A final array goes up
Two astronauts on Expedition 75 installed and deployed the last ISS Roll-Out Solar Array (iROSA) on Thursday, Nov. 5, according to Space. NASA's Anil Menon and Joshua Kutryk of the Canadian Space Agency worked outside the International Space Station for 6 hours and 59 minutes. The spacewalk began at 8:36 a.m. EST and ended at 3:35 p.m. EST.
The new array augments the station's older solar wings and lets the outpost produce as much as 30% more electricity, according to Space. "We got it done!" Menon said as the spacewalk ended.
The work repeated much of an Oct. 29 spacewalk that added the next-to-last array. This time the crew worked on the starboard side of the station's backbone truss, on the 3B power channel. They retrieved the 750-pound (340-kilogram) iROSA assembly from a temporary stowage platform and carried it to the worksite with the Canadarm2 robotic arm. They then mounted it to a bracket kit that had been assembled earlier.
A connector problem and a pause
After Menon attached the cables that tie the array into the station's systems, controllers saw a problem. "We are seeing half of the expected shunt current that we want," NASA astronaut Nichole Stilwell, the spacewalk officer in Mission Control, radioed to the crew. "In this current config, we are not necessarily going to deploy."
The connectors had to be inspected. Because the arrays generate electricity whenever sunlight hits them, the astronauts had to wait until the station passed into Earth's shadow before anything could be done, according to the report. In the meantime they tidied the worksite and returned Canadarm2 to its park site, as they would have after a normal deployment.
The issue was then cleared. "We are seeing good shunt currents on the ground, so we are go for deploy," Stilwell said.
Unfurling without a motor
Kutryk and Menon released two bolts and watched the array extend to its full 63-foot (19-meter) length. No motor was involved. As designed, the iROSA unrolled using only the energy stored in its rolled-up carbon composite booms. The whole process took about 10 minutes.
"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."
Five years of upgrades
SpaceX Dragon cargo spacecraft delivered each of the eight iROSAs and their mounting assemblies to the station. Starting in June 2021, four teams of two astronauts installed them. Shane Kimbrough of NASA and Thomas Pesquet of the European Space Agency worked on the 2B and 4B channels. Josh Cassada and Frank Rubio, both of NASA, handled 3A and 4A in December 2022. NASA's Steve Bowen and Woody Hoburg installed 1A and 1B in June 2023. Menon and Kutryk covered 2A and 3B.
Flight controllers identified the need for the upgrade when the station's eight original arrays began producing less power after exceeding their 15-year design life. The iROSAs supply the electricity needed to operate the station until its retirement and controlled deorbit, currently scheduled for late 2030.
Congratulations and milestones
Stilwell congratulated the crew on finishing the upgrades "that will take it to the end of its journey." She noted that the station had just passed 26 years of constant human presence, and said the astronauts had shown "the best of humanity" by making a difficult and dangerous job look easy.
Menon has now logged 33 hours and 30 minutes across four spacewalks, and Kutryk has logged 14 hours and 10 minutes across two. Thursday's outing was the 101st U.S. spacewalk at the station without a space shuttle present and the 286th overall in support of station assembly, maintenance and upgrades. It was the ninth spacewalk of 2026 and the sixth by the station's 75th resident crew.
