Yesterday, NASA astronauts Suni Williams and Butch Wilmore performed their ninth and fifth spacewalks respectively, with Williams setting the record for the longest total spacewalking time by a female astronaut. Among the objectives of the walk, there was an intriguing scientific objective: The duo swabbed the surface material around the Quest airlock and outside the Destiny laboratory. Why? Scientists want to see if bacteria have found a way to survive on the outside of the ISS!
“Williams and Wilmore completed their primary objectives, including removing a radio frequency group antenna assembly from the station’s truss and collecting samples of surface material for analysis from the Destiny laboratory and the Quest airlock,” NASA’s Space Station blog reports.
This is not the first time that such a collection has happened. It is part of the ISS External Microorganisms investigation – NASA astronauts Tracy C. Dyson and Matt Dominick did the same last June, collecting samples in the same areas outside the space station. There are life support system vents outside the Destiny module, and the airlock is exposed to both the inside and outside in turns. It is certainly possible that bacteria and fungi might have found a way out of the ISS.
The pressing question is: can these microorganisms find a way to survive – and maybe even thrive – out there? Experiments have tested the limits of certain lifeforms to withstand the truly extreme space environment: No air, lots of cosmic radiation, and temperatures going from about 120 to -156°C (250 to – 250°F). You need to be made of sturdy stuff to deal with that.
Lichens, bacteria, tardigrades, and more have been shown to have the stuff to survive the harsh space conditions. Actually, it’s possible that tardigrades might be still alive on the Moon after a private company crash-landed a bunch of them a few years ago. Apart from the crashed tardigrades, the rest were controlled experiments – and to be honest, they were not having the best time.
The samples are collected with a special payload caddy, with six swabs for the various surfaces and two controls. Following the spacewalk, the samples are stored in a freezer and will be brought down to Earth for detailed analysis, such as working out the type of bacteria, their genome, and more. The Russian Space Agency, ROSCOSMOS, has conducted a similar analysis called Test and found evidence of non-spore-forming bacteria growing outside the ISS.
There is a lot of interest in understanding how bacteria survive and evolve in space, as it might give new insights into how to treat bacteria on Earth. For example, recent work shows that some bacteria inside the ISS have already been seen to have mutated into something very different from their earthly counterparts.
Wilmore and Williams are the two astronauts stranded following safety concerns related to the Boeing Starliner spacecraft that took them to space. They were supposed to be in space for just a week last June, but their mission was extended. In this spacewalk, the duo also had to remove an antenna from the station truss, an operation that had been ongoing for a while.
