Gaia is a
space observatory of the
European Space Agency (ESA) designed for
astrometry. The mission aims to construct a 3D space catalog of approximately 1 billion
astronomical objects, mainly stars (approximately 1% of the
Milky Way population) brighter than 20 G
magnitude, where G is the
Gaia magnitude passband between about 400 and 1000
nanometres light wavelengths. Additionally
Gaia is expected to detect thousands to tens of thousands of Jupiter-sized planets beyond the Solar System, 500,000
quasars and tens of thousands of new asteroids and comets within the Solar System. The spacecraft will monitor each of its target stars about 70 times over a period of five years.