUULEUS), which aims to demonstrate orbit control capability of CubeSats in the cislunar space. The mission plans to observe the far side of the Moon from an Earth-Moon L2 (EML2) libration point orbit. The EQUULEUS trajectory design needs to react to uncertainties of mission design parameters such as the launch conditions, errors, and thrust levels. The main challenge is to quickly design science orbits at EML2 and low-energy transfers from the post-deployment trajectory to the science orbits within the CubeSat's limited propulsion capabilities. To overcome this challenge, we develop a systematic trajectory design approach that 1) designs over 13,000 EML2 quasi-halo orbits in a full-ephemeris model with a statistical stationkeeping cost evaluation, and 2) identifies families of low-energy transfers to the science orbits using lunar flybys and solar perturbations. The approach is successfully applied for the trajectory design of EQUULEUS.
  • Hiroyuki Koizumi, Jun Asakawa, Yuichi Nakagawa, Keita Nishii, Yoshinori Takao, Masakatsu Nakano, Ryu Funase
    JOURNAL OF SPACECRAFT AND ROCKETS 56(5) 1400-1408 2019年9月  査読有り
    This study proposes a micropropulsion system unifying ion thrusters and resistojet thrusters and assessing that propulsive capability. The remarkable features of the system are the usage of water propellant and unification of the two types of thrusters by the single propellant. Water has been regarded as an attractive propellant in the view points of safety, availability, handling ability, low molecular mass, and future procurement in space. A multimode propulsion system is an attractive solution for the increasing demand for nano-/microsatellite missions. The proposal is to use microwave discharge water ion thrusters, tolerant for oxidization by water, and low-temperature water resistojet thrusters, enabling reuse of the waste heat. As a result of the assessment, it was expected that the propulsion system would have 3U size (10 x 10 x 30 cm(3)) and 3.70 kg mass, which realize in total a 6U and 10 kg satellite with 3U and 6 kg satellite bus system. The ion thruster would provide the maximum Delta V of 630 m/s by 47 W system power and the resistojet thruster would have 3.80 mN thrust and 72 s specific impulse by 19.4 W. Additionally, reuse of the waste heat from ion-thruster power supplies would enable the simultaneous operations of the two thrusters even at 50 W, which is almost the same power as the single ion thruster operation.
  • Yuichiro Ezoe, Yoshizumi Miyoshi, Satoshi Kasahara, Tomoki Kimura, Kumi Ishikawa, Masaki Fujimoto, Kazuhisa Mitsuda, Hironori Sahara, Naoki Isobe, Hiroshi Nakajima, Takaya Ohashi, Harunori Nagata, Ryu Funase, Munetaka Ueno, Graziella Branduardi-Raymont
    JOURNAL OF ASTRONOMICAL TELESCOPES INSTRUMENTS AND SYSTEMS 4(4) 2018年10月  査読有り
    Toward an era of x-ray astronomy, next-generation x-ray optics are indispensable. To meet a demand for telescopes lighter than the foil optics but with a better angular resolution <1 arcmin, we are developing micropore x-ray optics based on micromaching technologies. Using sidewalls of micropores through a thin silicon wafer, this type can be the lightest x-ray telescope ever achieved. Two Japanese missions, ORBIS and GEO-X, will carry this telescope. ORBIS is a small x-ray astronomy mission to monitor supermassive blackholes, while GEO-X is a small exploration mission of the Earth's magnetosphere. Both missions need an ultralight-weight (<1 kg) telescope with moderately good angular resolution (<10 arcmin) at an extremely short focal length (<30 cm). We plan to demonstrate this type of telescope in these two missions around 2020. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License.
  • Naoya Ozaki, Stefano Campagnola, Ryu Funase, Chit Hong Yam
    JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 41(2) 377-387 2018年2月  査読有り
    Low-thrust propulsion is a key technology for space exploration, and much work in astrodynamics has focused on the mathematical modeling and the optimization of low-thrust trajectories. Typically, a nominal trajectory is designed in a deterministic system. To account for model and execution errors, mission designers heuristically add margins, for example, by reducing the thrust and specific impulse or by computing penalties for specific failures. These conventional methods are time-consuming, done by hand by experts, and lead to conservative margins. This paper introduces a new method to compute nominal trajectories, taking into account disturbances. The method is based on stochastic differential dynamic programming, which has been used in the field of reinforcement learning but not yet in astrodynamics. A modified version of stochastic differential dynamic programming is proposed, where the stochastic dynamical system is modeled as the deterministic dynamical system with random state perturbations, the perturbed trajectories are corrected by linear feedback control policies, and the expected value is computed with the unscented transform method, which enables solving trajectory design problems. Finally, numerical examples are presented, where the solutions of the proposed method are more robust to errors and require fewer penalties than those computed with traditional approaches, when uncertainties are introduced.
  • 神代 優季, 尾崎 直哉, 船瀬 龍, 中須賀 真一
    日本航空宇宙学会論文集 65(6) 219-226 2017年  査読有り
    Earth observation satellites can improve the flexibility of observation sites by having &ldquo;maneuverability,&rdquo; and low-thrust obtained by ion thruster will be a promising method for orbital change for micro-satellites. Designing low-thrust trajectories for these satellites is a multi-revolution and multi-objective (time/fuel-optimal) optimization problem, which usually requires high computational cost to solve numerically. This paper derives an analytical and approximate optimal orbit change strategy between two circular orbits with the same semi-major axis and different local time of ascending node, and proposes a graph-based method to optimize the multi-objective criteria. The optimal control problem results in a problem to search a switching point on the proposed graph, and mission designers can design an approximate switching point on this graph, by using two heuristic and reasonable assumptions that 1) the optimal thrust direction should be tangential to orbit and 2) the optimal thrust magnitude should be bang-bang control with an intermediate coast. Finally, numerical simulation with feedback control algorithm taking thrust margin demonstrates that the proposed method can be applicable in the presence of deterministic and stochastic fluctuation of aerodynamic disturbances.
  • Ikari, S., Inamori, T., Ito, T., Ariu, K., Oguri, K., Fujimoto, M., Sakai, S., Kawakatsu, Y., Funase, R.
    Transactions of the Japan Society for Aeronautical and Space Sciences 60(3) 181-191 2017年  査読有り最終著者
    This paper describes development strategies and on-orbit results of the attitude determination and control system (ADCS) for the world's first interplanetary micro-spacecraft, PROCYON, whose advanced mission objectives are optical navigation or an asteroid close flyby. Although earth-orbiting micro-satellites already have ADCSs for practical missions, these ADCSs cannot be used for interplanetary micro-spacecraft due to differences in the space environments of their orbits. To develop a new practical ADCS, four issues for practical interplanetary micro-spacecraft are discussed: initial Sun acquisition without magnetic components, angular momentum management using a new propulsion system, the robustness realized using a fault detection, isolation, and recovery (FDIR) system, and precise attitude control. These issues have not been demonstrated on orbit by interplanetary micro-spacecraft. In order to overcome these issues, the authors developed a reliable and precise ADCS, a FDIR system without magnetic components, and ground-based evaluation systems. The four issues were evaluated before launch using the developed ground-based evaluation systems. Furthermore, they were successfully demonstrated on orbit. The architectures and simulation and on-orbit results for the developed attitude control system are proposed in this paper.
  • Kameda, S., Ikezawa, S., Sato, M., Kuwabara, M., Osada, N., Murakami, G., Yoshioka, K., Yoshikawa, I., Taguchi, M., Funase, R., Sugita, S., Miyoshi, Y., Fujimoto, M.
