The flyby of asteroid (21) Lutetia on the 10 th July 2010 was another opportunity to test the operation of several of the instruments aboard Rosetta and to uncover the secrets of an enigmatic main-belt asteroid. Shape model data sources.

They are, from largest to smallest: 4 Vesta, 21 Lutetia, 253 Mathilde, 243 Ida and its moon Dactyl, 433 Eros, 951 Gaspra, 2867 Šteins, 25143 Itokawa. Asteroid Lutetia Asteroid 21 On July 10, 2010 the European Space Agency's spacecraft Rosetta, on its way to a 2014 rendezvous with a comet, flew by the metallic asteroid Lutetia. The largest asteroid in the previous image, Vesta (left), with Ceres (center) and the Moon (right) shown to scale. Asteroid (21) Lutetia Discovered in Paris by Hermann Goldschmidt in November 1852, asteroid (21) Lutetia has been a cosmic riddle for astronomers. The probe passed by at a minimum distance of 3160 kilometers, traveling at speeds of 15 km per second. Torppa et al., Shapes and rotational properties of thirty asteroids from photometric data. Icarus 164, 2003 link; Carry et al., Physical properties of ESA Rosetta target asteroid (21) Lutetia: Shape and flyby geometry. Earlier this month, ESA's robotic Rosetta spacecraft zipped past the asteroid 21 Lutetia taking data and snapping images in an effort to better determine the history of the asteroid and the origin of its unusual colors. The Asteroid 21 Lutetia, discovered in 1852, is one of the larger main-belt asteroids.

Asteroid 21 Lutetia, imaged by the ESA’s Rosetta spacecraft in July 2010 (Credit: ESA 2010 MPS for OSIRIS Team MPS / UPD / LAM / IAA / RSSD … In 2004, it became the flyby target asteroid for the Rosetta spacecraft mission.

Although of unknown composition, Lutetia is not massive enough for gravity to pull it … In an attempt to pin down its properties once and for all, ESA's Rosetta spacecraft flew past Lutetia at a distance of 3162 km, at a relative speed of 15 km/s on 10 July 2010 at 18:10 CEST.