Follow live takeoff Gaia, the star hunter telescope - 20minutes.fr

sensor billion pixels to map a billion stars. Thursday at 10:12 (Paris time), a Soyuz rocket will take off from Kourou, French Guiana, carrying on board the European Gaia telescope. Its mission in five points.

>> The live launch to follow below by CNES

1.Gaïa a European mission

Declared “cornerstone” of the European space program in 2000, the Gaia space observatory features a dual telescope that was assembled by a subsidiary of EADS Astrium in Toulouse. Its results over the next five years will be analyzed by more than 400 scientists worldwide.

2.Cartographier a billion stars

Gaia takes over from the Hipparcos satellite. Put into orbit in 1989, he helped to catalog accurately 120,000 stars in our galaxy. Gaia, he will tackle mapping, 3D, a billion stars. This represents less than 1% of the total number of stars Way lactée.Gaïa expected to accurately model the spiral shape of our galaxy, which is still very uncertain at present.

3.A super sensor billion pixels

Gaia will have the most accurate ever deployed in space camera. Combined, the 106 CCDs are more than a billion pixels. What detect a hair 1,000 miles away or a thumbnail from the Moon.

4.A distant orbit

Gaia will not be placed in geostationary orbit but the L2 Lagrange point, 1.5 million kilometers from Earth (seven times the Earth-Moon distance). It will take months to achieve the probe. This point, where the gravitational fields of the Earth and the Sun compensate, allows the satellite to maintain a fixed position relative to the other two bodies (animation here). Clearly, the three objects are always aligned in the same order. With a shield, the instruments of Gaia and always will be in the shade and cool.

5.Mission bonus detect extrasolar planets

So far, NASA’s Kepler mission has confirmed less than 200 extrasolar planets, with more than 3,000 others under examination. By mapping the stars, Gaia should be capable of measuring the light variation of transit of a planet when it passes in front of its star. According to estimates, the mission could help detect 2,500 new planets. Unfortunately, there will be no doubt that the “hot Jupiter” giant orbiting close to their stars. To find binoculars to Earth, it will probably wait for the launch of the James Webb Space Telescope, successor to Hubble, hopefully in 2018.

>> Gaia mission video

Gaia, our galaxy revealed by CNES

Philippe Berry