Farewell to Gaia after 12 successful years

The disappearance of Gaia!

On 4 March, astronomer Zhuo-Xiao Wang captured this view of the sudden disappearance of ESA’s Gaia spacecraft.

Credit: Zhuo-Xiao Wang, CC BY-SA 3.0 IGO
Observations performed on 4 March 2025 using an 11-inch telescope from Beijing, China (MPC site code: P13).

[image or embed]

— ESA Operations (@operations.esa.int) March 18, 2025 at 3:23 AM

Farewell, Gaia! Spacecraft powers down

Today, March 27, 2025, the European Space Agency (ESA) has powered down the Gaia spacecraft after 12 years of operations. But the good news is that there’s still a mountain of data from Gaia ripe for analysis. Johannes Sahlmann, Gaia project scientist, said:

Gaia’s extensive data releases are a unique treasure trove for astrophysical research, and influence almost all disciplines in astronomy.

In fact, the 4th data release from Gaia isn’t until 2026, with the final data release around 2030.

Gaia underwent testing in January, which temporarily made it brighter in the sky. Normally, Gaia has been a very faint magnitude 21 as it orbited the sun out at Lagrange Point 2. But for a couple months it brightened within reach of a large telescope. And in the video above, you can see its last appearance, courtesy of Zhuo-Xiao Wang.

The 2025 EarthSky lunar calendar is available now. Moon phases every day on a poster-sized calendar. Get yours today!

Best animation of our Milky Way galaxy

ESA’s Gaia spacecraft launched in 2013 and spent more than a decade measuring and mapping our home galaxy, the Milky Way. ESA ended its operations in January 2025. Scientists released a short animation giving a quick overview of a few of the new insights Gaia helped make possible. Gaia data were used to put together this animation of our galaxy. ESA said on January 15:

Gaia has changed our impression of the Milky Way. Even seemingly simple ideas about the nature of our galaxy’s central bar and the spiral arms have been overturned. Gaia has shown us that it has more than two spiral arms and that they are less prominent than we previously thought. In addition, Gaia has shown that its central bar is more inclined with respect to the sun.

No spacecraft can travel beyond our galaxy, so we can’t take a selfie, but Gaia is giving us the best insight yet of what our home galaxy looks like. Once all of Gaia’s observations collected over the past decade are made available in two upcoming data releases, we can expect an even sharper view of the Milky Way.

Enjoy the animation in the ESA video below.

Beloved spacecraft ends its operations

The goal of Gaia was to make a precise 3D map of the Milky Way. Over the past decade, it has tracked and measured the motions, luminosity, temperature and composition of nearly two billion objects.

Gaia’s mission was designed to last for five years. Like many space missions, it went longer. Gaia arrived in 2014 at Lagrange Point 2, or L2, in the Earth-sun system. Lagrangian points are places in a system where a craft can remain stable without using too much of its fuel for propulsion.

But, ESA said, Gaia did eventually run low on fuel. The cold gas propellant that keeps the mission working is nearly gone. While Gaia has now ceased taking measurements of our galaxy, the data releases from the project will continue for some years. Gaia’s first three data releases so far came in 2016, 2018 and 2022. The 4th data release should be ready in 2026. And the 5th and final data release covering all 10 1/2 years of data will be around the end of the decade. The massive amounts of data take a long time to process!

What will happen to Gaia next?

Gaia will not float around at the Lagrange Point 2 forever. Engineers have planned to remove Gaia from its current orbit. ESA said:

Gaia will be inserted into an orbit that makes sure it does not come too close to the Earth-moon system in the near future. The Gaia spacecraft will be fully passivated when it moves to its final orbit, to avoid any harm or interference with other spacecraft.

What has Gaia already shown us?

Astronomers have used the data from Gaia to make all sorts of new discoveries about our galaxy. Here are some highlights:

Also, Gaia has made discoveries outside the Milky Way, including spotting stars flying between galaxies and the discovery of an enormous ghost galaxy on the Milky Way’s outskirts.

Watch what Phil Plait had to say about Gaia during a recent livestream with Deborah Byrd.

Bottom line: ESA has now switched off the Gaia spacecraft, sending it into retirement on March 27, 2025. Gaia measured some two billion Milky Way objects and astronomers will still be processing data from it for years to come.

Via ESA