Nasas Swift Boost Mission Begins As Link Spacecraft Sets Out To Save Observatory

The mission sent a privately built spacecraft into orbit to rendezvous with the ageing Neil Gehrels Swift Observatory, which is gradually losing altitude and faces eventual destruction as atmospheric drag pulls it back toward Earth.

The mission also marked the final flight of Northrop Grumman’s Pegasus XL rocket, bringing an end to a launch vehicle that has served the space industry for more than three decades.

Instead of launching from a conventional pad, the Pegasus XL rocket was released mid-air from Northrop Grumman’s L-1011 Stargazer aircraft over the Marshall Islands before igniting its engines and carrying LINK into orbit.

The launch followed earlier delays caused by poor weather and a software issue affecting the rocket’s navigation system.

Launched in November 2004, the Swift Observatory was designed to study gamma-ray bursts and other high-energy cosmic events. More than 20 years later, the telescope continues to deliver valuable scientific observations.

However, increased solar activity has intensified atmospheric drag in low Earth orbit, causing Swift’s orbit to gradually decay. Unlike many newer spacecraft, Swift was not designed with propulsion systems capable of raising its own orbit, leaving it vulnerable to eventual re-entry.

Rather than retiring the observatory, Nasa opted to demonstrate a new satellite servicing capability that could extend the lifespan of valuable space assets at a fraction of the replacement cost.

Over the coming weeks, LINK will gradually approach Swift while observing the spacecraft to determine the safest location for capture.

The servicing spacecraft is equipped with three robotic arms that will secure the observatory before using ion thrusters to slowly raise both spacecraft back to a more stable orbit over several months.

Nasa aims to return Swift to an altitude of approximately 600 kilometres, potentially adding several more years to its operational life, provided its onboard systems remain healthy.

The mission also represents the first attempt by a private spacecraft to capture and service an uncrewed US government satellite.

The mission marked the 45th and final flight of the Pegasus XL rocket, which first flew in 1990.

Known for its unique air-launch system, Pegasus could reach orbital inclinations that are difficult to access from traditional launch sites. That flexibility made it well-suited for the Swift rescue mission, which required reaching the telescope’s relatively low orbital inclination.

Nasa awarded the Swift rescue mission to Katalyst Space Technologies in 2025, giving the company less than a year to design, build, and test the LINK spacecraft. The entire mission, including launch, cost Nasa approximately $30 million, significantly less than building and launching a replacement space observatory.