Ion drive to Mars

Assume a ship with

1.  an attached lander fueled with hydrogen and an oxidizer for descent and ascent and an orbital portion that functions as a space station with hinged modules rather than a torus so that it can spin in orbit but not in transit. 

2. A landing team would also functions as a backup crew for the boost stage, a main engineering crew, a farm crew and command crew and a science crew to analyze samples, build unmanned probes, etc.

3. Food production for the entire mission with hydroponics and lab grown meat

4. Assume Mars trip would be to the moon at each end, docking with an orbital station. Transfer to Earth orbital torus station from there, with lunar landing under power with modules and by catapult for ascent. and fuel modules to the lunar surface also from surface. 

5. Fuel modules would be produced on Moon, along with hydrogen reaction mass for ion engines. Modules would attach to Mars ships. 

6. Empty modules would be landed on Mars and converted to habitats. Some would be used as reaction mass for powered trips to Earth and back. Tanks for module conversion would need heat shielding, parachutes and balloons for landing. Eventually, an elevator would be built.

7.  Oxygen would be produced from regalith. Hydrogen would also be mined and be used as reaction mass.

Research questions:

1. How much hydrogen would be needed for 0.1 G acceleration. 

2. How much is required for 0.2 G for boost phase and 0.3 G gravity for deceleration with opposite speeds for return (assuming optimal orbital mechanics, as well as near optimal)? 

3. What about when hydrogen can be produced from martian soil (no fuel need be sent for return trip).

4. What percentage of ship weight and volume would be loaded fuel tanks, as well as expended empty tanks? 

5. What is ETD for each option?

6. For purposes and maximizing acceleration, how many ion plasma engines would be optimal?