In The Invisible Enemy episode of The Outer Limits (1964) astronauts aren't wearing their spacesuits on Mars because it was shown that the atmosphere on Mars is breathable. They are at the beginning, but later on they're not. Why is that?
It is because in '60 it was believed that the atmosphere on Mars is breathable, or because of something else?
My question is whether it was known that the air is not breathable, but it was only for the show, or whether at that time it was believed it was breathable, that's why they did it for the show.