Gaia space mission ready to launch
21 August 2013 Last updated at 12:50 BST
The European Space Agency's Gaia satellite is built and ready to embark on a mission to make the most detailed map yet of our Milky Way Galaxy.
In the UK, one of the leading scientists on the mission is Prof Gerry Gilmore from the Institute of Astronomy, University of Cambridge. He told our correspondent Jonathan Amos what Gaia could achieve.