  GAIA astrometric mission of ESA will be very efficient in discovering binary
and multiple stars with any orbital period, from minutes to millions of years.
Main parameters of the revised mission design are presented. Next we estimate
the fraction of binary stars discovered by means of astrometry, photometry and
on-board spectroscopy. Finally we summarize observations that confirm the
ability to measure physical parameters like masses, radii and spectroscopic
distance from GAIA data alone. GAIA will fly only in 2010, but the Radial
velocity experiment (RAVE) has started this year. We show that its
spectroscopic observations have the capacity to discover a large fraction of so
far unknown binary systems.
