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Rendezvous to asteroid with highly uncertain ephemeris: Hayabusa2’s Ryugu-approach operation result

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Astrodynamics 2020年第2期4卷 137-147页

作者： Yuichi Tsuda Hiroshi Takeuchi Naoko Ogawa Go Ono Shota Kikuchi Yusuke Oki Masateru Ishiguro Daisuke Kuroda Seitaro Urakawa Shin-ichiro Okumura Hayabusa2 Project Team Institute of Space and Astronautical Science Japan Aerospace Exploration AgencySagamihara252-5210Japan Research and Development Directorate Japan Aerospace Exploration AgencySagamihara252-5210Japan Research and Development Directorate Japan Aerospace Exploration AgencyTsukuba305-8505Japan Seoul National University Seoul08826Republic of Korea Okayama Observatory Kyoto UniversityAsakuchi719-0232Japan japan Spaceguard Association Bisei714-1411Japan 不详

This paper describes the guidance and navigation technique used by Hayabusa2 for the asteroid rendezvous operation to reach *** operation results,including the achieved guidance and navigation performance,are also *** assessment and navigation teams worked closely to provide reliable navigation solutions with a short solution delivery *** the uncertainty of the Ryugu’s ephemeris was considerable before Hayabusa2’s arrival,a combination of radiometric-optical hybrid navigation and a stochastic-constrained optimum guidance method was able to achieve an accuracy of less than 100 m and 1 cm/s,and the arrival was precisely timed.

关键词： solar system exploration sample return optical navigation trajectory optimization spacecraft guidance

Mechanism-free control method of solar/thermal radiation pressure for application to attitude control

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Astrodynamics 2020年第3期4卷 205-222页

作者： Toshihiro Chujo Motoki Watanabe Osamu Mori Tokyo Institute of Technology Tokyo152-8550Japan Aoyama Gakuin University Sagamihara252-5258Japan japan Aerospace exploration agency Sagamihara252-5210Japan

Solar radiation pressure(SRP)impinging on spacecraft is usually regarded as a disturbance for attitude motion,but it can be harnessed to solve the very problem it *** SRP control is possible with solar radiation powered thin-film devices such as reflectivity control devices or liquid crystal devices with reflective *** radiation pressure(TRP)can likewise be used to solve flight attitude problems caused by SRP,TRP,or other *** on solar cells can be controlled by switching regulators under the control of them,resulting in temperature *** SRP/TRP controls are free from mechanisms,such as reaction wheels,and thus they do not produce internal *** addition,the magnitude of SRP/TRP torques is generally much smaller than internal disturbance torques produced by reaction wheels,which creates a potential for precision far beyond that achieved with mechanical *** paper summarizes how SRP/TRP can be used by means of numerical simulations of typical control *** usefulness of this mechanism-free attitude control is verified for future use on both Earth orbiting satellites and interplanetary spacecraft including solar sails.

关键词： solar radiation pressure(SRP) thermal radiation pressure(TRP) attitude control solar sail

Self-excited oscillation of spinning solar sails utilizing solar radiation pressure

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Astrodynamics 2020年第3期4卷 177-192页

作者： Yuki Takao Osamu Mori Jun'ichiro Kawaguchi Department of Aeronautics and A stronautics The University of TokyoTokyo 113-8654Japan Institute of Space and Astronartical Science Japan Aerospace Exploration AgencySagamihara 252-5210Japan

The present paper proposes a control method to excite spinning solar sail membranes for three-dimensional *** optical property switching,the input is given as the change in magnitude of the solar radiation *** resonance point of this system varies with the vibration state due to its nonlinearity and the change in equilibrium *** deal with this,a state feedback control law that automatically tracks the resonance point is developed in the present *** proposed method enables decentralized control of the actuators on the sail,each of which determines the control input independently using only the information of vibration *** proposed method is validated using numerical *** results show that the nonlinear system behaves differently from the linear system,and the vibration grows using the decentralized control regardless of resonance point variation.

