The 0.5x1.0 m mosaic has been assembled at the Toulouse facility of Gaia prime contractor Astrium France. Technicians spent much of May carefully fitting together each CCD package on the support structure, leaving only a 1 mm gap between them. Each e2v-made CCD measures 4.7x6 cm. Working in double shifts in strict cleanroom conditions, technicians added an average four CCDs per day, finally completing their task on June 1st:
The completed mosaic is arranged in seven rows of CCDs. The main array comprises 102 detectors dedicated to star detection. Four others check the image quality of each telescope and the stability between the two telescopes that Gaia uses to obtain stereo views of stars. In order to increase the sensitivity of its detectors, the spacecraft will maintain their temperature of –110ºC.
