apologies for hypothesising about the first Space X mission to Mars when it’s all spelt out on wikipedia! Pretty much bears out what I was guessing, anyway. Once those first few supply & base building ships have done their job, the ITS becomes “Mars Rail”. 🙂 Over to wikipedia.
Musk has indicated that the earliest SpaceX-sponsored missions would have a smaller crew and use much of the pressurized space for cargo. The first cargo mission of the Interplanetary Spaceship would be named “Heart of Gold” and would be loaded with equipment to build the propellant plant.
The first crewed Mars mission would be expected to have approximately 12 people, with the primary goal to “build out and troubleshoot the propellant plant and Mars Base Alpha power system” as well as a” rudimentary base.” In the event of an emergency, the spaceship would be able to return to Earth without having to wait a full 26 months for the next synodic period.
Before any people are transported to Mars, some number of cargo missions would be undertaken first in order to transport the requisite equipment, habitats and supplies. Equipment that would accompany the early groups would include “machines to produce fertilizer, methane and oxygen from Mars’ atmospheric nitrogen and carbon dioxide and the planet’s subsurface water ice” as well as construction materials to build transparent domes for crop growth.
The early concepts for “green living space” habitats include glass panes with a carbon-fiber-frame geodesic domes, and “a lot of miner/tunneling droids [for building] out a huge amount of pressurized space for industrial operations.” But these are merely conceptual and not a detailed design plan.
(Image for fun, and not part of the wikipedia Space X page)