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Mars explorer 'Nozomi (PLANET-B)' experienced two earth swingbys in December 2002 and June 2003. During these swingbys period, radiometric data from Usuda tracking station were obtained, and orbit determination was carried out with an accuracy of a several km in position and a several mm/s in velocity. These results are compatible with the JPL orbit determination results. In this phase, Delta-VLBI observation were also experimentally performed, and fringe data can be obtained in several passes. In this paper, the preliminary evaluation of these Delta-VLBI data are briefly described., のぞみ(PLANET-B)は、2002年12月21日と2003年6月19日の2回の地球スウィングバイにより、火星巡航軌道に向けての大きな軌道変更が行われた。この2回のスウィングバイの前後、臼田局データを用いた電波航法による軌道決定により、位置で数km、速度で数mm/s程度の決定精度が得られ、この結果はJPLによる軌道決定の結果とも整合性のとれたものであった。またこの期間、日本では初めての本格的な相対VLBI観測実験が行われ、いくつかのパスに関して相関が得られた。しかし観測データ処理後に得られたディレイ値には数10 nsecレベルのノイズ成分やバイアス成分が含まれており、軌道決定精度の向上に寄与するためには、今後1桁以上の精度改善が必要であることがわかった。

In the present study, the launch windows in May and June, 2010 are applied to the PLANET-C (Venus Climate Orbiter) Venus exploring mission. So as to verify the system compatibility between the orbital design and the spacecraft capability, antenna elevation in the first visible pass from UDSC (Usuda Deep Space Center) and shadow duration of the elliptic orbit about Venus are evaluated in this paper. Required velocity amount for orbit and attitude correction is also estimated for the 2010 launch orbit. Currently, three weeks in total of launch possibilities, one week in May and two weeks in June 2010, are ensured for the PLANET-C mission., 現在、金星探査機(PLANET-C: Venus Climate Orbiter)は2010年打上げを前提に、ミッション解析が進められている。軌道計画の実現性を確認する目的で、打上げ直後の第1可視運用性、金星周回軌道中の日陰時間、探査機に要求される燃料重量などを算出し、探査機システムとの整合性を確認した。本稿では、これら2010年打上げ軌道の特徴と現状における打上げウィンドウを示す。

Japanese first Mars explorer NOZOMI, which was launched in July 1998, suffered several problems during the operation period of more than five years. It reached near Mars at the end of 2003, but it was not put into the orbit around Mars. Although NOZOMI was not able to execute its main mission, it provided a lot of good experiences from the point of the orbit determination of spacecraft. The related issues are the spin modulation, the solar radiation pressure, the small force related to the attitude change, the solar conjunction, and the orbit determination by the side lobe of the high gain antenna without the telemetry. It was tried to solve these issues by the conventional way using range and Doppler data. Also tried was the orbit determination by using the Delta-VLBI method (VLBI: Very Long Baseline Interferometry). In addition to this, optical observations of NOZOMI at the earth swingbys were tried., 日本の火星探査機「のぞみ」は、1998年7月に打上げられたが、その5年余りの運用期間においていくつかの問題に遭遇した。「のぞみ」は、2003年の終りには火星の近くに達したが、火星周回軌道に投入はなされなかった。「のぞみ」はミッションの本来の目的を達することはできなかったが、軌道決定の観点からは多数の非常に有用な経験をもたらしてくれた。軌道決定に関係した事項としては、スピンモジュレーション、太陽輻射圧、姿勢制御に伴う微小加速度、および、テレメトリーが取得できない状況下でのハイゲインアンテナのサイドローブによる軌道決定などが挙げられる。これらの問題については、従来からのレンジとドップラーを使う手法で対応した。また、新しい試みとして、相対VLBI(VLBI:超長基線電波干渉計)による観測を行った。さらに、地球スイングバイ時には、光学望遠鏡による観測も試みた。

Reported in this paper is the status of the trajectory analysis of the asteroid explorer mission now under study in JAXA/ISAS. In the previous symposium, we have reported the results of the preliminary analysis to select the candidates of the target asteroids and the exploration sequence. The global search of the targets and sequences in the space of the combinations of the ballistic trajectories and planetary swing-bys successfully made clear the mission candidates suited our objective. Following the preliminary analysis, more detailed trajectory analysis is performed assuming the usage of the electric propulsion, and the results of which are reported in this paper., 本発表では、次期小惑星探査ミッションの検討の中で進めている軌道計画の検討状況を報告する。昨年度のシンポジウムでは、対象天体と探査シーケンスを絞り込むための予備検討として、弾道飛行とスウィングバイを組み合わせた探査シーケンスの検討結果を報告した。今回は、その結果を元に選定したミッション候補に対し、電気推進を主推進として地球スウィングバイを組み合わせたE-ΔVEGAの使用を想定した軌道計画を検討したので、その結果を報告する。

One of important issues to be addressed to realize the practical space inflatable structure is how to control the movement during its deployment or extension and how to harden the structure and maintain the accuracy of shape for a long term after extended. To resolve this issue, two types of inflatable structure have been developed by making use of structural rigidizing method. One is to keep stiffness of the structure consistently during and after the extension by the shape recovery of open section tubular member that is called SPINAR (Space Inflatable Actuated Rod to keep here in after). The other is to store the tube made of aluminum/PET laminate material into pentalpha folding to ensure straight-ahead movement during the extension and to be rigidized by work-hardening of structural material after the extension. With those two individual methods, experimental model were developed and evaluated through extension test under the low-gravity environment using the plane, Gulfstream-2 in this study. Meanwhile, in this experiment, a semi-active controlled damper system using Electro Rheological Fluid (ERF) damper was applied.