NASA Astronauts Replace Canadarm2 Wrist Joint on ISS Spacewalk

Two NASA astronauts embarked on a critical spacewalk Tuesday, June 30, 2026, to repair the International Space Station's (ISS) primary robotic arm. Flight engineers Chris Williams and Jessica Meir exited the orbiting laboratory's Quest airlock for a mission designated US Spacewalk 95, aiming to replace a wrist joint on the Canadarm2 that experienced a malfunction in late May. NASA's live coverage of the event commenced at 7 a.m. EDT, with the spacewalk itself scheduled to last approximately six and a half hours.

Williams, identified as crew member 1, wore a suit marked with red stripes, while Meir, crew member 2, wore an unadorned suit as they navigated the vacuum of space. The Canadarm2, a vital component of the ISS, ceased proper function on May 27, 2026, during routine operations. The arm experienced elevated motor current and failed to move as expected, prompting an investigation by NASA and the Canadian Space Agency (CSA). The agencies determined that an extravehicular activity, or spacewalk, was necessary to swap the faulty joint with a spare that had been stored on the station.

Repairing a Quarter-Century of Service

The Canadarm2 has been an integral part of the ISS since its installation on April 26, 2001. NASA officials have characterized the repair as a standard maintenance procedure for hardware that has been in continuous operation for over 25 years. The robotic arm was designed with modularity and planned maintenance in mind, utilizing replaceable parts to ensure its longevity and continued functionality. This approach makes such repairs a normal and expected part of the station's operational lifecycle, especially for equipment that has endured decades of demanding use in the harsh environment of space.

The Canadarm2 plays a crucial role in the ISS's operations. It is responsible for capturing and releasing visiting cargo vehicles, maneuvering large equipment for assembly and maintenance tasks, and assisting astronauts during external repairs. A malfunctioning wrist joint significantly limits the arm's positional flexibility, directly impacting its ability to perform these critical functions. Restoring the joint's full range of motion is the primary objective of this spacewalk, ensuring the arm can continue to support the station's ongoing scientific research and operational needs.

While Williams and Meir performed the external repairs, they were not working alone. Inside the ISS, NASA's Jack Hathaway and European Space Agency (ESA) astronaut Sophie Adenot provided crucial support. Their tasks included assisting the spacewalkers with suiting up and de-suiting, as well as carefully maneuvering the Canadarm2 to provide the astronauts with optimal access to the faulty wrist joint. This collaborative effort, with internal and external teams working in concert, is standard procedure for complex spacewalks.

This spacewalk marked familiar territory for both Williams and Meir. The pair last worked together outside the station on March 18, 2026, when they successfully installed a solar array modification kit. Tuesday's outing represented their second spacewalk as a team. Prior to the mission, NASA and the CSA briefed the public on the repair procedures during a news conference on June 25, 2026, after which mission managers granted the final approval.

The timeline for a spacewalk, however, remains an estimate and is subject to change. Factors such as the complexity of the repair or unforeseen technical issues can lead to extensions or early completions. While the specific cause of the malfunction beyond the elevated motor current and lack of movement has not been publicly detailed by the agencies, the decision to replace the joint was made to restore functionality swiftly. The success of the repair will be confirmed once the new joint is installed and the Canadarm2 is tested through its entire range of motion. Should the swap proceed as planned, the arm will be returned to full capability, ensuring that the station's near-term operational schedule remains on track. This mission was the second spacewalk for Williams and the fifth for Meir, contributing to the 280 spacewalks conducted in support of the ISS's assembly, maintenance, and upgrades since its inception.