GSA Annual Meeting in Indianapolis, Indiana, USA - 2018

Paper No. 284-12
Presentation Time: 4:40 PM


TACHIBANA, Shogo1, YURIMOTO, Hisaoshi2, NAKAMURA, Tomoku3, NOGUCHI, Takaaki4, OKAZAKI, Ryuji5, YABUTA, Hikaru6, NARAOKA, Hiroshi5 and ABE, Masanao7, (1)UTokyo Organization for Planetary and Space Science, University of Tokyo, 7-3-1 Hongo, Tokyo, 1130033, Japan, (2)Department of Natural History Sciences, Hokkaido University, Sapporo, 0600810, Japan, (3)Department of Earth and Planetary Materials Science, Tohoku University, Aramaki, Aoba, Sendai, 9808578, Japan, (4)Faculty of Arts and Science, Kyushu University, 744, Motooka, Nishi-ku, Fukuoka, 8190395, Japan, (5)Department of Earth and Planetary Sciences, Kyushu University, 744, Motooka, Nishi-ku, Fukuoka, 8190395, Japan, (6)Department of Earth and Planetary Systems Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, 7398526, Japan, (7)Institute of Space and Astronautical Science, JAXA, 3-1-1 Yoshinodai, Sagamihara, 2525210, Japan

The JAXA’s spacecraft Hayabusa2 arrived at its target asteroid (162173) Ryugu in June 2018, and will investigate Ryugu for 18 months. Ryugu is a near-Earth C-type asteroid with a diameter of ~900 m, and could preserve the long history of the Solar System from its birth to the present. Hayabusa2 will collect minimum 100 mg of surface samples at (at most) three different locations (Tachibana et al., 2014; Sawada et al., 2017), and the samples will be delivered to the Earth late 2020.

The returned Ryugu samples will be characterized in a non-destructive way at the curation facility of Institute of Space and Astronautical Science (ISAS), JAXA for the first six months from the delivery. A part of the samples will then be delivered to the Hayabusa2 project team for the one-year science-oriented initial sample analysis. The initial analysis of Ryugu samples will focus on (1) detailed characterization of the samples and (2) understanding the history of Ryugu and the Solar System in order to maximize the scientific achievement of the project and to prove the scientific potential of the samples to the community.

The samples will be categorized into coarse grains obtained at different locations, <100 micrometer-sized fine grains that could be mixed inside the sample container and may show the average surface feature of Ryugu, and volatiles that are planned to be extracted from the sample container prior to its opening (Tachibana et al., 2014; Okazaki et al., 2017; Sawada et al., 2017). The initial analysis team consists of six sub-teams to analyze the samples; 1) chemistry (elements and isotopes) (Lead: H. Yurimoto), 2) petrology and mineralogy of coarse grains (Lead: T. Nakamura), 3) petrology and mineralogy of fine grains (Lead: T. Noguchi), 4) volatiles (Lead: R. Okazaki), 5) macromolecular organics (Lead: H. Yabuta), and 6) organic molecules (Lead: H. Naraoka). All the data will be integrated to understand the history of Ryugu and the Solar System.

Coordinated microanalysis is certainly a key tool for increasing the scientific yield of Ryugu samples. In this presentation, we will discuss the current plan of the initial analysis of Ryugu samples.