Elon Musk wants to build a city on Mars by 2050. Unfortunately, based on current cost calculations, it wouldn't be possible.
Musk's firm SpaceX is currently developing the Starship, a giant stainless steel rocket designed to send humans to Mars and beyond. The ship can carry over 150 tons or 100 people to orbit at a time, and its liquid oxygen and methane fuel means humans could refuel using Mars' natural resources and return home – or even venture out further. Musk has suggested that a city could be built in the space of 10 orbital synchronizations, sending ships every time the Earth and Mars get close enough.
But on Twitter this week, Musk suggested more needs to happen to bring this grand vision to life. Musk responded to a video from Bloomberg anchor Jon Erlichman, who shared a video of the Falcon 9 successfully returning in 2015. Musk replied to the video:
"5 years ago. We need to accelerate progress towards fully reusable rockets. Cost per ton to orbit needs to improve by >1000% from where Falcon is today for there to be a self-sustaining city on Mars."
A tenfold increase in cost per ton sounds like a lot, but Musk has explained before that this is how the city can come to life. Part of SpaceX's business plan has been to reduce the cost of rocket flying, using innovative methods like landing a booster after it's flown. While it was big news in 2015, five years later it's a relatively common occurrence for SpaceX. This has enabled the firm to save around $46.5 million of the estimated $62 million price tag for each launch. The Falcon 9 can send over 20 tons to low Earth orbit.
Starship could send make these figures even more favorable. That ship is expected to send over 150 tons to low-Earth orbit. In November 2019, Musk suggested the ship could fly for around $2 million per flight. That suggests the ship could send cargo into orbit at less than $20,000 per ton.
Those figures would mean Musk could potentially fulfil his dream of reaching a city on Mars. When asked about the price of his plans in October 2019, Musk explained the project could cost between $100 billion and $10 trillion. That assumes a cost of $100,000 per ton to Mars. It also assumes such a city would need around one million tons of cargo to get established, a figure Musk explained was to the nearest order of magnitude.
With those figures, it's easy to see why the cost per ton of orbit needs to drop to make it feasible.
Musk has spoken before about his concern that a Mars city is not a certainty. During the Satellite 2020 conference in Washington, D.C. in March 2020, Musk explained that "the thing that concerns me the most right now is that unless we improve of rate of innovation dramatically, then there is no chance of a city on the face of the Moon or Mars."
The Inverse analysis – The Mars city is perhaps one of Musk's most fascinating, and far-flung, visions. It assumes that humans will successfully set foot on Mars, successfully develop the capabilities to create a self-sustaining base, and successfully fly home. Oh, and that the money will come from somewhere. Perhaps Starlink, the internet connectivity constellation, could help there.
But while focusing on the big picture can help to steer the wider movement of the firm, it's important to note that SpaceX is already racking up achievements. On Wednesday, it will send two astronauts to the International Space Station using the Crew Dragon and kick-start a whole new era for NASA operations. Even if Musk feels progress is not going fast enough, it's still getting some impressive things done.