I base space travel on round earth and heliocentric solar system. All the physics and math can be used to calculate space travel (Finding orbits, transfer orbits, and ect.) which is based a calculus which I think we can agree is solid foundation to build on.
So I won't speak of space travel in the Flatearther's flat earth and geocentric solar system, As it has no mathematical bases or proof.
Also iwanttobelive are you flat Earther, I've wondered for some time now.