矢野 創

第26回宇宙利用シンポジウム(2010年1月25日-26日, 宇宙航空研究開発機構宇宙科学研究本部相模原キャンパス)共催: 日本学術会議資料番号: AA0064730052

第25回宇宙利用シンポジウム(2009年1月14日-15日, 宇宙航空研究開発機構宇宙科学研究本部相模原キャンパス)著者人数: 16人資料番号: AA0064297070

第27回宇宙利用シンポジウム (2011年1月24日-25日, 宇宙航空研究開発機構宇宙科学研究所相模原キャンパス), 相模原市, 神奈川県資料番号: AA0065129068

To enhance the currently studied asteroid sample return mission HAYABUSA-2 by in-situ science the Institute of Space Systems of the German Aerospace Center (DLR) is in lead of a proposal for a lander called MASCOT (Mobile Asteroid Surface Scout). Its mass of 10 kg lies in between those of the HAYABUSA small lander MINERVA (1 kg) and the legged ROSETTA comet lander PHILAE (100 kg). In the successfully completed feasibility study the design of the MASCOT converged to a landing package with 10 kg total mass, 3 kg of payload and the capability of hopping. As a result of its reduced size and the highly demanding constraints regarding e.g. mobility, the design as well as the landing and mobility cannot be adapted from MINERVA and PHILAE. This paper is intended to give an overview over the demanding landing and mobility concept for MASCOT. The current MASCOT baseline design is presented, which has to deal with tight budgetary limitations leading to a consolidated and widely integrated design, while still offering excellent performance in terms of mobility and resulting science. The focus lies on the mission analysis tasks and the mobility concept, which is studied in detail during the ongoing preliminary design phase. The general mission constraints including the parameters of the target asteroid (162173) 1999 JU3 are presented, while emphasis is put on the modelling of the asteroid's inhomogeneous gravity field. Therefore different gravitational models are implemented and their effect on the descent trajectory is compared. Of equal importance is the design support by investigating the two major mobility aspects, i.e. the self-uprighting mechanism and hopping over the asteroid's surface. These two issues are studied by applying both multi-body system and contact dynamics approaches. Moreover, this analysis will support the design of the actuator system for uprighting and hopping. After a presentation of the surface modelling and simulation approach an overview over first results and a short outlook on future mobility analysis and test activities for MASCOT is given. Copyright ©2010 by the International Astronautical Federation. All rights reserved.

Hayabusa spacecraft finally came back to the earth on June 13, 2010. It has a quite dramatic story and we had a lot of experiences about planetary mission. And now we have proposed Hayabusa follow-on mission, Hayabusa-2. It is an asteroid sample return mission again, but the type of the target asteroid is C-type, which is different from the target of Hayabusa, Itokawa (S-type). The scale of the spacecraft is similar to Hayabusa, but many parts will be modified so that we will not have the troubles that we experienced in Hayabusa. Also the spacecraft has new equipment, which is called impactor. The impactor will make an artificial crater on the surface of the asteroid, and we will try to get the sample inside the crater. Then we can get much fresh material. The planned launch year is 2014 or 2015, arriving at the target asteroid 1999 JU3 in 2018, and coming back to the earth 2020. We hope we can start this mission as soon as possible. Copyright ©2010 by the International Astronautical Federation. All rights reserved.

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.

私たちのグループは、地球低軌道 (400 km) を周回する国際宇宙ステーション(ISS)のきぼうの曝露部を利用して微生物の捕集実験を行う宇宙実験（たんぽぽ計画）を提案している。低密度エアロゲルを宇宙空間に一定期間曝露し、衝突する微粒子を捕集する。地上でエアロゲル表面と衝突トラックの顕微鏡観察を行った後、微粒子をエアロゲルから単離する。微粒子内もしくは微粒子に付着していると考えられる微生物のDNAを鋳型としてPolymerase chain reaction (PCR)で特定の遺伝子の増幅を試みる。増幅が認められたのであれば塩基配列を決定し、地上の生物と比較する事で種の同定を行う予定である。本研究では、捕集される微生物を検出するためのPCR法の確立する事を目的とする。模擬サンプルを用いて、捕集したサンプルを解析するための条件検討を行った結果を報告する。

