Assembly of the Gaia CCD array (flight model)
A total of 106 CCDs make up Gaia's focal plane. Technicians from Astrium France, the Gaia mission's prime contractor, are seen here carefully bolting and aligning the CCDs onto the CCD support structure (CSS), at the company's facility in Toulouse.
The CSS (the grey plate underneath the CCDs, with the gaps and holes for the integration and wiring of the CCDs) weighs about 20 kg and is made of silicon carbide (SiC), a material that provides remarkable thermal and mechanical stability.
Gaia's CCDs are provided by e2v Technologies of Chelmsford, UK. Each CCD measures 6 × 4.7 cm, with a thickness of only a few tens of microns. Precisely fitted together on the CSS, the gap between adjacent CCD packages is about 1 millimetre.