Gaia (spacecraft)
Videos
Gaia is a retired space observatory of the European Space Agency that was launched in 2013 and operated until March 2025. The spacecraft was designed for astrometry: measuring the positions, distances
Artist's impression of the Gaia spacecraft
Model of Gaia at Paris Air Show 2013
Gaia from different angle
Gaia at its final phase of construction, 2013
Hipparcos
Videos
Hipparcos was a scientific satellite of the European Space Agency, launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement
Gaia (spacecraft)
…evolutionary history of the Milky Way Galaxy. As of 2026, the last scheduled data release is not expected before the end of 2030. The successor to the Hipparcos mission (1989–1993), Gaia is part of ESA's Horizon 2000+ long-term scientific program. Gaia was launched on 19 December 2013 by Arianespace using a…
Hipparcos satellite in the Large Solar Simulator, ESTEC, February 1988
Artist's concept of the Milky Way galaxy, showing two prominent spiral arms attached to the ends of a thick central bar. Hipparcos mapped many stars in the solar neighbourhood with great accuracy, though this represents only a small fraction of stars in the galaxy.