MISSIONWhat is "Akatsuki"?

3-D CG illustration of Venus and Akatsuki

The Venus Climate Orbiter Akatsuki is a spacecraft developed in order to unravel the mysteries of the atmosphere on Venus.

The spacecraft was launched from the Tanegashima Space Center on May 20, 2010 (UTC) and became the first Japanese probe to enter orbit around a planet other than the Earth on December 7, 2015.

Akatsuki is equipped with five cameras capable of obtaining images of Venusian atmosphere in the infrared, visible, and ultraviolet ranges, and also with an ultra-stable oscillator used to measure the vertial profiles of temperature and other factors. It traces an elliptical orbit around Venus in about 10 days and allows for investigating the flow and constituents of the atmosphere, as well as the presence of lightning and volcanic activity.

Akatsuki's target of Venus is a planet approximately the same size as our own and considered the "sibling" to the Earth. However, its atmosphere is about 100 times as thick as that of the Earth's, and it is covered in high-temperature carbon dioxide. The "super rotation" reaching 100 m/s at high altitudes is a fierce wind the cause of which remains unknown.

Akatsuki takes advantages of the six instruments to observe meteorological phenomena on Venus in detail. These findings are expected to lead to a better understanding of meteorological phenomena not only on Venus, but also on other planets and further help explicate why the the Earth's atmosphere is the way it is, as well as how it may change in the future.