    Geophysical Research Letters 44(23) 192-197 2017年  査読有り
  • 栁沼 和也, 船瀬 龍, 小紫 公也, 小泉 宏之, 河原 大樹, 浅川 純, 中川 悠一, 稲垣 匡志, 笠木 友介, 五十里 哲, 尾崎 直哉
    日本航空宇宙学会論文集 64(2) 131-138 2016年  査読有り
    We propose thrust vector management by correctly positioning the thruster on a spacecraft by thrust vector measurement to decrease unwanted torque of thrust vector misalignment. A ground test was performed to measure 2-dimensional ion current distribution of 10W-class miniature ion thruster by electrostatic probe. The thrust vector measurement test showed that the thrust vector inclining angle was 1.4&ordm; from the geometrically symmetric axis of the thruster. The thruster was positioned on the first interplanetary micro-spacecraft: PROCYON after redesigning thruster bracket. Thrust vector estimation in the initial on-orbit operation of 6.5 hours showed that thrust vector passes through within 5mm of the PROCYON's center of gravity.
  • Hiroki Hihara, Kaori Iwase, Junpei Sano, Hisashi Otake, Tatsuaki Okada, Ryu Funase, Ryoichi Kashikawa, Isamu Higashino, Tetsuya Masuda
    JOURNAL OF APPLIED REMOTE SENSING 8 2014年4月  査読有り
    A thermal-infrared (TIR) imager system is developed for HAYABUSA2, which is planned to be launched in 2014 and aims at sample-return from a C-class near-Earth asteroid 162173 (1999JU3) considered to contain organic or hydrated materials. The system consists of a TIR imager and digital electronics, which are used not only for the scientific investigation of physical properties of the asteroid surface, but also for the assessment of landing site selection and safe descent operation onto the asteroid surface with in situ measurement. TIR adopts an uncooled bolometer. Image operations such as multiple images summation, dark image subtraction, and the compensation of dead pixels are processed onboard. A processing module is connected to sensor interfaces through SpaceWire in order to provide deterministic processing time. Data compression is also provided to reduce the restriction of transmission time, which provides the equivalent compression ratio as JPEG2000 in 1/30 processing time in average. A high-speed data recorder is connected through SpaceWire in order to record TIR data in parallel with other sensor data. The modularity of SpaceWire enables us to use these as built devices for TIR and inherits the same design as the long-wavelength infrared imager developed for the Venus climate orbiter Akatsuki. (C) 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)
  • Yoshinori Takano, Hajime Yano, Yasuhito Sekine, Ryu Funase, Ken Takai
    ADVANCES IN SPACE RESEARCH 53(7) 1135-1142 2014年4月  査読有り
    Planetary protection has been recognized as one of the most important issues in sample return missions that may host certain living forms and biotic signatures in a returned sample. This paper proposes an initiative of sample capsule retrieval and onboard biosafety protocol in international waters for future biological and organic constituent missions to bring samples from possible habitable bodies in the solar system. We suggest the advantages of international waters being outside of national jurisdiction and active regions of human and traffic affairs on the condition that we accept the Outer Space Treaty. The scheme of onboard biological quarantine definitely reduces the potential risk of back-contamination of extraterrestrial materials to the Earth. (C) 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/).
  • Yuichi Tsuda, Takanao Saiki, Ryu Funase, Yuya Mimasu
    JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 36(4) 967-974 2013年7月  査読有り
    An attitude model for a general spinning solar sail spacecraft under the influence of solar radiation pressure is presented. This model, called "Generalized Spinning Sail Model", can be applied to realistic sails with nonflat surfaces that have nonuniform optical properties. The unique behaviors predicted by the generalized spinning sail model are verified by actual operation of the Japanese spinning solar sail spacecraft IKAROS. It is shown how imperfections in the sail surface affect the attitude motion of spinning sails, and a compact mathematical model that can precisely reproduce the spin-averaged motion of the spinning sails is derived. The stability conditions and a reduced model that preserves the key characteristics of the generalized spinning sail model are also derived to reveal the unique properties of the attitude behavior of spinning sails.
  • Yuichi Tsuda, Osamu Mori, Ryu Funase, Hirotaka Sawada, Takayuki Yamamoto, Takanao Saiki, Tatsuya Endo, Katsuhide Yonekura, Hirokazu Hoshino, Jun'ichiro Kawaguchi
    ACTA ASTRONAUTICA 82(2) 183-188 2013年2月  査読有り
    This paper describes achievements of the IKAROS project, the world's first successful interplanetary solar power sail technology demonstration mission. It was developed by the Japan Aerospace Exploration Agency (JAXA) and was launched from Tanegashima Space Center on May 21, 2010. IKAROS successfully deployed a 20 m-span sail on June 9, 2010. Since then IKAROS has performed interplanetary solar-sailing taking advantage of an Earth-Venus leg of the interplanetary trajectory. We declared the completion of the nominal mission phase in the end of December 2010 when IKAROS successfully passed by Venus with the assist of solar sailing. This paper describes the overview of the IKAROS spacecraft system, how the world's first interplanetary solar sailer has been operated and what were achieved by the end of the nominal mission phase. (c) 2012 Elsevier Ltd. All rights reserved.
  • Osamu Mori, Yoji Shirasawa, Yasuyuki Miyazaki, Hiraku Sakamoto, Mitsue Hasome, Nobukatsu Okuizumi, Hirotaka Sawada, Hiroshi Furuya, Saburo Matunaga, Michihiro Natori, Yuichi Tsuda, Takanao Saiki, Ryu Funase, Yuya Mimasu, Junichiro Kawaguchi
    Journal of Aerospace Engineering, Sciences and Applications 4(4) 79-96 2012年10月  査読有り
    The Japan Aerospace Exploration Agency (JAXA) makes the world's first solar power sail craft IKAROS demonstration of photon propulsion and thin film solar power generation during its interplanetary cruise. The spacecraft deploys and spans a membrane of 20 meters in diameter using the spin centrifugal force. It also deploys thin film solar cells on the membrane, in order to evaluate its thermal control property and anti-radiation performance in the real operational field. The spacecraft weighs approximately 310kg, launched together with the agency's Venus Climate Orbiter, AKATSUKI on May 21, 2010. This paper presents the summary of development and operation of IKAROS.
  • 関根 康人, 薮田 ひかる, 木村 淳, 古川 善博, 高野 淑識, 矢野 創, 船瀬 龍, 高井 研, 石原 盛男, 渋谷 岳造, 橘 省吾, 倉本 圭
    日本惑星科学会誌遊星人 21(3) 229-238 2012年  査読有り
    エンセラダスの南極付近から噴出するプリュームの発見は,氷衛星の内部海の海水や海中の揮発性成分や固体成分の直接サンプリングの可能性を示した大きなブレイクスルーであるといえる.これまでカッシーニ探査によって,プリューム物質は岩石成分と相互作用する液体の内部海に由来していることが明らかになったが,サンプリング時の相対速度が大きいこと,質量分析装置の分解能が低いことなどの問題があり,内部海の化学組成や温度条件,海の存続時間など,生命存在の可能性を制約できる情報は乏しい.本論文では,エンセラダス・プリューム物質の高精度その場質量分析とサンプルリターンによる詳細な物質分析を行うことで,内部海の化学組成の解明,初期太陽系物質進化の制約,そして生命存在可能性を探ることを目的とする探査計画を提案する.本提案は,"宇宙に生命は存在するのか"という根源的な問いに対して,理・工学の様々な分野での次世代を担う若手研究者が惑星探査に参入し結集する点が画期的であり,我が国の科学・技術界全体に対しても極めて大きな波及効果をもつ.
