The arm has a mass of nearly two metric tons and can handle payloads of up to 116 tons.

For much of its lifetime, the arm was essential in getting supplies to the International Space Station. The first version of SpaceX’s cargo vehicle, as well as Northrop’s Cygnus and Japan’s HTV-X transfer vehicles, was designed to be grabbed by the arm when it got close to the station and then be moved into a berth at the facility.

Modern versions of Dragon, both crew and cargo, now undergo autonomous docking, as does Boeing’s Starliner crewed spacecraft.

Can an armless space station survive?

If NASA were unable to use it to berth spacecraft, there could be serious implications for cargo missions, especially with SpaceX planning to retire the Dragon vehicle within four years. NASA’s other principal cargo supply vehicles, Cygnus and HTV-X, cannot dock with the station.

The robotic arm is also used for moving large hardware around the exterior of the station, such as large cooling pumps, in preparation for astronaut spacewalks. NASA and its partners could probably work around this loss of functionality, but it would certainly make operations more difficult.

The potential loss of the robotic arm, even if temporary due to software issues, serves as a reminder that the space station is approaching its 30th anniversary. Much of the facility has been operating in orbit for decades, in hard vacuum, beyond its planned lifetime. So far, most of the aging process has been graceful, but that does not necessarily mean this run of good fortune (and preparation) will continue.

NASA plans to eventually replace the International Space Station with one or more privately developed space stations, but this contracting process has not gone particularly smoothly. What happens if the bedrock of NASA’s space-based operations for the last quarter of a century suddenly becomes a bedrock no longer?