A smoke alarm started sounding on the International Space Station (ISS) on Thursday, NASA has confirmed.
The alarm went off inside the Zvezda Service Module of the Russian segment of the ISS as a battery was being charged in the same area, though it’s not clear if this was the cause. The seven crewmembers were resting at the time, but quickly emerged from their sleep stations to respond to the emergency.
According to the Russian space agency Roscosmos, the crew activated an atmosphere-cleaning filter to purify the air. Once the astronauts were satisfied the situation had been safely dealt with, they were able to complete their night’s rest.
“All systems are operating normally, the air composition on board the station is nominal,” Roscosmos said a short while later.
NASA confirmed the incident in a tweet on Thursday, describing a “a faint burnt smell that subsided with air filters.” The space agency declined to offer more details.
French astronaut Thomas Pesquet, who arrived at the orbiting outpost in April, said a smell of “burning plastic or electronic equipment” drifted into the U.S. segment of the station, according to CBS News.
The disturbing incident came just over a week after it was reported that small cracks had been found in Russia’s Zarya module.
“Superficial fissures have been found in some places on the Zarya module,” Vladimir Solovyov, chief engineer of rocket and space firm Energia, told the Russian RIA news agency.
Adding to the concern, Solovyov said: ”This is bad and suggests that the fissures will begin to spread over time.”
According to Reuters, the same official has said before that after 20 years of operation, much of the equipment on the ISS is now getting old, which may lead to an “avalanche” of problems around 2025.
The space station is currently approved to operate until the end of 2024, though there’s a chance it could continue to host astronauts until the end of 2028 and possibly beyond.
Much will depend on how the station and its equipment continues to handle the extremities of space, and whether any issues that occur can be easily fixed.
Despite Thursday’s incident, Russian cosmonauts Oleg Novitsky and Pyotr Dubrov went ahead with their scheduled spacewalk on Thursday.