Lift-off for Gaia's billion-star mission

Europe’s most advanced space telescope Gaia, built for the European Space Agency (ESA), will produce a highly accurate 3D map of the galaxy, the Milky Way, and discover and map objects beyond its boundaries.

The Gaia mission is also expected to discover hundreds of thousands of unknown celestial objects, including extra-solar planets and failed stars (brown dwarfs).

Further science impacts anticipated through Gaia include mapping dark matter and finding potentially dangerous asteroids.

Gaia’s telescope draws on expertise developed by Astrium in the field of silicon carbide (SiC) telescopes, such as that used for the space telescope on ESA’s Herschel mission, as well as for all the instruments made by Astrium for Earth observation missions.

‘Gaia is an unparalleled space system: the precision of its instruments and its technical conception once again prove Astrium‘s unique expertise in optical payloads,’ said Eric Béranger, CEO of Astrium Satellites in a statement. ‘Mastering these exceptional technologies enables us to maintain Astrium’s rank as the world leader in the export of Earth observation satellites.’

Gaia will also use a ‘photographic’ sensor of unprecedented accuracy.

Astrium say the precision of the measurements taken by the mission’s optical instruments will be extremely high: Gaia would be capable of picking out a strand of hair from a distance of 700km by using its huge focal plane made up of 106 of e2v’s CCD detectors gathering one billion pixels.

For its attitude control, the spacecraft will use a cold gas propulsion system with micro-thrusters, enabling it to remain perfectly stable and point with the required extreme accuracy.

Gaia will be located at one of the five Lagrangian points in the Sun-Earth system, at the L2 point. The Lagrangian points in the solar system are points of gravitational balance where a body such as a spacecraft orbits around the Sun at the same rate as Earth, remaining in a fixed position relative to the Earth-Sun line.

Located 1.5 million kilometres from Earth, the L2 point is vital for astronomy observation missions, which require high pointing stability.

Speaking at the Royal Astronomical Society in November, 2013 Dr ChrisCastelli, acting director for technology and science exploration, UK Space Agency said: ‘These kinds of missions act as a beacon to attract the next generation of engineers, scientists and entrepreneurs to high-tech activities that are vital to sustaining the economic growth of the UK.’