Mission ObjectivesGaia was adopted within the scientific programme of the European Space Agency (ESA) in October 2000. The mission aims to:
The gathered large datasets will provide astronomers with a wealth of information covering a wide range of research fields: from solar system studies, galactic astronomy, cosmology to general relativity.
Mission NameGaia originally stood for Global Astrometric Interferometer for Astrophysics. As the project evolved, the single interferometer concept was replaced by a new payload design. The mission name remained, however, even though it no longer reflects the methods used to perform the science operations.
SpacecraftThe Gaia spacecraft consists of three major functional modules: the payload module, the mechanical service module and the electrical service module. It carries a single integrated instrument that comprises three major functions: astrometry, photometry and spectrometry. The three functions use two common telescopes and a shared focal plane, with each function having a dedicated area on the large 0.5m × 1m CCD detector array.
InstrumentsThe payload consists of a single integrated instrument the design of which is characterised by:
OrbitGaia will operate in a Lissajous-type orbit, around the L2 point of the Sun-Earth system, which is located 1.5 million km from the Earth in the anti-Sun direction. The orbit is not impacted by Earth eclipses. The orbit period is about 180 days and the size of the orbit is typically 340 000 × 90 000 km. An operational lifetime of 5 years is planned.
Operations CentreThe Gaia spacecraft will be controlled from the European Space Operations Centre (ESOC, Darmstadt, Germany) using the two ground stations Cebreros (Spain) and Perth (Australia).