Eye of Gaia: billion-pixel camera to map Milky Way

While the naked human eye can see several thousand stars on a clear night, Gaia will map a billion stars within our own Milky Way Galaxy and its neighbours over the course of its five-year mission from 2013, charting their brightness and spectral characteristics along with their three-dimensional positions and motions.

In order to detect distant stars up to a million times fainter than the eye can see, Gaia will carry 106 charge coupled devices (CCDs), advanced versions of chips within standard digital cameras.

Developed for the mission by e2v Technologies of Chelmsford, UK, these rectangular detectors are a little smaller than a credit card, each one measuring 4.7×6 cm but thinner than a human hair.

The 0.5×1.0 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. Working in double shifts in strict cleanroom conditions, they added an average four CCDs per day, finally completing their task on 1 June.

“The mounting and precise alignment of the 106 CCDs is a key step in the assembly of the flight model focal plane assembly,” said Philippe Garé, ESA’s Gaia payload manager.

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 of the 106.5º angle 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.

Gaia’s CCD support structure, like much of the rest of the spacecraft, is made of silicon carbide – a ceramic like material, extraordinarily resistant to deforming under temperature changes.

First synthesised as a diamond substitute, SiC has the advantage of low weight: the entire support structure with its detectors is only 20 kg.

Gaia will operate at the Earth–Sun L2 Lagrange point, 1,5 million kilometers behind the earth, when looking from the sun, where Earth’s orbital motion balances out gravitational forces to form a stable point in space. As the spinning Gaia’s two telescopes sweep across the sky, the images of stars in each field of view will move across the focal plane array, divided into four fields variously dedicated to star mapping, position and motion, colour and intensity and spectrometry.

Scheduled for launch in 2013, Gaia’s three-dimensional star map will help to reveal the composition, formation and evolution of the Milky Way, sampling 1% of our Galaxy’s stars.

Gaia should also sample large numbers of other celestial bodies, from minor bodies in our own Solar System to more distant galaxies and quasars near the edge of the observable Universe.

Media Contact

Markus Bauer EurekAlert!

All latest news from the category: Physics and Astronomy

This area deals with the fundamental laws and building blocks of nature and how they interact, the properties and the behavior of matter, and research into space and time and their structures.

innovations-report provides in-depth reports and articles on subjects such as astrophysics, laser technologies, nuclear, quantum, particle and solid-state physics, nanotechnologies, planetary research and findings (Mars, Venus) and developments related to the Hubble Telescope.

Back to home

Comments (0)

Write a comment

Newest articles

Lighting up the future

New multidisciplinary research from the University of St Andrews could lead to more efficient televisions, computer screens and lighting. Researchers at the Organic Semiconductor Centre in the School of Physics and…

Researchers crack sugarcane’s complex genetic code

Sweet success: Scientists created a highly accurate reference genome for one of the most important modern crops and found a rare example of how genes confer disease resistance in plants….

Evolution of the most powerful ocean current on Earth

The Antarctic Circumpolar Current plays an important part in global overturning circulation, the exchange of heat and CO2 between the ocean and atmosphere, and the stability of Antarctica’s ice sheets….

Partners & Sponsors