Two astronauts completed the installation of the eighth and final International Space Station Roll-Out Solar Array (iROSA) during a spacewalk on Thursday, Nov. 5, finishing a power upgrade that began more than five years ago. Expedition 75 flight engineers Anil Menon of NASA and Joshua Kutryk of the Canadian Space Agency mounted and unfurled the array on the starboard side of the station's truss, on the 3B power channel, according to Space.
The extravehicular activity started at 8:36 a.m. EST and ended at 3:35 p.m. EST, a duration of 6 hours and 59 minutes. "We got it done!" Menon said at the close of the spacewalk, Space reports.
The new arrays work alongside the station's original solar wings and can raise electricity output by as much as 30%, according to USA Today.
Why it matters
The station's eight original solar arrays have been producing less power as they passed their 15-year design life, a decline flight controllers noticed in the station's power output. The iROSAs make up the shortfall and are meant to supply the electricity the orbiting laboratory needs through its planned retirement and controlled deorbit, currently scheduled for late 2030.
Spaceflight Now describes the completed work as the end of a five-year effort to upgrade the station's power supply. Menon, speaking at the end of the spacewalk, noted that the new arrays are half the size of the older ones while delivering 40% more power, Space reports.
A cable reading, a wait for darkness, then deployment
The procedure repeated much of what the two astronauts had done on an Oct. 29 spacewalk that installed the second-to-last array. The pair pulled the 750-pound (340-kilogram) iROSA assembly from a temporary stowage platform, moved it to the worksite with the Canadarm2 robotic arm and secured it to a bracket kit that had been assembled on an earlier spacewalk.
Menon then connected the cables linking the array to station systems, but the readings were not what flight controllers wanted. Nichole Stilwell, the NASA astronaut serving as spacewalk officer in Mission Control, radioed that only half the expected shunt current was showing and that deployment would not proceed in that configuration, according to Space.
Because the arrays generate electricity whenever sunlight strikes them, the connectors could only be inspected safely once the station passed into Earth's shadow. While they waited, the astronauts tidied their worksite and returned Canadarm2 to its parking position, the same housekeeping they would have done after a deployment.
Once in darkness, the issue was resolved. Stilwell reported good shunt currents on the ground and gave the go-ahead to deploy. After Kutryk and Menon released two bolts, the array extended to its full 63-foot (19-meter) length in about ten minutes. No motor was involved: the iROSA unrolls using only the stored energy of its rolled-up carbon composite booms, as designed.
Eight arrays, four crews, one Dragon at a time
SpaceX Dragon cargo spacecraft delivered each of the eight iROSAs and their mounting hardware to the station. Four pairs of astronauts carried out the installations, starting in June 2021.
Shane Kimbrough of NASA and Thomas Pesquet of the European Space Agency installed the arrays on the 2B and 4B channels. Josh Cassada and Frank Rubio, both of NASA, followed in December 2022 on the 3A and 4A channels. NASA's Steve Bowen and Woody Hoburg handled 1A and 1B in June 2023. Kutryk and Menon completed the set with the 2A and 3B channels.
Thursday's spacewalk was the 101st U.S. EVA at the station conducted without a space shuttle present, and the 286th overall in support of station assembly, maintenance and upgrades, Space reports. It was the ninth spacewalk of 2026 and the sixth by the station's 75th resident crew.
Menon has now accumulated 33 hours and 30 minutes across four spacewalks. Kutryk has logged 14 hours and 10 minutes over two.
In remarks after the deployment, Stilwell congratulated the pair and noted that the station had just passed 26 years of continuous human presence. She said the timing was fitting and praised the astronauts for carrying out difficult and dangerous work, Space reports.
Watch for NASA's planning for the station's end of life, with retirement and controlled deorbit currently targeted for late 2030.
