Thank you for the reply. I did preliminary research on the Michelson-Morley experiment. It does not prove that the earth is flat.https://www.khanacademy.org/science/physics/special-relativity/michelson-and-morleys-luminiferous-ether-experiment/v/michelson-morley-experiment-introduction
It was an important experiment because it showed that there was no luminiferous aether. I don't see how this be generalized to having a flat earth.

I don't know why they would go east to west however the more logical conclusion would be for fuel since Antarctica is not inhabited. Also the rock idea was not that good because you can probably use dimensional analysis and arrive at 10k. 537 is low number because it is expensive to send people up there.

As for gravity yes it would not work. That does not mean that the earth is flat either. We do not understand gravity there is ongoing research on that. We can prove that is here though and in the planets we have orbited around. Once spaceX takes people to the moon/space we will not be having this discussion.