[meteorite-list] Akatsuki to Try Again to Enter Orbit Around Venus

[Ron Baalke]

http://the-japan-news.com/news/article/0001832475

Akatsuki to reattempt to enter orbit of Venus
The Japan News
January 06, 2015

The Japan Aerospace Exploration Agency plans to have 
its probe Akatsuki reattempt an entry into the orbit of Venus in early 
December, probably its last chance due to low fuel, following a failed 
endeavor to do so in December 2010 because of engine trouble.

According to JAXA, the agency has been looking for an opportunity to have 
Akatsuki make a new attempt, while checking if the probe was still functional.

If the second attempt succeeds, Akatsuki will be Japan's first probe 
to enter the orbit of a planet other than Earth.

According to JAXA, Akatsuki is currently located about 134 million kilometers 
from Venus and is shortening the distance by about 400,000 kilometers 
a day.

In the previous attempt, Akatsuki tried to enter Venus' orbit by burning 
its main rocket in reverse to decelerate. But the rocket stopped working 
midway and the probe passed Venus. JAXA believes the engine likely malfunctioned 
due to abnormally high temperatures.

JAXA made gradual adjustments to Akatsuki's course, eventually having 
the probe orbit the sun on the off chance Akatsuki could approach Venus 
once more.

The agency initially considered a second attempt at the end of 2016, but 
decided instead to aim for an orbit in November this year over concern 
that the probe's body is deteriorating from the sun's heat. Following 
calculations, the agency said the ideal orbital insertion window was in 
early December.

According to the plan, Akatsuki aims to enter an oval orbit several hundreds 
to 400,000 kilometers above the planet by reducing its speed with four 
of its 12 small engines to control the probe, as its main engine is out 
of order.

Venus is almost the same size as Earth, which is why it is called "Earth's 
sister planet." But Venus has surface temperatures of 500 C, not to 
mention atmospheric pressure about 90 times stronger than its "sister." 
JAXA says Akatsuki is scheduled to observe Venus by revolving around the 
planet, taking eight to 10 days in each orbit over two years as it delves 
into why the planet's conditions became so severe.

The second attempt will have fewer observation opportunities as well as 
degraded image quality taken by its on-board camera as the orbit is farther 
from Venus than initially planned. But JAXA Prof. Masato Nakamura who 
leads the Akatsuki project said, "Provided the equipment works, we should 
be able to make most of the planned observations."

The biggest hurdle looms ahead: Akatsuki will approach the sun in February 
and August before orbit insertion. By then, some of the probe's equipment 
will encounter temperatures as high as nearly 200 C. Nakamura added the 
minimum requirements for the second attempt will be met if the probe survives 
unscathed with no fuel leakage.Speech