Spacewalkers Anil Menon and Joshua Kutryk spent 6 hours 59 minutes outside the ISS installing its last roll-out solar array, lifting power to about 215 kilowatts

NASA astronaut Anil Menon and Joshua Kutryk of the Canadian Space Agency worked outside the International Space Station for 6 hours 59 minutes on Nov. 5, finishing at 3:35 p.m. EST. Their job was to install and deploy the eighth and final roll-out solar array, known as an IROSA, and doing so closed out a power upgrade that began in 2021.

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With the array in place, the station’s generating capacity is put at about 215 kilowatts, up from 160 kilowatts. NASA’s flight controllers confirmed good electrical readings on the ground before telling the crew to proceed with the deployment, and the agency says the work completes the station’s power augmentation upgrades after more than five years of preparation and installation. The orbiting laboratory has been continuously occupied since November 2000, so the arrays are being added to a platform that is now in its third decade.

The 3B channel and the 286th station spacewalk

NASA’s spacewalk report from Nov. 5 places the new array on the station’s 3B power channel, on the starboard truss. The outing was U.S. spacewalk 101, Menon’s fifth and Kutryk’s second, and the 286th spacewalk supporting station assembly, maintenance and upgrades. Before the crew went out, a NASA preview post put the start at about 8:30 a.m. EST, with exit through the Quest airlock.

Menon and Kutryk had already worked together a week earlier, and a NASA account of the Oct. 29 outing records 7 hours 11 minutes outside, a finish at 3:08 p.m. EDT, and the installation of the seventh IROSA on the 2A power channel. That spacewalk, U.S. spacewalk 100, was Menon’s fourth and Kutryk’s first, and it also covered preparatory work for the November job.

Live coverage of the Nov. 5 outing was scheduled to begin at 6:45 a.m., the suited-up astronauts left through the Quest airlock around 8:30 a.m. EST, and NASA’s closing report logged the end of the spacewalk at 3:35 p.m. The Oct. 29 outing ran 12 minutes longer than the November one, so the two sessions tracked each other closely even though the second carried the final deployment.

Roll-out design: 63 feet, 750 pounds, no motor

Each array unfurls to 63 feet (19 meters) and weighs 750 pounds, according to Space.com’s coverage of the Nov. 5 spacewalk. No motor is involved in the deployment: the arrays extend using energy stored in their rolled-up carbon composite booms. The same report says installations began in June 2021 and that the original wings had degraded after passing their 15-year design life.

Menon summed up the hardware after the spacewalk by calling the arrays incredible, half the size of the old ones and bringing 40% more power. NASA spacewalk officer Nichole Stilwell told the crew over the loop that shunt currents looked good from the ground, which cleared the deployment. The agency says astronauts completed 18 spacewalks in all to prepare the power channels and place the eight arrays, starting in February 2021.

The station these arrays serve is large. NASA’s facts page gives its length as 356 feet end to end, with a 310-foot truss, and a mass of 925,335 pounds, in orbit about 250 miles above Earth. All of that hardware, plus the laboratories, runs on electricity from the solar wings, so each added kilowatt matters for experiments, life support and the thermal systems that keep equipment from overheating. Since the original wings now produce less than at launch, the new arrays recover capacity that aging had taken away.

Two percentages circulate and they are not the same claim. Menon credited each new array with 40% more power than the older wing it supports, while NASA’s total is that the full set of eight lifts station capacity by up to 30 percent. The per-array figure compares one new unit against one old one; the station-wide figure spreads that gain across a power system that also contains wings the new hardware does not replace. Both can be true at once, and the kilowatt numbers tie to the second.

From 160 to about 215 kilowatts

NASA’s Oct. 29 post said the eight arrays were expected to raise available power by up to 30 percent, taking capacity from 160 kilowatts to about 215 kilowatts. The agency’s station facts page still lists a figure of 75 to 90 kilowatts for the eight original arrays, and it was last updated in July 2024, and the two numbers appear to describe different things: the older figure looks like the output of the legacy wings, while 215 kilowatts is the station-wide generating capacity with the new arrays included.

Those added arrays are meant to outlast the lab’s working life. The preview post says the eighth array will provide extra power for critical operations, including the station’s safe and controlled deorbit, and the Space.com report gives late 2030 as the scheduled retirement. Whether the aging legacy wings keep producing enough power through that date is the open question that the new arrays are supposed to cover.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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