On September 27, 2016, Elon Musk introduced the world to the SpaceX Interplanetary Transport System, or ITS. Although SpaceX had already changed the face of the aerospace industry through the introduction of a reusable first stage, the ITS concept is one of the largest leaps forward in the history of human spaceflight.

Designed to deliver large payloads to any solid surface in the Solar System, the ITS spaceship would be the architecture that would enable the human colonization of Mars. Capable of transporting up to a hundred colonists to the surface of Mars, ITS would launch from Earth on a reusable first stage booster. In Earth orbit, it would be refueled by a fleet of fuel tankers based on the same system. After several months en route to Mars, the ITS would enter the Martian atmosphere, land, and begin colonization efforts. As the ITS crew built their new home, they would also begin converting the resources of Mars - water ice and atmospheric carbon dioxide - into the fuel needed for the return trip to Earth. After nearly two years on the red planet, the ITS spaceship would launch from the Martian surface, return to Earth, enter its atmosphere and land, ready for its next sortie to the red planet.

SpaceX's stated goal is to enable the human colonization of Mars. Although the ITS was the first system ever proposed to truly enable such a mission, it was still one of the most ambitious aerospace architectures ever proposed. Potential challenges included the construction of composite carbon fiber fuel tanks, environmental control and life support for a long term spacecraft, and the entry, descent and landing of such a large payload on the surface of Mars. One question loomed large among the others: How would SpaceX pay for a Martian colony?

SpaceX Mars 2.0