This is another success for Europe in Space: European Gaia satellite was launched on Thursday without snares of the Kourou Space Center (6:12 local time) Guyana, a Russian Soyuz. The aim is to explore the galaxy using an embedded ultra-sophisticated telescope. Clarification.
> What is the satellite?
Gaia has a diameter of 3.8 meters and a height of 4.4 meters. Its mass is two tons, a featherweight compared to the American Hubble and 11 tonnes.
Gaia account on board three different instruments: an instrument for astrometry to determine the position, movement and distance of stars, a photometric instrument to measure the brightness and color of stars and a spectrometer specify the type of their light.
Hopefully, Gaia will be set for five years to about 1.5 million kilometers from Earth, in a privileged location, Lagrange point 2 .
> What is its mission?
mission Gaia will map our galaxy in 3D. Astronomers estimate that it will locate a billion stars in the Milky Way, or 1% of stars in our galaxy. Scientists also hope that it can also detect 300,000 asteroids, 1000-2000 Cepheids , giant stars whose brightness varies extremely regular, nearly 500,000 quasars and yet 10000-20000 exoplanets.
The harvest should be done with unprecedented precision: 7 microseconds of arc (the arc is a subunit of the degree) for the brightest stars (magnitude 12 or less) to 300 microseconds of arc the lower (20 magnitude). By comparison, 10 arc microseconds correspond to the thickness of a human hair seen 1,000 miles away.
> Who will analyze the data?
satellite will send its data collection on Earth daily for eight hours each day. Mission represent a volume of the order of petabytes of data, or a million billion bytes. 30 laboratories and 450 people will be involved in Europe to interpret the huge amount of information, including a hundred in France.
> How much is this scientific adventure?
The cost of the mission is estimated at EUR 740 million, to which must be added that the consortium in charge of data processing, the DPAC, estimated at around 200 million euros. Gaia was built at Astrium Toulouse , on behalf of the European Space Agency.