  • 中村 良介, 松浦 周二, 船瀬 龍, 矢野 創, 森 治, 津田 雄一, 吉田 二美, 高遠 徳尚, 小久保 英一郎
    日本惑星科学会誌遊星人 21(3) 253-259 2012年  査読有り
    原始太陽系円盤を構成していた初期物質を探るためには,惑星形成時の熱変成の影響を免れた小惑星・彗星・惑星間塵といった小天体の研究が不可欠である.なかでも木星のラグランジュ点付近に存在するトロヤ群小惑星は,小惑星と彗星の間をつなぐ天体であり,原始太陽系円盤の物質分布や微惑星の成長・移動プロセスを調べる上で重要なターゲットである.本稿では,日本が世界に先駆けて実証したソーラー電力セイル技術を用いたトロヤ群小惑星探査ミッションを提案する.この探査は(1)トロヤ群小惑星の詳細な物質組成や熱史・衝突史を調べることで,その起源と進化を明らかにする, (2)惑星間塵の空間分布を測定することで,彗星・小惑星からの生成率や軌道進化に関する理解を深め,その結果を他の惑星系に応用する, (3)惑星間塵の影響の少ない小惑星帯以遠からの宇宙赤外線背景放射観測によって,宇宙初期に形成された第一世代の星を調べる,という科学目標をあわせ持つ,惑星科学・天文学・宇宙工学の融合ミッションである.
  • Ryu Funase, Yoji Shirasawa, Yuya Mimasu, Osamu Mori, Yuichi Tsuda, Takanao Saiki, Jun'Ichiro Kawaguchi
    Advances in Space Research 48(11) 1740-1746 2011年12月1日  査読有り筆頭著者責任著者
    This paper introduces a new attitude control system for a solar sail, which leverages solar radiation pressure. This novel system achieves completely fuel-free and oscillation-free attitude control of a flexible spinning solar sail. This system consists of thin-film-type devices that electrically control their optical parameters such as reflectivity to generate an imbalance in the solar radiation pressure applied to the edge of the sail. By using these devices, minute and continuous control torque can be applied to the sail to realize very stable and fuel-free attitude control of the large and flexible membrane. The control system was implemented as an optional attitude control system for small solar power sail demonstrator named IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun). In-orbit attitude control experiments were conducted, and the performance of the controller was successfully verified in comparison with the ground-based analytical performance estimation. © 2011 COSPAR. Published by Elsevier Ltd. All rights reserved.
  • Yuya Mimasu, Tomohiro Yamaguchi, Michihiro Matsumoto, Masaki Nakamiya, Ryu Funase, Jun'Ichiro Kawaguchi
    Advances in Space Research 48(11) 1810-1821 2011年12月1日  査読有り
    The orbit of a solar sail can be controlled by changing the attitude of the spacecraft. In this study, we consider the spinning solar power sail IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun), which is managed by Japan Aerospace Exploration Agency (JAXA). The IKAROS attitude, i.e.; the direction of its spin-axis, is nominally controlled by the rhumb-line control method. By utilizing the solar radiation torque, however, we are able to change the direction of the spin-axis by only controlling its spin rate. With this spin rate control, we can also control indirectly the solar sail's trajectory. The main objective of this study is to construct the orbit control strategy of the solar sail via the spin-rate control method. We evaluate this strategy in terms of its propellant consumption compared to the rhumb-line control method. Finally, we present the actual flight attitude data of IKAROS and the change of its trajectory. © 2011 COSPAR. Published by Elsevier Ltd. All rights reserved.
  • Shinichi Kimura, Akira Miyasaka, Ryu Funase, Hirotaka Sawada, Nobuomi Sakamoto, Naoki Miyashita
    IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE 26(3) 19-25 2011年3月  査読有り
    It is becoming imperative to have visual capabilities for space activities. There are increasing opportunities to use visual Images coupled with image processing technologies for spacecraft sensing and control. To fill this need, we have developed a small, low-cost, high-performance image acquisition and processing unit (HP-IMAP), which uses commercial off-the-shelf technologies. In 2010, the HP-IMAP was launched to monitor a deployable structure. Herein, we describe the BP-IMAP and discuss Its qualification tests.
  • 船瀬 龍, 中村 友哉, 永井 将貴, 江野口 章人, 小松 満仁, 中須賀 真一, 川北 史朗
    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, SPACE TECHNOLOGY JAPAN 6(6) 1-9 2008年  査読有り筆頭著者責任著者
    Small satellites, especially pico or nano-class satellites, which can be developed in a very short period and at very low cost, are considered to provide good opportunities for technology demonstration in a space environment. Based on the success of the first pico-satellite XI-IV, which was intended to establish the basic technologies required for this class of satellites, Intelligent Space Systems Laboratory (ISSL) at the University of Tokyo developed its second pico-satellite XI-V with the mission to demonstrate new space technologies such as the verification of copper indium gallium di-selenide (CIGS) thin-film solar cells in space. The pico-satellite bus verified by XI-IV was used for this mission, so that the satellite was completed within as short a development period as one year. XI-V was launched on October 2005 and has been successfully conducting its missions. In this paper, following the introduction of the pico-satellite bus system and its demonstrated results on XI-IV, the details of the missions and on-orbit experimental results of XI-V are described.
  • Ryu Funase, Ernesto Takei, Yuya Nakamura, Masaki Nagai, Akito Enokuchi, Cheng Yuliang, Kenji Nakada, Yuta Nojiri, Fumiki Sasaki, Tsukasa Funane, Takeshi Eishima, Shinichi Nakasuka
    ACTA ASTRONAUTICA 61(7-8) 707-711 2007年10月  査読有り筆頭著者責任著者
    Small satellites, especially pico- or nano-class satellites, are considered to provide good opportunity for technology demonstration. University of Tokyo's pico-satellite "XI-V", which was scheduled to be launched in September 2005, was developed in I year with the mission to test newly developed solar cells. This paper introduces the details of the mission and its effective operation using the network of ground stations. (c) 2007 Elsevier Ltd. All rights reserved.
  • Ryu Funase, Shinichi Nakasuka, Nobutada Sako, Takeshi Fuiiwara, Yuichi Tsuda, Shinichi Ukawa, Shinichi Kimura, Hidekazu Hashimoto, Keisuke Yoshihara, Toru Yamamot
    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES 50(168) 97-104 2007年8月  査読有り筆頭著者責任著者
    Capture of tumbling objects in space will be one of the important on-orbit service technologies in the future. It requires a series of technologies such as camera-image tracking of the target, target attitude motion estimation, and attitude control of the chaser to approach and grasp the target. Based on theoretical and simulation-based research, the University of Tokyo successfully performed an on-orbit experiment of some of these technologies on a Japan Aerospace Exploration Agency's (JAXA, formerly NASDA) microsatellite named "mu-LABSAT." In this paper, the objectives and procedures of these experiments, the control and estimation algorithms, and the results are described.
  • 中須賀 真一, 酒匂 信匡, 津田 雄一, 永島 隆, 船瀬 龍, 中村 友哉, 永井 将貴
    電子情報通信学会論文誌. B, 通信 = The transactions of the Institute of Electronics, Information and Communication Engineers. B 88(1) 41-48 2005年1月1日  査読有り
    2003年6月30日,東京大学中須賀研究室が開発した超小型衛星CubeSat-XI(1kg,10cm立方)がロシア連邦プレセツクより高度820kmの太陽同期軌道に打ち上げられた.その後,当初の予想を超え1年以上の長期にわたり順調に動作し,バス機器の軌道上実証,画像取得・ダウンリンクなどの実験を行って大きな成果を収めた.この衛星は学生の手作りにより開発された衛星で,その第一の目的は宇宙工学教育であるが,民生品をベースに低コスト・短期に衛星を提供することによる新しい宇宙開発を試行することをその先の目的としている.本論文では,CubeSat-XIの概要と軌道上実証の成果を述べ,その開発経験や成果を踏まえ,宇宙開発の低コスト化・短期開発化を目指した小型・超小型衛星開発のあり方を論じる.
