Elon Musk is never one to shy away from answering the difficult questions regarding his ambitious projects, which is why we now have a delivery time for the first Mars city.
As TechCrunch reports, earlier this week Musk spoke at an Air Force Pitch Day in San Francisco, which offer investment to interesting startups that could advance military technology. The talk and questions that followed touched on Musk's business interests including Tesla and SpaceX, but also resulted in further discussion on Twitter.
So it will take about 20 years to transfer a million tons to Mars Base Alpha, which is hopefully enough to make it sustainable — Elon Musk (@elonmusk) November 7, 2019
The tweeted questions stemmed from the claim each SpaceX Starship launch would only cost $2 million, because as Musk explained, "the economics have to be something like that to build a self-sustaining city on Mars."
As the discussion continued, Musk shared further details in response to the questions posed. We now know that Musk believes he'll require 1,000 Starships in order to create the first sustainable Mars city. The reason so many are required is due to the two planets only aligning once every two years and the fact each Starship is limited to 150 tons of cargo.
As to how long the city would take to build, Musk also has an answer. He believes the city will require a million tons of resources transported from Earth, so using those 1,000 Starships it would take roughly 20 years to complete. In other words, Musk could be living on Mars before 2050, assuming he's capable of making the journey in his 70's.