ELON Musk has detailed his plot to build a "glorious" city on Mars – but says early visitors will probably die.

The star-gazing billionaire has reaffirmed his vision for a Martian colony that doesn't rely on support from Earth.

Musk has previously told of how his Starship rocket – currently in testing – will one day ferry Earthlings to Mars.

And he's said he'll need a fleet of 1,000 ships to create a sustainable city, as orbits mean the trip is only viable once every two years.

Now speaking at the Humans to Mars summit, Musk says the journey won't be the hard part.

"Getting to Mars, I think, is not the fundamental issue," said Musk, as quoted by CNBC.