[P-PS03] Small Solar System Bodies: Latest results and new perspectives on the Solar System evolution

[PPS03-17] Current status of DESTINY+ project and science

*Tomoko Arai¹, Masanori Kobayashi¹, Ko Ishibashi¹, Hiroshi Kimura¹, Takayuki Hirai¹, Peng Hong¹, Takaya Okamoto¹, Manabu Yamada¹, Hiroki Senshu¹, Koji Wada¹, Fumi Yoshida², Ralf Srama³, Harald Krüger⁴, Sho Sasaki⁵, Hikaru Yabuta⁶, Masateru Ishiguro⁷, Tomohiko Sekiguchi⁸, Junichi Watanabe⁹, Takashi Ito⁹, Takafumi Ootsubo⁹, Shinsuke Abe¹⁰, Katsuhito Ohtsuka¹¹, Seitaro Urakawa¹², Tomoki Nakamura¹³, Takahiro Hiroi¹⁴, Shuji Matsuura¹⁵, Motoo Ito¹⁶, Akira Yamaguchi¹⁷, Mutsumi Komatsu¹⁸, Keiko Nakamura-Messenger¹⁹, Takashi Mikouchi²⁰, Shogo Tachibana²⁰, Tomokatsu Morota²⁰, Naru Hirata²¹, Hirohide Demura²¹, Goro Komatsu²², Takaaki Noguchi²³, Hidehiro Kanada²⁴, Jin Beniyama²⁰, Eri Tatsumi²⁵, Sean Marshall²⁶, Aiko Nakato²⁷, Hajime Yano²⁷, Makoto Yoshikawa²⁷, Takayuki Yamamoto²⁷, Naoya Ozaki²⁷, Hiroyuki Toyota²⁷, Kazutaka Nishiyama²⁷, Hiroshi Imamura²⁷, Takeshi Takashima²⁷ (1.Planetary Exploration Research Center, Chiba Institute of Technology, 2.University of Occupational and Environmental Health, 3.University of Stuttgart, 4.Max Planck Institute, 5.Osaka University, 6.Hiroshima University, 7.Seoul National University, 8.Hokkaido University of Education, 9.National Astronomical Observatory of Japan, 10.Nihon University, 11.Tokyo Meteor Network, 12.Japan Spaceguard Association, 13.Tohoku University, 14.Brown University, 15.Kwansei Gakuin University, 16.JAMSTEC, 17.National Instsitute of Polar Research, 18.SOKENDAI, 19.NASA Johnson Space Center, 20.The University of Tokyo, 21.Aizu University, 22.University of d'Annunzio, 23.Kyoto University, 24.Nagoya University, 25.Instituto de Astrofísica de Canarias, 26.Arecibo Observatory, 27.JAXA)

Keywords:DESTINY+, Asteroid (3200) Phaethon, Geminid meteor shower, Flyby

DESTINY⁺ (Demonstration and Experiment of Space Technology for INterplanetary voYage with Phaethon fLyby and dUst Science) was selected in 2017 as a mission for JAXA/ISAS small class program. It will be launched in 2024 by an Epsilon S rocket and flyby Phaethon in January, 2028. It is a joint mission of technology demonstration and scientific observation. The engineering mission is led by ISAS/JAXA and the science mission is led by PERC, Chiba Inst. of Technology (ChiTech). It will test high performance electric propelled vehicle technology and high-speed flyby of asteroid (3200) Phaethon and possibly asteroid 2005UD, a likely break-up body from Phaethon, as an extended mission. Engineering challenges include an up-close encounter at a distance of 500 km from Phaethon with radio-optical hybrid navigation guidance and control, and autonomous imaging based on optical information for target tracking during a high-speed flyby of 36 km/sec. The science goal is to understand the nature and origin of cosmic dust brought onto the Earth, in the context of exogenous contribution of carbon and organics for possible prebiotic seeds of the terrestrial life. Phaethon is a parent body of Geminid meteor shower, and thus a known source to periodically provide dust to the Earth, via its dust stream. The science objectives are two folded: (1) in-situ analyses of velocity, arrival direction, mass and chemical composition of interplanetary and interstellar dust particles around 1 au, the dust trail, and nearby Phaethon, and (2) flyby imaging of Phaethon to study its geology, for understanding dust ejection mechanism of active asteroid and the surface feature and composition which are affected by extensive solar heating. Science payloads include a panchromatic, telescopic camera with a tracking capability (TCAP), a visible-NIR multi-band camera with four bands of 425, 550, 700, 850 nm (MCAP), and a dust analyzer (DDA), which is an upgrade version of Cassini Cosmic Dust Analyzer (CDA). While the two cameras are developed by PERC/Chitech, DDA is developed by Univ. of Stuttgart, as an international collaboration with DLR. Ground calibration for DDA is being performed with German/Japanese joint efforts. International observation campaign for Phaethon was conducted in December 2017, and that of asteroid 2005 UD in October, 2018. Also, international observation campaign for stellar occultation by Phaethon was performed in 2019. Continuing efforts to better define the size, shape and albedo of Phaethon have been performed in 2021. Observation of stellar occultation by Phaethon was successfully conducted in the southwestern part of Japan Main Island and the southern part of South Korea in Oct. 4^th, 2021. Photometric observation was conducted by the SEIMEI Telescope of Kyoto University and in JAXA Bisei Space Guard Center from October to November with small solar phase angles. Polarimetric observation was performed in Nishi-Harima Observatory and Higashi Hiroshima Observatory from October through late December with small solar phase angles. Here, we present the current status of DESTINY⁺ project and its science.