Thelarger digital cameraever built for a space mission, withbillion pixels, will constitute the Eye of Gaia, an ESA satellite designed to map the Milky Way and in whose mission nearly 400 European scientists collaborate, including scientists from the University of Barcelona (UB).
The human eye can see several thousand stars with the naked eye on a clear night. Gaia will be able to study one billion stars within the Milky Way and neighboring galaxies, throughout the five years that its mission will last. In this way, you will createan unprecedented catalog specifying brightness, spectral characteristics, and position and three-dimensional displacementof each observed object.
To study the most distant stars, whose brightness is on the order of a million times less than that which the human eye is capable of detecting, Gaia has adetector consisting of 106 CCD, an advanced version of the sensors that we can find in conventional digital cameras, developed specifically for this mission by the company e2v Technologies of Chelmsford, United Kingdom. Each of them is a little smaller than a credit card (4.7 x 6 cm) and finer than a human hair.
Thus, the focal plane of Gaia – in which the light captured by the telescopes is collected – is made up of a 0.5 x 1.0 m CCD mosaic, which has just been assembled at the main contractor’s facilities. mission, Astrium France, in Toulouse. The complete mosaic has seven rows of CCDs which, to increase the sensitivity of the sensors, will be kept at a temperature of -110 ° C.Gaia will operate one million kilometers from Earth in the opposite direction to the Sun, at the so-called Lagrange point, in which the Earth-Sun gravitational forces balance creating a stable point in space. As Gaia’s telescopes scan the sky, the light from each star will reach the focal plane to map its position and displacement in three dimensions, its color and intensity, and its emission spectrum.
The launch of Gaia is scheduled for 2013. This mission will allow to obtain a three-dimensional map of 1% of the stars in our Galaxy, which will help to revealthe composition, formation and evolution of the Milky Way. Gaia will also study a large number of other celestial bodies, from small objects in our own solar system to distant quasars and galaxies, near the limits of the observable universe.
ESA’s Gaia mission will generate about a petabyte of information, or one million gigabytes, which will need to be processed and analyzed to obtain results.
