My initial post was related to more of bacteria or organisms on space suits or moon walks and then flown back to earth in the comfort of a shuttle.
In: Biology
With wide enough boundaries, they can’t. If a tardigrade, or mad space bacteria, can survive a ship going from the vacuum of space to re-entering earth’s atmosphere at enormous heat and then being barracked by the thick earth asmosphere ,then there’s nothing that can reasonably be done. It’s considered sufficiently unlikely to not be a realistic concern.
Space isn’t usually filled with hot acid. Standard autoclaving procedures handle most terrestrial organisms, but you can use other chemicals and conditions to attack organic molecules directly.
Living things generally have a hard time dealing with bleach. Life may be hardy, but humans have developed more than enough harsh chemicals to kill anything organic
Tardigrades can handle being frozen and in vacuum and some UV, but probably not all of them for extended periods and definitely not reentry procedures.
To add to what others have said, Even if “something” survives the odds of it being able to live and thrive here on Earth are pretty small. Most living creatures we know of require a lot of additional amino acids, proteins and other various biological compounds to be available to them, and tolerate many others that they don’t need.
An organism from another planet would likely require different ones that don’t exist here, and possibly be poisoned by much of what IS here.
Spacecraft reentry is significantly harder to survive than just “living in space.”
Organisms are usually good at surviving one type of environment very well. Going from the “very cold vacuum of space” to the “very hot and very high pressure entry” is extremely difficult for any organism. Impossible for most.
For things that aren’t exposed to reentry conditions, they are autoclaved (high pressure, high temperature, for lots of time.) Nothing we know can survive that.
In case you haven’t noticed, we ONLY know of life that exists on earth, and if we can kill everything we KNOW of, then that’s generally considered “good enough.”
Furthermore, the organisms that we do know of that can survive conditions like that (for shorter periods of time) aren’t dangerous to humans so we don’t care.
I’m thinking most things that can survive all that already live here or don’t need us to bring them here.
A lot of people are mentioning reentry. What about EVA’s and these organisms attaching themselves to the EVA suits? Once inside, assuming they can survive that atmosphere, they could surely move from the suit to another object.
It is my understanding that the harder a creature leans, evolutionarily, into defense; the less it has to attack with. Look at a turtle. They have a slow metabolism, not really good range of motion, barely any claws, and most of them dont have a particularly good bite. But they have that shell. Very few things in nature can successfully penetrate an adult turtles shell. But as a consequence of growing that shell they have nothing left over to fight with. A turtle isnt taking down a shark any time soon.
Or look at a cheetah. Very very fast and deadly. But they are incredibly fragile compared to any other big cats. They put all their points into speed and attack, none in defense.
So a tardigrade has all its evolution points in defense. It can survive almost anything. But it also barely kills anything. They mostly prey on each other I think.
That’s not to say there couldnt be some space bacteria that is incredibly survivable that could be brought back to earth. But chances are likely if that happened it wouldnt be able to survive an oxygen rich environment. Or water. Or the bacteria in our bodies. Speccing into space survival would potentially mean you have no planetary survival adaptations.
There are real earth viruses that are very hard to kill. Like HIV. It has a hard protein shell that protects it from vaccines. But break that shell and our immune system easily kills it. The challenge is breaking enough shells of enough HIV virus bodies to offset the speed they breed.
ELI5: what the hell are tardigrades and why does OP seem worried about them?
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