Gaia | CAMCEAD

ESA space mission. Launched December 2013, science operations ended 2025

About 1 billion objects mapped
267 billion transits observed
141,038 GB of science data
DR4 planned for December 2026

About Gaia

Gaia is an ESA space observatory. For more than ten years it measured the positions, distances, motions, brightness and colours of about a billion stars and other objects in the Milky Way and beyond, producing the most precise three-dimensional map of our Galaxy so far. Gaia was launched in December 2013 and carried out 3,827 days of science operations before it was switched off (passivated). The Gaia Data Processing and Analysis Consortium (DPAC) is still processing and analysing the data, and the next major release, DR4, is planned for 2 December 2026.

Dec 2013
Launch
Gaia launched from Kourou, followed by six months of commissioning

Jul 2014 to Jun 2019
Nominal mission
Five years of science operations, followed by the extended mission

DR1 to DR3 and FPR
Data releases
Public releases of astrometry, photometry and spectra, each building on the last

2025
Passivation
Science operations ended, while DPAC processing continues

2 Dec 2026
DR4
Data release based on the first 5.5 years of observations

Within the Gaia Data Processing and Analysis Consortium (DPAC), CamCEAD designs, maintains and runs the systems that process billions of stellar observations. Most of our work is for CU5 (photometric processing) and DPCI, the Cambridge data processing centre, which is the largest single contribution to Gaia's photometric data.

Photometric data flow at DPCI

CamCEAD is mainly responsible for the PhotPipe calibration pipeline and DPCI processing. Together these cover photometric calibration, science alerts and data products for the community in every Gaia data release.

Gaia SatelliteRaw telemetry

ESOC / ESACData receipt and L0 triage

PhotPipeInternal and external calibration of photometry and BP/RP spectra (CamCEAD)

DPCI ProcessingScience Alerts, SEAPipe, SIF photometry (CamCEAD)

Main DBConsolidated DPAC dictionary

DocumentationCU9 release documentation

CommunityGaiaXPy data access tools

Running the DPCI pipelines

These systems produce Gaia's brightness and colour measurements and detect transient events:

Operations: maintaining and running the data processing pipelines hosted on Cambridge's computing systems.
PhotPipe: running the internal and external photometric calibrations.
Other pipelines: further reduction pipelines developed by CU5/DPCI, including Science Alerts for detecting transients quickly, SEAPipe and SIF photometry.

GaiaXPy for the community

GaiaXPy is an open-source Python library written by the CU5/DPCI team for people who use Gaia data:

Spectra: it processes and calibrates Gaia's sampled BP/RP spectra and turns them into a form that can be used for science.
Synthetic photometry: it computes magnitudes in standard photometric systems directly from the calibrated spectra.
Availability: it is free to use and available on PyPI and GitHub.

CU9 work

Through Coordination Unit 9, CamCEAD helps make sure that what the processing teams know reaches the people using the catalogues:

Release documentation: writing, collecting and checking the documentation that comes with each public catalogue.
Support for users: preparing technical notes that help people start working with each new data release.

Computing on IRIS

CamCEAD uses the IRIS National Facility for the heavy distributed and cloud processing that Gaia's data volumes need.

Kubernetes clusters

Kubernetes runs our containerised processing jobs across many machines, so the work can be spread out and scaled up for each Gaia data release.

Spark and PySpark

Apache Spark and PySpark are our main tools for large distributed data reduction and for running queries over billions of Gaia observations in parallel.