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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.
もっとみる

MISC

 279
  • Naoya Ozaki, Ryu Funase, Stefano Campagnola, Chit Hong Yam
    SPACEFLIGHT MECHANICS 2016, PTS I-IV 158 239-258 2016年  査読有り
    This paper proposes a robust-optimal trajectory design method for uncertain system to minimize the expected value of cost-to-go function in Dynamic Programming. The fundamental idea is introducing Stochastic Differential Dynamic Programming (SDDP), which solves stochastic-optimal control problem by the second-order expansion of Bellman's equation around reference trajectory. Most recent studies have focused on trajectory optimization assuming that the spacecraft can control the trajectory perfectly as planed; however, the assumption is violated in realistic operations where uncertain events, such as navigation error or uncertainty on dynamical system, perturb the predetermined trajectory. Conventionally, experienced specialists empirically determine "margin" on optimal low-thrust trajectory by duty cycle or forced coast period. A proposed SDDP autonomously provides "margin" in optimization for future feedback as well. Numerical results by V-infinity leveraging problem show that SDDP has "margin" without duty cycle or coast period. Monte-Carlo simulation shows the SDDP solution has better performance than DDP considering uncertainty.
  • 船瀬 龍, 川勝 康弘, PROCYONプロジェクトチーム
    宇宙科学技術連合講演会講演集 59 6p 2015年10月7日  査読有り
  • 中島 晋太郎, 中須賀 真一, 船瀬 龍
    宇宙科学技術連合講演会講演集 59 6p 2015年10月7日  査読有り
  • 船瀬 龍, 稲守 孝哉, 尾崎 直哉
    宇宙科学技術連合講演会講演集 59 5p 2015年10月7日  査読有り
  • 五十里 哲, 海老沼 拓史, 船瀬 龍
    宇宙科学技術連合講演会講演集 59 6p 2015年10月7日  査読有り
  • 船瀬 龍
    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 115(67) 45-50 2015年5月29日  査読有り
  • 小林雄太, 冨木淳史, 伊藤大智, 船瀬龍, 川勝康弘
    宇宙科学技術連合講演会講演集(CD-ROM) 59th 2015年  
  • 尾崎直哉, 川端洋輔, 小倉聡司, 杉本理英, CAMPAGNOLA Stefano, YAM Chit Hong, SARLI Bruno, CHEN Hongru, 蟻生開人, 船瀬龍, 川勝康弘
    宇宙科学技術連合講演会講演集(CD-ROM) 59th 2015年  
  • 川端洋輔, YAM Chit Hong, 尾崎直哉, 小倉聡司, 杉本理英, CAMPAGNOLA Stefano, SARLI Bruno, CHEN Hongru, 蟻生開人, 船瀬龍, 川勝康弘
    宇宙科学技術連合講演会講演集(CD-ROM) 59th 2015年  
  • 竹内央, 冨木淳史, 小林雄太, 中島晋太郎, 船瀬龍
    宇宙科学技術連合講演会講演集(CD-ROM) 59th 2015年  
  • 五十里哲, 中谷俊洋, 稲守孝哉, 伊藤琢博, 坂井真一郎, 川勝康弘, 船瀬龍
    計測自動制御学会制御部門マルチシンポジウム(CD-ROM) 2nd 2015年  
  • 伊藤琢博, 五十里哲, 小栗健士朗, 藤本將孝, 蟻生開人, 川端洋輔, 稲守孝哉, 坂井真一郎, 川勝康弘, 船瀬龍
    宇宙科学技術連合講演会講演集(CD-ROM) 59th 2015年  
  • 藤本將孝, 五十里哲, 蟻生開人, 小栗健士朗, 稲守孝哉, 伊藤琢博, 坂井真一郎, 川勝康弘, 船瀬龍
    宇宙科学技術連合講演会講演集(CD-ROM) 59th 2015年  
  • 小林大輔, 三田信, 梯友哉, 伊藤大智, 廣瀬和之, 冨木淳史, 川勝康弘, 船瀬龍, 久米恭, 長谷川崇, 長谷川崇
    若狭湾エネルギー研究センター研究年報 17 2015年  
  • 伊藤大智, 小林大輔, 三田信, 廣瀬和之, 冨木淳史, 川勝康弘, 船瀬龍, 久米恭
    宇宙科学技術連合講演会講演集(CD-ROM) 59th 2015年  
  • 米倉 克英, 星野 宏和, 船瀬 龍, 佐伯 孝尚, 澤田 弘崇, 津田 雄一, 南野 浩之, 森 治
    日本航空宇宙学会誌 63(2) 47-50 2015年  査読有り
    ソーラー電力セイル実証機「IKAROS」の運用は,IKAROSと地上局との距離が近い場合や通信環境に余裕がある場合には,地球周回の探査機と同様な運用が可能であるが,距離が遠くなった場合や通信環境に余裕がない場合には,深宇宙航行する探査機特有の運用を行う.本稿では,この運用(IKAROSの地上局,テレメトリ/コマンド運用,ビーコン運用,後期段階運用,探索運用)について概説する.
