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The International Space Station will receive a power boost during a spacewalk on Saturday, as NASA astronauts Josh Cassada and Frank Rubio install a solar array outside the floating laboratory.
The spacewalk is on track to begin at 7:25 a.m. ET and will last for about seven hours, with live coverage streaming on NASA’s website.
During the event, Cassada will serve as extravehicular crew member 1 and will wear a suit with red stripes, while Rubio will wear an unmarked white suit as extravehicular crew member 2. The duo conducted 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 truss.
This hardware allows for the installation of more rollout solar arrays, called iROSAs, to increase electrical power on the space station.
The first two rollout solar arrays were installed outside the station in June 2021. The plan is to add a total of six iROSAs, which will likely boost 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 the 26th SpaceX Dragon commercial resupply mission, which also carried dwarf tomato seeds and other experiments to the orbiting laboratory.
The arrays were rolled up like 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 on the station’s starboard truss.
Once the array is unfurled and bolted into 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 experienced “unexpected tripping” on November 26.
“By isolating a section of the impacted array, which was one of several damaged strings, the goal is to restore 75% of the array’s functionality,” according to a release from NASA.
Cassada and Rubio will go on another spacewalk on December 19 to install a second roll-out solar array on another power channel, located on the station’s port truss.
The original solar arrays on the space station are still functioning, 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 thruster plumes, which come from both the station’s thrusters and the crew and cargo vehicles that come and go from the station, as well as micrometeorite debris.
The new solar arrays are being placed in front of the original ones. It’s a good test for the new solar arrays, because this same design will power parts of the planned Gateway lunar outpost, which will help humans return to the moon through NASA’s Artemis program.
The new arrays will have a similar 15-year life expectancy. However, since the degradation on the original arrays was expected to be worse, the team will monitor the new arrays to test their true longevity, because they may last longer.