矢野 創

The Memorandum of Understanding signed between the Japanese Aerospace Exploration Agency (JAXA) and the German Aerospace Centre (DLR) during the 63rd International Astronautical Congress (IAC) in Naples, paves the way for the Mobile Asteroid Surface Scout (MASCOT) participation in JAXAs Hayabusa-II mission. Like its famous predecessor, Hayabusa-II is foreseen to study and return samples from a Near-Earth Asteroid. In contrast to the previous mission, Hayabusa-II will also include a small lander package being developed by DLR and the Centre National d'Etudes Spatiales (CNES): the aforementioned MASCOT. Scheduled for a launch in 2014, Hayabusas-II journey will take 4 years until it will arrive at 1999JU3, a C-type asteroid. Following the initial remote sensing operations, MASCOT will be released to the surface and perform its science operations at its first location. Once this is complete, MASCOT will be able to 'hop' from one measurement site to the next. The payload suite will comprise a near-infrared microscope (MicrOmega, IAS Paris), a camera (CAM, DLR Berlin), a radiometer (MARA, DLR Berlin) and a magnetometer (MAG, TU Braunschweig). Realizing MASCOTs mission is difficult due to the strict mission requirements, the harsh landing environment and a short development time for a piggyback deep space mission. Aiming for high performance and reliability requires creative design solutions and novel developments in order to meet all challenges and to stay inside the mass limit of 11 kg. The status of MASCOT up to end of Phase B was presented at the 63rd IAC. With a flight model delivery scheduled for March 2014, the mission is now in the final stage of development and testing. The results of these tests have shown the strict limits of the structure and thermal design, and highlighted the risk in such a short project development. Lessons have also been learned regarding margin policy for such small spacecraft. Despite these challenges, the project is on-track, with all delivery milestones expected to be met. These last few months will serve to verify all of the design assumptions, before the launch in late 2014.

The JAXA Hayabusa-II mission is the follow-up to the original Hayabusa mission launched in 2003 \ which succeeded in returning the first dust particles from a near-Earth asteroid to Earth. JAXA intends to launch Hayabusa-II in 2014 for similar measurements of the asteroid 1999 JU3, a C-type asteroid, and invited the German Aerospace Centre (DLR) to contribute a small lander package to the mission. Based on this invitation, DLR is developing the Mobile Asteroid Surface Scout (MASCOT) to complement the main spacecraft's scientific objectives, with the Centre National d'Etudes Spatiales (CNES) providing payload and subsystem support. MASCOT will provide in-situ surface science and allow investigation of up to three sites on the asteroid surface. A short on-asteroid lifetime of two complete asteroid rotations (-16 hours) will provide measurements under different illuminations and thermal conditions, with Hayabusa-II being used to transmit all of the scientific data back to Earth. The harsh landing environment and strict mission requirements lead to some difficult design challenges. An innovative "hopping" mechanism will allow MASCOT to leap across the asteroid surface in bounds of up to 220m, albeit robustness of this concept must first be proven in a comprehensive suite of simulations and tests. Mass, limited to 10 kg, is critical: savings via the use of a carbon-fibre main structure and simplified subsystems allows the carriage of four scientific payloads, namely a multispectral wide angle camera, a radiometer, a magnetometer and an IR microscope. Thermal control is a challenge given the contrasting requirements of deep-space cruise and on- surface operation. Available energy also puts a strict limit on operations and restricts the lifetime of the mission. Copyright © (2012) by the International Astronautical Federation.

Japan Aerospace Exploration Agency (JAXA) plans to launch the small asteroid explorer "HAYABUSA2" in 2014, following the HAYABUSA mission. By improving the HAYABUSA probe, we are planning to visit the small asteroid "1999JU3", and aiming sample-return from an asteroid of different type from Itokawa. The 1999JU3 is a C- Type asteroid, considered to contain more organic or hydrated materials than S-type asteroids like ITOKAWA. The basic configuration of the spacecraft is mainly the same as HAYABUSA, with several minor modifications. The spectroscopic equipment and sampling system will be improved to be more suitable to C-type asteroids, because the surface of C-type asteroids is expected to differ from that of S-type ones. We will report the details of the sampling system of HAYABUSA2, and introduce our developing status of the sampling system. Copyright © (2012) by the International Astronautical Federation.

The Japanese asteroid explorer HAYABUSA launched in 2003 arrived at its target asteroid ITOKAWA in September, 2005. HAYABUSA has made amount of scientific discoveries and technological achievements during its stay at ITOKAWA and it came back to the Earth on June 13, 2010. Under this situation, the next asteroid exploration mission started. The spacecraft is called HAYABUSA-2. Although its design basically follows HAYABUSA, some new components are planned to be equipped in HAYABUSA-2 mission. A small carry-on impactor is one of the new challenges that were not seen with HAYABUSA. One of the most important scientific objectives of HAYABUSA-2 is to investigate chemical and physical properties of the internal materials and the internal structures in order to understand the formation history of small bodies. In order to achieve this objective, the impactor is required to remove the surface regolith and create an artificial crater on the surface of the asteroid. Ulis paper presents the overview of our small carry-on impactor system and impact operation of HAYABUSA-2 mission. And how to improve this impactor when it is applied to another small body exploration mission is also presented in this paper. Copyright ©2011 by the International Astronautical Federation. All rights reserved.

The minorbody explorer called "HAYABUSA" conducted sampling mission on the minorbody "ITOKAWA", and now it is planning to develop next minorbody explorers. The LSS, laboratory for space systems at the Tokyo Institute of Technology, and JAXA, propose the adhesive based sampling system for next minorbody explorers. By using this sampling system, it becomes possible to get larger size and heavier mass samples compare with the samples which are able to get by HAYABUSA's sampling system. In this paper, Description of the adhesive based sampling system, results of evaluation experiments and analy...

始原小天体有機物は、太陽系および生命原材料物質の起源と進化を理解するための重要な情報を記録している。「たんぽぽ計画」では、大気圏突入時の熱変成や地上での汚染を受けていない宇宙塵を、国際宇宙ステーション上に超低密度シリカエアロゲルを設置して回収を試みる予定である。しかし、この方法では、宇宙塵のエアロゲルへの衝突により変成する可能性を考慮する必要がある。そこで本研究では、宇宙科学研究所・スペースプラズマ実験施設の二段式高速ガス銃を用いて、隕石微粒子の高速衝突模擬実験を行い、マーチソン隕石微粒子をシリカエアロゲルに撃ち込んだものを取り出し、2枚のアルミ板にはさみハンドプレスして圧着された隕石微粒子を、片方のアルミ板に載せた状態で、赤外顕微分光装置と顕微ラマン分光装置で測定を行った。また、SPring-8, BL43IRの高輝度赤外顕微分光装置IFS120HRでイメージング測定を行い、衝突前後の隕石有機物の分子構造の変化を見出すことを目的とした。

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.

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.