Access key links:

This site uses cookies to help make it more useful and reliable. Our cookies page explains what they are, which ones we use, and how you can manage or remove them.



The European Space Agency's Gaia mission will examine the Milky Way in unprecedented 3-D detail.

A mission to map the stars and their movements

 Artist's impression of the Gaia satellite. Credit: ESA (JPG, 667 Kb) 
Artist's impression of the Gaia satellite.
Credit: ESA

  • In development since 2007
  • Successfully launched 19th December 2013
  • Following a four month commissioning phase, GAIA will be ready to begin its science mission in mid 2014

The European Space Agency's Gaia mission will examine the Milky Way in unprecedented 3-D detail.

The spacecraft will survey more than one billion stars to make the largest, most precise map of our Galaxy to date. Gaia will be scanning the sky continuously for five years. This will enable each object to be observed on average about 80 times. Gaia will log the position, brightness and colour of every celestial object of sufficient brightness that falls within its field of view. Gaia will be using the same principle of measurements that was successfully employed by the Hipparcos mission.

The repeated observations will allow astronomers to calculate positions, distances and velocities relative to the Sun for the objects that are observed. Any variations in brightness will also be followed and analysed. With this wealth of data, astronomers will be able to get a better understanding of the history and evolution of our Galaxy.

Gaia will also be able to detect large numbers of double stars throughout the Milky Way, as well as nearby planets that are the same size - or bigger - than Jupiter. It will do this by measuring small disturbances in the positions of stars caused by a planet's gravitational field. Scientists predict Gaia could find up to 50,000 planets during its five-year mission!

Mission facts

Gaia originally stood for Global Astrometric Interferometer for Astrophysics. As the project evolved, the double-interferometer concept was replaced with different instruments. However, the mission name remained even though it no longer uses an interferometer as part of its telescope design.

The measurement accuracy expected for Gaia will be about 10 to 100 times greater than what was achieved for the Hipparcos mission. The number of objects observed will be 10,000 times greater.

As part of its mission, Gaia is expected to detect tens of thousands of stars that failed to ignite. These are known as brown dwarves. The information gathered will help scientists understand the formation of stars.


Gaia will be equipped with two telescopes, projecting images onto a single integrated camera instrument. This will be able to record the position, brightness and colour of the objects under observation.

The spacecraft will be equipped with a 'micro propulsion' system, allowing fine adjustments to be made to its position.


UK involvement

Gaia is one of the most important current space projects for the UK, which has won about €80M of contracts from ESA (European Space Agency) to build the spacecraft.

EADS Astrium at Stevenage is responsible for the spacecraft's super precision guidance and control system as well as the powerful computers needed to process the torrent of data it will produce.

The 'eye' of Gaia's camera will be the most sensitive set of light detectors ever assembled for a space mission. It will use 106 CCDs made by UK company E2V Ltd with nearly 1 billion pixels covering an area of 2.8 square metres. 

The UK Space Agency is funding a £12M project with institutes across the UK. Cambridge leads the prime photometric processing and real-time science unit, and along with Leicester, Edinburgh, The Open University and Rutherford Appleton Laboratory (RAL) are undertaking activities such as database definition and construction, framework development, iteration start-up procedures development and testing and final integration implementation and testing.

University College London’s Mullard Space Science Laboratory (MSSL) has a major role in spectroscopic science, and in conjunction with The Open University, are involved in software development including architecture, integration and validation, pre-processing development, spectra extraction and calibration.

SciSys UK Ltd are responsible for the spacecraft’s operational simulator. Also in the UK, Selex Systems are providing system support, Aero Stanrew Ltd provided the avionics test bench, and ABSL provided the battery.

For more information, see the Gaia Mission homepage.

  • Print this page

The UK Space Agency

The UK Space Agency is at the heart of UK efforts to explore and benefit from space.

The UK's thriving space sector contributes £9.1 billion a year to the UK economy and directly employs 28,900 with an average growth rate of almost 7.5%. (The Size and Health of the UK Space Sector 2010/11, preliminary survey results.)

View a list of organisations that we work with.