  • 森 治, 寺元 祐貴, 矢野 創, 中村 良介, 松浦 周二, 川口 淳一郎, 佐伯 孝尚, 白澤 洋次, 加藤 秀樹, 船瀬 龍, 大野 剛, 松本 純, 中条 俊大, 菊地 翔太
    日本航空宇宙学会誌 63(4) 117-122 2015年  査読有り
    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,太陽から遠く離れた場所でも,大面積の薄膜太陽電池を利用して探査機に十分な電力を確保できる.ソーラー電力セイルで得た電力を用いて,高性能なイオンエンジンを駆動すれば,ソーラーセイルと合わせたハイブリッドな推進が可能となる.JAXA ではこのコンセプトを踏まえ,ソーラー電力セイルによる外惑星領域探査計画を提案している.本計画では,日本独自の外惑星領域探査技術を確立し,日本が太陽系探査を先導すること,および,新しい科学分野であるスペース天文学等を切り拓くことを目指している.本稿では,本計画について紹介し,初期検討結果を示す.
  • 澤田 弘崇, 森 治, 白澤 洋次, 津田 雄一, 船瀬 龍, 佐伯 孝尚, 米倉 克英, 川口 淳一郎, 相馬 央令子
    日本航空宇宙学会誌 63(11) 355-359 2015年  査読有り
    IKAROSとは宇宙航空研究開発機構(JAXA)が開発した小型ソーラー電力セイル実証機であり,2010年5月21日に種子島宇宙センターよりH-IIAロケット17号機によって打ち上げられた.IKAROSは将来の外惑星領域探査ミッションを想定してソーラーセイルおよびソーラー電力セイルを世界で初めて実証した.2011年以降も運用を継続し,数多くの成果をあげている.IKAROSは小規模プロジェクトのため,広報活動に関して,予算をほとんど割くことができない状況であったが,チームメンバーが創意工夫を凝らし,精力的に活動を行った.特にツィッターやブログを通して開発・運用の現場の様子をタイムリーに発信したことで多くのファンを獲得できた.また,TPSにも発信してもらったことでIKAROSの成果が世界中に知れ渡ることとなった.さらに,はやぶさ地球帰還との相乗効果もあり,日本の探査技術が大きく取り上げられる機会となった.本稿では,我々が取り組んできたIKAROSの広報・アウトリーチ活動全般について報告する.
  • 土田 和幸, 鳴海 智博, 木村 真一, 五十里 哲, 中島 晋太郎, 船瀬 龍
    スペース・エンジニアリング・コンファレンス講演論文集 2015 _B04-1_-_B04-6_ 2015年  査読有り
    短期間かつ高信頼度での開発が求められる超小型衛星では,ハードウェア,およびソフトウェアにおいて実績品を再利用することが有効である.しかし,衛星によって構造やミッションが異なることから,ソフトウェアは各機関が毎回個別に開発することが多い.そこで本研究では,姿勢制御系ソフトウェアのモジュールを衛星の構造に応じて自動生成するシステムの構築を行った.これにより,多様な超小型衛星において再利用性の高い姿勢制御系ソフトウェアを実現する.
  • Hiroki Hihara, Yousuke Takano, Junpei Sano, Kaori Iwase, Satoko Kawakami, Hisashi Otake, Tatsuaki Okada, Ryu Funase, Jun Takada, Tetsuya Masuda
    INFRARED REMOTE SENSING AND INSTRUMENTATION XXIII 9608 2015年  査読有り
    Infrared sensor system is a major concern for inter-planetary missions in order to investigate the nature and the formation processes of planets and asteroids. Since it takes long time for the communication of inter-planetary probes, automatic and autonomous functions are essential for provisioning observation sequence including the setup procedures of peripheral equipment. Robotics technology which has been adopted on HAYABUSA2 asteroid probe provides functions for setting up onboard equipment, sensor signal calibration, and post signal processing. HAYABUSA2 was launched successfully in 2014 for the exploration of C class near-Earth asteroid 162173 (1999JU3). An optical navigation camera with telephoto lens (ONC-T), a thermal-infrared imager (TIR), and a near infrared spectrometer (NIRS3) have been developed for the observation of geology, thermo-physical properties, and organic or hydrated materials on the asteroid. ONC-T and TIR are used for those scientific purposes as well as assessment of landing site selection and safe descent operation onto the asteroid surface for sample acquisition. NIRS3 is used to characterize the mineralogy of the asteroid surface by observing the 3-micron band, where the particular diagnostic absorption features due to hydrated minerals appear.Modifications were required in order to apply robotics technology for the probe due to the difference of operation on satellites from robot operation environment. The major difference is time line consideration, because the standardized robotics operation software development system is based on event driven framework. The consistency between the framework of time line and event driven scheme was established for the automatic and autonomous operation for HAYABUSA2.
