Russian Spacewalkers Complete ISS Nauka Module Upgrade

Roscosmos spacewalkers Sergey Prokopyev and Dmitri Petelin work outside the International Space Station’s Roscosmos segment.

Credit: NASA

HOUSTON—Two Russian cosmonauts conducted a more than 5-hr. spacewalk outside the International Space Station on May 12 to complete a round of upgrades to the Russian segment Nauka multipurpose laboratory module.

Sergey Prokopyev and Dmetri Petelin deployed and activated a radiator moved from the Rassvet module to Nauka during an April excursion.

Once a pair of mechanical restraints was released with wrenches, the three rectangular panels of the radiator began to extend. The extension was completed about 45 min. into the spacewalk, which got underway at 11:47 a.m. EDT. It concluded at 5:01 p.m. for a total duration of 5 hr., 14 min.

“It was all very, very smooth,” noted one of the cosmonauts through English translation on cosmonaut exchanges with Russia’s Mission Control. “The radiator is deployed.”

The spacewalk was initially set to last 6 to 6 1/2 hr. But Prokoyev and Petelin managed to take on additional tasks and still finish the excursion ahead of schedule.

After the radiator was deployed, the spacewalkers opened two valves and associated connectors on hydraulic coolant loops to initiate the flow of coolant into the radiator, while monitoring the process closely to ensure there was no leakage.

The spacewalk was the third and final planned for a set of external activities by the two cosmonauts that began with an April 19 spacewalk to move the radiator from Rassvet, a 20-ft.-long cargo module with a docking port that was launched to the ISS aboard a NASA shuttle mission in May 2010. The radiator transition was followed by a spacewalk relocation of an experiment airlock from Rassvet to Nauka on May 3.

The 43-ft.-long Nauka module was launched to the ISS in July 2021 to provide new research volume, a docking port and airlock. Nauka was equipped with a multi-jointed, 36-ft.-long European Space Agency (ESA) robot arm, which played an essential role in the relocations of the radiator and experiment airlock during the first two spacewalks.

After monitoring the initial coolant flow into the radiator, Prokopyev and Petelin moved to the ESA robot arm to install handrail extensions for use during future spacewalks. The European robot arm joined other robot arms provided to the ISS by the Canadian and Japanese space agencies to enhance access to the exterior of the ISS for spacewalk maintenance activities and repairs.

Prokopyev—who currently serves as commander of the ISS’s seven-person U.S., Russian and United Arab Emirate crew—and Petelin also proceeded with the installations of two handrails between Nauka and the Russian segment Prichal module, which includes multiple docking ports. Prichal was launched to the ISS to dock with Nauka in November 2021.

With the handrail installations complete, Prokopyev and Petelin returned to the radiator to conduct more coolant leak checks and adjustments to six additional valves to complete emptying the flow from the coolant reservoir into the radiator panels.

With those tasks complete, the cosmonauts returned to the Poisk airlock, jettisoned a bundle of hand towels and re-entered Poisk to complete their excursion.

Mark Carreau

Mark is based in Houston, where he has written on aerospace for more than 25 years. While at the Houston Chronicle, he was recognized by the Rotary National Award for Space Achievement Foundation in 2006 for his professional contributions to the public understanding of America's space program through news reporting.