An advanced space astrometry mission that will build on the work started by Hipparcos. GAIA, an ESA (European Space Agency) mission will measure the distance, velocity and photometric properties of more than a billion stars in the Galaxy to an accuracy 2 to 3 orders of magnitude greater than that possible with Hipparcos. More specifically, with respect to astrobiology, it will rigorously scrutinize some 200,000 stars within 200 parsecs (650 light-years) of the Sun for the presence of planetary companions, including terrestrial planets and gas giants. GAIA is expected to find as many as 10,000 new extrasolar planets.

GAIA is currently scheduled for launch no later than 2012.

See the website for more details.  http://www.daviddarling.info/encyclopedia/G/GAIA.html（SY）