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Astrodynamics 2024年第1期8卷 47-60页

作者： Yuki Kubo Toshihiro Chujo Institute of Space and Astronautical Science Japan Aerospace Exploration AgencyKanagawa252-5210Japan Department of Mechanical Engineering Tokyo Institute of TechnologyTokyo152-8550Japan

The solar sail is one of the most promising space exploration systems due to its theoretically infinite specific impulse achieved through solar radiation pressure(SRP).Recently,researchers have proposed“transformable spacecraft”capable of actively reconfiguring their body configurations using actuatable *** spacecraft,if used similarly to solar sails,are expected to significantly enhance orbit and attitude control capabilities owing to their high redundancy in control degrees of ***,controlling them becomes challenging due to their large number of inputs,leading previous researchers to impose strong constraints to limit their potential control *** study focuses on novel attitude control techniques for transformable spacecraft under *** developed two methods,namely,joint angle optimization to obtain arbitrary SRP force and torque,and momentum damping control driven by joint angle *** proposed methods are formulated in a general manner and can be applied to any transformable spacecraft comprising front faces that can predominantly receive the SRP on each *** validity of our proposed method is confirmed through numerical *** study contributes to making most of the high control redundancy of transformable spacecraft without the need for expendable propellants,thus significantly enhancing the orbit and attitude control capabilities.

关键词： solar sail transformable spacecraft attitude-joint coupled motion attitudestabilization

Flow separation control by using bowed blade in highly loaded turbine cascades

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Science China(Technological Sciences) 2009年第6期52卷 1471-1477页

作者： YAMAMOTO Atsumasa japan Aerospace exploration agency

Due to the serious flow separations and centralized vortices,there are high secondary losses in highly loaded *** is imperative to find measures to control the flow separation and vortices hence improve the turbine *** paper reports our recent progress on flow separation and vor-tices control in highly loaded turbine cascades by using bowed *** sets of highly loaded tur-bine cascades with the turning angles of 113° and 160°,and each with 7 bowed blade angles 0°(straight),±10°,±20° and ±30° were experimentally *** internal flow field measurement and flow visualization on the blade surfaces were conducted,and the effects of blade bowing on the flow topology,distribution of vorticity and the flow energy loss were *** results show that,for the cascade with the turning angle of 113°,the appropriately positive bow angle could reduce the flow energy loss;whereas for the cascade with the turning angle of 160°,the well selected negative bow angle can give the better aerodynamic performance.

关键词： turbine cascade turning angle flow separation bowed blade

Simultaneous intermetallics suppression and residual-stress relaxation of heat-resistant Nb-interlayer-inserted Ti-6Al-4V/Si_(3)N_(4)joints via one-step transient liquid phase bonding and brazing

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Journal of Materials Science & Technology 2023年第8期139卷 79-91页

作者： Fei Shen Ong Hirobumi Tobe Eiichi Sato Institute of Space and Astronautical Science Japan Aerospace Exploration Agency3-1-1 YoshinodaiChuoSagamihara 252-5210Japan Department of Materials Engineering Graduate School of EngineeringThe University of Tokyo7-3-1 HongoBunkyoTokyo 113-8656Japan

