Astronauts aboard the International Space Station (ISS), led by Commander Sunita Williams, took immediate safety measures after Russian cosmonauts reported a strange, "toxic" smell upon opening the Progress MS-29 cargo spacecraft.
The incident unfolded after the uncrewed Progress 90 resupply spacecraft docked to the ISS’s Poisk module on November 23. As the hatch opened, the cosmonauts detected an unusual odor and observed small droplets, prompting swift action to close the Poisk hatch and isolate the affected area from the rest of the station.
NASA and Roscosmos immediately activated air-scrubbing systems across the station. The U.S. segment deployed the Trace Contaminant Control Subassembly (TCCS), while Russian segments used additional purification systems. Crew members donned personal protective equipment (PPE) as a precaution while monitoring systems assessed the air quality.
NASA flight controllers later confirmed that the station’s atmosphere had returned to normal by Sunday, November 24. “There are no safety concerns for the crew, and all operations are proceeding as planned,” the agency stated.
Despite the quick resolution, the source of the smell remains a mystery. Investigators are probing whether it originated from within the Progress spacecraft or the vestibule connecting it to the ISS.
Progress MS-29, which launched from Baikonur Cosmodrome on November 21, was delivering routine supplies such as food and fuel. The spacecraft will remain docked for six months before returning to Earth with waste materials.
The incident comes as astronauts face ongoing challenges aboard the ISS. NASA astronauts Sunita Williams and Butch Wilmore, who have been stranded since June due to delays with the Boeing Starliner spacecraft, are relying on strict rations, including water recycled from sweat and urine. Their rescue mission, using a SpaceX Dragon craft, is not scheduled until early 2025.
While the smell raised alarms, swift action ensured no disruption to station operations, demonstrating the resilience of the ISS crew and mission teams in managing unexpected challenges 254 miles above Earth.