Eli5: If creatures such as tardigrades can survive in extreme conditions such as the vacuum of space and deep under water, how can astronauts and other space flight companies be confident in their means of decontamination after missions and returning to earth?

Question

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

Answer 1

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.