ESA’s Rosetta comet-chaser is en route to its main target, comet 67P/ Churyumov-Gerasimenko, arriving in 2014. On Saturday, 10 July it will fly past the previously unvisited asteroid Lutetia.
Lutetia will be the second asteroid studied during Rosetta’s journey. The Steins flyby [video] took place on 5 September 2008, approaching to within 800 km.
Lutetia is a much bigger asteroid, so the flyby will be no closer than about 3200 km. Any nearer and Rosetta would not be able to fit the whole asteroid into the camera’s field of view.