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Mission control ready for Gaia launch– Dec 17, 2013– Paris, France (Techreleased) – Shortly after a powerful Soyuz launcher lofts Gaia, ESA’s new star mapper, into space on Thursday, teams on the ground will establish initial radio contact. Even then, tension will run high in ESA’s mission control as Gaia must still perform a critical […]
Mission control ready for Gaia launch– Dec 17, 2013– Paris, France (Techreleased) – Shortly after a powerful Soyuz launcher lofts Gaia, ESA’s new star mapper, into space on Thursday, teams on the ground will establish initial radio contact. Even then, tension will run high in ESA’s mission control as Gaia must still perform a critical automatic sequence.
Gaia launch
An astrometry mission, Gaia will observe a thousand million stars on average 70 times over a five-year period.
It will precisely chart their positions, distances and movements, and is expected to discover thousands of new celestial objects, such as extrasolar planetary systems and brown dwarfs. It will also observe hundreds of thousands of asteroids within our own Solar System.
The first step in its journey is set to happen on 19 December, when it will be launched towards the Sun–Earth L2 orbital position on a Soyuz rocket from ESA’s Spaceport in Kourou, French Guiana.
Gaia will be controlled from ESA’s European Space Operations Centre (ESOC) in Darmstadt, Germany, where engineers are ready after months of intensive preparations and simulations.
The team will monitor the satellite 24 hours a day during the crucial Launch and Early Orbit Phase – the famous LEOP – which will last for around four days, and will focus around the time that Gaia separates from the Soyuz upper stage 42 minutes after liftoff.
Before separating, Gaia will ‘phone home’, sending a first radio signal to ESA’s Australian Perth ground station to inform controllers of its immediate health status. Signals will subsequently be picked up by several other of the Agency’s Estrack ground stations.
“But after separation, Gaia must still perform a critical automated sequence that includes pressurising its attitude control thrusters and deploying its sunshield, a very delicate step,” says Dave Milligan, Gaia Spacecraft Operations Manager.
During the sequence, Gaia will be in ‘free drift’, meaning that its attitude in space is not controlled and separating from its launcher may cause it to spin or tumble. As a result, it may rotate out of line-of-sight radio communication with the stations below.
“During about 17 minutes, we may lose radio contact, but so long as the onboard sequence runs OK, we’ll regain communications afterwards.
“Nonetheless, those minutes in the main control room will be very long and tense for us. Operations engineers never like being out of contact with their satellites,” says Dave.
