NASA is set to execute two distinct orbital servicing operations on Tuesday, each addressing the physical decay of critical space infrastructure. A rescue spacecraft named Link is scheduled to lift off from Kwajalein Atoll in the Pacific Ocean aboard an air-launched Pegasus XL rocket at 10:23 GMT, tasked with halting the uncontrolled descent of the 20-year-old Swift gamma-ray observatory. Hours later, two American astronauts will exit the International Space Station to replace a faulty wrist joint on the Canadarm2 robotic arm, restoring its full range of motion after a motor anomaly was detected in May.

The Swift telescope, launched in 2004 on a planned two-year mission, has been losing altitude faster than anticipated because of heightened solar activity expanding Earth’s upper atmosphere. Its orbit has decayed from an initial 585 km to roughly 360 km, and without intervention it would reach the critical 300 km threshold by October, after which atmospheric drag would make a rescue impossible. The Link robot, built by the startup Katalyst Space Technologies under a $30 million contract signed last September, will take about a month to rendezvous with Swift, then use three articulated arms with finger-like grippers to latch onto the spacecraft—whose rear geometry remains partially unknown to engineers—and gradually raise it to a 600 km orbit over two months. NASA officials in Washington describe the mission as a high-risk demonstration with no guarantee of success, noting that Swift was never designed to be serviced.

Aboard the ISS, astronauts Chris Williams and Jessica Meir will conduct a 6.5-hour extravehicular activity beginning at 12:35 GMT, the 280th spacewalk in the station’s assembly and maintenance history. Their task is to swap out a 90 kg wrist joint on Canadarm2, a 17-metre robotic arm installed in 2001 that is used for berthing visiting vehicles and moving equipment. The component had been drawing excessive current and failing to move correctly, prompting a suspension of operations. A spare joint is already stored on the station, allowing the repair to proceed without waiting for a resupply mission.

Viewed from Moscow, the Swift rescue echoes a 2022 Chinese operation that successfully relocated a satellite to a higher graveyard orbit, though this is the first American attempt at such a manoeuvre. Katalyst executives, speaking to US media, frame the mission as the start of a new commercial servicing model that could eventually extend to larger observatories like Hubble, which faces a similar orbital decay. NASA astrophysics division director Shawn Domagal-Goldman acknowledged the long odds, telling reporters, “Nobody thought we would get this far,” while agency scientists placed the probability of success at roughly even. The telescope, valued at $250 million, remains in high demand for rapid-response gamma-ray burst detection and has no funded replacement.

The Pegasus launch and the spacewalk are both scheduled for Tuesday, with the Link robot’s arrival at Swift expected in late July and the orbit-raising phase extending into September. The Canadarm2 repair is expected to be completed within a single spacewalk, after which ground controllers will test the joint’s functionality.