Comet hunter reveals crater world on Lutetia

Spacecraft Rosetta delivers first pictures of the asteroid

The surface of the asteroid Lutetia is covered with craters. In places also show in parallel
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The ESA spacecraft Rosetta flew past at 6pm on Saturday just past the asteroid Lutetia. The first images of this unique event show numerous craters, single boulders and parallel grooves on the surface of the celestial body.

With a resolution of about 60 meters per pixel, the images from the OSIRIS camera system allow for a first-time look at Lutetia. "This is a whole new world that nobody has ever seen before, " said Holger Sierks of the Max Planck Institute for Solar System Research (MPS), head of the OSIRIS team, that same night.

The asteroid, whose longest axis measures about 126 kilometers, has an oval shape. Its surface is dotted with numerous large and small craters. In one of the larger craters, the pictures even show evidence of a landslide. In places, parallel grooves also cover the surface of Lutetia, whose origin is still unclear.

running grooves. © ESA / MPS for OSIRIS Team / UPD / LAM / IAA /

World full of craters

"Even from a distance of 500, 000 kilometers, it was clear that Lutetia, with its very irregular shape, is an exceptional asteroid. But when the camera system OSIRIS took its best pictures from a good 3, 000 kilometers, we really did recognize the beauty of this object, "says planetary scientist Stefano Mottola from the German Aerospace Center (DLR).

"Lutetia's surface is littered with huge craters, ridges, and landslides, suggesting a story of massive events. On the surface are rocks that are hundreds of meters tall. The tremendous quality of the data will allow us scientists to better understand the processes that caused these phenomena, "Mottola continued in an initial assessment. display

Lutetia images are evaluated

Already on the morning of 10 July 2010, the OSIRIS camera system developed and built on the MPS had targeted the asteroid. Around 6 pm, the space probe and asteroid approached at the shortest distance. "Both the wide-angle and telephoto cameras from OSIRIS worked perfectly, " reports Sierks. The data collected during the flyby led the ESA control center directly to the Max Planck Institute, where researchers filtered images from the raw data over the day and night. At about 11 pm, the scientists were able to present their first results.

In the next few days and weeks, the scientists at the MPS will further evaluate the images of Lutetia. Then it will be possible to more accurately determine the color of the asteroid and thus the chemical composition of its surface. The data from other measuring instruments that were active during the flyby will help.


Spectrometer experiment VIRTIS

Like the spectrometer experiment VIRTIS, which has already been transmitted to Earth. "Our team immediately started evaluating the data, " reports DLR researcher Gabriele Arnold. In contrast to the images of the camera system, the spectral data obtained in visible and infrared light up to a wavelength of five micrometers are more difficult to interpret; a detailed evaluation takes time.

In addition to the spring guidance on the ROLIS camera for observing the surface of the comets during the landing phase, the SESAME experiment for the seismic investigation of the cometary nucleus and the device MUPUS, which determines the surface temperature and strength of the comet, the DLR planetary scientists are scientifically involved in the ROMAP magnetometer and the COSAC experiment. The latter analyzes the chemical composition of the frozen surface down to a depth of 20 centimeters.

Arrival at Churyumov-Gerasimenko in May 2014

The Rosetta spacecraft has been on the way since 2004 to the comet Churyumov / Gerasimenko, on which the landing unit Philae 2014 will be based. From July 2011, however, the comet probe will begin its almost two-and-a-half year rest period: in January 2014 Rosetta awakens from this deep sleep and prepares to arrive at Churyumov-Gerasimenko in May 2014.

In September 2008, the probe had first passed an asteroid with the teins rendezvous. In general, the study of the so-called small bodies, which include the asteroids Lutetia and teins, provides important clues to the earliest times of the solar system. With a diameter of about 100 kilometers, Lutetia is much larger than the only five kilometer asteroid. Lutetia is the largest asteroid a space mission has ever visited.

More about this topic can be found in our special about Rosetta and Lutetia ...

(Max Planck Institute for Solar System Research / German Aerospace Center (DLR), 12.07.2010 - DLO)