The crew of the Russian segment of the International Space Station (ISS) have reported smoke and the smell of burned plastic as fire and smoke alarms went off.
Russia’s space agency Roscosmos said the incident took place at 01:55 GMT on Thursday in the Russian-built Zvezda module as the station’s batteries were being recharged.
According to Roscosmos, the crew activated air filters and returned back to their “night rest” once the air quality was back to normal. The crew will proceed with a spacewalk scheduled for Thursday as planned, the agency noted.
The incident is the latest in a string of problems that have raised safety concerns over conditions in the Russian segment.
“A smoke detector was triggered in the Zvezda service module of the Russian segment of the International Space Station during automatic battery charging, and an alarm went off,” Roscosmos said in a statement.
French astronaut Thomas Pesquet said “the smell of burning plastic or electronic equipment” wafted to the US segment of the station, Russian state news agency RIA Novosti reported, citing a NASA broadcast.
The ISS 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 Pesquet.
Novitsky and Dubrov are scheduled to carry out a six-hour spacewalk on Thursday to continue integrating the Russian-built Nauka science lab that docked with the space station in July.
“All systems are operating normally,” Roscosmos said.
The Russian segment of the ISS has experienced several problems recently and a space official warned last month that out-of-date software could lead to “irreparable failures”.
The Zvezda service module, part of the Russian segment, has experienced several air leaks, including earlier this year and in 2019.
Citing concerns stemming from ageing hardware, Russia has previously indicated that it plans to leave the ISS after 2025 and launch its own orbital station.
In July, the entire ISS tilted out of orbit after the Nauka module’s thrusters reignited several hours after docking – an incident Russian space officials blamed on a software failure.