Mapping the Milky Way

Advanced versions of the chips found in digital cameras, a series of charged coupled devices comprises the camera. With dimensions of 45 mm x 59mm, each CCD contains 1,966 x 4,500 pixels which each detect light which will then be transformed into electronic data. A supercomputer is then used to procces the data and generate a 3D map of the Milky Way. Powerful enough to detect a human hair (which is 17µm wide) from a thousand kilometres waay, the camera will be able to view stars 400,000 times fainter than the human eye can see.

Fitting with the ESA budget, the E2V is compressed into a single focal plane that could fit into a Soyuz rocket rather than the more expensive Ariane 5. This design uses flexible circuits manufactured by Printech. Enabling E2V to gold wire bond to the end of the gold pad, Printech have selectively ‘bump’ plated the gold fingers on the flexible circuit. This minimises the dead space between devices and makes it buttable on 4 sides.

Maintaining the flatness of the CCD array, it is mounted in a cryogenic chamber with a constant temperature of -143°C. The flexible circuits take the data collected from the pixels to the main electronics for processing. They also feature low themal conductivity, running from a chamber at -143°C to a processing area at +25°C.

Due to be launched at the end of December 2013, the GAIA satellite will send out a billion pixels to map a billion stars.