NASA Astronauts Replace Failed Wrist Joint on Space Station Robot Arm

Two NASA astronauts replaced a failed 200-pound wrist joint on the International Space Station's Canadarm2 robot arm during a seven-hour, 20-minute spacewalk Tuesday, CBS News reported. Jessica Meir, on her fifth spacewalk, and Chris Williams, on his second, switched their spacesuits to battery power at 8:20 a.m. ET from the Quest airlock.

They first detached a 900-pound assembly of the arm's latching end effector and two healthy joints, stowed it on a nearby shelf, then removed joint No. 5. The replacement joint was installed four and a half hours into the walk.

Flight director Fiona Antkowiak had described the sequence in advance. Canadian astronaut Jenni Gibbons called from mission control near the end of the excursion: "That is a good install, you guys. I know that was tough.

Flight controllers powered up the arm afterward and confirmed good electrical connections. " Williams returned the failed joint to the airlock for eventual return to Earth. The joint had drawn excess current and stopped moving properly on May 27.

NASA and Canadian Space Agency experts determined it required replacement with a spare from an external platform. ISS operations and integration manager Bill Spetch said the arm was designed with replaceable components and will continue to receive maintenance through the station's planned retirement at the end of 2030.

The Canadarm2 arm captures Northrop Grumman's Cygnus cargo ships and moves components and spacewalkers during maintenance.

The spacewalk occurred 260 miles above Earth and marked the year's third ISS spacewalk and the 280th overall.