There is enough proof without going to space, so it’s safe to assume proof has no effect.

You can always find some superficially credible alternative explanation to any proof. With those, you can use the language of reason and logic to construct a belief consistent with what you had in the first place.

As long as the person has their identity tied to a certain belief, and is of a mindset to find ways in which the belief is correct, they are immune to change. Those are the areas you will need to work on to change their mind.

The spacecraft windows were curved, causing an optical illusion