Astronauts Experience a Robot Arm Glitch During an ISS Spacewalk

Tuesday, 23 January 2018 - 6:40PM
NASA
Robotics
Tuesday, 23 January 2018 - 6:40PM
Astronauts Experience a Robot Arm Glitch During an ISS Spacewalk
< >
NASA

It sounds like the plot to a sequel to Gravity. Astronauts aboard the International Space Station (ISS) ran intro trouble today when, as part of a routine space walk, they encountered a rogue robot arm that was suffering from a software glitch.

Thankfully, the circumstances weren't nearly as terrifying as it all sounds, as the astronauts were taking part in the space walk primarily to replace part of the robot arm in the first place. The problem was that things got more complicated once they were outside the space station.

Having just returned to work after this week's government shut-downs, NASA had an important mission for Mark Vande Hei and Scott Tingle to undertake today; they needed to climb out onto the exterior hull of the ISS in order to replace one of the hands on the Canadarm2 robotic arm that holds supply ships in place when they dock with the space station.

The Canadarm2 has two Latching End Effectors (LEE), which are grippers that allow the arm to hold ships tightly while they're docked. Over time, these LEE hands wear out, and today's mission involved heading out to manually replace part of the arm. All went well for the first five hours of this delicate operation, until the Canadarm2 was powered back up, and it suffered from a severe programming glitch.







Thankfully, this didn't involve it spinning around wildly or aiming to destroy human life; instead, the arm simply failed to respond to orders. According to NASA TV commentator Rob Navias, during the live broadcast of the mission:

Opening quote
"The Canadarm2 software is not communicating properly with the newly installed spare LEE. They believe the problem may be associated with this mate/de-mate mechanism that connects all of the electrical and communications connections for the arm, so they're going to do a cycle of that and see if that corrects the problem."
Closing quote


This attempt to reboot the arm - essentially turning it off and on again - managed to fix the problem, and the arm responded just fine afterwards.

Nevertheless, it's likely that NASA's programmers will look into the glitch and attempt to figure out what might have caused it. This could be a very rare occurrence, but no matter how uncommon it might be, if it affects the arm's ability to hold a supply ship in place, it could cause significant damage to the ISS if something goes wrong at an inopportune moment.

It's interesting watching the astronauts working while out in the vacuum of space, tethered to the hull of the ISS with such a short cable. While Tingle and Vande Hei are no doubt very experienced at working in zero gravity, there's an element of clumsiness that's introduced thanks to their thick space suits which no doubt slows down this kind of procedure.

At one point in the space walk, capsule communicator (often shortened to "capcom") officer Victor Glover made a joke about Tingle's impressive "origami" skills as he struggled to fold up a foil blanket - it's completely normal for astronauts to have a hard time with fiddly movements while on these kinds of space walks.

It'd be a lot easier if astronauts could rely on Doctor Octopus style robotic limbs while out in space, but, as this entire story proves, you can't always rely on your robot arms to function correctly when you're clinging to the side of a space station.

Science
Space
NASA
Robotics
No