Elon Musk plans to start building a “self‑growing city” on the Moon in less than a decade.

The world’s richest man also said he would “strive” to build on Mars – and start that in as little as five year’s time.

The intergalactic boast from the Tesla founder – whose fortune is estimated at £600 billion – comes as Nasa prepares to launch Artemis II next month.

The test flight will demonstrate what would be necessary for a crewed mission to land on the Moon. But Musk’s ambitions through his SpaceX project are in a different universe.

But Musk’s celestial ambition puts that in the shade.

He said: “For those unaware, SpaceX has already shifted focus to building a self-growing city on the Moon, as we can potentially achieve that in less than 10 years, whereas Mars would take 20+ years.

“The mission of SpaceX remains the same: extend consciousness and life as we know it to the stars.

“It is only possible to travel to Mars when the planets align every 26 months (six month trip time), whereas we can launch to the Moon every 10 days (2 day trip time). This means we can iterate much faster to complete a Moon city than a Mars city.

“That said, SpaceX will also strive to build a Mars city and begin doing so in about 5 to 7 years, but the overriding priority is securing the future of civilisation and the Moon is faster.”

SpaceX, the private American aerospace and artificial intelligence company based in Starbase, Texas, has told investors it would prioritise going to the moon and attempt a trip to Mars afterwards.

The unmanned lunar landing is pencilled in for March 2027.

The US faces intense competition from China in the race to return humans to the lunar surface, which has not happened since the Apollo 17 mission in 1972.

Last week Musk, who as US President Donald Trump’s right-hand-man headed The Department of Government Efficiency to cut excess regulations and spending within the federal government, announced that SpaceX had acquired the artificial intelligence company he also leads, xAI, in a deal that values the rocket and satellite company at $US1 trillion ($1.4 trillion) and the artificial intelligence outfit at $US250 billion ($355.7 billion).

Proponents of the move view it as a way for SpaceX to bolster its plans for space-based data centres, which Mr Musk sees as more energy efficient than terrestrial facilities, as the demand for computing power soars with AI development.

Four astronauts have been selected for NASA’s Artemis II mission: Commander Reid Wiseman (NASA), pilot Victor Glover (NASA), mission specialist Christina Koch (NASA), and mission specialist Jeremy Hansen (Canadian Space Agency).

If Artemis II succeeds, the next mission will be Artemis III, the first crewed Moon landing mission since the Apollo era.

NASA is aiming to conduct this roughly 30-day mission to land astronauts on the lunar south pole by 2028.