2024-10-03 Gaia's end of observations coming up

The Gaia spacecraft relies on a cold gas propellant to keep it spinning and scanning the sky. The amount of remaining cold gas decreases by about a dozen grams per day and is reaching its end in early 2025. The Gaia science observations will therefore end on 15 January 2025, meaning that no more nominal science data will be acquired by Gaia after that date. This is, however, far from being the end of this transformative mission!

The Gaia scientific and engineering teams will continue to work full steam on the preparations for Gaia Data Release 4, which is not “more of the same” but will make new groundbreaking science possible by including a much larger data volume, many more data products, and data of overall better quality compared to Gaia Data Release 3. In the course of 2025, once all of Gaia’s nominal science data have been downlinked to Earth, the processing for the final Gaia Data Release 5 will ramp up to full speed and run in parallel to the processing of Gaia Data Release 4. Gaia Data Release 4, covering 5.5 years of mission data, is expected in 2026 and Gaia Data Release 5, covering the full 10.5 years of mission data, around the end of the decade.  

After Gaia’s science observations end on 15 January 2025, a period of technology tests will commence. These technology tests will allow us to study in more detail the behaviour of some spacecraft and instrument components, with the potential of further improving the Gaia calibrations and aiding the design of future space missions. After these tests, which will last several weeks, the Gaia spacecraft will leave its orbit around the Lagrange point L2 to be put into its final heliocentric orbit, away from Earth’s sphere of influence. Eventually, the Gaia spacecraft will be passivated in March/April 2025 and reach its well-deserved retirement.

Find lots more details on this milestone for the Gaia mission here, including details on how to follow-up on Gaia when it becomes more visible from ground due to changes in its attitude.

Access the pages on the Gaia end of observations here