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  • 田中 孝治, 相馬 央令子, 横田 力男, 船瀬 龍, 森 治, 津田 雄一, 遠藤 達也
    日本航空宇宙学会誌 61(6) 221-224 2013年  査読有り
    本報告では,H22年5月に打ち上げられたソーラー電力セイル実証機IKAROSに搭載された薄膜発電システムの軌道上実験に関して述べる.ソーラーセイルの膜面上にa-Si太陽電池を用いた薄膜太陽電池アレイを搭載し,軌道上での展開及び発電実験を行った.太陽電池アレイは8個の発電ブロックに分けて搭載し,各発電ブロック間のばらつきは少なく,製造管理,収納及び軌道上での展開の影響評価が実施できた.ただし,打ち上げ前にフレキシブルハーネスの一部が不具合を起こしており,ハーネスの構造,管理には課題がある.発電特性は,初期特性は地上検証データと近い値を示しているが,時間変化の特性は若干劣化が大きくなる傾向が得られている.発電特性の継続的取得により,惑星探査機用薄膜超軽量発電システム開発のための知見を得る.
  • 三桝 裕也, 森 治, 吉川 真, 川口 淳一郎, 山口 智宏, 池田 人, 中宮 賢樹, 竹内 央, 佐伯 孝尚, 津田 雄一, 谷口 正, 船瀬 龍
    日本航空宇宙学会誌 61(7) 247-252 2013年  査読有り
    本稿は,世界初のソーラー電力セイル実証機IKAROSが打ち上げられてからおよそ2年間という期間に実証された,ソーラーセイルの誘導・航法に関する成果をまとめたものである.世界初となるソーラーセイルの軌道上での実際の航法・誘導において,光圧加速度・光圧トルクのその類稀なる大きさから,一般的な手法だけでは評価しきれない点が少なからず存在し,そのため,IKAROSの誘導・航法技術に関しては,いくつかの工夫がなされた.ここでは,航法技術に関して,セイルによって発生する光圧加速度を精密に計測するための推定法,及び評価結果を,また,誘導技術に関しては,光圧トルクによって発生する姿勢のドリフト運動を考慮した誘導法,及びその評価結果について紹介する.また,航法技術に関連して,IKAROSに搭載されたDDOR用のトーン生成器によって得られたデータの評価結果についても紹介する.
  • Lucas Bremond, Yuichi Tsuda, Ryu Funase, Jun'ichiro Kawaguchi
    SPACEFLIGHT MECHANICS 2013, PTS I-IV 148 1007-1022 2013年  査読有り
    In the overall context of a solar sail mission in the vicinity of the Trojan asteroids swarm around the L4 Lagrange point, the purpose of this work is to find an optimal sequence of asteroids rendezvous that accommodates given mission constraints. A currently considered strategy to solve this problem will be presented and design choices will be outlined. A subset of the Trojan asteroids database is first extracted based on orbital elements considerations and a tree containing all the potential sequences is generated. A first set of pruning techniques is applied to the tree in order to quickly reduce the search space by several orders of magnitude. A global optimization method is then used: it combines a branch-and-bound approach and an evolutionary algorithm to find good sequence order, departure date, transfer and coasting durations. In order to enable a fast computation of potential transfer costs, the dynamics are linearized around L4 and the Delta Vs are computed analytically. Preliminary results show a drastic reduction of the search space along with a reasonable accuracy on the cost prediction. This method has been used to analyze a tour scenario starting from 588 Achilles and including three rendezvous; the final result provides a list of sequences of potential interest.
  • Satoshi Ikari, Takuji Ebinuma, Ryu Funase, Shinichi Nakasuka
    PROCEEDINGS OF THE 26TH INTERNATIONAL TECHNICAL MEETING OF THE SATELLITE DIVISION OF THE INSTITUTE OF NAVIGATION (ION GNSS 2013) 1234-1241 2013年  査読有り
    QZS-1 is the first satellite of Japanese Quasi-Zenith Satellite System (QZSS) launched in September 11, 2010. QZSS is a regional navigation satellite system, which provides the signals interoperable with GPS as well as integrity and correction information. The L-band experimental (LEX) signal broadcasted in L6 band (1278.75 MHz) contains high-precision corrections for GPS and QZSS satellite orbit and clock errors. QZS-1 is at an altitude of geo-synchronous orbit, where the solar radiation pressure (SRP) is the largest non-gravitational orbit perturbation acting on the satellite body and its solar panels. This paper describes newly proposed physics-based SRP models specially designed for the QZS-1 satellite and makes a comparison of the orbit determination accuracies with the conventional SRP models such as an empirical DBY model and a simple box-wind model. Although the orbit determination accuracy achieved by the empirical model is still much better than those obtained by the physics-based models, the newly proposed SRP models effectively reduce periodic acceleration errors from the conventional box-wing model and improve the orbit determination accuracy.
  • Yuya Mimasu, Sho Taniguchi, Hiroshi Takeuch, Yoji Shirasawa, Katsuhide Yonekura, Osamu Mori, Ryu Funase, Takanao Saiki, Yuichi Tsuda
    SPACEFLIGHT MECHANICS 2013, PTS I-IV 148 3161-3179 2013年  査読有り
    The world's first solar sail IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun) which is operated by Japan Aerospace Exploration Agency (JAXA) lost communication with the ground station due to the power shortage on December 24, 2011. In order to acquire IKAROS again after the power comes back, we immediately initiated to predict the attitude and orbit for the spacecraft. As the result of the effort for the prediction, finally we acquire IKAROS after 9 months. This paper presents that the attitude and orbit prediction technique, while IKAROS was lost in space.
  • Hisashi Otake, Tatsuaki Okada, Ryu Funase, Hiroki Hihara, Junpei Sano, Kaori Iwase, Ryoichi Kashikawa, Isamu Higashino, Tetsuya Masuda
    INFRARED REMOTE SENSING AND INSTRUMENTATION XXI 8867 2013年  査読有り
    Thermal infrared imager system is developed for HAYABUSA2, which is planned to be launched in 2014 and aims at sample-return from a C class near-Earth asteroid 1999JU3 considered to contain organic or hydrated materials. The system consists of a thermal-infrared imager (TIR) and a digital electronics, which is used not only for the scientific investigation of physical properties of the asteroid surface, but also for the assessment of landing site selection and safe descent operation onto the asteroid surface with in situ measurement.Since round trip communication time between the asteroid and the Earth is more than thirty minutes, onboard automatic data processing function and high speed data recording capability are provided to exploit the limited downlink capacity which is up to 32kbps.TIR adopts an uncooled bolometer with 320 x 240 effective pixels. Image operations as multiple images summation, dark image subtraction, and the compensation of dead pixels are processed onboard. A processing module is connected to sensor interfaces through SpaceWire in order to provide deterministic processing time. Data compression is also provided to reduce restriction on storage capacity and operation time, which provides the equivalent compression ratio as JPEG2000 in 1/30 processing time in average. A high speed data recorder is also connected through SpaceWire in 50Mbps in order to record TIR data in parallel with other sensor data.The modularity of SpaceWire enables to use as built devices for TIR and inherits the same design as the long-wavelength infrared imager developed for the Venus climate orbiter Akatsuki.
