How One Bad Smell Led the ISS To Shut Down a Russian Spacecraft

Astronauts aboard the International Space Station (ISS) were met with a bizarre and unwelcome arrival when a Russian spacecraft docked: a foul smell.

The "unexpected odor" was detected after the Progress 90 cargo spacecraft—carrying several tons of food, fuel, and supplies—docked on the Russian Poisk module of the ISS on Saturday, perturbing the Russian cosmonauts that opened the hatch.

Along with the noxious smell, the cosmonauts also noticed droplets floating in the air, leading the hatch to the Progress to be immediately shut, and the Russian module closed off to the rest of the ISS while air quality levels were tested and scrubbed.

"After opening the Progress spacecraft's hatch, the Roscosmos cosmonauts noticed an unexpected odor and observed small droplets, prompting the crew to close the Poisk hatch to the rest of the Russian segment," NASA said in a statement posted to X on Sunday.

Anatoly Zak, a writer for the independent space-watching site Russian Space Web, says that the smell was "toxic", and that NASA astronaut Don Pettit mentioned the smell resembling "spray paint."

Mission Control in Houston eventually determined that there were no dangerous gases present in the ISS, and as of Sunday afternoon, the astronauts were in the process of reopening the hatches to the Russian module and the Progress craft.

"Space station air scrubbers and contaminant sensors monitored the station's atmosphere following the observation, and on Sunday, flight controllers determined air quality inside the space station was at normal levels," the statement said.

"There are no concerns for the crew, and as of Sunday afternoon, the crew is working to open the hatch between Poisk and Progress while all other space station operations are proceeding as planned."

The identity of the smell and the droplets have not yet been confirmed. Newsweek has contacted Roscosmos for comment.

NASA officials told CNN that the odor and droplets likely originated from "outgassing from materials inside the (Russian) Progress spacecraft."

Stock image of the ISS. A Russian spacecraft released a strange smell and mysterious droplets into the station after it docked. ISTOCK / GETTY IMAGES PLUS

Outgassing refers to the release of gases or volatile compounds from materials and items transported aboard spacecraft. Cargo items made of materials like plastics, adhesives, rubbers, or certain fabrics may release gases under the vacuum of space, and items containing air pockets or absorbed gases (like moisture or volatile organic compounds) can release them when exposed to low-pressure environments.

Items sent to the ISS, such as food, clothing, and scientific equipment, usually undergo rigorous testing to minimize outgassing. Some outgassed substances can be toxic or irritating, potentially compromising the air quality inside spacecraft or space stations.

This strange incident comes after years of issues aboard the ISS, one of the most recent of which involved the Boeing Starliner spacecraft, resulting in Sunita "Suni" Williams and Barry "Butch" Wilmore becoming stranded on the station until next year.

Additionally, the Russian module Zvezda has been mostly closed off from the rest of the station due to a slow air leak.

There have also been several other leaks involving Russian spacecraft docking with the ISS, with coolant leaks during the arrival of the Soyuz MS-22 spacecraft in December 2022 and the Progress MS-21 craft in February 2023. Roscosmos blamed these leaks on impacts from micrometeoroids or orbital debris, which NASA publicly accepted.

"The NASA team has also looked at it, independent of the Russian team, and we also cannot find anything, based on the information we've been given by our Russian colleagues, of anything other than some type of external force or debris or something else like that," Joel Montalbano, NASA ISS program manager at the time, said at a briefing in July 2023.

Who owns the ISS?

The International Space Station (ISS) is not owned by any one country or company, but is a collaborative effort managed and operated through international partnerships. NASA provides the majority of the funding and modules like the Destiny Laboratory and Node modules, while Roscosmos has contributed key modules, and handles propulsion and docking systems.

The European Space Agency (ESA), Japan Aerospace Exploration Agency (JAXA), and Canadian Space Agency (CSA) are also involved in the scientific experiments aboard the station.

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