  • Yoshihide Sugimoto, Stefano Campagnola, Chit Hong Yam, Bruno Sarli, Hongru Chen, Naoya Ozaki, Yasuhiro Kawakatsu, Ryu Funase
    SPACEFLIGHT MECHANICS 2015, PTS I-III 155 903-915 2015年  査読有り
    PROCYON (PRoximate Object Close flyby with Optical Navigation) is a 50kg-class micro-spacecraft developed by the University of Tokyo and the Japan Aerospace Exploration Agency (JAXA), to be launched in an Earth resonant trajectory at the end of 2014 as a secondary payload with Hayabusa 2 mission. The mission objective is to demonstrate low cost and applicability of a micro-spacecraft bus technology for deep space exploration and proximity flyby to asteroids performing optical navigation. This paper introduces the spacecraft and mission design for PROCYON, as well as, the operation strategy mainly for the deep-space cruising period
  • 中島 晋太郎, 船瀬 龍
    宇宙科学技術連合講演会講演集 58 1-6 2014年11月12日  査読有り
  • 尾崎 直哉, 船瀬 龍
    宇宙科学技術連合講演会講演集 58 6p 2014年11月12日  査読有り
  • 船瀬 龍, 川勝 康弘, PROCYONプロジェクトチーム
    宇宙科学技術連合講演会講演集 58 5p 2014年11月12日  査読有り
  • 五十里 哲, 海老沼 拓史, 船瀬 龍
    宇宙科学技術連合講演会講演集 58 6p 2014年11月12日  査読有り
  • 船瀬 龍, 滝澤 潤一, Ryu Funase, Jun'ichi Takisawa
    人工知能 = journal of the Japanese Society for Artificial Intelligence 29(4) 344-349 2014年7月1日  査読有り
  • 冨木 淳史, 小林 雄太, 小島 要, 新家 隆広, 青木 勝, 土屋 慎二郎, 重田 修, 布村 仁志, 羽賀 俊行, 奥野 秀一, 石川 雅澄, 神田 泰明, 大森 義智, 船瀬 龍, 川勝 康弘, 福島 洋介, 川崎 繁男
    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 114(48) 1-6 2014年5月23日  査読有り
    PROCYONは,超小型衛星による小惑星フライバイ探査ミッションを目的として,はやぶさ2のピギーバック搭載機会である2014年12月の打ち上げを目指している.超小型衛星による深宇宙探査ミッションは,大型衛星とは異なる信頼性基準,コストのバランスによって成立させる必要がある.特に搭載重量や発生電力の制約条件は大きく,従来の宇宙用通信コンポーネントの設計概念を大きく変えて積極的な民生部品の活用と小型軽量化に最適な技術の導入が不可欠である.本稿では,PROCYON通信系構成,並びに,各コンポーネントの詳細を紹介する.
