When Rosetta reaches Lutetia, it will fly by at a separation of 3,200 kilometres, at a relative speed of 54,000 km/hr. They will be some 454 million km from Earth. Approximately two hours of high quality imaging will be recorded, which will be immediately piped back to Earth. The time of closest approach is currently estimated (8 July) at 9:10 AM Phoenix time (16:10 UTC), and the spacecraft’s accompanying lander, Philae, will be switched on earlier that day in order to collect data throughout the flyby.
The Rosetta probe was built by EADS Astrium. Rosetta consists of a 3,065-kg spacecraft (1,578-kg dry mass) and a 100-kg lander, Philae. Rosetta will enter orbit around the nucleus of comet Churyumov-Gerasimenko in August 2014, following three gravity assists from Earth and one from Mars.
Philae (excellent interactive graphic of the orbits and Rosetta accompanying C-G) was created by a European consortium under the leadership of the German Aerospace Research Institute (DLR). Other members of the consortium are ESA and institutes from Austria, Finland, France, Hungary, Ireland, Italy and the UK.
After Rosetta‘s rendezvous with Lutetia, she will be off to Churyumov-Gerasimenko, a comet with a current orbital period of 6.6 years, and discovered accidentally in 1969. Based on the orbital parameters, it appears that in 1959 C-G was nudged by an encounter with Jupiter into its present orbit, with a perihelion of 1.28 AU This is sufficiently close to create a comet tail. Prior to this, C-G had a perihelion of 3.0 AU. This orbit was established by an encounter with Jupiter around 1840. Prior to that, the perihelion was 4.0 AU.
Rosetta Observing Lutetia
Image Credit: ESA/ AOES Medialab.