Astronauts report ‘toxic smell’ coming from Russian spacecraft docked to ISS – and nobody knows exactly what it is

ASTRONAUTS aboard the International Space Station have reported a “toxic” smell coming from a recently docked Russian spacecraft.

The unpiloted Progress 90 resupply spacecraft, which reached the orbital outpost on Saturday, has attached to the Russian Poisk module.

Russian cosmonauts immediately identified the smell after opening the Poisk hatch, and have since sealed it off from the rest of the Russian segment.

Nasa astronaut Don Pettit also reported a “pray paint” smell in the Node 3 module of the US segment, but it was not clear if it had originated from Progress.

“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 social media post.

The US space agency did not describe the odor, but Russian space news outlet Russianspaceweb.com reported that the crew had described it as “toxic.”

The “droplets” are likely a result of “outgassing from materials inside the (Russian) Progress spacecraft,” Nasa told CNN.

“Outgassing” is a phenomenon where gas trapped inside a solid is squeezed out during the high-pressure journey from Earth to space, where temperatures can range from 121C to -158C degrees (250F to -250F).

Kelly O. Humphries, the news chief at Nasa’s Johnson Space Centre in Houston, said the outgassed droplets inside the Progress capsule would not be fuel.

Previous Russian vehicles have leaked coolant in space.

The air quality inside the space station has been determined to be at normal levels.

“Space station air scrubbers and contaminant sensors monitored the station’s atmosphere following the observation,” Nasa shared in its statement.

“And on Sunday, flight controllers determined air quality inside the space station was at normal levels.”

Humphries added: “There are no concerns for the crew.”

The spacecraft will be docked on the ISS for six months to be filled with rubbish loaded by crew, before it departs for Earth.

The Progress 90 mission delivered about three tons of food, fuel and supplies for the Expedition 72 crew.

The space station’s current crew includes Roscosmos’ Aleksandr Gorbunov, Ivan Vagner and Alexey Ovchinin, and Nasa’s Pettit, Nick Hague, Suni Williams and Butch Wilmore.

It comes just months after Nasa and Roscosmos reported 50 “areas of concern” on the orbital outpost, which include cracks and leaks, one of which has been leaking oxygen since 2019.

The five-year-old leak is present in the Russian service module, adjacent to a hatch, which was installed in 2000.

In a recent report from Nasa’s Office of the Inspector General (OIG), the agency dubbed it a “top safety risk”, escalating the threat rating to five out of five.

Nasa is closely monitoring four cracks and 50 other “areas of concern” on the ageing ISS – which is due to be retired by the end of the decade.

While astronauts can cover the cracks with patches or sealant, these are largely temporary solutions.

If the leaks get significantly worse, and start to present a danger, astronauts can close off the tunnel completely.

Although that will mean losing a valuable docking port used by Progress and Soyuz spacecraft.