岡田 達明

宇宙航空研究開発機構（JAXA）はやぶさ探査機が，近地球型小惑星のイトカワから持ち帰った微小試料についてラマン分光分析を行い，樹脂に包埋された直径30から150 μmの試料中の鉱物の同定を試みた．ラマン分光分析によって同定されたケイ酸塩鉱物及び酸化鉱物は，カンラン石，輝石，斜長石，クロム鉄鉱である．それらは，エネルギー分散型スペクトロメーター付走査電子顕微鏡観察で同じ研磨断面試料から同定されたケイ酸塩鉱物・酸化鉱物と一致した．また，斜長石が衝撃により固相状態で非晶質化したマスケリナイトはラマン分光法で同定可能であるが，完全にマスケリナイト化した斜長石は見いだされなかった．このことは，本研究で分析したイトカワ微小試料が経験した衝撃ステージは，S4には到達していないことを示唆しており，他の初期分析の結果と整合的である．

宇宙環境で使用可能な岩石加工法として，ワイヤソー切断加工を検討している．本報では，真空中の加工特性として，切断時の動力を測定した結果について述べる．ワイヤ走行速度が0.3～1m/sの範囲で主分力および切り込み荷重を同時に測定した．主分力は大気中，真空中ともにほぼ一定であった．したがって，動力はワイヤ走行速度に比例した．また，動力は真空中の方が大きかった．

宇宙環境で使用可能な岩石加工法として，ワイヤソー切断加工を検討している．本報では，真空中の加工特性として，加工速度，研削比，加工中の真空度の変化を求めた結果について述べる．ニッケル付着により加工速度が低下する．ニッケル上でダイヤモンド砥粒がしゅう動するが，切り込み荷重が小さいため摩耗量は大きくなかった．

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.

In future lunar, planetary or asteroid explorations, in-situ analysis of rock samples are strongly demanded to obtain many data from various aspects. For precise composition analysis, a sample surface should be smoothed. In this report, a surface shaver with a piezoelectric actuator is proposed and its machining performance in air is investigated. Shaving teeth are mounted at the ends of a lever mechanism. The device is pressed through four springs onto the specimen with a linear actuator. When a sinusoidal voltage of 50 Vp-p and an offset voltage of 25 V ware applied, the natural frequency was 556 Hz and the unloaded amplitude of shaving teeth were 0.77 mmp-p. Basalt samples were machined for 10 minutes in air. The surface roughness was small with an increase of the pressing force. However, the removal amount was smaller with an increase of the pressing force further. The surface roughness varied widely not only due to removal amount but also due to pores.

This report deals with a rock-crasher embedded in the science integrated package for future lunar exploration. The crusher measures 59×60×129 mm and weighs 490 g. The generative impact force and consumption power were 150 N and 6 W at a voltage of 24 Vp-p and a driving frequency of 50 Hz device. A tool bit with pyramids driven with a solenoid was made from tungsten carbide. Hard basalt, granite and anorthosite were smoothed.