The asteroid explorer "Hayabusa (MUSES-C)" has challenged the sample return mission in asteroid for the first time in the world and the success in this mission is expected. The development of the succession explorer to "Hayabusa" is examined now and more certain sample return methods are requested. In this paper, it reports on the examination and the progress in development of a new sample collection mechanism for equipping with the asteroid explorer for the next term.

Marco Polo is being studied in the ESA Cosmic Vision programme as a sample return mission to a near-Earth asteroid (NEO) with participation by JAXA, with launch planned in the 2018-19 timeframe. In reponse to ESA's Declaration of Interest call in 2008, the Institute of Space Systems of the German Aerospace Center (DLR) led a proposal for a separate lander 'MASCOT' (Marco Polo Surface Scout) to be carried on the mission. The proposal was recommended by ESA for a feasibility study which was subsequently carried out from late 2008 to September 2009. In parallel to the Marco Polo flight opportunity, MASCOT was studied for the Hayabusa-2 mission currently studied by JAXA as the immediate successor to the currently flying Hayabusa mission. Launch would be earlier, taking place in 2014. The MASCOT study started with a preliminary assessment of lander type, landing mode, mobility options and their impact on minimum achievable mass and volume. Differentiation was made between legged landers ('landing in a defined orientation'), landing packages ('landing with uncontrolled orientation') and the number of achievable landing sites (single vs. multiple) and thus the degree of mobility. The analysis showed that a legged lander in the mass range of 70 kg-100 kg - with full mobility - , a weeks-long lifetime and ≃14 kg P/L is feasible, given the weak gravity of potential target NEOs. Reducing size and capability, a legged lander of 30-40 kg was then conceived by giving up mobility, reducing lifetime and by cutting the P/L to ≃10 kg. Finally, a mobile package version with an uprighting mechanism ('MASCOT-XS') and 3 kg of P/L was found feasible for a total mass of 10-15 kg. The constraints imposed by both the Marco Polo and Hayabusa-2 missions mandate MASCOT-XS to be the baseline for the MASCOT design.

Dust particles which are observed as zodiacal light exist around the Earth's orbit and can create a characteristic distribution by the Earth's gravity. This paper investigates the distribution by numerical simulation on the assumption that dust particles trapped in horseshoe orbits contribute the distribution, because the orbit has the following characteristics. The velocity of a trapped dust varies by its location on the horseshoe orbit and the dust will transit with time to wider horseshoe orbit. And this paper also considers the possibility that these particles are trapped or not and reveals that the possibility depends on the dust diameter.

In the Hayabusa-2 pre-project, science case and onboard instruments are studied to conduct in situ observation at the surface of NEO 1999JU3, with a candidate 10kg class small lander. Science requirements, strawman payloads, and operation scenario will be briefly described at the meeting.

太陽系を構成する始原的な物質である炭素質コンドライト（Murchison, Murray, Ivuna, Orgueil, Tagish Lake）と南極微隕石の圧裂引張強度を、微小圧縮試験機を用いることにより100 μmサイズの微小サンプルについて求めることができた。炭素質コンドライト強度の平均値はおおよそ1-5 MPa程度の値であり、CM＞CI＞TLの順に強度が低くなる傾向をもっている。微隕石の引張強度は炭素質コンドライトに比べて大きいが、これは測定した宇宙塵が大気圏突入の際に受けた加熱の影響のためであると考えられる。今回の研究により熱変成の影響を受けていない貴重なサンプルについても強度測定が可能であるだけでなく、破壊後のサンプルが回収できることもわかった。Murchison隕石は、少なくとも100 μmから1 cmのサイズ範囲では、ほとんどサイズ依存性をもっていない可能性がある。