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Yahoo
31-03-2025
- Science
- Yahoo
European Space Agency Bids Farewell to Gaia Mission
The European Space Agency (ESA) has said goodbye to Gaia, its "billion star surveyor." After nearly 11 years of celestial science—twice its planned lifetime—the spacecraft's fuel supplies reached critically low levels, leading the ESA to cut Gaia's power on Thursday. The ESA launched Gaia in December 2013 to build a 3D map of "more than a thousand million stars throughout our Milky Way galaxy and beyond." The spacecraft hitched a ride to space via a Soyuz-STB/Fregat-MT launch vehicle, which injected Gaia into the Sun-Earth Lagrange point 2, where Earth's and the Sun's gravitational pulls are balanced. Since then, Gaia has orbited the Sun at the same pace as Earth, collecting star data in unprecedented detail since the completion of its three-month post-launch calibration. Gaia is known for having created the largest and most precise 3D map of the Milky Way to date. According to the ESA, it significantly surpassed its scientific goal by "racking up more than three trillion observations of about two billion stars. " It has also contributed to the discoveries of exoplanets, black holes, quasars, and neighbor galaxies outside our own. Though the spacecraft was only supposed to last a little over five years, it remained functional for more than double that time. Credit: ESA/Gaia/DPAC, Milky Way impression by Stefan Payne-Wardenaar But a decade-plus of continuously adjusting a spacecraft's positioning and movements burns fuel, and in January, it became clear that Gaia didn't have much time left. The ESA planned a series of technology tests and data downlinks to ensure the transmission of Gaia's last findings, then sent the spacecraft into its heliocentric "retirement" orbit far from Earth's gravitational influence. This would ensure the passive spacecraft wouldn't interfere with active missions in Gaia's original stomping grounds. On March 27, the Gaia team deactivated and powered off Gaia's instruments and subsystems. They then corrupted the spacecraft's onboard software before deactivating Gaia's communication subsystem and central computer. The ESA notes that personal farewell messages from the mission team were written into Gaia's memory prior to its retirement. "We will never forget Gaia, and Gaia will never forget us," mission manager Uwe Lammers said. Though Gaia will never communicate with Earth again, a wealth of scientific findings are yet to come. In 2026, the Gaia team will publish Gaia Data Release 4, a 500TB trove of data covering the mission's first five and a half years. This data will expand Gaia's binary star catalog, as well as its list of exoplanets and "wobbling" stars. Gaia's findings also inform the ESA's Euclid mission and its upcoming Plato mission, ensuring the beloved spacecraft will benefit science for years to come.
Yahoo
28-03-2025
- Science
- Yahoo
So long, Gaia: Europe officially retires prolific star-mapping space telescope
When you buy through links on our articles, Future and its syndication partners may earn a commission. Europe's star-mapping Gaia space observatory has entered its final orbit, after gathering valuable cosmic data for more than a decade. The spacecraft's control team at the European Space Operations Centre in Paris switched off Gaia's subsystems today (March 27) and sent the venerable craft into a safe "retirement orbit." "We will never forget Gaia, and Gaia will never forget us," Gaia Mission Manager Uwe Lammers said in a statement. In January, the European Space Agency (ESA) shut down Gaia's science operations, as the spacecraft's fuel reserves were nearly depleted. This ended Gaia's data collection, but more work was needed to put Gaia to bed. Related: Goodnight, Gaia! ESA spacecraft shuts down after 12 years of Milky Way mapping For example, the team needed to move the probe from its science orbit at the Earth-Sun Lagrange Point 2 — a gravitationally stable spot about 930,000 miles (1.5 million kilometers) away from us — to a retirement orbit around the sun that minimizes the chances Gaia gets within 6.2 million miles (10 million km) of Earth for at least the next century. That was accomplished today via a final firing of the spacecraft's thrusters, team members said. Though Gaia's work is now officially done, the mission will continue expanding our knowledge of the Milky Way far into the future, team members said. "Gaia's extensive data releases are a unique treasure trove for astrophysical research, and influence almost all disciplines in astronomy," Gaia Project Scientist Johannes Sahlmann said in the same statement. Gaia set out to map the Milky Way after launching in 2013. It charted the positions of nearly two billion stars, providing a precise 3D map of our galaxy. The mission's accomplishments include discovering evidence of galactic mergers, identifying new star clusters, tracking hundreds of thousands of asteroids and comets, and helping discover exoplanets and black holes. The Gaia team releases big batches of mission data every couple of years. The three such releases to date occurred in 2016, 2018 and 2022. "Data release 4, planned for 2026, and the final Gaia legacy catalogues, planned for release no earlier than the end of 2030, will continue shaping our scientific understanding of the cosmos for decades to come," Sahlmann added. Related Stories: — New trove of Gaia data will uncloak the Milky Way's dark past and future — Like the '90s, binary stars are back in style — Star-mapping Gaia spacecraft spots a pair of Jupiter-like planets It turns out that ending Gaia's useful life cycle wasn't easy. "Switching off a spacecraft at the end of its mission sounds like a simple enough job," Gaia Spacecraft Operator Tiago Nogueira said in the same release. "But spacecraft really don't want to be switched off." The observatory was designed to withstand the extreme conditions it would face during spaceflight, such as radiation storms and micrometeorite impacts. To this end, Gaia has built-in redundancies to make sure it could reboot after a disruption. "We had to design a decommissioning strategy that involved systematically picking apart and disabling the layers of redundancy that have safeguarded Gaia for so long," Nogueira added, "because we don't want it to reactivate in the future and begin transmitting again if its solar panels find sunlight." This was a sobering and bittersweet task, team members said. "Today, I was in charge of corrupting Gaia's processor modules to make sure that the onboard software will never restart again once we have switched off the spacecraft," Spacecraft Operations Engineer Julia Fortuno said in the same statement. "I have mixed feelings between the excitement for these important end-of-life operations and the sadness of saying goodbye to a spacecraft I have worked on for more than five years," Fortuno added. "I am very happy to have been part of this incredible mission."
