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Gaia (ESA astrometric survey)

node · earth · Sun-Earth L2, then heliocentric orbit

The European Space Agency astrometric observatory that measured positions, parallaxes and proper motions for nearly two billion sources, converting the Hertzsprung-Russell diagram from a schematic into a measured distribution and pinning down distances - and therefore luminosities, radii and ages - across the Galaxy. Its science observations ended on 15 January 2025 after about twelve years, and the spacecraft was passivated and moved to a heliocentric retirement orbit on 27 March 2025. The data releases lag the observations by years: Data Release 3 appeared in 2022, Data Release 4 is planned for December 2026 and is described by ESA as the first release covering all data types for the full nominal five and a half year mission, and the final legacy catalogue is not expected before the end of the decade. The mission is therefore over while its principal scientific output is still ahead of it. Not a place on Earth.

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Evidence · 2
Timeline

No dated observations are stored for this object. Atlas shows what was observed and when — it does not infer a history.

Connections · 1
Assembled narrative · 1

Assembled from 19 blocks · 2 evidence · 13 related

  1. Story
  2. The European Space Agency astrometric observatory that measured positions, parallaxes and proper motions for nearly two billion sources, converting the Hertzsprung-Russell diagram from a schematic into a measured distribution and pinning down distances - and therefore luminosities, radii and ages - across the Galaxy. Its science observations ended on 15 January 2025 after about twelve years, and the spacecraft was passivated and moved to a heliocentric retirement orbit on 27 March 2025. The data releases lag the observations by years: Data Release 3 appeared in 2022, Data Release 4 is planned for December 2026 and is described by ESA as the first release covering all data types for the full nominal five and a half year mission, and the final legacy catalogue is not expected before the end of the decade. The mission is therefore over while its principal scientific output is still ahead of it. Not a place on Earth.
  3. Knowledge
  4. Hertzsprung-Russell diagram
  5. Gaia (ESA astrometric survey)
  6. Connections
  7. Hertzsprung-Russell diagram
  8. Gaia stops observing
  9. Gaia Data Release 4 scheduled
  10. Ejnar Hertzsprung
  11. Henry Norris Russell
  12. Main sequence (core hydrogen burning)
  13. Gaia (ESA astrometric survey)
  14. Hertzsprung and Russell independently plot luminosity against temperature
  15. Gaia stops observing
  16. Gaia Data Release 4 scheduled
  17. Evidence
  18. Supports the 15 January 2025 end of science observations, the 27 March 2025 passivation, the December 2026 planned date for Data Release 4 and the description of DR4 as covering all data types for the full nominal mission. The pages were not fetched because the domain was blocked; content comes from search summaries of those ESA pages.
  19. Supports the statement that Gaia parallaxes produced an empirical Hertzsprung-Russell diagram from a very large stellar sample. The paper was not fetched; the source count of nearly two billion refers to the Gaia catalogue as a whole rather than to this paper's sample.
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Observed changes · 0

No public Signals are attached to this object. Signals show what changed and when it was observed — never a direction or a rank.

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/atlas?object=MISSION_GAIA&experience=MISSION_GAIA