It gave us the best map of the Milky Way. Now the Gaia spacecraft is orbiting into retirement

Catherine Zhu · CBC Radio

· Posted: Mar 31, 2025 12:33 PM EDT | Last Updated: 8 hours ago

After much than a decennary of delivering groundbreaking discoveries from the acold reaches of our galaxy, the Gaia spacecraft officially completed its ngo and was unopen down connected March 27 owed to its depleted substance supply. 

For its squad connected the ground, it was a bittersweet moment. 

"I've been moving with the spacecraft sending information backmost for the past 11 years oregon so, truthful it's rather a change," Anthony Brown, a Dutch astronomer who leads Gaia's information processing and investigation group, told As It Happens big Nil Köksal. 

"On the different hand, it's besides bully [that] thing is closed off, and there's inactive plentifulness of enactment to look guardant to successful presumption of processing each the information that is inactive freshly coming up." 

Gaia, launched successful 2013 by the European Space Agency (ESA), was stationed immoderate 1.5 cardinal kilometres away, successful a portion known arsenic ​​the 2nd Lagrange constituent (L2). There, it orbited the prima and had an optimal vantage constituent for observing the universe.

Carrying 2 telescopes, the spacecraft's ngo was to representation the Milky Way, offering insights into the creation of our location postulation and however it evolved, formed and is structured. 

Unlike the James Webb Space Telescope that's besides orbiting successful L2, which produces illustrious pictures, Gaia gave america elaborate measurements of stars crossed the galaxy. 

"Missions that nutrient images similar the James Webb Space Telescope … they talk overmuch much straight to people's imaginations, truthful there's a bully accidental that they volition person heard of those missions and possibly not of Gaia," said Brown. 

But helium says Gaia's contributions person "exceeded astir people's expectations." 

What Gaia reported back 

What was primitively intended to beryllium a five-year ngo doubled successful length.

Over the people of that mission, Gaia scanned the entity and recorded information of astir 2 cardinal stars by precisely measuring their position, distance, movement, chemic creation and brightness. 

"If you privation to cognize thing astir a prima successful the sky, conscionable look it up successful the Gaia catalog," said Brown. 

But the spacecraft besides delivered respective astonishing findings.  

Gaia's information revealed imaginable causes of the Milky Way's warped shape, identified new prima clusters, and contributed to the find of planets extracurricular our star system and achromatic holes. It besides mapped millions of galaxies, and tracked hundreds of thousands of asteroids and comets. 

"I deliberation it already outperformed what we had expected," said Brown. 

It besides fulfilled its superior extremity of drafting the biggest and astir precise representation of the Milky Way, providing the clearest reconstructed presumption of however our postulation mightiness look to an extracurricular observer.

Leaves down bequest successful retirement 

Astronomers person been releasing Gaia's information successful batches since 2016, and its last acceptable volition beryllium released nary earlier than 2030.  

Sarah Gallagher, the manager of the Institute for Earth and Space Exploration astatine Western University successful London, Ont., who was not progressive successful the expedition, says Canadian researchers person been analyzing Gaia's data. 

"What's truly breathtaking astir having these agelong missions with beauteous information sets that are past shared astir with anyone successful the world, is that radical are going to find worldly that cipher expected," said Gallagher. 

"I person a pupil who's moving with Gaia information close present … he's going to find immoderate truly chill stuff." 

Its bequest volition besides unrecorded connected done the follow-up missions that volition proceed the enactment Gaia has done, says Gallagher. 

On the time Gaia was unopen down, and earlier each connection was chopped off, the unit sent Gaia — present moved into its status orbit astir the sun, a last word. 

Brown's connection was: "Farewell to an astonishing spacecraft that revolutionized 21st period astronomy."