T – 0 sec: The engines of the first and second stages were ignited – the Soyuz-Fregat with Gaia as payload lifts off from the launch pad of the ESA/Arianespace spaceport near Kourou, French Guiana. The lift off has to occur during the predetermined second. If there is any delay during the countdown then the launch has to be postponed for at least 24 hours.
T + 288 sec: The second stage separates from the third stage after its burnout. Two seconds earlier the engine of the third stage was ignited. This early start with the core stage still accelerating the stack allows a better control of the movement of the fuel in the third stage during the ignition sequence of the third stage engine. The lattice between core stage and third stage in combination with a heat shield on top of the core stage allows the exhaust of the third stage engine to leave during this short phase.
T + 623 sec: The third stage has burned out and the Fregat upperstage – Gaia combination has separated from it. The Fregat upperstage is ignited for a short first burn of 136 sec to reach a parking orbit at 185 km altitude.
T + ~21 min: When the final destination, the Lagrange point L2, is in sight as well as the ground station in Perth, Australia, a second burn of the Fregat upperstage will occur with a duration of about 15 minutes.
T + 1 hour: The 11m diameter sunshield of Gaia is starting to unfold in an automatic sequence to protect the payload from the intensive light of the Sun. Solar panels on the backside (always orientated towards the Sun) of the sunshield will generate power for Gaia on its one month journey to L2 and during the entire mission (video source: ESA/ATG medialab).
The video above was provided by ESA. The animations are taken from a video about the Gaia satellite which is property of our Gaia UB team. The entire video can be found here at the GaiaUB youtube channel: http://www.youtube.com/watch?v=rrCxVTh3HCM
Update Dec. 14: The timing of some events was updated based on the latest planning for the launch given in the Arianespace launchkit http://www.arianespace.com/images/launch-kits/launch-kit-pdf-eng/VS06-launchkit-GB2.pdf.