NASA officially ended the Swift mission on Friday, Oct. 23, announcing that the Neil Gehrels Swift Observatory collected its final scientific data on Oct.

20 and will reenter Earth's atmosphere within the next few weeks. The spacecraft entered safe mode that day after sinking below 171 miles (275 kilometers), an altitude too low for its telescopes to hold steady on targets.

Controllers at Penn State then sent a command ending operations and preparing the vehicle for its uncontrolled reentry, according to Nature World News.

NASA says most of the spacecraft is expected to burn up, though some components may survive; a NASA spokesperson described the risk of harm to anyone on Earth as unlikely.

In September 2025, NASA awarded Arizona-based Katalyst Space Technologies a $30 million contract to rescue Swift, which has no thrusters to counter atmospheric drag. Katalyst built the refrigerator-sized LINK servicing spacecraft in about nine months and launched it on July 3.

About three weeks after liftoff, LINK suffered problems with its propulsion system and attitude-maintaining reaction wheels and began spinning at an unexpected rate, according to space.com.

The unprecedented mission — no private spacecraft had ever captured and boosted a satellite not designed for servicing — never attempted the boost, but LINK did get within 12 to 15 kilometers of Swift and photographed the observatory before falling back to Earth in September.

Swift launched in November 2004 with no onboard propulsion, so its orbit was always slowly decaying. Nature World News reports that elevated solar activity heated and expanded Earth's upper atmosphere, increasing drag and accelerating Swift's descent.

Controllers paused pointed science operations for months to reduce drag and buy time, then resumed observing in late August — a choice that increased drag again as the observatory sank rapidly. By Oct.

20, the spacecraft could no longer offset the rising drag and entered safe mode, ending a 22-year run that began as a two-year mission.

Built to chase gamma-ray bursts — the most powerful explosions in the cosmos — Swift observed more than 2,000 GRBs and studied more than 1,400 supernova explosions, while also eyeing asteroids, comets, black holes and completing an all-sky X-ray survey, per space.com.

Its 2005 detection of the first afterglow from a short GRB helped link such bursts to merging neutron stars, Nature World News reports.

The mission's data has contributed to roughly 7,000 published scientific papers, and NASA says the archive of about 12 terabytes of observations will remain publicly available.

Swift's loss leaves a real hole: it was a key tool for fast follow-up of gamma-ray bursts, neutrino alerts and gravitational-wave events. NASA has no direct replacement.

Division director Shawn Domagal-Goldman said the agency will explore using and augmenting its existing telescope fleet, fast-to-orbit commercial capabilities and new missions to maintain rapid response in a post-Swift world, The Register reported via news.lavx.hu.

NASA and U.S. tracking authorities are expected to publish updated reentry estimates as the date nears, since forecasts for uncontrolled satellites narrow only in the final days.

Swift's reentry will be uncontrolled, meaning NASA cannot steer it to a remote ocean zone, though oceans cover most of Earth's surface so surviving debris most often falls into water, Nature World News notes.

Readers are advised not to touch any suspected debris, since fragments can have sharp edges or residues, and to report finds to local law enforcement. Exact timing and location cannot be predicted weeks out because solar activity keeps shifting the decay rate.

Meanwhile, the observatory's public archive of brightness measurements, spectra and more than 1.5 million ultraviolet and optical images will keep fueling discoveries for decades.