|Gaia builds upon the European heritage of precision stellar mapping that was exemplified by ESA’s Hipparcos satellite in the late 1980s. Whereas that mission catalogued a hundred thousand stars to high precision, and more than a million to lesser accuracy, Gaia will map a thousand million stars to unprecedented levels of precision.
Gaia’s name was originally derived as an acronym for Global Astrometric Interferometer for Astrophysics. This reflected the optical technique of interferometry that was originally planned for use on the spacecraft. However, the working method has now changed. Although the acronym is no longer applicable, the name Gaia remains to provide continuity with the project.