This work has successfully proposed a solution to produce robust Nb-interlayer-inserted Ti-6Al-4V/Si_(3)N_(4)joints optimized for a maximum operating temperature of 873 K;transient liquid phase bonding(TLPB)of Ti-6Al-4V/Nb side was carried out with Cu and Ni fillers to suppress brittle intermetallic compounds(IMCs),whereas brazing of Nb/Si_(3)N_(4)side was performed using a highly ductile Ti-added Ag-rich filler for effective residual-stress relaxation.A sound yet simple one-step bonding process incorporating simul-taneous TLPB and brazing was achieved with a relatively short holding time of 10 min at 1213 *** of Ti-6Al-4V/Nb side with Cu and Ni foils of 2-μm-thick each as a laminated filler suppressed brittle Ti-based IMCs and developed a homogenized microstructure consisting mainly of(α+β)-Ti via isothermal ***,brazing of Nb/Si_(3)N_(4)side with 100-μm-thick SILVER-ABA filler(92.75Ag-5Cu-1Al-1.25Ti mass%)foil enhanced interfacial bonding with sufficient total Ti content and accommodated residual stress better than conventional eutectic Ag-Cu-based fillers,and it was verified by finite element analysis with consideration of materials’temperature-dependent elasto-plastic *** joints with a bonding area of 10 mm×10 mm were tested via symmetrical four-point bending from room temper-ature(RT)to 873 K fractured from Nb/Si_(3)N_(4)*** re-heating the joints from RT to 673 K,frac-ture initiation gradually shifted from Si_(3)N_(4)towards interfacial-compounds/Si_(3)N_(4)interface and bending strengths maintained∼220 MPa as weakening of SILVER-ABA filler was compensated by residual-stress relaxation in Si_(3)N_(4).When tested at 873 K,joints fractured mainly across the Ag-rich solid solution in a ductile manner and bending strength degraded by∼20%to 171 MPa as weakening of SILVER-ABA filler dominated.

关键词： Transient liquid phase bonding Brazing Ceramics Residual stress Finite element analysis

Orbit insertion strategy of Hayabusa2’s rover with large release uncertainty around the asteroid Ryugu

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Astrodynamics 2020年第4期4卷 309-329页

作者： Yusuke Oki Kent Yoshikawa Hiroshi Takeuchi Shota Kikuchi Hitosi Ikeda Daniel JScheeres Jay WMcMahon Junichiro Kawaguchi Yuto Takei Yuya Mimasu Naoko Ogawa Go Ono Fuyuto Terui Manabu Yamada Toru Kouyama Shingo K ameda Kazuya Yoshida Kenji Nagaoka Tetsuo Yoshimitsu Takanao Saiki Yuichi Tsuda japan a erospace exploration agency T'sukuba 305-8505Japan japan Aerospace exploration agency Sagamihara 252-5210Japan University of Colorado BoulderCO 80309USA Planetary exploration Research Center Chiba Institute of TechnologyNarashino 275-0016Japan National Institute of Aduanced Industrial Science and Technology Koto-ku 135-0064Japan Rikkyo University Toshima-ku 171-8501Japan Department of A erospace Engineering Tohoku UniversitySendai 980-8579Japan Kyushu Institute of Technology Kitakyusyu 804-8550Japan

This paper describes the orbit design of the deployable payload Rover 2 of MINERVA-II,installed on the Hayabusa2 *** Rover 2 did not have surface exploration capabilities,the operation team decided to experiment with a new strategy for its deployment to the *** rover was ejected at a high altitude and made a semi-hard landing on the surface of the asteroid Ryugu after several *** on the orbital analysis around Ryugu,the expected collision speed was tolerable for the rover to function *** the rover could not control its position,its motion was entirely governed by the initial ***,the largest challenge was to insert the rover into a stable orbit(despite its large release uncertainty),and avoid its escape from Ryugu due to an environment strongly perturbed by solar radiation pressure and gravitational *** study investigates the solution space of the orbit around Ryugu and evaluates the orbit’s robustness by utilizing Monte Carlo simulations to determine the orbit insertion *** analyzing the flight data of the rover operation,we verified that the rover orbited Ryugu for more than one period and established the possibility of a novel method for estimating the gravity of an asteroid.

关键词： solar radiation pressure augmented elliptic Hill three-body problem gravitational irregularity

Guidance, navigation, and control of Hayabusa2 touchdown operations

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Astrodynamics 2020年第4期4卷 393-409页

作者： Fuyuto Terui Naoko Ogawa Go Ono Seiji Yasuda Tetsuya Masuda Kota Matsushima Takanao Saiki Yuichi Tsuda Institute of Space and A stronautical Science Japan A erospace Exploration AgencyKanagawa 252-5210Japan The 3nd Space Technology Department Space System DirisionNEC CorporationTokyo 183-8501Japan

