The International Space Station’s eighth roll-out solar array unfurled on November 5 after astronauts Anil Menon of NASA and Joshua Kutryk of the Canadian Space Agency installed it on the station’s starboard truss. Its deployment completed the ISS solar power upgrade, raising generating capacity from 160 kilowatts to approximately 215 kilowatts, according to NASA’s spacewalk report.
The astronauts attached the final array to power channel 3B. They ended the spacewalk at 3:35 p.m. Eastern Standard Time after six hours and 59 minutes outside the station. Just one week earlier, on October 29, the same pair had installed the seventh array on channel 2A.
How a Rolled Array Becomes a Generating Surface
A roll-out array carries its photovoltaic cells on a flexible blanket. That design lets a long generating surface fit into a compact roll for transport. Once the astronauts have positioned the assembly and secured its base, the blanket can unfurl. Its deployed surface exposes the cells to sunlight, which they convert into electricity.
The design solves a packaging problem familiar from other satellite solar power systems. The launch vehicle has to accommodate the array in its stowed form, but the spacecraft generates power with the much larger surface it exposes in orbit. NASA tested the roll-out design aboard the station in 2017 before crews began installing the operational arrays.
Eighteen Spacewalks Across Eight Power Channels
The installation campaign began in February 2021. Preparing the power-channel equipment and installing the eight arrays took 18 spacewalks. The preparation work accounts for the difference between the number of arrays and the number of excursions needed to put them into service.
The November 5 excursion was Menon’s fifth spacewalk and Kutryk’s second. It was the 286th devoted to station assembly, maintenance, and upgrades. The difference between NASA’s before-and-after figures is approximately 55 kilowatts of additional generating capacity from the completed campaign.
