Gaia is a European Space Agency (ESA) astrometry space mission, and a successor to the ESA Hipparcos mission. It was included within the context of the ESA Horizon 2000 Plus long-term scientific programme in 2000. It is expected to be launched by the ESA in the second half of 2011, and will be operated in a Lissajous orbit around the Sun-Earth L2 Lagrangian point. Gaia will compile a catalogue of approximately one billion stars to magnitude 20. Its objectives comprise:
- astrometric (or positional) measurements, determining the positions, distances, and annual proper motions of stars with an accuracy of about 20 µas (microarcsecond) at 15 mag, and 200 µas at 20 mag
- spectrophotometric measurements, providing multi-epoch observations of each detected object
- radial velocity measurements.
Gaia will create an extremely precise three-dimensional map of stars throughout our Milky Way galaxy and beyond, and map their motions which encode the origin and subsequent evolution of the Milky Way. The spectrophotometric measurements will provide the detailed physical properties of each star observed, characterising their luminosity, effective temperature, gravity, and elemental composition. This massive stellar census will provide the basic observational data to tackle a wide range of important problems related to the origin, structure, and evolutionary history of our Galaxy. Large numbers of quasars, galaxies, extrasolar planets, and solar system bodies will be measured at the same time. Gaia will also be capable of discovering asteroids with orbits that lie between Earth and the Sun, a region that is difficult for Earth-based telescopes to monitor since this region is only in the sky during or near the daytime.[1]
References
External links
- ESA Gaia mission
- Gaia in Depth
- Gaia page at ESA Spacecraft Operations
- Gaia pages for the scientific community
- Gaia Study Report Summary of the scientific goals of the mission, March 2000
- Origins Billion Star Survey (OBSS) A similar project proposal as collaboration between NASA and U.S. Naval Observatory.
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| Great Observatories program | Hubble Space Telescope · Compton Gamma-Ray Observatory · Chandra X-ray Observatory · Spitzer Space Telescope |
| NASA | Swift Gamma-Ray Burst Mission · Wilkinson Microwave Anisotropy Probe |
| European Space Agency | COROT · INTEGRAL · XMM-Newton |
| Other countries | ASTRO-E (Japan) |
| Future telescopes | Gamma-ray Large Area Space Telescope (2008) · Herschel Space Observatory (2008) · Kepler Mission (2009) · Wide-field Infrared Survey Explorer (2009) · NuSTAR (2011) · Gaia mission (2011) · James Webb Space Telescope (2013) · New Worlds Mission (2013) · Space Interferometry Mission (2015) · Darwin Mission (2015) · Laser Interferometer Space Antenna (2015) · Terrestrial Planet Finder (TPF) |
| Completed missions | Cosmic Background Explorer · Einstein Observatory · Far Ultraviolet Spectroscopic Explorer · IRAS · Infrared Space Observatory · AKARI |
| Canceled telescopes | Eddington mission |
