Launched on December 19, 2013, the fuel tank of ESA’s star-mapping satellite Gaia is now approaching empty, but this is far from the end of the mission. Technology tests are scheduled for the weeks ahead before Gaia is moved to its ‘retirement’ orbit, and two massive data releases are tabled for around 2026 and the end of this decade, respectively.
An artist’s impression of the Milky Way Galaxy, based on data from ESA’s Gaia space telescope. Image credit: ESA / Gaia / DPAC / Stefan Payne-Wardenaar.
“Today marks the end of science observations and we are celebrating this incredible mission that has exceeded all our expectations, lasting for almost twice its originally foreseen lifetime,” said ESA Director of Science Carole Mundell.
“The treasure trove of data collected by Gaia has given us unique insights into the origin and evolution of our Milky Way Galaxy, and has also transformed astrophysics and Solar System science in ways that we are yet to fully appreciate.”
“Gaia built on unique European excellence in astrometry and will leave a long-lasting legacy for future generations.”
“After 11 years in space and surviving micrometeorite impacts and solar storms along the way, Gaia has finished collecting science data,” said Gaia project scientist Johannes Sahlmann.
“Now all eyes turn towards the preparation of the next data releases.”
“I am thrilled with the performance of this incredible mission, and excited about the discoveries that await us.”
An artist’s impression (annotated) of the Milky Way Galaxy, based on data from ESA’s Gaia space telescope. Image credit: ESA / Gaia / DPAC / Stefan Payne-Wardenaar.
Gaia has been charting the positions, distances, movements, brightness changes, composition and numerous other characteristics of stars by monitoring them with its three instruments many times over the course of the mission.
This has enabled Gaia to deliver on its primary goal of building the largest, most precise map of the Milky Way, showing us our home Galaxy like no other mission has done before.
“It contains major changes from previous models, because Gaia has changed our impression of the Milky Way,” said Stefan Payne-Wardenaar, scientific visualizer for the Haus der Astronomie and the IAU Office of Astronomy for Education.
“Even basic ideas have been revised, such as the rotation of our Galaxy’s central bar, the warp of the disc, the detailed structure of spiral arms, and interstellar dust near the Sun.”
“Still, the distant parts of the Milky Way remain educated guesses based on incomplete data.”
“With further Gaia data releases our view of the Milky Way will become even more accurate.”
The Gaia scientific and engineering teams are already working full steam on the preparations for Gaia Data Release 4 (DR4), expected in 2026.
The data volume and quality improves with every release and Gaia DR4, with an expected 500 TB of data products, is no exception.
Furthermore, it will cover the mission’s first 5.5 years, corresponding to the length of the originally foreseen duration of the mission.
“This is the Gaia release the community has been waiting for, and it’s exciting to think this only covers half of the collected data,” said Dr. Antonella Vallenari, an astronomer at the Istituto Nazionale di Astrofisica.
“Even though the mission has now stopped collecting data, it will be business as usual for us for many years to come as we make these incredible datasets ready for use.”
Gaia has completed the sky-scanning phase of its mission, racking up more than three trillion observations of about two billion stars and other objects over the last decade to revolutionize our view of our home Galaxy and cosmic neighborhood. Image credit: ESA / Gaia / DPAC / Stefan Payne-Wardenaar.
After several weeks of testing, Gaia will leave its current orbit around Lagrange point 2, 1.5 million km from the Earth in the direction away from the Sun, to be put into its final heliocentric orbit, far away from Earth’s sphere of influence.
The spacecraft will be passivated on March 27, 2025, to avoid any harm or interference with other spacecraft.
During the technology tests Gaia’s orientation will be changed, meaning it will temporarily become several magnitudes brighter, making observations through small telescopes a lot easier.
“Gaia will treat us with this final gift as we bid farewell, shining among the stars ahead of its well-earned retirement,” said Gaia mission manager Uwe Lammers.
“It’s a moment to celebrate this transformative mission and thank all of the teams for more than a decade of hard work operating Gaia, planning its observations, and ensuring its precious data are returned smoothly to Earth.”
