
Artist's impression of ESA's Gaia satellite observing the Milky Way. Image: Spacecraft: ESA/ATG medialab; Milky Way: ESA/Gaia/DPAC; CC BY-SA 3.0 IGO; Acknowledgement: A Moitinho
Although Earth is saying goodbye to the spacecraft this year, Gaia’s observations will result in two more data releases by 2030.
On 27 March this year, the European Space Agency (ESA) will be saying goodbye to Gaia, a one-of-a-kind digital camera to capture the secrets of the Milky Way system.
Gaia was launched towards the end of 2013 to study our galaxy, its stellar content, asteroids and other minor cosmic bodies, providing Earth with accurate astrometric measurements. It began 3D mapping the Milky Way in 2014, producing its first results in 2016 – a rendition of the Milky Way that was “1,000 times more accurate” than anything before.
However, even a decade into its life, the Gaia mission continued to stun researchers with its findings, collecting and transferring a “treasure trove” of data back to Earth. With data from the spacecraft, the ESA released the largest-ever chemical map of the galaxy in 2022, while last year, it spotted the most massive stellar black hole discovered in the Milky Way yet, with a mass 33 times that of our sun.
Gaia’s trip in our galaxy has helped answer big questions – including how the Milky Way was formed. In 2024, the spacecraft spotted two star streams named Shakti and Shiva, named after a divine Hindu mythological couple. The data provided scientists with evidence to suggest that the star streams may have formed as distinct fragments that merged with our galaxy early in its composition billions of years ago.
However, after 11 years on constant duty peering into the Milky Way, the ESA announced yesterday (15 January) that the cold gas used to keep Gaia spinning with pinpoint precision is nearly empty.
ESA director of science Carole Mundell said: “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.
“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 several weeks of scheduled testing, Gaia will leave its current orbit around Lagrange point 2, 1.5m km from Earth, to be put into its final orbit away from Earth’s sphere of influence. The mission has made enough observations for two new “massive data releases”, one scheduled for 2026 and the other before the end of the decade.
“After 11 years in space and surviving micrometeorite impacts and solar storms along the way, Gaia has finished collecting science data. Now all eyes turn towards the preparation of the next data releases,” said Gaia project scientist Johannes Sahlmann. “I am thrilled with the performance of this incredible mission, and excited about the discoveries that await us.”
The spacecraft will be made inactive by the end of March, leaving us all feeling thankful for its long service fulfilling humankind’s thirst for knowledge of our cosmos.
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