\n<\/p>\n
On the morning of May 27, during routine operations, one of Canadarm2’s wrist joints drew elevated motor current and refused to move as commanded. The fault signature \u2014 power consumed, no motion produced \u2014 pointed to a seized or failed motor-gearbox assembly inside the joint. NASA engineers and the Canadian Space Agency<\/a> placed the arm in a safe, stable configuration and suspended all standard operations while they analyzed the fault.<\/p>\n Canadarm2 is not optional equipment. The arm \u2014 formally the Space Station Remote Manipulator System<\/a> \u2014 is the mechanism that captures every unpiloted cargo ship approaching the station’s U.S. segment, including SpaceX Dragon and Cygnus vehicles carrying food, supplies, and scientific hardware for the seven-person crew. Without it, the station faces severe limitations in receiving cargo and conducting exterior work. A July crew rotation is already waiting: the Soyuz MS-29 crew vehicle is due to launch to the station next month, and a functional Canadarm2 is a prerequisite for the operations that schedule depends on.<\/p>\n Canadarm2 launched to the ISS on April 19, 2001, aboard Space Shuttle Endeavour. It was designed with a 15-year service life. It has now operated for 25 years \u2014 a decade beyond what engineers originally projected \u2014 because of a design decision made before it ever left Earth: every major component of the arm was built to be removed and replaced in orbit.<\/p>\n The Canadian Space Agency<\/a> built the arm around seven motorized joints \u2014 one elbow in the middle and three rotary joints at each wrist-and-shoulder end \u2014 each one a discrete, bolt-on unit. The arm’s two Latching End Effectors, the grappling hands at each tip, are similarly swappable. At 17.6 metres and 1,800 kilograms of titanium, Canadarm2 can never be brought back to Earth for depot-level servicing: it was never designed to survive re-entry, and it never will be. The modular architecture was the only engineering path to a long operational life. The arm was built so that people in spacesuits can take it apart and put it back together, piece by piece, indefinitely.<\/p>\n This is not the first time that approach has been called upon. In June 2002, just over a year after installation, spacewalkers replaced a wrist roll joint<\/a> that had seized. Across two spacewalks in late 2017 and early 2018, both Latching End Effectors were swapped after showing signs of wear. Tuesday’s procedure follows the same maintenance logic that has been baked into the program since launch.<\/p>\n “Canadarm2 was originally designed for 15 years of use, but as the space station exceeded expectations, so did the Canadarm,” Jason Dyer, the Canadian Space Agency’s<\/a> deputy liaison manager for the spacewalk, said at the June 25 briefing at Johnson Space Center. “Now just passing 25 years of use, it is aging gracefully and it is showing signs of wear.”<\/p>\n Bill Spetch, NASA’s ISS operations and integration manager, confirmed at the same briefing that the arm is essential to station operations through the planned decommissioning of the facility in 2030.<\/p>\n The wrist joint that failed weighs 91 kilograms. Reaching it, however, requires a larger first step: Williams and Meir must begin by detaching a 408-kilogram Latching End Effector \u2014 one of the arm’s two grappling hands \u2014 that is currently blocking access to the faulty component<\/a>. Once the Latching End Effector is moved aside, the two astronauts will unbolt the failed wrist joint, install the spare that has been pre-positioned aboard the station, restore all electrical, data, and video connections, and reattach the Latching End Effector. Every movement is monitored by engineers on the ground to protect both the arm and the station’s other systems.<\/p>\n Inside the station, SpaceX Crew-12 pilot Jack Hathaway and ESA astronaut Sophie Adenot<\/a> will carry out their own task with a certain irony: they will operate Canadarm2 itself to carefully position the arm so that Williams and Meir can work on it. CSA astronaut Jenny Gibbons will guide the pair from mission control in Houston.<\/p>\n Williams will wear a suit with red stripes for identification. Meir will wear an unmarked suit.<\/p>\n Williams and Meir previously worked together on Spacewalk 94 in March 2026, where Meir logged a seven-hour, two-minute EVA. Meir has considerably more time outside the station: on October 18, 2019, she and Christina Koch conducted the first all-female spacewalk in history, a seven-hour-and-seventeen-minute job replacing a battery charge-discharge unit on the station’s power system. The pair completed two more all-female spacewalks together in January 2020.<\/p>\n Williams arrived at the station in November 2025 aboard the Soyuz MS-28 spacecraft and has been on orbit for approximately seven months.<\/p>\n A successful repair would restore Canadarm2 to full operational capability and clear the way for NASA’s planned schedule over the coming weeks: three additional spacewalks and the July crew rotation. The station’s ability to capture the Soyuz MS-29 crew vehicle depends, in no small part, on getting this arm’s wrist working again.<\/p>\nWhy the Arm Was Built to Be Fixed in Space<\/h3>\n
What Williams and Meir Will Actually Do Out There<\/h3>\n
A Crew That Has Done This Before<\/h3>\n
What Comes Next for Canadarm2 and Its Successor<\/h3>\n