Yeah I can buy tolerating more exposure than humans when it comes to space but to survive it completely and indefinitely, no, it just adds more need to suspend disbelief. They are supposed to be aliens, not supernatural creatures. If something is science fiction, then it should at least make some effort at the science part. The first movie for example is fairly gritty, other than a few things such as maybe how the ship travels and how stasis works etc, most of what you see is within the realm of plausibilty.