For more than 20 years, the Landsat 7 satellite circled Earth every 99 minutes or so, capturing images of almost all the planet’s surface each 16 days. One of many craft that observed the changing globe, it revealed melting glaciers in Greenland, the growth of shrimp farms in Mexico, and the extent of deforestation in Papua New Guinea. But after Landsat 7 ran short on fuel, its useful life effectively ended. In space, regular servicing has not been an option.

Now, though, NASA has a potential fix for such enfeebled satellites. In a few years, the agency plans to launch a robot into orbit and maneuver it to within grabbing distance of Landsat 7. The robot will use a mechanical arm to catch hold of it and refuel it, mid-air.

If successful, the mission would mark a milestone—the first time a satellite would be refueled in space. And this mission is just one of a number of planned public and private ventures intended to use robots to repair and improve the billions of dollars’ worth of satellites in orbit.