The Akatsuki Space Probe Blasts into Orbit
An image of the Venus probe Akatsuki. The mission is due to enter Venus's orbit in December 2010. (C) Akihiro Ikeshita, JAXA.
Akatsuki just before its launch into space. The box-shaped probe is 1 meter long, 1.5 meters wide, 1.4 meters tall, and weighs 500 kilograms. (C) JAXA.
The Venus probe Akatsuki and solar sail Ikaros were launched aboard the No. 17 H-IIA rocket on May 18, 2010. The H-IIA rocket is Japan’s major large-scale launching vehicle, and one of the best in the world in terms of cost-performance. The rocket has a diameter of 4 meters and stands 53 meters tall. (C) JAXA.
In 2010, Japan launched its first mission to Venus. Named Akatsuki, after the Japanese word for "dawn," this is the first attempt ever to put a satellite in orbit to measure conditions on another planet, just like a weather satellite on Earth. Venus is the next planet to the sun from Earth, and because it is almost the same size, it is sometimes called Earth's "twin." Venus can be seen twinkling in the skies from earth in the early morning and just after sunset.
The reason Venus seems to shine so brightly is that the planet is covered with a thick layer of cloud of sulfuric acid that reflects 78% of the sun's rays. Although very little sunlight gets through to the surface of the planet, the atmosphere on Venus is made up almost entirely of carbon dioxide, which acts like a greenhouse to trap heat. The temperature on the surface is a blistering 460 degrees centigrade. And although it takes Venus a full 243 days to turn on its axis, winds in its atmosphere are rushing constantly from east to west at an incredible 400 kilometers per hour. This atmospheric movement on Venus is called "super rotation," and it is one of the biggest mysteries of the Solar System. Both about 4.6 billion years old, why have Venus and the Earth followed such different paths? Bringing together the very latest Japanese technology, the Akatsuki satellite will attempt to answer this riddle.