US Spacewalk 100: Astronauts Deploy New Solar Array On 100th EVA

NASA astronaut Anil Menon and Canadian Space Agency astronaut Joshua Kutryk, wearing NASA's extravehicular mobility unit (EMU) spacesuits, completed the 100th U.S. spacewalk (or extravehicular activity, EVA) from the International Space Station (ISS) on Thursday, beginning at about 1200 UTC, and ending 7 hours and 11 minutes later at 1908 UTC. The Expedition 75 crewmates installed and deployed the seventh International Space Station Roll-Out Solar Array (IROSA) on the station’s 2A electrical power channel.

Once outside the ISS, Menon and Kutryk worked on unbolting the iROSA from a temporary stowage platform. The 3-by-0.6-by-1.2-meter rolled-up assembly was delivered to the space station inside the unpressurized trunk of SpaceX's Dragon cargo capsule earlier this month, on the company's 35th ISS resupply mission for NASA.

Menon then secured himself at the end of the Canadarm2 robotic arm and carried the 340-kilogram iROSA to the space station's port side, where he and Kutryk next installed it on the 2A electrical power channel. Kutryk made his way to the worksite along the station's backbone truss.

Using bolts to mount the IROSA in place and connecting its electrical cables to tie it into the station's power system (during a night pass, out of safety concerns), the array was ready to be extended. No motor was needed to deploy the iROSA to its 19-meter length. The potential energy held by the assembly's rolled-up carbon composite booms was enough to fully unroll the panel.

"And we see the iROSA deploying now," reported Mission Control four hours and 23 minutes into the spacewalk.

About 12 minutes later, the array had fully extended, draping over about half of the larger but less capable legacy panel on the P4 truss. The station's eight original arrays are showing degraded power output as they have exceeded their 15-year design life. The iROSAs, when used in tandem with their older counterparts, have increased the station's power supply by 20% to 30%.

Having worked ahead of their schedule, Menon and Kutryk removed some of the beams holding the final iROSA in place on its temporary platform and rotated two launch locks that were used in its delivery on Dragon. The crew completed preparatory tasks for the final IROSA installation, which is scheduled for November 5, 2026, on the 3B power channel.

"Being outside, I can say it is always sunny in space," said Menon at the conclusion of Thursday's EVA. "I find it incredible what we have been able to do to provide new solar arrays to the space station. In fact, we have been ... doing complex operations like this for over 26 years."

"This is USOS [United States Operating Segment] EVA 100, which is an incredible milestone. I think it really signifies how much we have done," he said.

This installation is part of a multi-year upgrade to increase the ISS power-generating capacity by up to 30%, raising output from 160 kilowatts to roughly 215 kilowatts to support operations through the station's planned retirement in 2030.

This was Menon’s fourth spacewalk, adding to his total of 26 hours and 31 minutes in space, while it was Kutryk’s first, making him the fifth Canadian to perform a spacewalk and the first since 2019.

Thursday's EVA was the 100th U.S. outing from the space station without a now-retired space shuttle docked to the complex. Overall, it was the 285th spacewalk in support of ISS assembly, maintenance and upgrades, including 66 EVAs out of the Russian segment of the station and 119 by visiting shuttle crews.

The first U.S. spacewalk outside of the Quest airlock was made by Expedition 4 crewmates Carl Walz and Daniel Bursch on Feb. 20, 2002. The 5-hour-and-47-minute EVA mostly tested Quest's systems and completed "housekeeping chores."