If we can build a large ship in orbit, why not use it to run a sort of shuttle path to Mars? This ship would never break orbit, and be a true Star Trek-style ship. Better yet, build Two of these things, and make them huge. Star Trek TOS Enterprise size...Build the first, use orbital lifts to supply it. First trip will be an infrastructure trip. Bring along a skeleton crew to man the place, as well as a vehicle capable of shuttling to Mars orbit and back for them. Would rendezvous with the Interplanetary Shuttle. While the first ship is on its way to Mars, build your second ship. Load it with Oxy tanks and fuel and whatever supplies they need. Send it on its 17 month voyage as the first is leaving on its way back. (8 there plus 1/2 there plus 8 back) After 5 or 6 of these trips we have solved all of our problems. Need to get back home? take the interplanetary shuttle. Want to get to mars? Take the interplanetary shuttle. we need shit shipped from one place to the other? Take the Shuttle!!