ISS astronauts install final iROSA solar panel to augment aging ISS power systems

5 min read · reported by NASASpaceflight

The International Space Station program completed a critical power upgrade that had been ongoing for over five years, as astronauts Anil Menon of NASA and Joshua Kutryk of the Canadian Space Agency embarked on a successful US EVA-101 to install the final set of iROSA solar panels on the Station’s truss on Thursday.

This upgrade, started in June 2021, was approved by NASA due to the degradation of the Station’s original solar panels, launched aboard Space Shuttle flights from 2000 to 2009. The iROSA solar panels are smaller but can each produce eight kilowatts of power, giving the ISS around 215 kilowatts of power after the upgrade is complete.

Originally, six iROSA units were planned to upgrade the Station’s power system, and they were installed between 2021 and 2023. However, additional projections indicated the need for additional power beyond that, so two more iROSA units were procured from Redwire for the 2A and 3B power channels on the ISS truss.

The last two iROSA solar panel upgrade units were launched aboard Cargo Dragon C211, which docked to the zenith docking port on the Station’s Harmony node module on Oct. 15, as part of the CRS-35 mission. Anil Menon and Joshua Kutryk installed the first new iROSA unit on the 2A channel during EVA-100 on Oct. 29.

EVA-100 started at 11:57 UTC with Menon, as EV1 with the red stripes, and Kutryk, as EV2 with the all-white suit, unbolting the iROSA from its carrier before moving to the worksite at the P4 truss on the port side of the Station to work on the installation. Menon was mounted in a foot restraint on the end of the Canadarm2, while Kutryk was the free-floating spacewalker, as the duo began their work.

The astronauts maneuvered the iROSA unit and fitted it to a mounting bracket on the modification kit installed on the P4 truss over two spacewalks. The first EVA to install the kit was conducted by Anne McClain and Nichole Ayers during EVA-93 in May 2025, but the astronauts had issues with installing the telescoping booms for the two side struts.

A second EVA was needed to finish the job, and Jessica Meir teamed up with Chris Williams during EVA-94 in March 2026. They used special tools to successfully help install the telescoping booms, and the 2A power channel was ready to receive its iROSA upgrade when it was launched.

After Menon and Kutryk installed the iROSA unit, they waited for orbital night to hook up four electrical power connections between the unit and the 2A channel. This was done to prevent the astronauts from risking electric shock, as power would pass through the connectors during orbital daylight.

The astronauts successfully hooked up three of the connections during an orbital night pass; Menon and Kutryk were going to wait until the next orbital night pass to hook up the fourth and final connections. The astronauts tightened up bolts around the modification kit while they waited.

However, controllers decided the iROSA solar arrays could be deployed starting at four hours and 23 minutes into the spacewalk, as the arrays were in a safe configuration for deployment, with three of the four connections hooked up. After Anil Menon released two bolts on the bottom of the IROSA unit, the arrays rolled out to their full length of 18.3 m.

Menon finished the deployment by releasing two bolts to tension the array; the entire procedure, from start to finish, lasted around 12 minutes. The astronauts finished hooking up the last connection during the next orbital night pass, and worked on get-ahead tasks to prepare the eighth and final iROSA unit for removal from the storage pallet during the remainder of their work time outside.

EVA-100 finished successfully at 19:08 UTC after seven hours and 11 minutes. The spacewalk was the 100th U.S. segment EVA at the ISS without the Shuttle present, and was the eighth EVA at the Station in 2026. In addition, the spacewalk was the fifth one for Expedition 75, and the 285th overall spacewalk for ISS assembly, maintenance, and upgrades.

After EVA-100, Anil Menon had four spacewalks totaling 26 hours and 31 minutes to his credit, while Kutryk finished his first EVA. The duo prepared for EVA-101, which began on Thursday, Nov. 5 at 13:36 UTC, to install the final iROSA solar panels on the 3B power channel on the starboard side of the Station at the S6 truss. For this spacewalk, Kutryk was EV1 with the red stripes, as the astronaut on the end of the Canadarm2, while Menon was EV2 and the free-floating astronaut.

EVA-101 was very similar to EVA-100 in its tasks and progression, with the astronauts removing the final iROSA array unit from its storage pallet before installing it on the 3B modification kit’s mounting bracket. Menon and Kutryk connected the electrical system in the same manner as on EVA-100, while inspecting and redoing connections during the second night pass. The inspection was called because only half of the expected current was flowing through the 3B power channel, and the issue was ultimately resolved.

The only major difference between EVA-101 and the previous spacewalk was a manual handoff of the iROSA unit between the astronaut on the Canadarm2’s foot restraint and the free-floating crewmember. This was done because the robotic arm could not reach the worksite on the S6 truss. After the manual handoff, the astronauts were in position to install the iROSA on the modification kit for channel 3 B, added by Jessica Meir and Anil Menon during EVA-96 on Aug. 6.

The astronauts deployed the array in the same manner as with the 2A iROSA unit. Once the 3B IROSA was deployed, the astronauts cleaned up their equipment and ended their EVA after six hours and 59 minutes, finishing at 20:35 UTC. EVA-101 was the sixth spacewalk for Expedition 75, the ninth EVA at the Station in 2026, and the 286th overall spacewalk for ISS assembly, maintenance, and upgrades. The spacewalk was also Menon’s fifth and Kutryk’s second. Anil Menon now has 33 hours and 30 minutes of total EVA time, while Kutryk has 14 hours and 10 minutes total EVA time to his credit, and there have now been 75 days, 14 hours, and 13 minutes of spacewalking time at ISS.

After EVA-101, the ISS will have enough power margin for normal operations and science up to its planned end of life around 2030. The exact date of the Station’s disposal at Point Nemo in the Pacific is in question, as NASA administrator Jared Isaacman recently discussed operating the ISS longer in an interview on NSF’s The Flame Trench, stating that he does not want a gap until a commercial successor is ready.

Reported by NASASpaceflight. Reproduced unedited by Everything Space. View the original →