1 3D Particle Characteristics of Highland Lunar soil (No. 60501) obtained by Micro X-ray CT T. Matsushima, J. Katagiri University of Tsukuba, Tsukuba, Ibaraki, 305-8573, JAPAN tmatsu@kz.tsukuba.ac.jp K. Saiki, A. Tsuchiyama Osaka UniversityOsaka, 560-0043, JAPAN M. Ohtake JAXA, Tokyo, 229-8510, JAPAN T. Nakano GSJ, AIST, Ibaraki, 305-8567, JAPAN K. Uesugi JASRI/ SPring-8, Hyogo, 679-5198, JAPAN Abstract A lunar surface soil sample from Descartes highland (No. 60501) is investigated by micro X-ray CT. Based on the obtained 3D information on particle shape and enclosed voids and cracks together with the information from microscopic images, we classified the particles into four groups: (1) monomineralic particles mostly corresponding to plagioclase, (2) micro breccias composed of a lot of mineral fragments, (3) agglutinate particles with relatively smooth surface and enclosed voids and (4) spherical glass beads. The detailed shape indices such as elongation ratio, flatness ratio and sphericity are computed for representative particles by image processing. Furthermore, in order to evaluate the mechanical properties of lunar soil from the particle information, image-based DEM is applied to directly model the particles, and simple shear simulations with such modeled particles are demonstrated. The computed shear resistance is in good agreement with the best estimate of Apollo model. Coupling such numerical tool with the above-mentioned particle statistics, we can evaluate the mechanical properties of various lunar soil from their petropraphic information. Introduction Recent lunar exploration program in NASA includes lunar base construction and in-situ resource utilization, which requires the cooperation among various engineering fields such as civil, mechanical, and chemical engineering. Among others a full understanding of physical, chemical and engineering properties of lunar soil is the most crucial issue. Although they have been extensively studied during and after the Apollo program (Heiken et al. 1991), it remains necessary to examine various aspects to ensure safe and efficient exploration planning. Earth & Space 2008.3, Long Beach