  • 高野淑識, 高井研, 渋谷岳造, 矢野創, 船瀬龍, 関根康人, 吉村義隆, 山岸明彦, 木下大輔, TSOU Peter, TSOU Peter, TSOU Peter
    宇宙利用シンポジウム 28th 230-232 2012年3月  
  • Yuichi Tsuda, Yuya Mimasu, Ryu Funase, Yoshinobu Okano
    AIAA/AAS Astrodynamics Specialist Conference 2012 2012年  査読有り
    This paper describes design criteria for sail surface quality derived from requirements about attitude dynamics of spinning solar sail spacecraft. The method has been developed by an experience of the Japanese interplanetary solar sail mission IKAROS. The authors derived, in their previous work, a combination of a generalized spinning attitude model and a finite element model-based sail deformation analysis method to directly relate the sail surface wrinkling and the attitude disturbance via solar radiation pressure effect. Based on this work, this paper attempts to derive design criteria for the sail surface quality, which is useful for the mission analysis and the quality control in sail production. Specifically, this paper provides an acceptable deformation level as a function of scale length for given attitude stability requirements against the solar radiation pressure disturbance, which is then compared and verified by the post-flight analysis of IKAROS. © 2012 by Yuichi Tsuda.
  • 米倉 克英, 星野 宏和, 森 治, 津田 雄一, 澤田 弘崇, 船瀬 龍, 佐伯 孝尚, 白澤 洋次, 三桝 裕也, 尾川 順子, 南野 浩之, IKAROS, デモンストレーションチーム
    第 12 回宇宙科学シンポジウム講演集録 P3-05B 2012年1月  
  • 船瀬龍, 森治, 白澤洋次, 津田雄一, 矢野創
    宇宙科学技術連合講演会講演集(CD-ROM) 56th ROMBUNNO.1S20 2012年  
  • Osamu Mori, Yoji Shirasawa, Hirotaka Sawada, Yuya Mimasu, Yuichi Tsuda, Ryu Funase, Takanao Saiki, Takayuki Yamamoto, Norizumi Motooka, Yoshihiro Kishino, Junichiro Kawaguchi
    Proceedings of the International Astronautical Congress, IAC 10 8090-8096 2012年  査読有り
    This paper presents IKAROS extended missions. IKAROS entered its extended operation phase at the beginning of 2011. In the extended operation, the spin rate was decreased to observe the deformation of the sail under low centrifugal force environment. On Oct. 18, 2011, IKAROS transferred to the reverse spin to enhance the knowledge about the effect of stiffness of membrane against the solar radiation pressure. We investigated the change of the attitude motion by the reverse spin mission. At the end of 2011, IKAROS moved to hibernation mode because the Sun angle was increased. We searched for IKAROS considering the attitude and orbital motion during hibernation. On Sep. 6, 2012, we succeedcd in tracking IKAROS which came out of hibernation. A solar power sail can be a hybrid propulsion system with a solar sail by activating the ultra-high specific impulse ion engines with the power generated by thin film solar cells. This paper also introduces an advanced solar power sail mission toward Jupiter and Trojan asteroids via hybrid electric photon propulsion.©2012 by the International Astronautical Federation.
  • Ryu Funase, Go Kanno, Yuichi Tsuda
    Proceedings of the International Astronautical Congress, IAC 8 6131-6138 2012年  査読有り
    The authors had developed a propellant-free attitude control system for spinning solar sails that utilize only the solar radiation pressure and solar energy. This system implements specially developed thin-film reflectivity control devices (RCDs) that can electrically control their optical parameters such as reflectivity, and attitude control torque can be generated by switching the reflectivity of these devices synchronizing with the spin motion of the sail. In this paper, a precise attitude control torque model for the proposed system was derived considering arbitrary sail deformation. The derived torque model revealed three-axis controllability of the system, that is, the system can generate arbitrary three-dimensional attitude control torque. We further analysed the model and it was found that the switching control of RCDs can change the dynamical property' of natural spiral attitude motion observed for spinning solar sail. The proposed propellant-free attitude control system was demonstrated by the world's first solar sail demonstrator IKAROS and the on-orbit attitude control results showed the validity of the derived torque model. Copyright © (2012) by the International Astronautical Federation.
  • Marco Giancotti, Ryu Funase
    Proceedings of the International Astronautical Congress, IAC 7 5744-5752 2012年  査読有り
    In this paper we present a feasibility study of solar sail artificial equilibrium solutions close to an asteroid. This research is part of the in-progress effort by J AX A to design a mid-size solar power sail to rendezvous with Jupiter and its trojan asteroids. The idea of maintaining a stationary position only using solar radiation pressure is attractive, but several practical restrictions must be considered for use in a real mission. We describe the equilibrium solution surfaces in 3-dimensional space for various asteroid sizes, while keeping the baseline acceleration of the sail constant. These solutions are found in the context of Hill's problem with a point-like asteroid in a circular orbit. Different sail reflectivity indices are tested and the corresponding equilibrium solutions are shown. Finally, we present preliminary estimates of the time and At required to move from a solar sail equilibrium to a traditional hovering position powered by impulsive or ion thrusters. Copyright© (2012) by the International Astronautical Federation.
  • 森 治, 遠藤 達也, 白澤 洋次, 三桝 裕也, 川口 淳一郎, 津田 雄一, 澤田 弘崇, 船瀬 龍, 山本 高行, 佐伯 孝尚, 米倉 克英, 星野 宏和, 南野 浩之
    日本航空宇宙学会誌 60(8) 283-289 2012年  査読有り
    「ソーラーセイル」は,太陽光の圧力をセイルに受けて宇宙空間を航行する宇宙帆船であり,燃料なしで推進力を得ることができる.一方,「ソーラー電力セイル」は,薄膜太陽電池をセイルの一部に貼り付けて,発電も同時に行う.ソーラー電力セイルはソーラーセイルにより燃料を節約できるだけでなく,大面積の薄膜太陽電池を利用して,太陽から遠く離れた場所でも必要電力を確保できる.この電力を用いてイオンエンジンを駆動すれば,光子加速と合わせたハイブリッド推進が可能となる.JAXAではこれを踏まえてソーラー電力セイル探査機による木星圏探査計画を提案している.この計画のリスク軽減のフロントローディングとして開発されたのが,小型ソーラー電力セイル実証機「IKAROS」であり,世界で初めてソーラー電力セイルを実証することに成功した.本稿では,IKAROSのミッションおよびシステムの概要を説明し,開発・運用について紹介する.
  • 津田 雄一, 横田 力男, 川口 淳一郎, 森 治, 白澤 洋次, 三桝 裕也, 澤田 弘崇, 船瀬 龍, 遠藤 達也, 山本 高行, 田中 孝冶
    日本航空宇宙学会誌 60(10) 357-363 2012年  査読有り
    本稿では,小型ソーラー電力セイル実証機IKAROSのセイル展開方式として採用した,遠心力展開方式について, JAXAにて著者らが行ってきた研究開発を概説する. IKAROSは世界に先駆けてJAXAが実施したソーラー電力セイル技術の宇宙技術実証であり,宇宙機全体のスピンによる遠心力を利用してセイルの展開・展張をするという独特な方式を採用している.著者らは,軽量かつスケーラブルなセイル展開システムとして遠心力展開方式を採用し,研究開発を行ってきた.本活動は, 2002年にJAXA内に発足したソーラーセイルワーキンググループが中心となり,全国の多数の大学研究機関とともに行ってきたものである.最終的な目標はφ50m級のソーラー電力セイルを実現することにあり,φ20m級のセイルを搭載したIKAROSはその最終段階の宇宙技術実証試験と位置付けられたものである.ここでは,本研究開発活動の主要な柱である遠心力展開技術について紹介し, IKAROSプロジェクト発足以前に著者らが行ってきた主要な試験プロセスと数値シミュレーション技術について概説する.