  • 佐藤允基, 亀田真吾, 桑原正輝, 池澤祥太, 田口真, 吉川一朗, 船瀬龍, 川勝康弘
    地球電磁気・地球惑星圏学会総会及び講演会予稿集(CD-ROM) 136th 2014年  
  • 土田和幸, 鳴海智博, 木村真一, 五十里哲, 中谷俊洋, 滝澤潤一, 船瀬龍, 伊藤琢博
    宇宙科学技術連合講演会講演集(CD-ROM) 58th 2014年  
  • 曽根理嗣, 曽根理嗣, 田中康平, 遊馬貴之, 川添悠子, 飯島広行, 阿尾生地郎, 福田盛介, 福田盛介, 川勝康弘, 川勝康弘, 船瀬龍
    宇宙科学技術連合講演会講演集(CD-ROM) 58th 2014年  
  • 小林雄太, 冨木淳史, 川崎繁男, 小島要, 新家隆広, 青木勝, 土屋慎二郎, 羽賀俊行, 奥野秀一, 石川雅澄, 神田泰明, 大森義智, 北島邦美, 野々村拓, 三田信, 伊藤大智, 小林大輔, 福島洋介, 船瀬龍, 川勝康弘
    宇宙科学技術連合講演会講演集(CD-ROM) 58th 2014年  
  • 冨木淳史, 小林雄太, 川崎繁男, 小島要, 新家隆広, 青木勝, 土屋慎二郎, 羽賀俊行, 奥野秀一, 石川雅澄, 神田泰明, 大森義智, 北島邦美, 野々村拓, 三田信, 伊藤大智, 小林大輔, 福島洋介, 船瀬龍, 川勝康弘
    宇宙科学技術連合講演会講演集(CD-ROM) 58th 2014年  
  • 森 治, 白澤 洋次, 三桝 裕也, 津田 雄一, 佐伯 孝尚, 尾川 順子, 加藤 秀樹, 川口 淳一郎, 船瀬 龍, ソーラーセイル WG
    第 14 回宇宙科学シンポジウム講演集録 S2-010 2014年1月  
  • Satoshi Ikari, Takuji Ebinuma, Ryu Funase, Shinichi Nakasuka
    PROCEEDINGS OF THE 27TH INTERNATIONAL TECHNICAL MEETING OF THE SATELLITE DIVISION OF THE INSTITUTE OF NAVIGATION (ION GNSS 2014) 2440-2447 2014年  査読有り
    In order to achieve high precision GNSS (Global Navigation Satellite Systems) positioning, accurate modeling of the disturbance forces acting on GNSS satellites, including Japanese QZS-1 (Quasi-Zenith Satellite-1), is essential to minimize the contribution of the satellite orbit and clock errors. This study focuses on the development of analytical non-conservative force models for QZS-1 precise orbit determination, especially solar radiation pressure (SRP) and thermal re-radiation pressure (TRP) forces. In order to evaluate the performance of the proposed analytical model, the acceleration profile obtained by the traditional empirical SRP model was used as a reference. Results showed that TRP was major error sources and should be modeled separately from SRP. A ray tracing study also showed that the shadow effect of the large L-band antenna cover of the QZS-1 was not negligible and should be treated properly in the SRP calculation.
  • Hisashi Otake, Tatsuaki Okada, Ryu Funase, Hiroki Hihara, Junpei Sano, Kaori Iwase, Satoko Kawakami, Jun Takada, Tetsuya Masuda
    INFRARED REMOTE SENSING AND INSTRUMENTATION XXII 9219 2014年  査読有り
    Onboard signal processing system for infrared sensors has been developed for HAYABUSA2 for the exploration of C class near-Earth asteroid 162173 (1999JU3), which is planned to be launched in 2014. An optical navigation camera with telephoto lens (ONC-T), a thermal-infrared imager (TIR), and a near infrared spectrometer (NIRS3) have been developed for the observation of geology, thermo-physical properties, and organic or hydrated materials on the asteroid. ONC-T and TIR are used for those scientific purposes as well as assessment of landing site selection and safe descent operation onto the asteroid surface for sample acquisition. NIRS3 is used to characterize the mineralogy of the asteroid surface by observing the 3-micron band, where the particular diagnostic absorption features due to hydrated minerals appear.Since the processing cycle of these sensors are independent, data processing, formatting and recording are processed in parallel. In order to provide the functions within the resource limitation of deep space mission, automatic packet routing function is realized in one chip router with SpaceWire standard. Thanks to the SpaceWire upper layer protocol (remote memory access protocol: RMAP), the variable length file system operation function can be delegated to the data recorder from the CPU module of the digital electronics of the sensor system. In consequence the infrared spectrometer data from NIRS3 is recorded in parallel with the infrared image sensors. High speed image compression algorithm is also developed for both lossless and lossy image compression in order to eliminate additional hardware resource while maintaining the JPEG2000 equivalent image quality.