关键词： solar sail solar radiation pressure vibration mode self-excited oscillation mechanical resonance decentralized control

Land cover change detection based on satellite data for an arid area to the south of Aksu in Taklimakan desert

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Journal of Arid Land 2010年第1期2卷 14-19页

作者： Kiyoshi TSUCHIYA Tamotsu IGARSHI Muhtar QONG japan Meteorological Consultant Association EORC Japan Aerospace Exploration Agency (JAEA) Space and Earth Information Technology School of EngineeringKyushu Tokai University

An experiment is made to detect the land-cover change in the area located to the south of Aksu in the northern Taklimakan desert through analyses of satellite data pixel by pixel basis. The analyzed data are those observed in the late summer and early autumn of 1973, 1977, 1993 and 1995. As a parameter of land-cover, SAVI (Soil Adjusted Vegetation Index) derived from the data of Landsat MSS and JERS-1 OPS (Optical Sensor) is used. The result indicates the increase of vegetation in the oasis areas, confluent area of the Yarkant and Kashgar Rivers and around reservoirs while little change occurs in the desert area. The 1973 satellite image shows the abundant flow in the Yarkant River while the river is almost dried up in the satellite images of later years. The trend of the decrease in the Hotan River flow is recognized although not so dramatic as that of the Yarkant River.

关键词： Taklimakan Desert SAVI Landsat MSS JERS-1 OPS vegetation false color landcover change

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Visual localization for asteroid touchdown operation based on local image features

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Astrodynamics 2020年第2期4卷 149-161页

作者： Yoshiyuki Anzai Takehisa Yairi Naoya Takeishi Yuichi Tsuda Naoko Ogawa The University of Tokyo Tokyo113-8654Japan RIKEN Center for Advanced Intelligence Project Tokyo103-0027Japan japan Aerospace exploration agency Sagamihara252-5210Japan

In an asteroid sample-return mission,accurate position estimation of the spacecraft relative to the asteroid is essential for landing at the target *** the missions of Hayabusa and Hayabusa2,the main part of the visual position estimation procedure was performed by human operators on the Earth based on a sequence of asteroid images acquired and sent by the *** this approach is still adopted in critical space missions,there is an increasing demand for automated visual position estimation,so that the time and cost of human intervention may be *** this paper,we propose a method for estimating the relative position of the spacecraft and asteroid during the descent phase for touchdown from an image sequence using state-of-the-art techniques of image processing,feature extraction,and structure from *** apply this method to real Ryugu images that were taken by Hayabusa2 from altitudes of 20 km-500 *** is demonstrated that the method has practical relevance for altitudes within the range of 5-1 *** result indicates that our method could improve the efficiency of the ground operation in the global mapping and navigation during the touchdown sequence,whereas full automation and autonomous on-board estimation are beyond the scope of this ***,we discuss the challenges of developing a completely automatic position estimation framework.

关键词： visual navigation structure from motion asteroid touchdown Hayabusa2

Numerical Investigation of Flow Fields in Inductively Coupled Plasma Wind Tunnels

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Plasma Science and Technology 2014年第10期16卷 930-940页

作者：喻明浩 Yusuke TAKAHASHI Hisashi KIHARA Ken-ichi ABE Kazuhiko YAMADA Takashi ABE Department of Aeronautics and Astronautics Kyushu UniversityFukuoka 819-0395Japan Division of Mechanical and Space Engineering Hokkaido UniversitySapporo 060-8628Japan Institute of Space and Astronautical Science Japan Aerospace Exploration AgencySagamihara 252-5210Japan

Numerical simulations of 10 kW and 110 kW inductively coupled plasma （ICP） wind tunnels were carried out to study physical properties of the flow inside the ICP torch and vacuum chamber with air as tile working gas. Two-dimensional compressible axisymmetric Navier- Stokes （N-S） equations that took into account 11 species and 49 chemical reactions of air, were solved. A heat source model was used to describe the heating phenomenon instead of solving the electromagnetic equations. In the vacuum chamber, a four-temperature model was coupled with N-S equations. Numerical results for tile 10 kW ICP wind tunnel are presented and discussed in detail as a representative case. It was found that the plasma flow in the vacuum chamber tended to be in local thermoehemical equilibrium. To study the influence of operation conditions on the flow field, simulations were carried out for different chamber pressures and/or input powers. The computational results for the above two ICP wind tunnels were compared with corresponding experimental data. The computational and experimental results agree well, therefore the flow fields of ICP wind tunnels can be clearly understood.

