The UK has played a major role in Gaia, not least by providing the Gaia’s eyes in the sky. Gaia’s eyes are sensors called Charge-Coupled Devices (CCDs), which are also used in digital cameras and phones. Gaia has the largest array of CCDs ever flown in space (106). Each CCD is among the largest ever manufactured (4.5 cm by 5.9 cm). There are nearly 9 million pixels in each CCD, which means Gaia has nearly 1 billion pixels in total! Each pixel is one of the most complicated ever manufactured. A British company (e2v), won the Gaia CCD contract worth about €20 million and designed and made all of Gaia’s CCDs in Chelmsford. These were supplied to Astrium (Toulouse) who designed and constructed the Gaia focal plane.
Under its old name of English Electric Value (EEV), e2v made its name producing valves (also known as tubes) for televisions after the Second World War. In particular, EEV supplied the valves used in the TV cameras that broadcast the Coronation of Queen Elizabeth II at Westminster Abbey in 1953.
Since then CCDs have superseded valves but e2v is still at the forefront of designing, developing and manufacturing many different types of imaging sensors (including CCDs), although not for the mass market. You probably do not own an e2v sensor but you may have had your picture taken by one, either knowingly by an e2v X-ray dental sensor or unknowingly by one of the e2v CCDs onboard ESA’s Envisat Earth observation satellite! e2v CCDs are also currently flying in space on many other missions including the Hubble Space Telescope. Two e2v CCDs were flown in the Shuttle and installed inside Hubble during a space walk as part of the final Hubble servicing mission in 2009.
Next: How CCDs work
Page last updated: 16 December 2013