Hayabusa2 is a japanese sample return mission from the asteroid *** Hayabusa2 spacecraft was launched on 3 December 2014 and arrived at Ryugu on 27 June *** stayed there until December 2019 for in situ observation and soil sample collection,and will return to the Earth in November or December *** the stay,the spacecraft performed the first touchdown operation on 22 February 2019 and the second touchdown on 11 July 2019,which were both completed *** the surface of Ryugu is rough and covered with boulders,it was not easy to find target areas for *** were several technical challenges to overcome,including demanding guidance,navigation,and control accuracy,to realize the touchdown *** this paper,strategies and technical details of the guidance,navigation,and control systems are *** flight results prove that the performance of the systems was satisfactory and largely contributed to the success of the operation.

关键词： small body exploration touchdown astrodynamics guidance navigation control

Classification of solar sail attitude dynamics with and without angular momentum

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Astrodynamics 2019年第3期3卷 207-216页

作者： Yuichi Tsuda Go Ono Yuya Mimasu Institute of Space and Astronautical Science Japan Aerospace Exploration AgencySagamihara252-5210Japan japan Aerospace exploration agency Sagamihara252-5210Japan

This paper describes attitude dynamics properties of spinning,momentum-biased and zero-momentum solar sail *** model called“Generalized Sail Dynamics Model”(GSDM)is introduced,which can deal with general and practical sail configurations,such as arbitrary optical property distribution,shape and surface *** stability criteria and other key dynamical characteristics are derived and compared by compact analytical equations induced from the *** newly derived zero-momentum sail dynamics is compared with that of spinning and momentum-biased *** is shown that the spinning and momentum sails have an advantage in terms of dynamical stability whereas zero-momentum sails are only statically *** this special property,angular momentum-stabilized sails can realize a sun-pointing stable attitude with almost zero-fuel,which are discussed with actual space flight experience of the JAXA’s two interplanetary missions,IKAROS and Hayabusa2.

关键词： solar sail attitude dynamics stability solar system exploration

Design and flight results of GNC systems in Hayabusa2 descent operations

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Astrodynamics 2020年第2期4卷 105-117页

作者： Go Ono Fuyuto Terui Naoko Ogawa Yuya Mimasu Kent Yoshikawa Yuto Takei Takanao Saiki Yuichi Tsuda japan Aerospace exploration agency Sagamihara252-5210Japan

Hayabusa2 is a japanese sample return mission from the near-Earth asteroid *** Hayabusa2 spacecraft was launched on December 3,2014,and reached the asteroid on June 27,*** remained there until November 13,2019 for in situ observation and soil sample collection and will return to the Earth in November or December *** its stay at the asteroid,Hayabusa2 performed descent operations 16 *** paper presents an overview of a guidance,navigation,and control method used in such descent *** method consists of on-board and on-ground guidance systems to control the spacecraft and an image-based navigation technique that uses a shape model and ground control points of the *** results in the first touchdown operation are shown as an example,which demonstrate that the method showed a good performance overall and contributed to the success of the mission.

关键词： small body exploration astrodynamics guidance navigation control

Improvement of sail storage and deployment mechanism for spin-type solar power sail

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Astrodynamics 2020年第3期4卷 223-231页

作者： Osamu Mori Nobukatsu Okuizumi Toshihiro Chujo Yuki Takao Institute of Space and A stronautical Science Japan A erospace Exploration AgencySagamihara 252-5210Japan Department of Mechanical Engineering Tokyo Institute of TechnologyTokyo152-8550Japan Department of Aeronautics and Astronautics the University of TokyoTokyo 113-8654Japan

Deployable membrane structures are expected to be used for large area space structures,such as solar propulsion sails,magnetoplasma sails,drag-deorbiting sails,membrane antennas,and solar power *** are lightweight and can be compactly stored at *** achievement of the japan Aerospace exploration agency(JAXA)was the successful deployment of a 200 m2 sail using centrifugal force in the IKAROS mission,which was the first solar propulsion sail-craft in *** has long been studying the technology of spin deployment of sail membranes,and is currently planning the spin deployment of a class sail larger than 2000 m2 as the next step in the development of the IK AROS *** paper discusses the unexpected behaviors during on-orbit sail deployment by IKAROS,as well as problems with the sail holding method,and proposes an improved sail storage structure and deployment mechanism for the OKEANOS mission.