  • 遠藤 達也, 横田 力男, 宮内 雅彦, 三桝 裕也, 松本 純, 船瀬 龍, 白澤 洋次, 森 治, 津田 雄一
    日本航空宇宙学会誌 60(11) 413-420 2012年  査読有り
    本稿は,世界初のソーラー電力セイルであるIKAROS(Interplanetary Kite-craft Accelerated by Radiation Of the Sun)のソーラーセイル膜面の構成,その製作法,そして実際の製作の流れについて述べたものである.IKAROSのソーラーセイル膜面は,2種類のポリイミドによるベースフィルム上に,薄膜太陽電池や液晶デバイスをはじめとする各種デバイスを搭載する構造となっている.差し渡し20mの大きさを持つIKAROSのソーラーセイル膜面は,多数の試作モデルの製作を通じて確立した製作法により,ハンドメイドで製作された.その後,IKAROSは2010年5月21日に打ち上げられ,続く2010年6月9日に軌道上でソーラーセイル膜面の展開を完了した.展開後に撮影されたカメラの画像から,ソーラーセイル膜面は亀裂が発生することなく完全に展開できていること,ソーラーセイル膜面を構成する各構成要素が所定の機能を果たしていることなどが確認されている.また,その後の運用により,IKAROSのメインミッションの他に,各種デバイスの経年劣化に関するデータも取得できている.
  • Ryu Funase, Yuya Mimasu, Yoshikazu Chishiki, Yoji Shirasawa, Yuichi Tsuda, Takanao Saiki, Jun'ichiro Kawaguchi
    ASTRODYNAMICS 2011, PTS I - IV 142 1737-1754 2012年  査読有り
    A fuel-free attitude control system for a spinning solar sail which utilizes solar radiation pressure was developed. This system consists of thin-film devices attached to the sail that electrically control their optical parameters such as reflectivity, and the attitude control torque is generated by switching their optical parameters synchronizing with spin motion. Attitude control torque model for a sail of arbitrary shape and deformation was derived. The control system was implemented for Japanese interplanetary solar sail demonstration spacecraft IKAROS and the on-orbit attitude control performance was evaluated.
  • Yuya Mimasu, Tomohiro Yamaguchi, Masaki Nakamiya, Ryu Funase, Takanao Saiki, Yuichi Tsuda, Osamu Mori, Jun'ichiro Kawaguchi
    ASTRODYNAMICS 2011, PTS I - IV 142 3547-3560 2012年  査読有り
    It is well known that the thrust force of the solar sail due to the solar radiation pressure is changed by the orientation of the sail with respect to the Sun direction. Therefore, the orbit of the solar sail can be controlled by changing the attitude of the spacecraft. In this study, we consider the spinning solar power sail IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun), which succeeded to become the world's first flight solar sail in orbit. The IKAROS attitude, i.e. the spin-axis direction is nominally controlled by the rhumb-line control method. By utilizing the solar radiation pressure (SRP) torque, however, we are able to change the direction of the spin-axis only by controlling its spin rate. This is because the spin axis direction relates to the balance between the angular momentum of spinning and the SRP torque. Thus, we can control the solar sail's orbit by controlling the spin rate. The main objective in this study is to construct the orbit control strategy of the spinning solar sail via the spin rate control.
  • Yuichi Tsuda, Yoshinobu Okano, Yuya Mimasu, Ryu Funase
    SPACEFLIGHT MECHANICS 2012 143 1609-1625 2012年  査読有り
    This paper describes a method of evaluating sail quality utilizing in-flight attitude behavior of spinning solar sailer IKAROS. Since the successful deployment of the sail, IKAROS has received SRP which strongly affects both translational and rotational motion of the spacecraft. The authors have derived the "Generalized Spinning Sail Model (GSSM)" to reproduce observed unique attitude behavior of IKAROS. Following the previous work, this paper attempts to relate the GSSM with sail quality such as sail shape and flatness. An optical FEM model is constructed to evaluate the precise SRP effect on the spacecraft, and some candidates of deformed sail shape is reproduced which is consistent with the observed attitude motion. We also conclude by the in-flight attitude behavior that the surface roughness of the IKAROS sail is 0.33% at minimum.
  • Yuichi Tsuda, Takanao Saiki, Yuya Mimasu, Ryu Funase, Kenji Kitamura
    ASTRODYNAMICS 2011, PTS I - IV 142 1319-1331 2012年  査読有り
    This paper describes an attitude determination strategy for spinner spacecraft based on the Sun and the Earth angles. This method realizes a complete spin vector determination using only one sun sensor. Thus this method is suitable for low cost, resource-limited spacecraft with a moderate attitude determination accuracy requirement. The method has been developed for and is actually used in IKAROS, which is a Japanese interplanetary solar sail demonstration mission. This paper introduces theoretical backgrounds of Sun-Earth based attitude determination and shows how the actual implementation was done in the IKAROS mission. Then the attitude determination performance achieved during the actual operation is evaluated.
  • 森 治, 津田 雄一, 澤田 弘崇, 佐伯 孝尚, 船瀬 龍, Osamu Mori, Yuichi Tsuda, Hirotaka Sawada, Takanao Saiki, Ryu Funase
    人工知能学会誌 = Journal of Japanese Society for Artificial Intelligence 26(2) 164-175 2011年3月1日  査読有り
  • 佐伯孝尚, 津田雄一, 船瀬龍, 三桝裕也, 白澤洋次
    誘導制御シンポジウム資料 28th 2011年  
  • 船瀬龍, 三桝裕也, 津田雄一, 佐伯孝尚, 岡野仁庸, 管野剛
    宇宙科学技術連合講演会講演集(CD-ROM) 55th 2011年  
  • 三桝裕也, 船瀬龍, 佐伯孝尚, 津田雄一, 川口淳一郎
    アストロダイナミクスシンポジウム講演後刷り集(Web) 20th 2011年  
  • 森治, 津田雄一, 津田雄一, 澤田弘崇, 船瀬龍, 山本高行, 佐伯孝尚, 米倉克英, 星野宏和, 南野浩之, 遠藤達也, 川口淳一郎
    日本機械学会年次大会講演論文集(CD-ROM) 2011 2011年  
  • Yuichi Tsuda, Takanao Saiki, Ryu Funase, Yoji Shirasawa, Yuya Mimasu
    Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference 2011年  査読有り
    IKAROS is the Japanese deep-space solar sail technology demonstration mission launched in 2010. IKAROS is a spinner spacecraft with the 20m-span solar sail kept extended by the centrifugal force. During its solar sailing flight from Earth to Venus, IKAROS showed a unique attitude behavior due to solar radiation pressure attracted on the sail. This paper proposes a generalized model of spinning sail-craft, which clearly explains the attitude behavior observed in IKAROS. Then it is shown that this behavior has a clear dependency on the sail shape and the optical property distributions on the sail. We show the estimation results of the on-orbit sail shape using this new model. Copyright © 2011 by Yuichi Tsuda.
