NASA’s Neil Gehrels Swift Observatory has resumed science operations using two of its three instruments after commercial orbital rescue plans were abandoned. Launched in 2004, the aging space telescope now faces an October deadline as solar activity accelerates atmospheric drag in its low Earth orbit.
The Failed Rescue Mission and LINK Spacecraft Setback
Last year, NASA contracted Katalyst Space Technologies to attempt an orbital rescue mission. The company was awarded a $30 million contract in September to build a robotic servicing spacecraft named LINK, launch it, capture Swift, and boost the observatory into a higher orbit. LINK launched in July aboard a Northrop Grumman Pegasus rocket, but the mission hit severe technical hurdles.
Over a weekend in July, the servicing spacecraft experienced attitude control issues that sent it spinning. Preliminary investigations revealed that two of LINK’s three reaction wheels stopped working, alongside a partial loss of functionality in its cold gas thruster system. NASA and Katalyst Space announced that LINK would no longer attempt to capture and lift Swift.
“We knew this was a high-risk, high-reward mission – a first-of-its kind attempt, developed on an unprecedented timeline driven by the Sun’s activity.”
Shawn Domagal-Goldman, NASA astrophysics director
Despite abandoning the orbital boost, the mission is not entirely over. Katalyst still plans to bring LINK near Swift to perform rendezvous and proximity operations. The objective is to test in-space servicing technologies for future missions. NASA Administrator Jared Isaacman noted that while the outcome was not what teams worked toward, the attempt remained worthwhile.
Solar Maximum and Rapid Orbital Decay
Swift’s descent is driven by environmental pressures tied to the sun’s activity cycle. The observatory orbits in low Earth orbit, where trace layers of the atmosphere create drag that gradually slows satellites and drops their altitude.
That solar activity heated Earth’s outer atmosphere, causing it to expand farther into space. The resulting atmospheric drag increased friction on Swift, pulling the satellite down much faster than engineers originally anticipated. By July, the observatory descended to 360 kilometers, or 226 miles, above Earth. Models indicate a high probability of reentry before 2027.
Instruments Restart Amid Borrowed Time
To conserve power and reduce drag during the months of waiting for the rescue attempt, mission controllers powered down parts of the observatory. In February, engineers shut down the Ultraviolet/Optical Telescope and the X-ray Telescope. In April, the third instrument, the Burst Alert Telescope, was also paused to allow angle adjustments on Swift’s solar panels for maximum drag reduction.
Following the cancellation of the boost, operators switched the Ultraviolet/Optical Telescope and the X-ray Telescope back on. The Burst Alert Telescope remains offline for now, though engineers plan to restore its data collection capabilities within the next few weeks.
For two decades, Swift served as NASA’s multitool for studying the cosmos, pointing rapidly at short-lived outbursts and alerting other facilities. Now, the observatory operates on borrowed time. NASA previously projected that low-drag operations would keep the spacecraft above 185 miles, or 300 kilometers, until October. Once it drops below that threshold, operating the telescope becomes increasingly difficult as descent rates accelerate.
Next Steps for LINK and the Sinking Observatory
As Swift gathers final sets of data during its descent, Katalyst works to stabilize the crippled LINK spacecraft. Ground teams initiated a series of burns using gimbaled electric propulsion thrusters to reduce body rates and regain control.
“Over the coming days, Katalyst will work to reduce the body rates using the gimbaled electric propulsion thrusters and stabilize the spacecraft. We have already begun this series of burns and are seeing the intended effect.”
Katalyst Space, via mission update
Katalyst intends to update the control schemes to match the spacecraft’s remaining functional hardware. If those recovery efforts succeed, LINK will approach Swift to execute proximity maneuvers and complete a visual survey of potential grab points that have endured 20 years of space exposure. Meanwhile, NASA monitors Swift as it ticks closer to the October boundary.
