[meteorite-list] Rosetta Triumphs at Asteroid Lutetia

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Sun, 11 Jul 2010 11:15:08 -0700 (PDT)
Message-ID: <201007111815.o6BIF8Od014834_at_zagami.jpl.nasa.gov>

http://www.esa.int/export/esaCP/SEM44DZOFBG_index_1.html

Rosetta triumphs at asteroid Lutetia
European Space Agency
10 July 2010

Asteroid Lutetia has been revealed as a battered world of many craters.
ESA's Rosetta mission has returned the first close-up images of the asteroid
showing it is most probably a primitive survivor from the violent birth of
the Solar System.

The flyby has been a spectacular success with Rosetta performing
faultlessly. Closest approach took place at 18:10 CEST [1610 UTC], at a
distance of 3162 km.

The images show that Lutetia is heavily cratered, having suffered many
impacts during its 4.5 billion years of existence. As Rosetta drew close, a
giant bowl-shaped depression stretching across much of the asteroid rotated
into view. The images confirm that Lutetia is an elongated body, with its
longest side around 130km.

The images come from OSIRIS instrument, which combines a wide angle and a
narrow angle camera. At closest approach, details down to a scale of 60
metres can be seen over the entire surface of Lutetia.

"I think this is a very old object. Tonight we have seen a remnant of the
Solar System's creation," says Holger Sierks, OSIRIS principal investigator,
Max Planck Institute for Solar System Research, Lindau.

Rosetta raced past the asteroid at 15 km/s completing the flyby in just a
minute. But the cameras and other instruments had been working for hours and
in some cases days beforehand, and will continue afterwards. Shortly after
closest approach, Rosetta began transmitting data to Earth for processing.

Lutetia has been a mystery for many years. Ground-based telescopes have
shown that the asteroid presents confusing characteristics. In some respects
it resembles a C-type asteroid, a primitive body left over from the
formation of the Solar System. In others, it looks like an M-type asteroid.
These have been associated with iron meteorites, are usually reddish in
colour and thought to be fragments of the cores of much larger objects.

The new images and the data from Rosetta's other instruments will help to
decide but not tonight. Compositional information will be needed for that.

Rosetta operated a full suite of instruments at the encounter, including
remote sensing and in-situ measurements. Some of the payload of its Philae
lander were also switched on. Together they looked for evidence of a highly
tenuous atmosphere, magnetic effects, and studied the surface composition as
well as the asteroid's density. They also attempted to catch any dust grains
that may have been floating in space near the asteroid for on-board
analysis. The results from these instruments will come in time.

The flyby marks the attainment of one of Rosetta's main scientific
objectives. The spacecraft will now continue to its primary target, comet
Churyumov-Gerasimenko. It will rendezvous with the comet in 2014, mapping it
and studying it. It will then accompany the comet for months, from near the
orbit of Jupiter down to its closest approach to the Sun. In November 2014,
Rosetta will deploy Philae to land on the comet nucleus.

"Wunderbar!" says David Southwood, ESA Director of Science and Robotic
Exploration, "It has been a great day for exploration, a great day for
European science. The clockwork precision is a great tribute to the
scientists and engineers in our Member States in our industry and, not
least, in ESA itself. Roll on 2014 and our comet rendezvous."

But for now, analysing the Lutetia data will now become the focus for the
Rosetta instrument teams. Just twenty-four hours ago, Lutetia was a distant
stranger. Now, thanks to Rosetta, it has become a close friend.

[NOTE: Images and weblinks supporting this release are available at
http://www.esa.int/export/esaCP/SEM44DZOFBG_index_1.html]
Received on Sun 11 Jul 2010 02:15:08 PM PDT