NASA has launched a robotic mission to try to prevent one of its ageing telescopes from burning up in the atmosphere in a complicated operation expected to last several months.

Northrop Grumman launched the Link spacecraft – built by United States-based Katalyst Space Technologies – from the Marshall Islands in the Pacific Ocean on Friday.

A Pegasus rocket blasted off from the belly of a modified aircraft putting Link on course to reach and capture NASA’s Swift Observatory in about a month.

Initially scheduled for Tuesday, the robot’s launch was postponed due to weather, then technical issues. Blast-off happened on Friday at 0836 GMT from an atoll in the Pacific Ocean.

The unprecedented $30m effort involves sending a robot to rescue the Swift space telescope that is falling towards Earth. If successful, the mission could pave the way for giving other satellites a second life.

Launched in 2004, Swift is sinking faster than ever because of recent solar storms. The $250m telescope studies gamma-ray bursts, the most powerful explosions in the universe.

Once it reaches an orbit close to Swift’s, the robot will deploy its solar panels and perform a series of checks.

It will then have to locate the Swift telescope in the vastness of space, circle around it and dock using three robotic arms – manoeuvres expected to take several weeks.

Finally, it will attempt to propel the satellite approximately 300km (186 miles) higher above the Earth, roughly to its initial orbital position. That operation is expected to last at least a month.

“This is a lot of firsts stacked on top of each other,” Shawn Domagal-Goldman, director of NASA’s astrophysics division, told reporters on Tuesday. “I’m just deeply thankful that we’re even giving this a go.”