It never explains where they came from (the characters)
So the characters have never been to earth and they are nowhere near it seeing as Charlie's pod was floating around for 53 years.
So, where were they from? Are we supposed to assume they're from a space colony??? I mean what else would it be? They make no attempt whatsoever to explain why they've never been to Earth and why they're so far away.
It would've been so easy for the Ethan guy to say to Charlie when they were talking about Earth "I was born on a space colony"
That's the conclusion I've come to myself, however.