The SpaceX CEO has envisioned people living on the red planet in a self-sustaining city in 2 decades

Nearly buried underneath a recent avalanche of rightwing invective posted by Musk on the platform he owns, X, was one standout statement that made space watchers sit up and take notice: a highly optimistic assertion that humans could reach Mars within four years and be living there in a self-sustaining city in just 2 decades. It seems a whimsical boast, even by the standards of the SpaceX CEO and world’s wealthiest man, who altered the logistics and cost of shorter-duration, near-to-Earth orbit space travel with his remarkable fleet of reusable Falcon rockets. NASA (The US government space agency), which is collaborating with SpaceX over technology and knowledge to get astronauts to the red planet, believes that maiden crewed landing by 2040 would be “audacious”.

This is not the first time the enigmatic business magnate has floated such an idea. In 2016 he said he thought those first crewed launches to Mars could take place within six years, even though a heavy rocket to transport them was still at the concept stage. Yet while most might see Musk’s latest proclamation as another instance of his braggadocio, following stories he desired to help populate an extraterrestrial civilization with his own sperm, some experts see a sense of purpose. If a Mars settlement of a million people in 20 years time is an improbable goal, the prospect of regular shuttle flights aboard SpaceX’s next-generation Starship rockets, carrying the first human explorers and cargo, is undeniably achievable, they say.

And while Musk’s projected personal fortune of $250bn (£191bn) cannot come even close to funding what would be the most costly and extensive undertaking in spaceflight history, overshadowing the $280bn (in today’s money) Nasa spent on the Apollo program ( program that put man on the moon in 1969), potential investors from both private and public sectors stand to be enthused.

Musk’s tweet, the doyens say, has accelerated discussion about the immediate desires of SpaceX and the longer-term prospects for humankind itself. “If I were diagnosing why now to set this very aggressive timeline for Mars, it’s partly to show that SpaceX isn’t slowing down, it’s not resting on its laurels, it’s not turning into kind of a creaky dominant player in space, and it is still the innovative pushing-the-envelope startup that it is,” said Matthew Weinzierl (professor of business administration at Harvard Business School specializing in the economics of space).