Houston, Texas – Russian cosmonauts aboard the International Space Station faced a brief lockdown over the weekend due to an unusual odor detected in a visiting cargo spacecraft named Progress 90, as reported by NASA on Sunday.

The cosmonauts noticed the odor along with observed droplets, suspected to be from outgassing materials within the Russian Progress spacecraft, causing the brief lockdown. Kelly O. Humphries of NASA’s Johnson Space Center in Houston assured that there were no concerns for the crew’s safety.

Outgassing is a phenomenon that occurs as manmade objects transition from Earth’s atmosphere to the space environment, where temperatures can vary from 250 to minus 250 degrees Fahrenheit. The Progress capsule, which carries essential supplies to the ISS, runs on highly toxic fuel and oxidizers, but NASA confirmed that they were not the cause of the reported issue.

NASA put safety measures in place by shutting down the hatch connecting the Poisk module to the rest of the space station and activating air scrubbing equipment to dissipate the odor. The crew reported that the smell quickly dissipated, ensuring that cargo transfer operations continued as scheduled.

Despite the incident being isolated and brief, it adds to a series of challenges the ISS has faced over the years, including a slow air leak in the Russian-controlled Zvezda module. The space station has been hosting international crews since 2000, with NASA planning to continue operations through at least 2030 alongside partner agencies like Roscosmos, the Canadian Space Agency, European Space Agency, and Japan Aerospace Exploration Agency.

While NASA aims to secure commitments for the ISS’s future beyond 2028, Russian officials have yet to confirm their involvement post-2028, with a decision likely postponed until 2025 as per a recent report from NASA’s Office of the Inspector General.