This is actually not so bad. Returning to earth is (relatively) cheap. Returning to earth from the moon is really cheap, so the extra fuel mass is affordable. F

This is actually not so bad. Returning to earth is (relatively) cheap. Returning to earth from the moon is really cheap, so the extra fuel mass is affordable. From Mars you probably want to scavenge it. https://en.wikipedia.org/wiki/In_situ_resource_utilization https://en.wikipedia.org/wiki/In_situ_resource_utilization https://www.reddit.com/r/space/comments/29cxi6/i_made_a_deltav_subway_map_of_the_solar_system/ https://www.reddit.com/r/space/comments/29cxi6/i_made_a_delt...