NASA’s Swift telescope is headed for reentry after rescue fails

NASA’s Neil Gehrels Swift Observatory is expected to fall back through Earth’s atmosphere after an attempt to save the aging space telescope failed, KESQ.com reports.

Swift is now about 200 miles (325 kilometers) above Earth. NASA engineers expect operations to become increasingly difficult once it descends below 185 miles (300 kilometers), a threshold it could cross in early to mid-October. The observatory is then expected to continue dropping until it burns up during reentry.

The 3,200-pound (1,452-kilogram) spacecraft has been in low Earth orbit since November 2004. Its expected loss comes shortly before the 22nd anniversary of its launch and leaves no established replacement ready to take over its broad range of observations.

A telescope built for sudden cosmic events

Swift was designed to detect gamma-ray bursts, extremely powerful explosions that produce brief flashes of high-energy radiation. Its ability to turn quickly toward changing targets made it useful for studying other fleeting events, including flares from black holes, as well as objects within the solar system such as asteroids and comets.

The observatory’s instruments were temporarily switched off to reduce its power needs and slow its descent. Scientists have since been gradually bringing them back online so Swift can continue gathering data for as long as possible. That activity also uses energy and contributes to the spacecraft’s decline.

Swift’s orbit has been shrinking because of atmospheric drag. Solar activity has made the problem worse during the past several years. The sun reached the peak of its roughly 11-year cycle in 2024, producing flares and coronal mass ejections that heated and expanded Earth’s upper atmosphere. The thicker atmosphere increased resistance against the spacecraft and accelerated its loss of altitude.

The observatory was named for Neil Gehrels, a NASA astrophysicist who helped design the mission. Its rapid response and varied scientific work turned it into a versatile tool for astronomers beyond its original gamma-ray-burst assignment.

A rescue mission that changed course

NASA and Arizona-based Katalyst Space Technologies tried to extend Swift’s life with LINK, a small spacecraft developed, constructed and launched in nine months. The plan called for LINK to approach Swift, seize it with robotic arms and use its propulsion system to move the observatory into a higher, more stable orbit.

LINK launched in early July but began spinning unexpectedly, preventing it from carrying out the planned rescue. Katalyst engineers used the satellite’s thrusters to reduce the rotation and uploaded new flight software. The effort to regain control required a maneuver that consumed much of LINK’s remaining propellant.

By mid-August, NASA and Katalyst concluded that the satellite lacked enough fuel to capture Swift and raise its orbit safely. Rather than abandon the mission, the companies proceeded with a rendezvous as a technology demonstration.

During the first week of September, LINK approached to within roughly 7.5 to 9 miles (12 to 15 kilometers) of Swift. It extended the three robotic arms intended for the capture and activated its three electric propulsion thrusters. The encounter gave engineers an opportunity to test how a spacecraft might approach and work around an older satellite that had never been designed for servicing in orbit.

LINK remained in space for 85 days before reentering the atmosphere on September 25. Katalyst said the mission produced data and experience that will inform a future generation of spacecraft intended to repair or extend the lives of satellites already in orbit.

A controlled end, but little replacement capacity

Swift’s descent is not expected to create a major danger on the ground. Space-tracking company LeoLabs told CNN that some of the observatory’s larger components might survive reentry, but assessed the chance of serious damage or injury as very low. Any surviving material would most likely land in the ocean or an unpopulated area. NASA did not respond to a request for comment about reentry risks.

The failed boost effort was intended not only to protect Swift but also to test commercial spacecraft servicing on an accelerated schedule. NASA’s astrophysics division described the mission as a high-risk attempt to develop capabilities that could eventually help other observatories remain useful in low Earth orbit.

For Swift’s scientists, the mission will end without a direct successor waiting to replace its observations. Until the spacecraft drops too low to operate, its team plans to keep using the instruments and collecting information from a telescope that has spent more than two decades responding to the universe’s briefest and most energetic signals.