$\begingroup$ There is a close vote about your question, because it seems to like more about atmospherical flights than spaceflights. I suggest to edit it to be about spacflight. We have about aviation.stackexchange.com . I also suggest to make it more clear, "how feasible" looks too broad. How feasible for what? $\endgroup$ – peterh May 27 '19 at 20:00