Astronauts to boost space station power during Saturday’s spacewalk

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The International Space Station will get a power boost during a spacewalk Saturday as NASA astronauts Josh Casada and Frank Rubio install a solar array outside the floating lab.

The spacewalk is set to begin at 7:25 a.m. ET and will last about seven hours, with a live stream on NASA’s website.

During the event, Cassada will serve as a crew member outside Ship 1 and wear a red-striped suit, while Rubio will wear an unmarked white suit as a crew member outside Ship 2. The duo conducted their first spacewalk together in November. Against a backdrop of spectacular views of Earth, the team assembled a mounting bracket on the starboard side of the space station’s truss.

This hardware allows the installation of more solar arrays, called iROSA, to increase the space station’s electrical output.

The first two solar arrays were installed outside the station in June 2021. The plan is to add a total of six iROSAs, which will likely increase the space station’s power output by more than 30% once they are all operational.

Two more arrays were delivered to the space station on November 27 aboard the 26th SpaceX Dragon commercial resupply mission, which also carried dwarf tomato seeds and other experiments to the orbiting laboratory.

The arrays are rolled up like a carpet and are 750 pounds (340 kilograms) and 10 feet (3 meters) wide.

During Saturday’s spacewalk, Casada and Rubio will install a solar array to increase capacity in one of the space station’s eight power ducts located on the station’s starboard side.

Once the array is deployed and secured in place by the astronauts, it will be about 63 feet (19 meters) long and 20 feet (6 meters) wide.

The spacewalking duo will also disconnect a cable to reactivate another power channel that recently suffered an “unexpected trip” on November 26.

“By isolating a portion of the affected array, which is one of several damaged arrays, the goal is to restore 75 percent of the array’s functionality,” according to a NASA release.

Casada and Rubio will take another spacewalk on Dec. 19 to install a second solar array on another feed channel located on the station’s port farm.

The original solar arrays on the space station are still functional, but they have been supplying power there for more than 20 years and are showing some signs of wear after long-term exposure to the space environment. The arrays were originally designed to last 15 years.

Erosion can be caused by thrust jets that come from both the station’s thrusters and the crew and cargo vehicles coming and going from the station, as well as micrometeorite debris.

The new solar arrays are placed in front of the original ones. It’s a good test for the new solar arrays because the same design will power parts of the planned Gateway lunar outpost, which will help return humans to the moon in NASA’s Artemis program.

The new arrays will have a similar 15-year lifespan. However, as the deterioration of the original arrays was expected to be worse, the team will monitor the new arrays to test their true longevity as they may last longer.