关键词： inductively coupled plasma Joule heating vacuum chamber chemical reactions

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Solar power sail mission of OKEANOS

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Astrodynamics 2020年第3期4卷 233-248页

作者： Osamu Mori Jun Matsumoto Toshihiro Chujo Masanori Matsushita Hideki Kato Takanao Saiki Yuichi Tsuda Jun'ichiro Kawaguchi Fuyuto Terui Yuya Mimasu Go Ono Naoko Ogawa Yuki Takao Yuki Kubo Kaoru Ohashi Ahmed Kiyoshi Sugihara Tatsuaki Okada Takahiro Iwata Hajime Yano japan Aerospace exploration agency Sagarmihara 252-5210Japan Tokyo Institute of Technology Tokyo 152-8550Japan The University of Tokyo Tokyo 113-8654Japan Patchedconics LLCSagarmihara 252-5210Japan

The solar power sail is an original japanese concept in which electric power is generated by thin-film solar cells attached on the solar sail *** Aerospace exploration agency(JAXA)successfully demonstrated the world’s first solar power sail technology through IKAROS(Interplanetary Kite-craft Accelerated by Radiation of the Sun)mission in *** demonstrated photon propulsion and power generation using thin-film solar cells during its interplanetary *** up,solar power sails can generate enough power to drive high specific impulse ion thrusters in the outer planetary *** this concept,we propose a landing or sample return mission to directly explore a Jupiter Trojan asteroid using solar power sail-craft OKEANOS(Oversize Kite-craft for exploration and AstroNautics in the Outer Solar System).After rendezvousing with a Trojan asteroid,a lander separates from OKEANOS to collect samples,and perform in-situ analyses in three proposed mission sequences,including sending samples back to *** paper proposes a system design for OKEANOS and includes analyses of the latest mission.

关键词： solar power sail Trojan asteroid landing in-situ analysis outer solar system OKEANOS

Thermochemical Nonequilibrium 2D Modeling of Nitrogen Inductively Coupled Plasma Flow

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Plasma Science and Technology 2015年第9期17卷 749-760页

作者： YU Minghao Yusuke TAKAHASHI Hisashi KIHARA Ken-ichi ABE Kazuhiko YAMADA Takashi ABE Satoshi MIYATANI Department of Aeronautics and Astronautics Kyushu University Division of Mechanical and Space Engineering Hokkaido University Institute of Space and Astronautical Science Japan Aerospace Exploration Agency Department of Aeronautics and Astronautics The University of Tokyo

Two-dimensional（2D） numerical simulations of thermochemical nonequilibrium inductively coupled plasma（ICP） flows inside a 10-kW inductively coupled plasma wind tunnel（ICPWT） were carried out with nitrogen as the working *** axisymmetric NavierStokes（N-S） equations coupled with magnetic vector potential equations were solved.A fourtemperature model including an improved electron-vibration relaxation time was used to model the internal energy exchange between electron and heavy *** third-order accuracy electron transport properties（3rd AETP） were applied to the simulations.A hybrid chemical kinetic model was adopted to model the chemical nonequilibrium *** flow characteristics such as thermal nonequilibrium,inductive discharge,effects of Lorentz force were made clear through the present *** was clarified that the thermal nonequilibrium model played an important role in properly predicting the temperature *** prediction accuracy can be improved by applying the 3rd AETP to the simulation for this ICPWT.

关键词： inductively coupled plasma nonequilibrium electron transport properties,magnetic vector potential

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Shape control of multi-cellular infatable panels

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Frontiers of Mechanical Engineering 2013年第3期8卷 276-282页

作者： N.KATAYAMA K.ISHIMURA K.MINESUGI DANIEL J.INMAN The Graduate University for Advanced Studies japan Aerospace exploration agency Department of Aerospace Engineering University of Michigan

Multi-cellular infatable structures are ultralight and robust against membrane damage such as pinholes caused by space *** to their robustness,infatable structures supported by inner gases can be applied as space *** the present study,shape control for a simple multi-cellular infatable panel was achieved via a novel diaphragm *** the bending actuator in a center membrane bends,the inner pressures of sub-cells become different,and the diaphragm mechanism bends as a *** a sliding component is not included,this deformable system is a reliable *** addition,the proposed mechanism has higher rigidity than that of a bending actuator used *** the present paper,we investigate the feasibility of a novel diaphragm mechanism and its characteristics using experimental and numerical results.

关键词： Membrane structures inflatable structure shape control smart structures structural mechanics space engineering