A spacecraft is falling to its doom — can NASA save it?

NASA is racing to save a science satellite called the Neil Gehrels Swift Observatory before it falls out of the sky. The satellite has been circling Earth since 2004 and still sends back useful data about powerful explosions in space. A small robotic spacecraft is set to launch as early as this week to boost Swift into a higher, safer orbit. If it works, this mission will be a first in the history of space exploration.

Swift started its life about 600 kilometers above Earth's surface. But over the years, its orbit has slowly gotten lower due to a force called atmospheric drag — the slight pull that Earth's thin upper atmosphere has on objects in orbit. The Sun has made things worse. Right now the Sun is near the peak of its 11-year activity cycle, and solar storms have caused Earth's atmosphere to puff out slightly, creating more drag on Swift. By early this year, Swift had dropped to just 370 kilometers above Earth, and NASA realized it was falling faster than expected.

Even though Swift is old, it is still doing important science. The satellite helps identify high-energy cosmic explosions and quickly alerts other telescopes around the world so they can study them too. It has made many big discoveries, including studies of mysterious gamma-ray bursts and giant black holes. Its last target before NASA temporarily shut it down in February was a blazar — an incredibly bright core at the center of a distant galaxy. Scientists say Swift is still too valuable to let burn up in the atmosphere.

NASA awarded $30 million to a company called Katalyst Space Technologies, based in Flagstaff, Arizona, to carry out the rescue. The company built a small, boxy spacecraft called LINK to do the job. As early as June 27, a rocket will lift off from Kwajalein Atoll in the Marshall Islands, carrying LINK into space. From there, LINK will spend several weeks carefully making its way to Swift.

Once LINK reaches Swift, it will extend up to three robotic arms to grab hold of the observatory. Then it will fire its engines to push both spacecraft higher — up to about 600 kilometers above Earth. This process will take another month or two. In the best case, Swift could be doing science again before the end of the year, according to John Nousek, an astronomer at Pennsylvania State University who helps run the Swift mission.

This mission would be the first time a robotic spacecraft has moved a science satellite to a higher orbit to save it. A few crewed space stations have been boosted before by docking with small ships. Astronauts also boosted the Hubble Space Telescope five times using the space shuttle between 1993 and 2009. But those missions used human crews, not robots. If LINK succeeds, it could open the door to saving other satellites — and maybe even Hubble — the same way in the future.