After more than a decade of exploring the cosmos, the European Space Agency (ESA) has powered down its Gaia spacecraft, marking the end of an era in space observation.
On March 27, 2025, mission controllers at ESA’s European Space Operations Centre (ESOC) carefully shut down the spacecraft’s systems and directed it into a stable orbit around the Sun. While Gaia’s operational mission has concluded, the wealth of data it has collected will continue to shape our understanding of the universe for decades to come.
Launched in 2013, Gaia revolutionized the field of astronomy by creating the most detailed and precise map of the Milky Way ever produced. Over its operational lifetime, the spacecraft recorded the positions, distances, motions, and properties of nearly two billion celestial objects, including stars, asteroids, exoplanets, and galaxies. These observations have led to groundbreaking discoveries, from uncovering evidence of ancient galactic mergers to identifying thousands of previously unknown celestial bodies.
Gaia’s contributions extend beyond mapping the Milky Way. The mission has provided critical data that has influenced nearly every field of astrophysics, from stellar evolution to dark matter studies. According to Gaia Project Scientist Johannes Sahlmann:
“Gaia’s extensive data releases are a unique treasure trove for astrophysical research, influencing almost all disciplines in astronomy.”
Gaia’s mission far exceeded its original five-year plan, but dwindling fuel reserves and responsible space management prompted ESA to retire the spacecraft. To ensure that Gaia does not interfere with other missions near the Sun-Earth Lagrange Point 2 (L2), controllers executed a carefully planned series of decommissioning steps. The spacecraft was moved into a ‘retirement orbit’ around the Sun, where it will remain for at least a century.
Shutting down Gaia was not a simple task. Designed to withstand space hazards such as radiation storms and micrometeorite impacts, Gaia had built-in redundancy systems to ensure continuous operation. Engineers had to methodically disable these safeguards to prevent the spacecraft from unintentionally reactivating in the future.
“Switching off a spacecraft sounds simple, but Gaia was designed to keep itself operational no matter what,” said Tiago Nogueira, a Gaia spacecraft operator.
Though Gaia has gone silent, its influence on astronomy is far from over. The data it gathered continues to serve as a foundation for scientific discovery, with new insights expected from upcoming data releases. The next major release, planned for 2026, will provide even more refined measurements, and the final Gaia catalog, expected by 2030, will remain a crucial reference for future astronomical research.
Gaia’s data has already become an essential tool for astronomers worldwide. It has enabled the identification of exoplanets, refined models of stellar evolution, and provided insight into the structure and history of the Milky Way. ESA’s upcoming missions, including the Plato mission to study exoplanets, will build upon Gaia’s discoveries, ensuring its impact continues well beyond its operational lifetime.
For the scientists and engineers who worked on Gaia, saying goodbye to the spacecraft was an emotional moment. As part of its decommissioning, ESA engineers encoded the names of 1,500 team members into the spacecraft’s memory, along with personal farewell messages.
“We will never forget Gaia, and Gaia will never forget us,” said Mission Manager Uwe Lammers.
Although Gaia’s mission has come to an end, the knowledge it has provided will guide future explorations of our galaxy. The spacecraft may no longer be scanning the sky, but its data will continue to illuminate the mysteries of the universe for generations to come.
The New York Times and ESA contributed to this report.
