The ESA space probe Rosetta flew past the Lutetia planetoid at around 6 p.m. CEST on Saturday. The OSIRIS camera system, built under the direction of the Max Planck Institute, provided unique images of this rendezvous. They not only show a large number of craters on the surface of the celestial body, but also individual rocks and parallel grooves.

Fig. 1: A playground for geologists: The surface of the asteroid Lutetia is covered in craters. In some places, parallel grooves can also be seen.

Image: ESA 2010 MPS for OSIRIS Team/MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

With a resolution of around 60 metres per pixel, the images provide a fascinating view of Lutetia. "This is a completely new world, which no-one has ever seen before," says Max Planck researcher Holger Sierks, Head of the OSIRIS team. The planetoid, whose longest axis measures around 126 kilometres, is oval in shape. Its surface is marked by many craters, both large and small; in one of the larger craters, the images even show evidence of a landslide. In some parts, parallel grooves cover the cosmic rock, the origin of which is still unknown.

The camera system had already focused on the asteroid on Saturday morning. At approximately 6 p.m. the Rosetta space probe was within 3,162 kilometres of the asteroid. "Both the wide-angle and the telephoto camera worked perfectly," reports Sierks. The Control Centre of the European Space Agency ESA passed the data collected during the fly-by directly to the Max Planck Institute, where researchers worked all day and into the night filtering images from the raw data. On Saturday at around 11 p.m. they presented their initial results.

During the coming days and weeks the scientists want to further evaluate the images. It should then be possible to determine the colour of the asteroid and thus the chemical composition of its surface in more detail. They will also use data from other measuring instruments which were active during the fly-by as well.

Since 2004, the Rosetta space probe has been en route to the Churyumov/Gerasimenko comet, and the plan is for the Philae lander to touch down on the comet in 2014. In September 2008, Rosetta passed the planetoid Steins.

Fig. 2: Zooming in on Lutetia: A sequence of images taken during the fly-by.

Source: Max Planck Institute