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

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 6 Jan 2015 20:22:15 -0800 (PST)
Message-ID: <201501070422.t074MF16028650_at_zagami.jpl.nasa.gov>


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
Received on Tue 06 Jan 2015 11:22:15 PM PST

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