Original Title: Destination Moon In the original movie a privately funded us manned mission to the moon is attempted in order to beat the Commies there. Once there they find they do not have enough fuel to return and must eliminate a lot of weight in order to return. In the Steve Smith version they find that the zero gravity of outer space causes extreme constipation in all the crew members. This causes the ship to be extremely overweight and so the must eliminate as much weight as possible in order to return to earth. (thetvdb.com)