Gaia is now undergoing processing inside the Spaceport’s S1B payload preparation facility – where the advanced “star-mapper” was transported following its delivery this month to French Guiana by a cargo jetliner.

Today, another cargo aircraft arrived in French Guiana with Gaia’s deployable sunshield assembly and electrical ground support test equipment for the spacecraft’s pre-launch checkout.  The sunshield – which is to have a diameter of just over 10 meters when opened in space – will permanently shade Gaia’s telescopes and will serve as a power generator for the spacecraft.

In a mission organized by the European Space Agency, the spacecraft is designed to chart the locations and motions of a billion stars in order to create the largest-ever three-dimensional map of the Milky Way. Gaia was built by Astrium at its Toulouse, France facility.

Equipped with two optical telescopes to determine star locations and velocities, along with three science instruments and one of the largest digital cameras ever to be placed in space, Gaia is able to detect celestial objects that are a million times fainter than the unaided human eye can see.

For all objects brighter than magnitude 15 (which is 4,000 times fainter than the naked eye limit), Gaia will measure their positions to an accuracy of 24 microarcseconds – which is comparable to measuring the diameter of a human hair from a distance of 1,000 km.

After deployment by Soyuz, Gaia will monitor each of its target stars approximately 70 times over a five-year period and precisely chart their positions, distances, movements and changes in brightness. The spacecraft is expected to discover hundreds of thousands of new celestial objects – including asteroids, comets, extra-solar planets, brown dwarf “failed stars,” supernovae and quasars – from its orbital position at the L2 Lagrangian point some 1.5 million kilometers beyond Earth’s orbit.

A massive amount of data will be collected over Gaia’s planned five-year mission, with its full archive to exceed 1 petabyte in size – providing enough information to tackle many important problems related to the origin, structure and evolutionary history of the galaxy.

This upcoming Arianespace flight is designated VS07 in the company’s numbering system, denoting the seventh Soyuz liftoff from French Guiana since the medium-lift vehicle’s October 2011 service entry.