[in Japanese]

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The past study examined the effect of megaregolith on the lunar heat flow, thermal conductivities of megaregolith, and lateral variation of the megaregolith thickness at the Apollo 17 site. Correcting the effect of megaregolith on the lunar heat flow, Warren and Rasmussen (1987) estimated the global average heat flow to be 12 mW/m2, which is much lower than 30 mW/m2 that is estimated by Langseth et al. (1973). We studied the lunar crustal thickness on lunar heat flow constructing a lunar thermal model. Based on this result, we will discuss constructing a lunar thermal model.

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[in Japanese]

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ALIS (Advanced Lunar Imaging Spectrometer) is a telescopic imaging spectrometer which we developed for Space Station Lunar Observatory project. A future purpose of this project is to establish the photometric model of the moon as a spectral radiance standard of space-borne imaging instruments by repeated observation of the moon with VIS/NIR (Visible and Near Infra-red light) from the International Space Station. Even by the ground-based observation, ALIS enable us to study the spectroscopic properties of the lunar surface.

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The Apollo missions set up a seismic network on the nearside of the Moon (1969-1977), which dataset was recently re-investigated to clarify the mean lunar crustal thickness. Here we go a step further with the same data: we investigated the lateral variations of crustal thickness. We will present the first crustal thickness map made from seismic data and compare it to results from gravity analysis.

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[in Japanese]

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We report results of the ground tests for the flight model of Relay Satellite Transponder (RSAT) which will provide global lunar gravity mapping by 4-way Doppler measurement using SELENE. Mass properties of Relay Satellite (Rstar) are measured and adjusted, which allows the estimation of attitude fluctuations. Systematic errors caused by the phase noise have been confirmed by 4-way linked tests with Rstar bus equipments.

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[in Japanese]

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[in Japanese]

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Following up Hayabusa's heritage for asteroid sample return, the 'Minor Body Exploration Working Group' was officially approved this March, in order to design and propose a next generation minor body exploration mission by the end of FY 2006. At present, strategic developments include a sampling mechanism to retain stratigraphic information on a C-type asteroid surface and a rover system to observe the filed of occurrence of samples. This talk discusses its scientific objectives, possible mission targets, and status of such strategic developments.

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Analytical methods using synchrotron radiation imaging for extraterrestrial small samples, such as micrometeorites and IDPs, have been developed. Observation of dust tracks as well as dust particles in an aerogel dust collector is possible by micro-radiography using refraction imaging. This method can be applied to Stardust mission sample, which will be returned from comet Wild-2 in January, 2006. Density measurement of micrometeorites by micro-tomography can be applied to Hayabusa mission sample, which will be returned from S-type asteroid ITOKAWA in June, 2007.

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We have begun a lightcurve observing project of a very young asteroid family, the Karin family. Though our entire project is still on the way, a multi-color observation in visible wavelength of the biggest member of the family, (832) Karin, gave us a very interesting color variation on its surface. The asteroid has both an old, mature surface that probably had been a part of a parent body of the Karin family, and a new, fresh surface that the collisional event created.

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The meteorite-asteroid link has been strengthened through remote-sensing studies during the last than 35 years. However, more detailed quantitative comparison still faces with many challenges. Among them are effects of regolith physical properties, space weathering, and temperature. Although there are several tools such as Hapke's photometric and space weathering models, their use and limitations can pose problems. I will address such issues and possible contributions by Hayabusa Mission.

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We present the results of photometric observations of 65803 Didymos. Didymos is a near-Earth-asteroid belonging to the PHA (Potentially Hazardous Asteroid) group and one of the most accessible asteroids by spacecraft. Didymos has a complex lightcurve that can be described as the co-addition of two independent components: periodic wave with double peak and temporal depression of brightness. Therefore, it suggests a system of two bodies that secondary orbits around primary, displaying both eclipses and occultation.

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Our goal is to provide the entire shape of (25143) Itokawa with texture information during global mapping phase. This image-based modeling is a type of multi-viewpoints-epipolar method with AMICA. Ground control points are automatically extracted with Susan filtering. Their interval and size of polygons show about 10m. Hierarchical, Recursive, Sub-pixel matching the control points gives disparity, and its detailed procedure is demonstrated. Scientific topics of shape modeling are to know interior structure, catastrophic origin, and history.

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[in Japanese]

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[in Japanese]

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