“It’s a new world discovered by Rosetta and it will keep scientists busy for years,” said Holger Sierks, the principal investigator on the Osiris camera system (BBC).
At 18:10 CEST on 10 July, the probe—equipped with cameras, spectrometers, magnetic-field experiments and more—passed within 3162 km of Lutetia. The flyby itself was very brief—lasting only about a minute—as Rosetta swept past the asteroid at a speed of 15 km/s. The 400 images that were attained during the fly-by are now being sent back to Earth, with the first pictures arriving over the weekend.
Lutetia is the largest asteroid ever visited by a space probe. The new pictures reveal it has an uneven surface covered by craters, and a stretched-out body that is about 130 km at its longest side. Lutetia is located between Mars and Jupiter, some 454 million km away from Earth.
Although Lutetia was first observed back in 1852 from a balcony in Paris by astronomer and painter Hermann Goldschmidt, it has been something of an enigma to astronomers for many years. Earth-based telescopes have not been able to help determine whether it’s an old, carbon-bearing left-over from the formation of the Solar System (C-type), or if it has a surface containing metals (M-type). Hopefully, the new data from the probe will help shed some light on the problem.
“It is an historic day, Europe once again proving it can do major steps in Solar System exploration. Everything worked like clockwork. It really was picture perfect,” David Southwood, the European Space Agency’s director of science, told the BBC.
Rosetta will now continue its course towards its main destination: the comet Churyumov-Gerasimenko. After orbiting alongside the comet for a few months, it will send a lander to the surface in November 2014.
Image: asteroid Lutetia / ESA