关键词： solar sail solar power sail storage deployment IKAROS OKEANOS

Ground-based low altitude hovering technique of Hayabusa2

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Astrodynamics 2020年第4期4卷 331-347页

作者： Yuya Mimasu Kent Yoshikawa Go Ono Naoko Ogawa Fuyuto Terui Yuto Takei Takanao Saiki Yuichi Tsuda Institute of Space and Astronautical Science Japan Aerospace Exploration AgencySagamihara 252-5210Japan

The asteroid explorer Hayabusa2 carries multiple rovers and separates them to land on an asteroid *** of these rovers,called MASCOT,was developed under the international cooperation between the Deutsches Zentrum f¨ur Luft-und Raumfahrt and the Centre National d’Etudes *** rover was designed to be separated to land and perform several missions on an asteroid *** support these missions,the mother ship Hayabusa2 must separate this rover at a low altitude of approximately 50 m and hover at approximately 3 km after separation to achieve are liable communication link with *** the on-board guidance,navigation,and control(GNC)does not have an autonomous hovering function,this hovering operation is performed by ground-based *** paper introduces the GNC operation scheme for this hovering operation and reports on its flight results.

关键词： Hayabusa2 MASCOT low altitude hovering guidance,navigation,and control(GNC)

The deep-space multi-object orbit determination system and its application to Hayabusa2’s asteroid proximity operations

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Astrodynamics 2020年第4期4卷 377-392页

作者： Hiroshi Takeuchi Kent Yoshikawa Yuto Takei Yusuke Oki Shota Kikuchi Hitoshi Ikeda Stefania Soldini Naoko Ogawa Yuya Mimasu Go Ono Fuyuto Terui Naoya Sakatani Manabu Yamada Toru Kouyama Shingo Kameda Takanao Saiki Yuichi Tsuda Institute of Space and A stronautical Science Japan A erospace Exploration AgencySagamihara 252-5210Japan The Graduate University for Aduanced Studies Hayama 240-0193Japan Research and Development Directorate Japan Aerospace Exploration AgencySagamihara 252-5210Japan University of Liverpool Liverpool L693BXUK Chiba Institute of Technology Narashino 275-0016Japan National Institute of Aduanced Industrial Science and Technology Koto-ku 135-0064Japan Rikkyo University Toshima-ku 171-8501Japan

The deep-space multi-object orbit determination system(DMOODS)and its application in the asteroid proximity operation of the Hayabusa2 mission are *** was developed by the japan Aerospace exploration agency(JAXA)for the primary purpose of determining the trajectory of deep-space spacecraft for JAXA’s planetary *** weighted least-squares batch filter is used for the orbit estimator of *** orbit estimator supports more than 10 data types,some of which are used for relative trajectory measurements between multiple space objects including natural satellites and small *** system consists of a set of computer programs running on Linux-based consumer PCs on the ground,which are used for orbit determination and the generation of radiometric tracking data,such as delta differential one-way ranging and doppler tracking *** the asteroid proximity phase of Hayabusa2,this system played an essential role in operations that had very strict navigation requirements or operations in which few optical data were obtained owing to special constraints on the spacecraft attitude or distance from the *** example is orbit determination during the solar conjunction phase,in which the navigation accuracy is degraded by the effect of the solar *** large range bias caused by the solar corona was accurately estimated with DMOODS by combining light detection and ranging(LIDAR)and ranging measurements in the superior solar conjunction phase of *** the orbiting operations of target markers and the MINERVA-II2 rover,the simultaneous estimation of six trajectories of four artificial objects and a natural object was made by *** type of simultaneous orbit determination of multi-artificial objects in deep-space has never been accomplished before.

关键词： orbit determination optical navigation gravity measurements superior solar conjunction delta differential one-way ranging(delta-DOR)