Spacewalk 96: Astronauts Prep ISS Power Infrastructure For Solar Array Upgrade

Anil Menon and Jessica Meir completed a 6 hours 27 minutes U.S. Spacewalk 96 or extravehicular activity (EVA) on Thursday (Aug. 6). The NASA astronauts exited the International Space Station (ISS)’s Quest airlock to modify the 3B power channel on the Starboard 6 truss, preparing the station for the installation of a seventh ISS Roll-Out Solar Array (IROSA) later in the year.

Since 2021, astronauts on prior spacewalks have deployed six of the iROSA assemblies, leaving now just two awaiting delivery to the station later this year. The ISS relies on eight individual power channels fed by primary solar array wings deployed between 2000 and 2009. Over decades in low Earth orbit, radiation and thermal cycling gradually reduced the efficiency of these original arrays.

Thursday's spacewalk began at 1233 UTC when the astronauts switched their spacesuits to internal battery power. A veteran astronaut, Meir served as EV-1 and wore a spacesuit with red stripes; this is her sixth spacewalk since her first ISS mission between 2019 and 2020. Menon, a U.S. Space Force colonel and physician, is on his first mission to space and wore an unmarked spacesuit as EV-2.

Meir and Menon assembled the modification kit for one of the space station's eight power channels, which will allow for the future addition of a new iROSA. They worked to assemble and bolt together the triangular brackets on the 3B power channel, located on the far right, or starboard (S6) segment of the station's backbone truss.

Menon was positioned on an articulating portable foot restraint (APFR) atop a worksite interface (WIFEX), providing a stable angle to work from the truss.

Once the modification kit structure was built and secured to the 3B mast canister, the two spacewalkers routed cabling that will carry the electricity from the future iROSA into the 3B power channel and then covered the struts with multi-layer insulation to protect them from micrometeoroid strikes.

The iROSA wings sit forward of the legacy solar arrays, augmenting their electricity generation rather than replacing it. The station's eight original arrays began showing degraded power output as they exceeded their 15-year design life. When used in tandem with the new iROSA wings, the upgraded system will increase the station's electricity supply by 20% to 30%.

The other power channel currently without an iROSA deployed is 2A on the left, or port side, of the station.

"Anil, you can see the moon to the — well, I am not sure what way you're facing, but…," said Meir, taking a short break during the spacewalk to notice NASA's next destination for astronauts under its Artemis program.

"To my right. Yeah, I see it — thanks for the heads-up," said Menon. "I can see a future moon base there."

"I can see it, too!" Meir said.

Meir later turned her attention to Mars with her closing words of the day.

"On this day in 2012, NASA's robotic rover Curiosity successfully landed on the surface of Mars with the goal of understanding if the planet could have fostered life. Curiosity achieved that goal within a year," she said. "One day, humans will visit Curiosity, propelled by the groundbreaking science, technology demonstrations and operations conducted here on the International Space Station for almost 26 years now."

"Today, we made one more step toward expanding the ISS power system, further sustaining our human presence in low Earth orbit, as we prepare to take those next steps," said Meir.

Meir and Menon upgraded the ISS power infrastructure to support critical operations, including life support and scientific experiments, as the station ages. This upgrade is critical for sustaining the station’s power margin through its planned controlled deorbit in late 2030, requiring additional energy for attitude control and avionics during reentry.

After collecting their tools and reentering the Quest airlock, the spacewalk concluded at 1900 UTC.

This was the first spacewalk for the space station's Expedition 75 crew; the 96th U.S. EVA and 281st spacewalk overall in support of the space station's assembly, maintenance and enhancement.

There are two more U.S. spacewalks scheduled for this month: EVA 97 will work to replace a space-to-ground antenna on Aug. 13, and EVA 98 will connect power channel cables and data relay systems as part of ongoing maintenance, including preparations for the station's future deorbit, as well as replace a navigational aid used for spacecraft docking on Aug. 25.