NASA’s 3,200-pound Neil Gehrels Swift Observatory is expected to burn up in Earth’s atmosphere after an orbit-raising attempt failed, leaving the agency and its commercial partner without a rescue. The telescope sits about 200 miles above Earth, and engineers estimate it will become difficult to operate once it drops below 185 miles in early to mid-October.
The rescue effort runs out of fuel
NASA and Arizona-based Katalyst Space Technologies tried to boost Swift’s orbit with LINK, a satellite developed, built and launched in nine months. LINK launched in early July but spun out of control in space. A newly launched machine took on a high-stakes repair job—and it couldn’t complete the planned rescue.
NASA and Katalyst continued toward a planned mid-August rendezvous, recasting it as a demonstration rather than a rescue because LINK still had orientation issues. Engineers used its thrusters to slow the unexpected spin and uploaded new flight software. That maneuver used up propellant, leaving LINK without enough fuel to safely attempt the planned capture and orbit-raising phase, Katalyst said.
In the first week of September, LINK came within 7.5 to 9 miles of Swift, practicing how a future servicing mission might approach a satellite or telescope not designed for in-space servicing. It deployed the three robotic arms originally intended to grab Swift and fired its three electric propulsion thrusters. LINK operated in space for 85 days before re-entering Earth’s atmosphere on September 25, Katalyst said.
NASA Astrophysics Division director Shawn Domagal-Goldman called the effort “a high-risk, high-reward mission.” He said, “Without intervention, Swift was going to re-enter the atmosphere by year’s end.” The intervention didn’t save the observatory. NASA and Katalyst say the mission still advanced U.S. spacecraft-servicing technology and tested ways to extend satellites’ time in low Earth orbit.
A scientific tool with no replacement waiting
Swift launched in November 2004 to study gamma-ray bursts, the universe’s most powerful explosions. It has also observed other cosmic flashes, asteroids and comets, and can rapidly turn toward events such as flaring black holes. Its descent comes just shy of the 22nd anniversary of its launch, and no established observational replacement is waiting in the wings.
Atmospheric drag has been pulling Swift lower, intensified by increased solar activity over the past couple of years as the sun reached the peak of its 11-year cycle in 2024. NASA said intense flares and coronal mass ejections expanded Earth’s atmosphere, increasing the drag. The agency’s intervention plan has now become a test run for future servicing missions, while Swift continues toward re-entry.
Swift’s mission scientists gradually turned its instruments back on to collect data and make observations until the end. The instruments had been shut off for months to reduce power use and keep the observatory from sinking; switching them back on speeds its decline.
The remaining risk—and the official verdict
Space-tracking company LeoLabs said some Swift hardware might survive re-entry because of the spacecraft’s size, but the probability of debris causing significant property damage or physical harm is “very small.” Any surviving debris would more likely fall into the ocean or uninhabited land, LeoLabs said. NASA didn’t respond to a request for comment on the potential risks.
Katalyst Space CEO Ghonhee Lee said, “While we did not accomplish every objective we set out to achieve, in less than a year we went from mission concept to launching and operating the first commercial space robot. This is a foundation we can build on.” The company plans to apply LINK’s data and lessons to its next generation of spacecraft. NASA’s S. Bradley Cenko said Swift’s namesake would have celebrated that the boost effort let NASA “try something new and daring even though the outcome wasn’t guaranteed.” The observatory still falls; the institutions are already describing what they learned.