1. Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan
2. Okayama University, 1-1-1 Tsushima-naka Kita-ku, Okayama, Okayama 700-8530, Japan
3. Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai Chuo-ku, Sagamihara, Kanagawa 252-5210, Japan