  • Osamu Mori, Yoji Shirasawa, Yuichi Tsuda, Ryu Funase, Takanao Saiki, Yuya Mimasu, Ryo Jifuku, Norizumi Motooka, Takayuki Yamamoto, Junichiro Kawaguchi
    62nd International Astronautical Congress 2011, IAC 2011 7 5582-5588 2011年  査読有り
    In this paper, the attitude dynamics of IKAROS, which is spinning solar sail, is presented. Multi Particle Model (MPM) and First Mode Model of out-of-plane deformation (FMM) are introduced to analyze the out-of-plane oscillation mode of spinning solar sail. Considering the thruster configuration of IKAROS, the force on main body and membrane by thruster plume as well as reaction force by thruster are integrated into MPM. The attitude motion after sail deployment or reorientation using thrusters can be analyzed by MPM numerical simulations precisely. The out-of-plane oscillation of IKAROS is governed by three modes derived from FMM. FMM is simple and valid for the design of attitude controller. Copyright ©2010 by the International Astronautical Federation. All rights reserved.
  • Yoshinobu Okano, Yuichi Tsuda, Ryu Funase, Hironori Sahara, Yuya Mimasu
    62nd International Astronautical Congress 2011, IAC 2011 6 5062-5071 2011年  査読有り
    This paper discusses about attitude dynamics for spinning spacecraft under influence of solar radiation pressure (SRP). Generally spinning objects maintain its spin axis with reference to inertial frame. But if disturbance torque like SRP affects this object, the spinning motion indicates a unique behavior due to dynamical coupling between the SRP torque and the spin motion. IKAROS and HAYABUSA launched by Japan Aerospace Exploration Agency (JAXA) positively utilize this phenomenon in actual operation. For example, HAYABUSA was kept sun-oriented during spin stabilized phases without fuel utilizing this effect. In the IKAROS mission a method has been developed which controls both attitude and orbital trajectory by SRP. These two are the remarkable examples of how SRP is utilized for fuel-saving and efficient operation. To enable to this technique, it is essential to understand attitude dynamics including SRP influence correctly. In past papers, simplified attitude models including SRP effect are derived both for HAYABUSA and IKAROS missions. These models are cable of explain wide range attitude motions. But in the flight data of HAYABUSA and IKAROS, there are remarkable motions that these simplified models cannot explain. In past papers, these motions called wind mill effect and spiral behavior. There are two purposes in this paper. The one is alignment of microscopic theory and macroscopic theory. The other one is considering these remarkable motions theoretically. For these purposes, we construct FEM model including SRP effects and simulate attitude dynamics numerically. In the results of simulations, two causes were found. The one is optical property of surface. The other one is non-flat surface effect of spacecraft. In this paper, we indicate the background of constructing SRP model and the evaluation including flight data of HAYABUSA and IKAROS. Then we discuss about the relationship between simplified attitude models and microscopic models. Copyright ©2010 by the International Astronautical Federation. All rights reserved.
  • 有川 善久, 岡田 英人, 澤田 弘崇, 鶴見 辰吾, 野尻 悠太, 船瀬 龍, 坂本 啓, 田中 宏明
    年次大会 2011 _C191001-1-_C191001-7 2011年  査読有り
  • 森 治, 遠藤 達也, 川口 淳一郎, 津田 雄一, 澤田 弘崇, 船瀬 龍, 山本 高行, 佐伯 孝尚, 米倉 克英, 星野 宏和, 南野 浩之
    年次大会 2011 _J191063-1-_J191063-5 2011年  査読有り
    Japan Aerospace Exploration Agency (JAXA) successfully achieved the world's first solar power sail technology by IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun) mission in 2010. It demonstrated a photon propulsion and thin film solar power generation during its interplanetary cruise. The 200m2-span sail was deployed and kept extended by centrifugal force of the spacecraft rotation. IKAROS also succeeded in accelerating and controlling the orbit by actively exploiting solar radiation pressure, and thus became the world's first actual solar sailer flying an interplanetary voyage. This paper presents the design of IKAROS solar sail system, operation results and introduces a perspective of this new technology to apply to the next generation mission toward Jupiter and Trojan asteroids.
  • Yuichi Tsuda, Takanao Saiki, Yuya Mimasu, Ryu Funase
    SPACEFLIGHT MECHANICS 2011, PTS I-III 140 147-+ 2011年  査読有り
    This paper describes a method of modeling attitude dynamics of spinning solar sail spacecraft under influence of solar radiation pressure (SRP). This method is verified and actually exploited in the operation of Japanese interplanetary solar sail demonstration spacecraft IKAROS. MAROS shows a unique attitude behavior due to strong SRP effect. This paper shows a new attitude model of spinning sail, which is verified by flight data of MAROS. It is also shown that the model proposed in this paper has a direct relation with the Generalized Sail Model.
  • Mori Osamu, Tsuda Yuichi, Sawada Hirotaka, FUNASE Ryu, YAMAMOTO Takayuki, SAIKI Takanao, YONEKURA Katsuhide, HOSHINO Hirokazu, MINAMINO Hiroyuki, ENDO Tatsuya, KAWAGUCHI Junichiro
    電子情報通信学会技術研究報告. SANE, 宇宙・航行エレクトロニクス 110(250) 155-160 2010年10月20日  
    The Japan Aerospace Exploration Agency (JAXA) makes the world's first solar power sail craft IKAROS demonstration of photon propulsion and thin film solar power generation during its interplanetary cruise. The spacecraft deploys and spans a membrane of 20 meters in diameter using the spin centrifugal force. It also deploys thin film solar cells on the membrane, in order to evaluate its thermal control property and anti-radiation performance in the real operational field. The spacecraft weighs approximately 310kg, launched together with the agency's Venus Climate Orbiter, AKATSUKI on May 21, 2010. This paper presents the summary of development and operation of IKAROS.
  • 森 治, 白澤 洋次, 今泉 継男, 三桝 裕也, 元岡 範純, 佐藤 祥悟, 田中 啓太, 浦町 光, 善場 祐介, 北嶋 麻里絵, 羽染 円絵, 志田 真樹, 田中 孝治, 澤田 弘崇, 船瀬 龍, 遠藤 達也, 奥泉 信克, 矢野 創, 岡本 千里, 横田 力男, 津田 雄一, 佐伯 孝尚, 川口 淳一郎, ソーラーセイルWG
    宇宙航空研究開発機構研究開発報告 9 73-84 2010年3月  査読有り
    ソーラーセイルWG では,太陽の光子の圧力を受けて進む光子セイルに,薄膜太陽電池を貼り付けて大電力を発生し高比推力のイオンエンジンを駆動する推進システム,ソーラー電力セイルの検討を進めている.このシステムの確立において重要な技術課題である大型膜面の展開機能を検証するため,大気球を用いた大型膜面の展開総合実験を計画し,展開システムの開発を行った.あいにく実験場の天候不良により平成20 年度に続き,放球を実施できなかったが,本論文では,この実験の内容および位置付けについて紹介する.
