Elon Musk says it would take 40 to 100 years to build a self-sustaining civilization on Mars

Elon Musk thinks that it would take between 40 and 100 years for humanity to go from landing a ship full of colonists on Mars to establishing a self-sustaining civilization. At his company SpaceX's event today, Musk laid out how a fleet of ships that could carry a minimum of 100 people, flying every two years, could populate a Martian city:If we say the minimum threshold for a self-sustaining city on Mars, or civilization, would be a million people, and you can only go every two years, if you ha