Ralph Cordey, head of science and exploration at Astrium, said the spacecraft cost 400 million euros ($549 million) to build, with the total cost of the mission exceeding 740 million euros ($1.02 billion). If successful, Gaia will add to the knowledge gained from NASA's Hubble Space Telescope, which is still in operation, and ESA's Hipparcos satellite, which gathered data until 1993.
The value of putting a billion-pixel camera into space has been championed by Robert Massey from the UK's Royal Astronomical Society.
