[M-IS07] Astrobiology

[MIS07-01] METEOROID AND DEBRIS IMPACT FLUX IN LOW EARTH ORBIT WITNESSED BY THE TANPOPO CAPTURE PANELS ONBOARD THE ISS IN 2015-2017

*Hajime Yano¹, K. Yamamoto², E. Minakami², M. Eitel^1,3, S. Sasaki⁴, J. Imani⁵, K. Okudaira⁶, M. Higashide⁷, E. Imai⁸, Y. Kawaguchi⁹, Yoko Kebukawa¹⁰, H. Mita¹¹, M. Nishi¹², T. Noguchi¹³, Makoto Tabata¹⁴, A. Tsuchiyama¹², Hikaru Yabuta¹⁵, K. Arai⁸, H. Hashimoto¹, Kensei Kobayashi¹⁰, A. Yamagishi¹⁶ (1.Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 2.Hosei University, 3.University of Stuttgart, 4.Tokyo University of Technology, 5.Yuki Seimitsu, Co. Ltd., 6.University of Aizu, 7.JAXA/Aerospace Research and Development Directorate, 8.Nagaoka University of Technology, 9.Chiba Institute of Technology, 10.Yokohama National University, 11.Fukuoka Institute of Technology, 12.Kyoto University, 13.Kyushu University, 14.Chiba University, 15.Hiroshima University, 16.Tokyo University of Pharmacy and Life Science)

Twenty-three pairs of silica aerogels and aluminum covers consisted of the Tanpopo capture panels were optically investigated and over 200 hypervelocity impacts signatures were identified and documented for further detailed analyses.
Among them, a low Ca-pyroxene micrometeoroid was captured intact inside the 10mg/cc density silica aerogel. In particular, we compared these data from both space and ram pointing faces of the Tanpopo panels exposed on the International Space Station for deducing meteoroid impact flux by taking into account of effects of local shielding and secondary ejecta impacts. This direct measurement showed that the micrometeoroid impact flux in low Earth orbit in 2015-7 are generally consistent with the previous post-retrieval measurements of LDEF, EuReCa, and SFU in 1980’s to 1990’s.