NASA's Swift telescope falls to Earth on Wednesday as exoplanet science looks elsewhere

NASA shut the telescope down on 20 October, according to ABC News. Its orbit had decayed to 275 kilometres, and it could no longer compensate for atmospheric drag.

It now travels at roughly 8 kilometres a second. It has no propulsion left to steer it. NASA says most of the spacecraft will burn up, but some components will survive. The agency puts the risk of harm to anyone on Earth at about 1 in 2,100. Swift's low inclination means any surviving fragments can only come down between 20.6 degrees south and 20.6 degrees north latitude.

The Verge reported the re-entry window on 3 November. The estimates inside that window do not line up. ABC News reported that the NASA-funded Space Weather Operational Readiness Development program predicted a crash at about 4:37am AEDT on 4 November, give or take a few hours. The Aerospace Corporation put it at 8:11pm AEDT on 4 November, give or take 12 hours. Both work from the same decaying orbit. Neither can name a landing point yet.

What Swift was for

Swift launched in November 2004 on a two-year prime mission. It was built to study the origin of gamma-ray bursts, the most powerful explosions in the universe. It carried three instruments: a Burst Alert Telescope, an X-Ray Telescope and an Ultraviolet/Optical Telescope. It kept working long past its design life as a general-purpose multi-wavelength observatory, Space.com reported on 1 November.

Brad Tucker, an astrophysicist at the Australian National University, spoke to ABC News. He said the observatory had been a workhorse for cosmic explosions such as supernovas, stellar collisions and stars being ripped apart by black holes.

"It may not be as big or as popular as Hubble or James Webb Space Telescopes, but we have used it for ages," he said.

Its end was slow and then sudden. Drag from the atmosphere had been pulling Swift down for years. Increased solar activity over the past two years hastened the decline, per ABC News. That is the same activity behind the recent auroras. In July NASA backed a plan to boost it to a higher orbit using a private spacecraft. That attempt failed because of problems with the rescue craft's attitude control, The Verge reported.

Swift is not an isolated case. Darren McKnight is a senior technical fellow at the tracking firm LeoLabs. He told Space.com that 10 times more objects are re-entering each year than five years ago. He attributed the rise to the growth of low Earth orbit constellations and technology refresh cycles.

"It is unfortunate that Swift was not 'reorbited,' but from a reentry hazard perspective it is a small," he said, in a quote that Space.com published truncated.

The exoplanet hunt moved on without it

Swift's fall lands in a week when telescope news has been about what other observatories are finding, not what Swift is losing. On 2 November, Space.com reported that the James Webb Space Telescope had traced the interstellar comet 3I/ATLAS to tiny grains of ice mixed with dust. That mix is unlike the comets of our own solar system but similar to icy bodies beyond Neptune. The comet was only the third object found entering the solar system from elsewhere in the Milky Way, after 1I/'Oumuamua in 2017 and 2I/Borisov in 2019. The research suggests 3I/ATLAS formed in a planet-forming disk around a young star, possibly 10 to 12 billion years ago. That is more than twice the age of our solar system.

"We designed [JWST] to be ready the moment an active interstellar comet was found and to follow it over time," Martin Cordiner of NASA's Goddard Space Flight Center and the Catholic University of America said in a statement quoted by Space.com.

Cordiner leads the JWST programme for such objects and co-authored the new paper. Closer to home, NASA reported on 1 November that Hubble and Webb had together found 27 previously unknown trans-Neptunian objects. These are the small icy bodies beyond Neptune that never grew into planets. The two telescopes observed the same patch of sky at once, Hubble in visible light and Webb in infrared. The agency called it the deepest survey of its kind. The objects shine more than 100 million times more faintly than things visible to the naked eye. Two related papers appeared in The Astronomical Journal.

The puzzle is in the numbers. There were fewer small objects than some theories of planet formation predicted. Their colours closely matched those of much larger objects in the same regions. PhD candidates led the teams. One team was at the University of Victoria in Canada, working with the National Research Council of Canada. The other was at Northern Arizona University in Flagstaff.

Closer to Earth, other instruments

On the same day, ScienceDaily reported on a study in Nature Astronomy by Japanese scientists. They found all five nucleobases used in DNA and RNA in pristine samples from the asteroid Ryugu, returned by JAXA's Hayabusa2 mission in 2020. The team analysed 5.4 grams of material. It found the five molecules in roughly similar amounts in two samples. NASA's Bennu samples had already yielded all five in 2025. The Murchison and Orgueil meteorites have produced nucleobases before, though meteorites can be contaminated on the way down.

None of that work needed Swift. Nor does the next generation of instruments. NVIDIA published a description on 2 November of an agent-controlled telescope workflow. That is a sign that automated scheduling is moving into observatory operations. The company's post is a vendor account, not an independent assessment.

For anyone hoping to watch Swift come down, the practical advice is thin. ABC News reported that the final orbit could fall in daylight or over ocean. In that case nobody sees it. It could also fall over a populated area at night, and then there will be footage. Tucker's arithmetic is blunt:

"If 70 per cent of the Earth is ocean, 30 per cent is land. So three out of 10 times it's on land, not ocean."

NASA and the US Space Force will keep tracking the re-entry and updating predictions, the agency said. The window narrows over the final orbits, and the track maps shrink to a single line. Until then, the only firm facts are the mass, about 1,500 kilograms, the shutdown date of 20 October, and the 1 in 2,100 figure.

Swift's scientific legacy sits in two decades of gamma-ray burst alerts that other observatories followed up on. Its replacement is not one spacecraft but a queue of them. Webb's infrared work on interstellar visitors is one. Hubble's joint survey of the solar system's edge is another. The telescope that spent 22 years watching the most violent events in the universe will end its own mission quietly on Wednesday. It will come down somewhere between 20.6 degrees north and south.