Two astronauts are set to exit the International Space Station (ISS) later on a mission to gather living organisms growing on the facility.
NASA astronauts Tracy Dyson and Matt Dominick attempted the operation on 13 May but had to abort it due to “suit discomfort”.
Mr Dominick will be replaced for Monday’s walk by Mike Barratt.
During the six and a half hour operation, they will swab surfaces on two pieces of equipment to determine if microorganisms can survive the extreme environment.
So why are astronauts gathering tiny space organisms… and how did they get there?
Microorganisms have been living on the outside of the space station since it blasted off in 1998.
“When the space station was launched, it was inside space shuttles,” said Dr Carly Howett who works on NASA missions exploring the solar system and at the University of Oxford.
“They’re not necessarily pristine environments, so [the microorganisms] could have just hitched a ride on the way up, no problem at all.”
The organisms could have also been released from the space station over the years, according to Dr Howett.
“When we do a [space walk], there’s an airlock. We lose some of the air from inside the space station.
“Perhaps some of that air also carries with it some of these organisms.”
“Studying them should reveal a lot about life in space, as well as helping us make sure we don’t contaminate other planets as we explore the solar system and beyond.
“One of the really interesting things as we go out to explore the outer solar system is [the question], ‘Is there life?’
“To know whether there’s life out there, you have to go to places where you think life might exist. And to do that, you’ve got to make sure you’re not…
