Right now there are people living and working in an artificial satellite about the size of a football field zooming around the earth at 26 000 kilometers per hour which is awesome but we didn't learn how to do that overnight there were a few different space stations before we built the international space station and the one that stuck around for the longest was Mir a space station launched by the soviet union in the 1980s Mir was compared to everything from a graceful dragonfly to a hedgehog to a death trap and for good reason it taught us a lot and was home to tons of accomplishments but most days Mir was also a mess of mold and electrical problems even when it wasn't literally on fire near wasn't the soviet union's first space station instead it was designed to succeed the solute program which ran from the 1970s to the 80s like the ISS Mir was modular meaning it was launched in pieces and assembled in orbit over several years starting in 1986. it's hard to translate its name into English but Mir means something along the lines of world village and peace and many cosmonauts remember it fondly but by the time Americans began joining the Missions in 1995 the station was an accident-prone mess for one thing there was never enough on-board storage and there also wasn't enough room on the ship's returning from Mir to carry all the garbage away so over time the place became packed with junk then there was mir's microbe problem according to some astronauts after years of people continuously living there the place got a little uh smelly scientists knew the station might have basically turned into a giant orbiting petri dish so they had astronauts collect some samples and it was worse than they ever imagined when astronauts removed a few instrument panels they were greeted by floating basketball-sized globs of filthy water where unspeakable things were growing the water had gotten trapped behind the panels and the air back there was nice and warm making it a tropical paradise for mold mildew and bacteria besides the fact that that's totally disgusting it was also a risk to the crew's health in more ways than one because some microbes could have corroded steel and threatened the structural integrity of the station unfortunately humans are always carrying microbes in our body so we can't leave all the germs back on earth and even the ISS has had some problems but after Mir better monitoring techniques were developed to help astronauts stay on top of things and keeping the station in working order has also helped near had periodic power outages which helped the heat and humidity climb to those more microbe friendly levels since Mir we've also gotten a lot better at steering resupply modules which visit the ISS to drop off supplies and experiments once in 1994 and again in 1997 piloting problems cause modules to bump into mirror and the accident in 1997 was especially bad because of some risky piloting maneuvers there was a major crash that seriously damaged the station's spectre module a science lab designed to monitor earth from above the hull was breached and even though astronauts were able to patch the hole and stop air escaping spectre was never fully usable again now crashing something into your space station is never a good sign but there was one accident that was even more dangerous a fire a fire in space is a lot scarier than one on earth because you can't just run outside and get away from it you're trapped in a small enclosed area with a burning inferno this one could have injured or even killed the people on board but luckily no one was badly hurt the blaze came from a faulty oxygen generator these devices informally called candles were about the size of a spray paint can and they produced oxygen by burning lithium perchlorate a salt made of lithium chlorine and oxygen usually candles are pretty safe and they're still used as oxygen backups on the ISS today but this one malfunctioned and burned out of control it was so hot that one astronaut reported seeing what he thought was dripping wax but it was actually molten metal because the fire was so hot thankfully the blaze wasn't pointed at the station's outside walls where it could have damaged the hull and the crew had recently cleaned up the mess in the area so they had an escape path and could put out the fire afterward quality control of the candles was improved so something like this would never happen again and the ISS now takes multiple precautions if a fire is detected like cutting power and venting the oxygen in that area finally after 15 years of triumph and chaos Mir was sent back to earth in 2001 where it cannon balled into the pacific ocean even though it had its rough days Mir was only designed to fly for five years so it's pretty impressive that it lasted as long as it did it outlived the soviet union and stuck around long enough to see the ISS succeeded and a lot of the reason the ISS is so successful today is because of the lessons learned on Mir so even though we might sometimes poke fun at that orbiting struggle bus it also set records housed countless experiments and change the way we live in space today

we've learned a lot from the Mir space station and now take precautions to grow less bacteria in space or at least these days we try to only grow the bacteria we intend to grow we've sent bundles of bacteria to space on purpose from some random places like the liberty bell in Philadelphia USA so here's hank to talk about why we would do that

this week the lesson seems to be that some things that come down to us from space are more delightful than others first off back on April 20th SpaceX launched its third resupply Mission to the international space station delivering coffee an experimental vegetable garden and a whole bunch of bacteria the bacteria were a gift from project mercury a crowd-sourced NASA program that enlisted the help of citizen scientists all over the united states to collect samples of bacteria people collected bacteria by swabbing things like a basketball used in an NBA game the liberty bell and part of a fossilized t-rex a little weird maybe but that bacteria might help us answer some basic questions about the nature of pathogenic microbes NASA has been sending salmonella into space since 2006. and one of the scary things that they found is that compared to samples that stay on earth samples incubated on the ISS come back three to seven times more virulent don't panic though NASA’s on top of it biologists think this space-borne virulence may have to do with the effects of microgravity on the fluid that surrounds a microbe's outer surface typically this fluid exerts a force called fluid shear that tells the microbe where in the body it's located using computer simulations researchers have found that the fluid shear in microgravity is very similar to that of human intestines so it seems that space salmonella thinks it's in someone's intestines which activates genes that put it into overdrive biologists are thinking that messing with the pathogen's ability to detect fluid shear might be a key to creating antibiotics for it meanwhile the project mercury samples have just been sent back to earth along with swabs from around the space station itself and now they'll be compared with samples that remained on the ground to study if and how life in space changed them

so bacteria on space stations are way more virulent great we're gonna need a way to get rid of those guys so they don't harm us here's how astronauts are doing it today and some ideas for how they could do it in years to come

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 well-being 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 out 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 couple of 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 in 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 here 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 way in space as it does on earth and many kinds of medical care aren't readily available when you were hurdling around the earth hundreds of kilometers away at speeds of eight 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 here 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 of 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 could 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 spacecraft 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

Ultimately some microbes are good for us but we need to make sure the bad ones don't take over our space stations a lot of work goes into putting those space stations together so it's a real pity when they become overrun with bacteria for more details on how space stations are assembled you can watch the SciShow space video about how to build one

meanwhile on earth we have a climate crisis affecting us all there's too much carbon dioxide in the atmosphere contributing to the hotter summers that we're feeling today and that's the kind of problem that no one person can solve but together we could so the ren team is searching the globe for impactful climate projects like technologies to remove carbon one of wren's ongoing projects captures carbon in Scotland by restoring forests and adding rocks that will bind carbon to minerals for thousands of years first they reforest degraded land then they spread small particles of basalt rock over that land when rainwater falls on the rocks it makes the soil more basic and turns carbon from the air into solid calcium carbonate that can stay stored away for long periods of time ren helps you calculate your own carbon footprint and offset it by funding projects like this one that suck carbon from the air once you sign up to make it monthly contribution to offset your carbon footprint you receive monthly updates from the carbon removal projects you support and SciShow has partnered with ren to plant 10 extra trees for each of the first 100 people who sign up using the referral link in the description below thanks to ren for supporting SciShow and thank you for watching [Music]