  • 船瀬 龍, 川勝 康弘, 冨木 淳史
    宇宙科学技術連合講演会講演集 57 5p 2013年10月9日  査読有り
  • 稲垣 匡志, 小泉 宏之, 船瀬 龍
    宇宙科学技術連合講演会講演集 57 6p 2013年10月9日  査読有り
  • 管野 剛, 船瀬 龍
    宇宙科学技術連合講演会講演集 57 6p 2013年10月9日  査読有り
  • 尾崎 直哉, 船瀬 龍, 中島 晋太郎
    宇宙科学技術連合講演会講演集 57 5p 2013年10月9日  査読有り
  • 松本純, 森治, 白澤洋次, 船瀬龍, 大野剛, 林直宏, 濱崎拓, 中条俊大
    宇宙科学技術連合講演会講演集(CD-ROM) 57th 2013年  
  • MIMASU Yuya, TANIGUCHI Sho, TAKEUCHI Hiroshi, SHIRASAWA Yoji, YONEKURA Katsuhide, MORI Osamu, FUNASE Ryu, SAIKI Takanao, TSUDA Yuichi
    誘導制御シンポジウム資料 30th 2013年  
  • 森治, 白澤洋次, 三桝裕也, 米倉克英, 津田雄一, 佐伯孝尚, 星野宏和, 澤田弘崇, 山本高行, 川口淳一郎, 船瀬龍
    宇宙科学技術連合講演会講演集(CD-ROM) 57th 2013年  
  • 森治, 船瀬龍, 津田雄一, 澤田弘崇, 山本高行, 佐伯孝尚, 米倉克英, 星野宏和, 白澤洋次, 三桝裕也, 川口淳一郎
    航空原動機・宇宙推進講演会講演論文集(CD-ROM) 53rd 2013年  
  • 森治, 佐伯孝尚, 白澤洋次, 津田雄一, 松浦周二, 矢野創, 船瀬龍, 中村良介, 米徳大輔
    日本航空宇宙学会年会講演会講演集(CD-ROM) 44th 2013年  
  • 船瀬龍, 森治, 白澤洋次, 津田雄一, 矢野創
    航空原動機・宇宙推進講演会講演論文集(CD-ROM) 53rd 2013年  
  • S. Yoshida, Y. Kobayashi, G. Fukuda, R. Funase, O. Mori, M. Hasegawa, T. Suda, S. Kawasaki
    IEEE Antennas and Propagation Society, AP-S International Symposium (Digest) 1278-1279 2013年  査読有り
    This paper describes a basic characteristic of a 7/8-GHz band circular stacked patch active integrated array antenna (AIAA) unit for solar sail embedding application. The proposed AIAA unit mainly consists of a 2×2 stacked circular patch array, two low noise amplifiers (LNAs) and two power amplifiers (PAs). The array has stacked structure for dual band operation. Moreover, the stacked patch array has orthogonal feed structure for better isolation characteristics between transmitter and receiver ports. Radiation patterns and S-parameters are evaluated by 3-D electromagnetic field simulation and measurement. © 2013 IEEE.
  • Hiraku Sakamoto, Hiroshi Furuya, Yasutaka Satou, M. C. Natori, Akihito Watanabe, Nobuyoshi Kawabata, Ryoji Sakai, Nobukatsu Okuizumi, Osamu Mori, Yoji Shirasawa, Moto Takai, Nobuhisa Katsumata, Ayako Torisaska, Ryu Funase
    Proceedings of the International Astronautical Congress, IAC 6 4165-4172 2013年  査読有り
    The present study proposes ... Features (i) stiffer for ground testing, (ii) Synchronous boom-membrane deployment, (iii) Resist launch vibration, (iv) Repeatable and simpler folding pattern, ... to be written!. Copyright© (2013) by the International Astronautical Federation.
  • Yuya Mimasu, Sho Taniguchi, Hiroshi Takeuchi, Yoji Shirasawa, Katsuhide Yonekura, Osamu Mori, Ryu Funase, Takanao Saiki, Yuichi Tsuda
    Advances in the Astronautical Sciences 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. © 2013 2013 California Institute of Technology.
  • 津田 雄一, 白澤 洋次, 佐伯 孝尚, 三桝 裕也, 船瀬 龍, 河内 宏道, 卯尾 匡史, 谷口 正, 石橋 史朗
    日本航空宇宙学会誌 61(4) 136-142 2013年  査読有り
    IKAROSはJAXAが開発し,世界初の深宇宙ソーラーセイル航行を成し遂げたソーラー電力セイル実証機である.IKAROSの姿勢制御の観点での特徴は,機体全体がスピンすることによるスピン剛性でセイルの形状の維持とスピン安定を同時に得ることである.14m四方,代表厚み7.5μmという大面積柔軟構造物を有する機体を安定化し,かつ十分な制御性を有する姿勢制御を実現するために種々の工夫が施された.他方で,IKAROSは開発コスト制約を非常に厳しく課されたプロジェクトであり,姿勢制御系の簡素化と開発負荷の軽減が課題であった.結果として気液平衡推進系,太陽センサのみによる姿勢決定系など,独特の姿勢制御系構成となった.また,運用面では,迅速な運用実績の反映により,太陽光圧擾乱を逆用した省燃料の姿勢制御手法を実現した.本稿では,これらの点を中心にIKAROSの姿勢制御システムについて概説する.
  • 船瀬 龍
    日本機械学会誌 116(1134) 331-334 2013年  査読有り

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