Akatsuki

                                                                AKATSUKI

MISSION OVERVIEW:

Japan Aerospace Exploration Agency (JAXA) launched Akatsuki (“Dawn”), a meteorological satellite, in 2010. It arrived at its destination, Venus, later that year. Space exploration is hard, though, and due to an engine problem, the probe failed to enter Venus’s orbit.
Here’s what happened: On average, it takes about eight minutes for a radio signal to reach Venus from Earth. (Sometimes it’s shorter; sometimes it’s longer. It just depends on where the planets are.) Anything sent such vast distances, then, has to be somewhat self-sufficient. Not only did JAXA have to deal with that delay, but once Akasuki reached the Cloud Planet and began its maneuver into orbit, the probe had to enter a total communications blackout—it was, for a time, on the other side of the planet with no way for signals to reach Earth. Once communications were reestablished, JAXA learned that orbital maneuvers failed, the probe shot past Venus, and the system went into a kind of holding pattern. (Even in their setbacks, space probes are designed to be resilient and cunning.)
The bad news was that physics were no longer on the probe’s side and another try at Venus was impossible; entering orbit is typically a one-shot deal. The good news? Engineers are geniuses. They discovered that while its main engine was shot, its little thrusters were OK—so they put Akatsuki into hibernation mode and a heliocentric orbit (i.e. around the Sun), and the waiting game began. Rather than try to chase down Venus, they decided, why not just let Venus and Akatsuki chase down each other? The two will again line up in late 2015, at which point another attempt at establishing orbit will be made. It’s risky—this is the first time the thrusters have ever been used in such a way. But if it works, humanity’s understanding of the weather and volcanism of our “sister planet” will increase greatly.

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.

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

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.