Smoke alarms went off at the Russian segment of the International Space Station in the early hours of Thursday.
The crew reported noticing smoke and the smell of burnt plastic.
According to the Russian space agency Roscosmos, the incident took place in the Russian-built Zvezda module and occurred as the station’s batteries were being recharged.
The crew activated air filters and returned to their “night rest” once the air quality was back to normal, the agency stated.
The space station is currently operated by NASA astronauts Mark Vande Hei, Shane Kimbrough and Megan McArthur; Oleg Novitsky and Pyotr Dubrov of Russia’s Roscosmos; Japan Aerospace Exploration Agency astronaut Akihiko Hoshide and European Space Agency astronaut Thomas Pesquet.
Novitsky and Dubrov are scheduled to carry out a six-hour-long spacewalk on Thursday to continue integrating the Russian-built Nauka science lab that docked at the space station in July. Shortly after docking, the lab briefly knocked the orbital outpost out of position by accidentally firing its engines — an incident Russian space officials blamed on a software failure.