A picture of Itokawa was selected as the cover page of Science special issue on 2 June 2006.(Credit & Copyright: ISAS/JAXA)
Exciting scientific results obtained by Japanese asteroidal explore "Hayabusa" were published in Science on 2 June. 7 papers resulted from the exploration of asteroid Itokawa appeared on this special issue and researchers of Kobe University contributed to 6 papers of them. Above all, a paper "Mass and Local Topography Measurements of Itokawa by Hayabusa" was published by a team of ‘the 21st Century COE Program "Origin and Evolution of Planetary Systems" under the MEXT (Leader: Prof. Tadashi Mukai), Dr. Shinsuke Abe (COE researcher) as a first author.
Using laser altimetry, Kobe team investigated not only the surface topography of the asteroid within 1 m scale but also the gravity of the distorted and small asteroid Itokawa in order to estimate its mass, resulting in a density value of 1.95 g/cm3. If chondritic, it must have a porosity around 40%, which discovery shows the most porous asteroid among S-type asteroids. The interior of Itokawa would have to be extremely loose rubble rather than a solid monolithic rock.
Look at the following page, http://harbor.scitec.kobe-u.ac.jp/~avell/science_press/