Overview of the Rosetta Fly-by of 21-Lutetia as Observed by the OSIRIS Camera System

On July 10th 2010 the ESA Rosetta spacecraft flew past the asteroid 21-Lutetia on the way to it's 2014 rendezvous with Comet 67P/Churyumov-Gerasimenko. The closest distance to the asteroid was 3160 km. During the fly-by the scientific camera system OSIRIS observed the asteroid. The resolved observations started 9hours 30min before the closest approach and finished 18 min after the closest approach. During this period the camera system acquired 234 images with the Narrow Angle Camera (NAC) and 228 images with the Wide Angle Camera (WAC). The highest resolution obtained on the surface was 59 m/pixel. 21-Lutetia is the largest asteroid yet visited by a spacecraft. The surface shows a highly impacted surface with the largest impact craters reaching 60km. The surface also shows evidence of thick regolith layers and grooves as previously seen on the moon Phobos. This paper will give an overview of the observations made by the OSIRIS cameras.