US Spacewalk 101: Astronauts Install 8th & Final ISS Roll-out Solar Array

NASA's Anil Menon and Canadian Space Agency's Joshua Kutryk completed U.S. Spacewalk 101 (Extravehicular activity, EVA-101), the 286th spacewalk in International Space Station (ISS) history. The 7-hour, 59-minute extravehicular activity (EVA) began at 1336 UTC and concluded at 2035 UTC, with the the duo successfully installing and deploying the eighth and final ISS Roll-Out Solar Array (iROSA) on the station's starboard 3B power channel.

This spacewalk concluded a five-year power augmentation campaign that began in 2021, designed to compensate for the age-related degradation of the ISS's original solar arrays.

The final iROSA installation was the most complex of the series because the 3B channel on the S6 truss segment sits beyond the operational reach of the Canadarm2 robotic arm. To overcome this, Menon and Kutryk utilized a novel "leapfrog" handoff technique.

Menon rode the robotic arm to the worksite, transferred the 340-kilogramg array to Kutryk, and then secured himself to the station structure to assist in mounting. The deployment itself required no motors; the array unfurled to its full 19-meter length using stored potential energy in its carbon-composite booms.

The process was briefly paused during orbital night to inspect a power connector after controllers detected lower-than-expected current, but the array was successfully deployed shortly after.

"We are seeing half of the expected shunt current that we want," radioed Nichole Stilwell, a NASA astronaut serving as the spacewalk officer in Mission Control. "In this current config, we are not necessarily going to deploy."

Out of safety concerns — given that the arrays generate electricity whenever lit by the sun — the astronauts needed to wait for the space station to enter the shadow of Earth to see what could be done. In the interim, they spent the time cleaning up their worksite and returning the Canadarm2 to its park site as they would have done after the deployment.

They were able to clear the issue. "We are seeing good shunt currents on the ground, so we are go for deploy," said Stilwell.

"We got it done!" said Menon at the end of the 6-hour-and-59-minute spacewalk.

The eight new iROSA panels boost the station's total power output from approximately 152–160 kilowatts** to roughly 215 kilowatts, a 30% increase. This additional power is critical for sustaining station operations, including life support and research, through its planned controlled deorbit in 2030.

"Today marks the completion of not just one solar array but, over 15 years after its development, eight arrays," Menon said at the close of the spacewalk. "These solar arrays are incredible. Half the size of the old ones and bringing 40% more power."

The need for the iROSA augmentations was discovered by flight controllers when the space station's eight original arrays began to show degraded power output as they exceeded their 15-year design life. The iROSAs provide the additional electricity needed to support ISS operations through its retirement and controlled deorbit, which are currently scheduled to occur in late 2030.

The iROSA technology, developed by Redwire, is also selected to power the Power and Propulsion Element of NASA's Gateway lunar outpost.

Menon logged his fourth spacewalk (33.5 hours total in EVA suits), while Kutryk completed his first, becoming the fifth Canadian to walk in space. The duo had installed the seventh iROSA just one week prior (October 29, 2026), marking the 100th U.S. spacewalk conducted from the ISS without a docked Space Shuttle.

"Congratulations to you all on your stellar work to finish the last of the roll-out solar arrays and the upgrades to the ISS power system that will take it to the end of its journey," said Stilwell, addressing Menon and Kutryk. "It is fitting that we just surpassed 26 years of constant human presence on the International Space Station, and you all showed us what the best of humanity looks like executing one of the most difficult and dangerous [things] humans do and making it look easy. Congratulations!"

Each of the eight iROSAs and their mounting assemblies were delivered to the space station by SpaceX Dragon cargo spacecraft. Beginning in June 2021, four teams of two astronauts did as was done on Thursday to deploy each array. In addition to Kutryk and Menon's work on the 2A and 3B power channels, the spacewalkers included Shane Kimbrough of NASA and Thomas Pesquet of the European Space Agency for the 2B and 4B channels; Josh Cassada and Frank Rubio, both with NASA, on 3A and 4A in December 2022; and NASA's Steve Bowen and Woody Hoburg on 1A and 1B in June 2023.