Gaia's billion-pixel camera will map the Milky Way

Toulouse, France - A detector of 0.5 x 1.0 m mosaic was assembled at the plant's project manager for Astrium France (ESA) European Space Agency's Gaia space mission. The detector is part of the largest digital camera ever built for a space mission, and was jointly mosaic from 106 separate charge coupled device (CCD) developed for the mission Gaia by e2v technologies (Chelmsford, England). Each of the detectors 106 is slightly smaller than a credit card 4.7 x 6 cm, but thinner than a human hair.


The result is "a billion pixels table" will be the super-sensitive "eye" of the ESA mission Gaia Galaxy-mapping. While the naked eye can see thousands of stars on a clear night, Gaia will map a billion stars in our galaxy the Milky Way and its neighbors during his five-year mission from 2013, the mapping of their luminosity and spectral characteristics with their three dimensional positions and movements.


The completed mosaic is arranged in seven rows of CCDs. The main table includes 102 sensors dedicated to detecting star. Four other to check the image quality of each telescope and the stability of the angle of 106.5 ° between the two telescopes that Gaia uses to obtain stereo views of stars. To increase the sensitivity of its detectors, the spacecraft will maintain their temperature below 110 ° C.


The support structure of Gaia CCD, like many of the rest of the spacecraft, is made of silicon carbide (SiC). First synthesized as a substitute for diamond, SiC has the advantage of low weight: the entire support structure with its detector weighs only 20 kg.


Gaia will operate 1,500,000 km behind the Earth, when you look at the sun, where the orbital motion of the Earth's gravitational forces balance each other to form a stable point in space. As two of the spinning Gaia telescopes sweep across the sky, the images of stars in each field of view moves across the focal plane array, divided into four fields variously dedicated to mapping out the position and movement, the color and intensity, and spectroscopy.