NASA’s Neil Gehrels Swift Observatory is expected to reenter Earth’s atmosphere around Friday, November 6, according to the US Space Force. The exact location is unknown. The reentry zone includes parts of Africa, Australia, India, Southeast Asia, and Central and South America, though the surviving debris is most likely to fall into the ocean.
Most of the spacecraft is expected to disintegrate as it passes through the atmosphere. Some heavier components, including reaction wheels and parts of its telescopes, could survive, but only a small number of fragments are expected to reach the ground. The risk to the public is considered low.
Launched on November 20, 2004, Swift was built to detect gamma-ray bursts and alert observatories around the world so they could study them. Although designed for a primary mission of a few years, it operated for more than two decades, observing more than 2,000 gamma-ray bursts and nearly as many supernovas. Its data contributed to more than 7,000 research papers.
The observatory’s descent accelerated after increased solar activity in 2024 heated and expanded the upper atmosphere, increasing drag. Swift had no propulsion system to raise its orbit. A NASA rescue attempt also failed: a robotic spacecraft called LINK was intended to move Swift into a higher orbit, but problems with its control system prevented the mission from proceeding.
NASA said on October 26 that Swift was less than 170 miles above Earth. Its telescopes could no longer keep their targets stable, and the observatory made its final observation on October 20. The operations team at Pennsylvania State University then ended its operational status.
NASA’s mission chief scientist Brad Cenko told the Associated Press that some tungsten components and parts of the mirrors might survive reentry. Aerospace engineer Dean Sladen told Space.com that the most likely survivors include the spacecraft’s six reaction wheels and tougher telescope components, such as lenses and mirrors.
Sources: WIRED.