ELON: WE HAVE TO BUILD A SELF-SUSTAINING CITY ON MARS AS QUICKLY AS POSSIBLE “The important thing is that we build a self-sustaining city on Mars as quickly as possible. The key threshold is when that city can continue to grow and prosper even when the supply ships from Earth stop coming. It might not be World War III, but that civilization dies with a whimper rather than a bang, and simply loses the ability to send ships to Mars. So, you obviously need Mars to become self-sustaining and be able to grow by itself before the resupply ships from Earth stop coming. That is the critical civilizational threshold, beyond which the probable lifespan of civilization is much greater. I think it can be done in 20 years. We're going to need on the order of a million people, maybe a million tons of cargo.” Source: Verdict Podcast with Ted Cruz, March 2025, @elonmusk