European probe Rosetta successfully flies by asteroid: ESAPARIS, July 10, 2010 (AFP) - The European spacecraft Rosetta performed a fly-by of a massive asteroid on Saturday, the European Space Agency said, taking images that could one day help Earth defend itself from destruction.
Racing through the asteroid belt between Mars and Jupiter at 47,800 kph (29,925 mph), the billion-euro (1.25-billion-dollar) probe flew within 3,200 kms (2,000 miles) of the huge potato-shaped rock, Lutetia.
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"We have completed the fly-by phase," Rosetta's director of operations Andrea Accomazzo said on the ESA's website from the European Space Operations Centre in Darmstadt, Germany.
The aim of the fly-by of the asteroid, measuring 134 kms (83.75 miles) in diameter, is to measure Lutetia's mass and then calculate its density, knowledge which could one day be a lifesaver, according to ESA scientists.
If a rogue asteroid enters on a collision course with Earth, knowing its density will help the planet's defenders to determine whether they should try to deflect the rock or, instead, blow it up.
As Rosetta is around half a million kilometres from Earth, the probe's signal and images it has taken will take 25 minutes to be received. They will then be analysed and released by ESA scientists around 2100 GMT.
The flyby comes halfway through the extraordinary voyage of Rosetta, launched in 2004 on a 12-year, 7.1-billion-kilometre (4.4-billion-mile) mission.
One of the biggest gambles in the history of space exploration, the unmanned explorer is designed to meet up in 2014 with Comet 67/P Churyumov-Gerasimenko 675 million kms (422 million miles) from home.
The goal is to unlock the secrets of these lonely wanderers of the cosmos, whose origins date back to the dawn of the Solar System, some 4.5 billion years ago, before planets existed.
To get to its distant meeting point, Rosetta has had to play planetary billiards for five years, using four "gravitational assists" from Earth and Mars as slingshots to build up speed.
by Martin Bernetti
(c) 2010 AFP