NASA’s Neil Gehrels Swift Observatory is back to studying the universe with two of its three science instruments after plans to raise the spacecraft into a higher orbit were scaled back.
The observatory’s Ultraviolet/Optical Telescope and X-ray Telescope were switched back on Wednesday, Aug. 26. Both instruments had been shut down in February as part of an effort to reduce atmospheric drag and help Swift remain in orbit longer while NASA prepared for a possible orbital boost.
Swift’s third instrument, the Burst Alert Telescope, has not yet resumed science operations. NASA stopped using it in April to lower the spacecraft’s power needs, which allowed engineers to position Swift’s solar panels in a way that further reduced drag. The team now expects to restore that instrument to data collection within the next few weeks.
Swift Returns to Its Cosmic Watch
For 21 years, Swift has served as one of NASA’s most versatile observatories. It studies the universe across multiple wavelengths of light and is especially valuable for tracking sudden, short-lived cosmic events.
When Swift detects an outburst, it can quickly turn toward the source and alert other observatories on the ground and in space. That rapid response helps astronomers gather follow-up observations before fleeting events fade away.
One of Swift’s biggest challenges is its location in low Earth orbit. Even hundreds of miles above Earth, traces of the planet’s atmosphere remain. Those thin upper layers create drag on spacecraft, gradually slowing them and causing their orbits to drop.
Swift does not have a propulsion system that can raise its orbit, so it cannot directly counter that effect.
Solar Activity Increased the Drag
The problem became more urgent as recent solar activity caused Earth’s upper atmosphere to expand. When the Sun is more active, extra energy heats the atmosphere and makes its outer layers extend farther into space.
That expansion increases atmospheric drag on satellites in low Earth orbit. For Swift, the result was a faster-than-expected loss of altitude.
NASA responded in September 2025 by contracting Katalyst Space to attempt something unusual: send another spacecraft to Swift, capture it, and lift the observatory into a higher orbit.
Katalyst had one year to design, build, test, and launch a spacecraft called LINK, then guide it to Swift and carry out the boost.
The Planned Orbit Boost Was Abandoned
LINK launched in July aboard a Northrop Grumman Pegasus rocket. Later that month, however, the spacecraft developed problems with controlling its orientation.
On Aug. 19, NASA and Katalyst announced that LINK would no longer attempt to capture and raise Swift.
The mission is not ending entirely. Katalyst still plans to bring LINK near Swift and perform rendezvous and proximity operations. These maneuvers are intended to test technologies that could eventually be used for in-space satellite servicing, including future missions in which one spacecraft approaches and works near another.
Swift’s Remaining Time at Higher Altitude Is Shrinking
NASA had previously estimated that Swift’s low-drag operating mode would keep the observatory above 185 miles (300 kilometers) until October.
That altitude is an important threshold. Once Swift falls below 185 miles (300 kilometers), operating the telescope becomes more difficult, and the spacecraft is expected to lose altitude more quickly as atmospheric drag increases.
Now that science observations have resumed, the team expects Swift to reach that milestone within the next one to two months.
Until then, the observatory is once again watching the universe and gathering as much science as possible while its orbit continues to decline.
