Astronauts will give the space station a power boost 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 Cassada and Frank Rubio install a solar array outside the floating lab.

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

During the event, Cassada will serve as Extravehicular Crew 1 and wear a red-striped suit, while Rubio will wear an unbranded white suit as Extravehicular Crew 2. The duo performed their first spacewalk together in November. Against the backdrop of spectacular views of Earth, the team assembled a mounting bracket on the starboard side of the space station’s armor.

This hardware allows the installation of more deployable solar arrays, called iROSA, to increase electrical power on the space station.

The first two deployable solar panels 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 generation by more than 30 % once all are operational.

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

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

During Saturday’s spacewalk, Cassada and Rubio will install a solar array to increase capacity in one of the space station’s eight power channels, located in the station’s starboard armor.

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

The spacewalk duo will also disconnect a cable to reactivate another power channel that recently experienced “unexpected outbursts” on November 26.

“By isolating a section of the affected array, which was one of several damaged strands, the goal is to restore 75 percent of the array’s functionality,” according to a NASA statement.

Cassada and Rubio will make another spacewalk on Dec. 19 to install a second deployable solar panel in another power channel, located in the station’s port armor.

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

Erosion can be caused by propellant plumes, which come from both station propellants and the crew and cargo vehicles leaving and going from the station, as well as micrometeorite debris.

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

The new arrays will have a similar life expectancy of 15 years. However, since the degradation of the original arrays was expected to be worse, the team will monitor the new arrays to test their true longevity, because they can last longer.