Research on Space Science Venus Climate Orbiter "AKATSUKI" (PLANET-C)

Latter Phase In Operation

About Venus Climate Orbiter "AKATSUKI" (PLANET-C)

(Courtesy of Akihiro Ikeshita)

AKASTUKI will elucidate the mysteries of Venus, Earth’s twin sister.
Japan will initiate the beginning of a new era of Venusian exploration.

AKATSUKI (PLANET-C) is the next planetary exploration project for the Martian orbiter NOZOMI. Venus has long been referred to as Earth’s sister planet not only because its size and distance from the sun are similar to those of the Earth, but also because its birth formation is considered to be similar to that of the Earth at the genesis period of the solar system. However, Venus is actually very different from the Earth as it is veiled in high-temperature carbon dioxide and thick sulfuric-acid clouds. Also, above the surface of Venus, violent winds which reach some 400 kilometers per hour blow over. Clarification of the causes for such an environment will provide us with clues to understand why the Earth has become a peaceful and lively planet unlike Venus as well as to help understand climate change on Earth. Therefore, Venus is a very important subject for exploration to learn about the Earth’s environment.

Launch date: May 21, 2010

Project Topics

Sep. 5, 2017 Updated

Venus: Jet-setting atmosphere

Venus: Jet-setting atmosphere

Data from JAXA's Venus Climate Orbiter Akatsuki reports the evidence of a fast atmospheric flow near the planet's equator. JAXA and the team of researchers from the Hokkaido University and others used images from the Akatsuki orbiter to track jet*-shaping strong winds in the low and middle cloud region, which extends from 45 to 60 kilometers in altitude. The wind speed maximized near the equator. They named this phenomenon Venusian equatorial jet. Previously, the wind speed at this altitude w...

Re-execution of Venus orbit insertion and successful result

The AKATSUKI was launched by the H-IIA Launch Vehicle No. 17 in May 2010. After its smooth flight, JAXA attempted to insert the orbiter into the orbit circling around Venus on Dec. 7, 2010, but it failed as the main engine for orbit control was broken.
JAXA established an investigation team to find the cause of the failure while studying a feasible plan for a second attempt.
On Dec. 7, 2015, JAXA successfully inserted the orbiter into the Venus orbit by emitting thrust from the attitude control engine. We will perform function checks of onboard observation instruments for about three months and gradually shift the orbit to an elliptical orbit whose period is about nine days through orbit control operations. Full-scale observations are scheduled to begin in April 2016.

JAXA accepted support messages for the AKATSUKI between Nov. 5, 2015, thru Jan. 5, 2016. Thank you very much for your support.

Characteristics of Venus Climate Orbiter "AKATSUKI" (PLANET-C)

Infrared light enables more detailed investigation of Venus.

The probe vehicle of AKATSUKI will enter an elliptical orbit, 300 to 80,000 km away from Venus’s surface. This wide variation in distance will enable comprehensive observations of the planet’s meteorological phenomena and of its surface, as well as observations of the atmospheric particles escaping from Venus into space. It will also be possible to take close-up photos of Venus, and to observe the storm winds that blow on the Venusian surface, at speeds that reach 100 m a second - 60 times the speed at which Venus rotates. This phenomenon remains the biggest mystery of Venus, as it cannot be explained meteorologically. AKATSUKI will employ infrared light to observe and elucidate the mysteries surrounding the atmosphere under the clouds and the conditions on the planet’s surface. In addition, it will confirm the presence of active volcanoes and thunder.

Major Characteristics

International Designation Code 2010-020D
Launch Date 6:58, May 21, 2010 (JST)
Launch Vehicle H-IIA Launch Vehicle No.17
Location Tanegashima Space Center
Shape Box shape with two wing-type solar array paddles
Weight Mass at liftoff: about 500 kg
Orbital Altitude PeriVenus: 1,000-10,000km
ApoVenus: 370,000km
Type of Orbit Elliptical around Venus
Orbital Period 10.8 days

Mission talk by team leaders

Project manager Masato Nakamura

Here are messages from Project Managers.