An audacious mission to save one of NASA's most important space telescopes, the Neil Gehrels Swift Observatory, is now underway. The telescope, which has been in orbit for over two decades, is perilously close to re-entering Earth's atmosphere, but a newly launched satellite hopes to give it a life-saving boost.
Swift, launched in 2004 to study powerful cosmic phenomena like gamma-ray bursts, has seen its orbit decay significantly. Initially orbiting at approximately 600 kilometres above Earth, it has now descended to around 375 kilometres. This accelerated descent in recent years is partly attributed to increased solar flare activity, which energises the upper atmosphere, causing it to expand and increase drag on satellites.
To prevent Swift's imminent re-entry, NASA approved a proposal from US start-up Katalyst Space Technologies. Their solution involves a satellite named LINK, which launched on 3 July aboard a Northrop Grumman Pegasus XL rocket. LINK, though smaller than Swift, is equipped with robust robotic arms and large solar panels to power its thrusters, designed to physically grab the observatory.
Following a few weeks of in-orbit testing, LINK is expected to rendezvous with Swift. It will then slowly push the telescope upwards for approximately two months, aiming to restore it to its original 600-kilometre altitude. If successful, this manoeuvre could extend Swift's operational life by as much as a decade, allowing it to continue its crucial observations of the universe.
Beyond saving Swift, this mission holds significant implications for the future of space exploration. Ghonhee Lee, CEO of Katalyst, stated that demonstrating the ability to extend the life of a non-serviceable spacecraft like Swift could create a cost-effective blueprint for maintaining other satellites, including the iconic Hubble Space Telescope, which is also predicted to fall back to Earth in the 2030s without intervention. This pioneering approach could transform how valuable space assets are managed, offering a sustainable alternative to simply letting them decay.