A Soyuz spacecraft experienced an unplanned depressurization event as it returned to Earth, it has been revealed – but NASA says the crew were not in danger.
The incident occurred on April 10, reports Space News, when the Soyuz MS-02 vehicle was returning to Earth. On board were NASA astronaut Shane Kimbrough, and Roscosmos cosmonauts Sergey Ryzhikov and Andrey Borisenko.
In a committee meeting at NASA’s International Space Station Advisory Committee on October 16, former astronaut Thomas Stafford revealed the incident, which hadn't been disclosed before now.
He said that when the main parachute deployed about 8 kilometers (5 miles) above the landing site in Kazakhstan, a buckle struck the capsule. The incident appears to have been fine, although the crew were wearing Sokol pressure suits anyway, so they would have been able to cope with a depressurization event.
“The buckle struck a welding seam and, as a result, there was a depressurizing event that resulted in some air escaping the capsule,” Stafford said.
Sensors in the spacecraft picked up the incident, caused possibly by the way the parachute was folded, according to Stafford. There’s no evidence of anything like this happening before on any other Soyuz landings, so it seems to be an isolated anomaly.
Depressurization means that some of the air in the capsule escaped. Without proper safety measures, the effects of this can be fatal – but fortunately the Russian space agency, Roscosmos, has measures in place to prevent that happening.
In 1971, three Soviet cosmonauts died on re-entry when their spacecraft depressurized. None of the three were wearing pressure suits, and they remain the only three people to die in space. Since that incident, all crews have been required to wear pressure suits on launches and landings.
A NASA spokesperson confirmed the incident to IFLScience, again noting that it “presented no issue for the crew”. The landing was broadcast on NASA TV, they said, so if anything had gone dramatically wrong it would have been obvious.
At the time of writing, Roscosmos had not responded to a request for comment.
[H/T: Space News]