This episode is sponsored by Fabulous, an app that helps you form  healthy habits that stick.

Click the link in the description to get 25% off a Fabulous premium subscription! [Intro] Space is pretty inhospitable, but humans have managed to maintain  a permanent presence up there, a few hundred kilometers above the  threshold we call the edge of space, since November 2000. But we’ve also carried up some unwanted stowaways, which can threaten the  wellbeing of both the astronauts and the station that separates  them from the vacuum of space.

Microbes. Bacteria, fungi, and the like. Thankfully, scientists have figured out a few ways to keep things clean.

Now you may have heard that the human  body is full of non-human cells. Collectively, these microscopic  critters make up your microbiota, and they are basically in  every corner of the human body. So, astronauts provide a  steady supply of microorganisms to the space-based environments they inhabit, no matter how clean they  were before they got there.

Equipment and supplies are  cleaned inside special rooms to remove any unwanted travelers,  but it’s never a 100% success rate. So with each round of deliveries, be  they new people or new experiments, microbial invaders try to  settle into their new home. Life trying to find a way.

Over the years, scientists have closely studied  the kinds of invisible life forms living on the International Space Station. Back in 2019, one team published a catalog  of both bacterial and fungal species, in part to figure where they  were actually coming from. Are humans the primary source, or  insufficiently cleaned supplies?

Well, it turned out to be the former. Members of the astronauts’ microbiota were  migrating to various parts of the station... ... From the toilets to the panel next to that  pretty cupola window they take pictures from.

The most prominent types of bacteria  were Staphylococcus and Enterobacteria, which are commonly found on your skin and  up your nose, and in your gut, respectively. Altogether, the exact  combination of microbes living on all of the surfaces inside the ISS is unique. Like, it’s different from  the ones in the air filters or the prototype Martian habitation units humans   have been testing living  inside down here on Earth.

Scientists have even discovered  new species up there, though that isn’t necessarily a huge revelation. Because they also find new  species on Earth all the time. And these new ones aren’t that  different from the Earthly ones.

But there is one way they are adapting. Some species are evolving to tolerate living on  certain surfaces that would ordinarily kill them. So scientists are worried about  the threats these microbes could have to both astronauts and the  International Space Station itself.

The human immune system doesn’t work  the same in space as it does on Earth, and many kinds of medical  care aren’t readily available when you are hurtling around the  Earth hundreds of kilometers away, at speeds of 8 kilometers a second. The human microbiota naturally includes  “bad” microbes as well as “good” ones, but normally our bodies can handle them. However, pathogens could take advantage  of a decreased immune response in space.

Also, studies back on Earth have demonstrated that patients admitted to the ICU are  at higher risk of getting an infection if the previous person in their bed had one. So the enclosed space of the ISS could mean a  later crew could get infected by a previous one. There’s also the threat of how life in  outer space affects antibiotic resistance.

But the results on this appear mixed. And certain microbes can also be a  problem for the ISS’s equipment too. Back in 1998, cosmonauts on the MIR  space station discovered microbes were breaking down the rubber  around the station’s windows, as well as dissolving electrical  cables by excreting some kind of acid.

And some of the species aboard the ISS have been shown to corrode  metals down here on Earth. But how much they’re doing that  up in space is still unknown. There’s also the possibility  that in sufficient quantities, they could actually cause mechanical  blockages, and make equipment overheat.

So astronauts need a way to get  rid of all these unwanted microbes, but they can’t go too hard on sanitizing because  their microbiota is so crucial to their health. It turns out that the cleaning  methods are pretty similar to what you or I have to do down here on the ground, except for the whole floating debris and  the completely closed air system thing… Everything they touch gets  hit with disinfectant wipes. Handrails.

Computers. And so forth. The air filters have to get changed regularly,  so colonies don’t grow there, either.~ They also vacuum a bunch.

That’s also to prevent dust from  floating around and getting stuck where it is not supposed to  be, because in microgravity, it doesn’t get collected in the carpet. Down here on Earth, scientists  are looking for new technology   to make the ISS less habitable to microbes, too. Metals like silver and copper are already  known for their antibacterial properties, so making things like handles out  of certain alloys could kill bugs before they even get a fighting chance.

But not everything on the  space station can be metallic, so they’re testing polymers, too. Ultimately, studying how these microbe  colonies act differently from those on Earth will help us prepare for longer missions  to the Moon, to Mars, and beyond. Also, studying how much these  little bugs can tolerate the extreme conditions of space   helps future missions that will  require sanitizing the space crafts to protect the distant world from  being unintentionally inhabited   by earthlings like our little bugs.

Preventing the spread of germs to  astronauts and to other corners of space. So if you want to add “deep-clean the apartment” to your habit list to keep germs at bay  you should check today’s sponsor, Fabulous. They are a habit and self-care  forming app that’s fully customizable to support your personal goals, like keeping a relatively germ-free  International Space Station or crafting a distraction-free work space.

With Fabulous premium subscription, you’ll also unlock coach sessions and  Journeys to inspire a shift in mindset, like incorporating small simple  habits in your evening routine. If you wanna check them out, the  first 100 people who click on the link will get 25% off a premium Fabulous subscription! Which also helps us --so thanks. [ OUTRO ]