Gaia's main aim is to create a highly accurate 3D map of Milky Way Galaxy by repeatedly observing a billion stars to determine their positions in space and their movement through it.
Other measurements will assess the vital physical properties of each star, including temperature, luminosity and composition.
Gaia will map the stars from an orbit around the Sun, near a location some 1.5 million km beyond Earth's orbit known as the L2 Lagrangian point.
The probe is going to spin slowly, sweeping its two telescopes across the entire sky and focusing their light simultaneously onto a single digital camera, the largest ever flown in space - it has nearly a billion pixels.
Earlier this month the spacecraft's sunshield passed the final deployment test in the cleanroom in Kourou and has now been stowed in its final configuration ready for the launch.
Shortly after launch, the sunshield will be deployed, forming a 10.5 m-wide 'skirt' around Gaia's base.
The shield has two purposes: to shade Gaia's sensitive telescopes and cameras from sunlight, allowing them to cool to their operating temperature of -110 degree celsius, and to provide power to operate the spacecraft.
The Sun-facing side of the shield is partially covered with solar panels to generate electricity.
--ANI (Posted on 22-10-2013)