The European Space Agency’s GAIA ( Global Astrometric Interferometer for Astrophysics) mission was successsfully launched from Sinnamary launch site, near Kourou, French Guiana, at 0912 GMT on 19 December by a Soyuz ST-B (Fregat M). GAIA is to study the composition, formation and evolution of the galaxy by high precision mapping of a billion stars. After a being placed in a 175km parking orbit, a second firing of the Fregat upper stage took the craft into a transfer orbit. GAIA will be eventually be placed into a halo orbit around the gravitationally balanced L2 Lagrangian position, 1.5 million km from the Earth. The spacecraft carries 10m sunshield which also has solar cells for power generation.GAIA will provide information for a 3-D map of the galaxy. Mission cost was valued at €460 milliion as part of Horizon 2000+ programme.
Comment by David Todd: It is interesting to note that Arianespace and Astrium has just signed a contract for the production of another 18 Ariane 5 ECA launch vehicles to add to its 35 launcher order of 2009. This might mean that Arianespace expects to continue to use the Ariane 5 to launch smaller satellites to GTO as part of matched pairs with larger spacecraft than use Soyuz for this role. Both launch vehicles, of course, would ultimately be replaced by Ariane 6.