The first Japan's planetary orbiter AKATSUKI and its scientific results

Masato Nakamura, Nobuaki Ishii, Takeshi Imamura, Takehiko Satoh, Takumi Abe, Chikako Hirose, Atsushi Yamazaki, Junichi Nakatsuka, Tsutomu Ichikawa, Tomoaki Toda, Hiroyuki Toyoda, Sumitaka Tachikawa, Yukio Kamata, Makoto Suzuki, Takao M. Sato, Shin Ya Murakami, Yukio Yamamoto, Naomoto Iwagami, Makoto Taguchi, Tesuya FukuharaShigeto Watanabe, Yukihiro Takahashi, Munetaka Ueno, Manabu Yamada, George L. Hashimoto, Naru Hirata, Toru Kouyama, Kazunori Ogohara, Hiroki Ando, Koichiro Sugiyama, Hiroki Kashimura, Shoko Ohtsuki

Research output: Contribution to journalConference articlepeer-review


Japan's Venus Climate Orbiter Akatsuki was proposed to ISAS (Institute of Space and Astronautical Science) in 2001 as an interplanetary mission. We made 5 cameras with narrow-band filters to image Venus at different wavelengths to track the cloud and minor components distribution at different heights to study the Venusian atmospheric dynamics in 3 dimension. It was launched on May 21st, 2010 and reached Venus on December 7th, 2010. With the thrust by the orbital maneuver engine, Akatsuki tried to go into the westward equatorial orbit around Venus with the 30 hours' orbital period, however it failed by the malfunction of the propulsion system. Later the spacecraft has been orbiting the sun for 5 years. On December 7th, 2015 Akatsuki met Venus again after the orbit control and Akatsuki was put into the westward equatorial orbit whose apoapsis is about 0.44 million km and orbital period of 14 days. Its main target is to shed light on the mechanism of the fast atmospheric circulation of Venus. The systematic imaging sequence by Akatsuki is advantageous for detecting meteorological phenomena with various temporal and spatial scales. We have five photometric sensors as mission instruments for imaging, which are 1 m-infrared camera (IR1), 2 m-infrared camera (IR2), ultra-violet imager (UVI), long-wave infrared camera (LIR), and lightning and airglow camera (LAC). These photometers except LIR have changeable filters in the optics to image in certain wavelengths. Akatsuki's long elliptical orbit around Venus is suitable for obtaining cloud-tracked wind vectors over a wide area continuously from high altitudes. With the observation, the characterizations of the meridional circulation, mid-latitude jets, and various wave activities are anticipated. The technical issues of Venus orbit insertion in 2015 and the scientific new results will be given in this paper.

Original languageEnglish
JournalProceedings of the International Astronautical Congress, IAC
Publication statusPublished - 2016
Event67th International Astronautical Congress, IAC 2016 - Guadalajara, Mexico
Duration: Sep 26 2016Sep 30 2016


  • Exploration
  • Venus

ASJC Scopus subject areas

  • Aerospace Engineering
  • Astronomy and Astrophysics
  • Space and Planetary Science


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