The spacewalk continued as planned, although the space station crew was awakened by a fire alarm around 10pm ET on Wednesday night. The alarm sounded for a minute after the sensors detected smoke in the Russian Zvezda module. The smell of smoke and burning plastic was also present in the U.S. parts of the space station.
The crew reacted quickly and replaced the air filters and all signs of smoke dissipated, according to NASA. However, the source of the smoke was not identified.
This is the second of up to 11 spacewalks by cosmonauts while working on Nauka, a multipurpose lab module that includes additional space for research and bedrooms.
Nauka launched from the Baikonur Cosmodrome in Kazakhstan on July 21 and docked on July 29.
During Thursday’s spacewalk, Novitskiy and Dubrov will install railings and complete any unfinished cable routing work during the Sept. 3 spacewalk, which initiated power cable and ethernet connections for in the module.
Novitskiy is extravehicular crew member 1 of the Russian space suit Orlan with red stripes and Dubrov wears the blue striped space suit as a member of the extravehicular crew 2.
The exit will be the third spacewalk for both Dubrov and Novitskiy, as well as the 243rd spacewalk to support the assembly, maintenance and upgrade of the space station.
Meanwhile, a spacewalk scheduled for Aug. 24, which was to include NASA astronaut Mark Vande Hei and Japan Aerospace Exploration Agency astronaut Akihiko Hoshide, will now take place on Aug. 12. September, with some changes.
While no further details have been shared on the issue, other than the fact that it was not a medical emergency, Vande Hei will provide internal support during the Sept. 12 spacewalk as he continues to recover.
European Space Agency astronaut Thomas Pesquet will take his place alongside Hoshide. During the walk, Hoshide and Pesquet will install a modification kit that will be prepared for future Solar Array Roll-Out installation tasks.
According to NASA, this will be the first spacewalk carried out from the lab’s Blackboard Quest orbiting by two international partner astronauts at the space station.
CNN’s Kristin Fisher contributed to this report.