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"This is just the beginning," said David Southwood, ESA's director of science and robotic exploration. "If this is the way the thing begins, try and imagine how it's going to end. It is an historic day, Europe, once again, proving that it can do major steps in solar system exploration."Rosetta also visited asteroid Steins in 2008, but the much larger Lutetia offered a chance for ground-breaking science.
"Of the two asteroid flybys that we were able tosneak in on the way to the comet, Lutetia has always been our main asteroid target because we believe this will provide us with the most precious information about how the planets have formed, and what the status of the material was like during the period of planet formation," Schulz said before the flyby.
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A possible landslide and bloulders on asteroid Lutetia. Photo credit: ESA |
Despite its maximum diameter of about 80 miles, Lutetia's exact shape and mineral make-up was still a mystery to scientists before Rosetta's visit. The probe confirmed Lutetia has a slightly elongated shape, but it will be several more weeks before scientists know its chemical composition.
Lutetia was discovered in 1852, but the best pictures of the asteroid from telescopes on Earth and in space only show a pixelated object.
The best guess is Lutetia is a C-type asteroid, meaning it has stayed relatively untouched through most of the violent 4.6-billion-year history of the solar system.
C-type asteroids are dark and rich in carbon and organic molecules. Scientists believe they are leftover relics from the formation of the solar system.
"If it does turn out to be a C-type, which we all hope, then we have a large object which is rather pristine showing us what the solar system was like shortly after the planets formed," said Rita Schulz, Rosetta's project scientist, before the Saturday's flyby.
But some measurements suggest Lutetia could harbor metals, a signature of an M-type asteroid. Schulz said metallic M-type asteroids formed from rock from the interior of a larger body after massive collisions fractured the parent object.
The Lutetia flyby was the final waypoint for Rosetta on the 10-year voyage from Earth to Churyuomov-Gerasimenko.
Since its launch in 2004, Rosetta completed four gravity assists to bend the robot's trajectory toward the comet, including three flybys of Earth and a single visit to Mars.
Check out a gallery of images from Rosetta fly by
+ July 14, 2010 NASA Science Release
+ Space Flight Now: Rosetta Visits Asteroid
+ European Space Agency Rosetta Triumphs at Asteroid Lutetia
