NASA Restarts Swift Telescope's Instruments as Its Orbit Keeps Shrinking

NASA's Neil Gehrels Swift Observatory is back to studying the universe, even as the ageing spacecraft continues to lose altitude and a planned mission to lift it into a higher orbit has been scaled back. On August 26, the Swift team reactivated the spacecraft's Ultraviolet/Optical Telescope and X-ray Telescope, both switched off in February to reduce atmospheric drag and preserve orbital lifetime while preparations for the boost continued. That same day, the X-ray Telescope captured an image of Tycho's supernova remnant, about 13,000 light-years away in the constellation Cassiopeia.

Swift's third instrument, the Burst Alert Telescope, has stayed inactive since April; shutting it down cut power needs and let engineers angle its solar panels to further limit drag. NASA says the team is working to restart it within the next few weeks. For more than 21 years, Swift has observed the cosmos across multiple wavelengths and quickly turned toward sudden events, alerting other observatories so astronomers can investigate before the events fade.

Swift's problem is its orbit, not its science. Traces of Earth's atmosphere still reach low Earth orbit and gradually drag spacecraft down, and Swift has no propulsion system to reverse that loss on its own. Increased solar activity has recently heated and expanded the upper atmosphere, adding drag and making Swift descend faster than NASA expected. In September 2025, NASA had contracted Katalyst Space to build a spacecraft called LINK to rendezvous with Swift, capture it and lift it into a safer orbit. LINK launched in July aboard a Northrop Grumman Pegasus rocket but developed orientation-control problems later that month, and on August 19, NASA and Katalyst announced LINK would no longer attempt to capture and boost Swift. The mission will instead rendezvous with Swift to test technologies for approaching, inspecting and servicing satellites already in orbit.

Before the boost plan was dropped, NASA predicted that low-drag operations would keep Swift above 185 miles (300 kilometres) until October — a threshold below which operating the telescope becomes increasingly difficult. Now that science observations have resumed, Swift is no longer in its most aggressive drag-reducing configuration, and NASA expects it to reach that altitude within the next one to two months.