A total of 106 CCDs make up Gaia’s focal plane. Technicians from Astrium France, the Gaia mission's prime contractor, are seen bolting and aligning the CCDs onto their support structure, at the company's facility in Toulouse.
The structure (the grey plate underneath the CCDs) weighs about 20 kg and is made of silicon carbide, a material that provides remarkable thermal and mechanical stability.
Gaia's CCDs are provided by e2v Technologies of Chelmsford, UK. Each CCD measures 4.7x6 cm, with a thickness of only a few tens of microns. Precisely fitted together on the support structure, the gap between adjacent CCD packages is about 1 mm.