  • 石橋史朗, 吉川真, 竹内央, 加藤隆二, 市川勉, 船瀬龍, 森本睦子
    アストロダイナミクスシンポジウム講演後刷り集(Web) 19th 2010年  
  • 津田雄一, 佐伯孝尚, 三桝裕也, 船瀬龍, 山口智宏, 中宮賢樹, 白澤洋次, 池田人
    宇宙科学技術連合講演会講演集(CD-ROM) 54th 2010年  
  • 三桝裕也, 山口智宏, 池田人, 中宮賢樹, 船瀬龍, 佐伯孝尚, 津田雄一, 川口淳一郎
    宇宙科学技術連合講演会講演集(CD-ROM) 54th 2010年  
  • 船瀬龍, 川口淳一郎, 森治, 津田雄一, 佐伯孝尚, 澤田弘崇
    宇宙科学技術連合講演会講演集(CD-ROM) 54th 2010年  
  • 森治, 津田雄一, 澤田弘崇, 船瀬龍, 山本高行, 佐伯孝尚, 米倉克英, 南野浩之, 星野宏和, 遠藤達也, 森本睦子, 川勝康弘, 川口淳一郎
    宇宙科学技術連合講演会講演集(CD-ROM) 54th 2010年  
  • 佐伯孝尚, 津田雄一, 船瀬龍, 三桝裕也, 白澤洋次
    宇宙科学技術連合講演会講演集(CD-ROM) 54th 2010年  
  • 船瀬龍, 三桝裕也, 白澤洋次, 津田雄一, 佐伯孝尚, 森治
    宇宙科学技術連合講演会講演集(CD-ROM) 54th 2010年  
  • 羽染円絵, 杉田昌行, 白澤洋次, 船瀬龍, 森治, 津田雄一, 川口淳一郎
    アストロダイナミクスシンポジウム講演後刷り集(Web) 19th 2010年  
  • 山口智宏, 三桝裕也, 津田雄一, 船瀬龍, 澤田弘崇, 森治, 森本睦子, 竹内央, 吉川真
    アストロダイナミクスシンポジウム講演後刷り集(Web) 19th 2010年  
  • 三桝裕也, 船瀬龍, 津田雄一, 森治, 川口淳一郎
    アストロダイナミクスシンポジウム講演後刷り集(Web) 19th 2010年  
  • 照井冬人, 津田雄一, 尾川順子, 森治, 船瀬龍, 池田聖悟
    アストロダイナミクスシンポジウム講演後刷り集(Web) 19th 2010年  
  • Tomohiro Yamaguchi, Yuya Mimasu, Yuichi Tsuda, Hiroshi Takeuchi, Ryu Funase, Osamu Mori, Makoto Yoshikawa
    Advances in the Astronautical Sciences 136 2097-2112 2010年  査読有り
    This paper investigates the solar sail modeling and its estimation approach of solar power sail spacecraft IKAROS. Estimation of solar sail force model in space is the key factor for successful solar sail navigation because the solar sail have large uncertainty due to the flexible membrane. Since the sail wrinkles after the deployment and its surface will suffer from degradation, the solar sail force model is difficult to develop before the launch. In this paper, a practical analysis of estimating the solar sail force model from radiometric tracking data is investigated. This is demonstrated by orbit determination including parameter estimation of generalized sail model.
  • Ryu Funase, Osamu Mori, Yuichi Tsuda, Yoji Shirasawa, Takanao Saiki, Yuya Mimasu, Junichiro Kawaguchi
    61st International Astronautical Congress 2010, IAC 2010 6 4720-4725 2010年  査読有り
    This paper introduces new attitude control system for solar sail which leverages solar radiation pressure and achieves completely fuel-free and oscillation-free attitude control of flexible spinning solar sail. Novel attitude control device was developed, which is a thin film-type device and can electrically control its optical parameters such as reflectivity to generate unbalance of the solar radiation pressure applied to the edge of the sail. By using this device, minute and continuous control torque can be applied to the sail so that very stable and fuel-free attitude control of large and flexible membrane is realized. The control system was implemented as an optional attitude control system for small solar power sail demonstrator IKAROS. On-orbit attitude control experiments were conducted and the performance of the controller was successfully verified compared with the ground-based analytical performance estimation. Copyright ©2010 by the International Astronautical Federation. All rights reserved.
  • 宮坂 昭, 木村 真一, 澤田 弘崇, 船瀬 龍, 坂本 信臣, 稲川 慎一, 松永 三郎
    スペース・エンジニアリング・コンファレンス講演論文集 2009 23-27 2010年  査読有り
    宇宙システムにおいて画像のもつ可能性は非常に大きく,画像はミッションを遂行する上で必要不可欠な情報である.しかし従来搭載されてきたカメラシステムは,視点が固定されている場合が大半であり,監視対象が巨大な場合には,全体を観測することが非常に困難であるという問題があった.そこで今回我々は,大型の展開構造物を監視する用途向けに,固定カメラヘッダ4台と非回収発射型の分離プローブカメラ1台から構成される,プローブ分離型搭載カメラシステムを開発した.本稿では,このプローブ分離型カメラの電気システム構成について詳しく議論する.
  • 岡野 仁庸, 佐原 宏典, 船瀬 龍, 川口 淳一郎
    スペース・エンジニアリング・コンファレンス講演論文集 2009 45-49 2010年  査読有り
    As many varieties of microsatellite missions have been purposed, microsatellite's performances are becoming higher level. It is important to develop higher level 3-axis attitude control mechanics. We purpose an innovative 3-axis attitude control for microsatellite by using Reflectivity Control Device, RCD which is capable of changing its reflectance by imposed voltage. This paper shows one example of 3-axis attitude control using RCD, and advantages of this method by being compared to non RCD methods which used only reaction wheel.
  • Ryu Funase, Masayuki Sugita, Osamu Mori, Yuichi Tsuda, Junichiro Kawaguchi
    PROCEEDINGS OF ASME INTERNATIONAL DESIGN ENGINEERING TECHNICAL CONFERENCES AND COMPUTERS AND INFORMATION IN ENGINEERING CONFERENCE, VOL 4, PTS A-C 983-994 2010年  査読有り
    In this paper, the attitude motion and attitude control strategy of spinning solar sail are discussed. As the spinning type solar sail does not have any rigid structure to support its membrane, the impulsive torque by the RCS can introduce oscillatory motion of the membrane. Thus, an "oscillation free" attitude controller is needed, which takes into account the flexibility of the membrane and avoid unnecessary oscillatory motion. First, the dynamics model and numerical model were introduced, and the validity of these models and dominant out-of-plane membrane vibration mode is examined by membrane vibration experiment and comparison between both models. Then, based on the analysis of the dynamics of torque-free motion, it was shown that a spinning solar sail has three oscillation modes of nutation, one of which is equal to the spinning rate of the spacecraft. The dominancy of each nutation mode was analytically and numerically discussed. Then, we discussed the spin axis maneuver control using conventional RCS. It was analytically shown that continual impulsive torque synchronizing the spin rate can excite nutation velocity and that a controller is needed to damp the nutation while controlling the spin axis at the same time. The authors proposed new controller named Flex-RLC and improved one. Their effectiveness was verified by numerical simulations using precise multi-particle numerical model which can express higher order oscillatory motion of the flexible membrane, and it was found that the proposed method can control the attitude of spinning solar sail while drastically reduces the nutation velocity compared with conventional control logic. So, it can 983 be said that the proposed method is promising fast and stable controller for spinning solar sail.
  • Shinichi Kimura, Masato Terakura, Akira Miyasaka, Nobuomi Sakamoto, Naoki Miyashita, Ryu Funase, Hirotaka Sawada
    APPLICATIONS OF SPACE TECHNOLOGY FOR HUMANITY 138 407-414 2010年  査読有り
    It is becoming imperative to have visual capabilities for space activities. We have developed a very small, high-performance image processing unit that is based on COTS technologies. It has a 500 MIPS calculation capability in a single, 50 mm x 50 mm printed circuit board, and it incorporates various types of interfaces using field-programmable gate array (FPGA) technology. The camera is called the high-performance image acquisition and processing unit (HPIMAP). The HP-IMAP technologies are being utilized in the IKAROS (Interplanetary Kite-craft Accelerated by Radiation of the Sun) that was launched May 21, 2010. In this article, we describe the HPIMAP and technical demonstration in IKAROS mission.

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