ISS astronauts prepare mount for new solar array on first U.S. spacewalk in 10 months

NASA astronauts Jessica Meir and Chris Williams spent 7 hours and 2 minutes on a March 18 spacewalk to install a bracket on the ISS for a future roll-out solar array; it was the first U.S. EVA in nearly a year.

Two NASA astronauts exited the ISS Quest airlock on March 18 for a spacewalk that lasted 7 hours and 2 minutes to prepare the station for an additional roll-out solar array. Jessica Meir and Chris Williams worked on the port side of the station’s backbone truss to assemble and attach a bracket that will hold an iROSA unit to be installed on a later EVA. The iROSA roll-out arrays are smaller than the station’s legacy wings and unfurl to about 63 feet (19 meters) without motors. The upgrades to the U.S. segment began in 2021 and new arrays are intended to increase the station’s electrical supply. Known details: - The spacewalk began at 8:52 a.m. EDT and ended at 3:54 p.m. EDT, totaling 7 hours and 2 minutes. - Meir and Williams installed a mount for an ISS Roll-Out Array (iROSA) on the port-side truss; the panel itself will be unrolled during a future spacewalk. - iROSA units use carbon-composite booms that can unfurl a panel in about six minutes and are smaller than the legacy four solar wings. - When all planned iROSAs are in place, they are reported to increase the ISS’s electricity supply by 20% to 30%. - Two tasks planned for this EVA — swabbing for microorganisms and installing a lens cover on the Canadarm2 camera — were deferred to a future outing and were not listed as mission critical. Summary: The work completed on March 18 prepares the station’s port truss to receive another roll-out solar array, continuing a multi-year effort to restore and expand power on the U.S. segment. The new arrays are intended to raise the ISS’s available electricity and support future activities; the specific installation of the iROSA and the deferred tasks will be carried out on a future spacewalk, undetermined at this time.