The first europeanr asteroid 'ELYBY': Rosetta operations for the flyby of asteroid 2867 steins

Rosetta operations, the first planetary mission of ESA's Scientific Program, launched on March 2, 2004, a ten year journey to a rendezvous with Churyumov-Gerasimenko, passed asteroid 2867 Steins at a distance of about 800 km and at relative velocity of 8.6 km/s on September 5, 2008. The flyby conditions such as direction, speed, and time of flyby were defined by the overall geometry of the interplanetary orbits of Steins and Rosetta. Rosetta entered Near Sun Hibernation Mode until early July 2008, allowing all teams to focus on the Steins flyby phase, perform further validation tests, and complete the flyby operations timeline. The preliminary results by Rosetta showed that the asteroid is dominated by a large crater on the northern part and an a chain of craters. After the flyby, the processing of OSIRIS camera images provided very precise and navigation results, showing that the distance to Steins at closest approach is 802.6 km.