Gaia, funded by ESA with EADS Astrium as the prime contractor, is an ambitious space observatory designed to
measure the positions of around one billion stars with unprecedented accuracy and is currently planned for launch in
2011. The Gaia instrument will feature a focal plane containing 106 large area CCD91-72s manufactured by e2v
technologies. This will be the largest CCD focal plane ever flown in space covering an area of 0.286m2. To ensure that
the devices meet the required high specification, they undergo significant testing before being accepted by the end user.
This involves geometrical, mechanical, environmental, endurance, electrical and electro-optical testing. With the flight
phase contract for Gaia requiring the delivery of 130 flight grade devices (plus another 40 engineering devices of
various grades), the volume of testing is an order of magnitude greater than and of similar timescale to, the typical space
programmes e2v technologies are involved with. This paper will begin by providing an overview of the Gaia mission
and the custom CCD91-72 that e2v technologies have designed for it. Next the various phases of the Gaia programme
will be outlined and how e2v approached the test requirements for each stage. Problems encountered, lessons learned,
and technical and logistical solutions implemented at each stage will be presented, to discuss how e2v technologies
improved the quality of the test data whilst reducing the test times. There will be particular emphasis on the electro-optical
testing and the test cameras on which this is performed.