Elon Musk unveils plan to build city on Mars 'in our lifetimes'

Entrepreneur Elon Musk has outlined his vision to build a colony on Mars "in our lifetimes" - with the first rocket propelling humans to the Red Planet by 2025.

He said a return ticket would drop over time from $200,000 (£154,000) to $100,000 (£77,000) per person.

"We need to go from these early exploration missions to actually building a city," Mr Musk told the International Astronautical Congress in Guadalajara, Mexico.

A video showed off his ambitions: an interplanetary transport system based on reusable rockets, a propellant farm on Mars, and 1,000 spaceships on orbit - each carrying about 100 people.

The Tesla cars boss said spacecraft would be "fun or exciting" not "cramped or boring" - with a restaurant, cabins, zero-gravity games and movies.

The self-sustaining city would include iron foundries and even pizzerias.

The aerospace company the billionaire founded in 2002, SpaceX, has already started work on his vision of a Mars fleet, which he believes could take people to the moons of Jupiter and beyond.

Mr Musk said the venture would require a "huge public-private partnership".

NASA is offering technical support, but no cash, with its own plans to send people to Mars by the 2030s.

Mr Musk acknowledged the was "dangerous" - with the risk of fatality high at least for the first few trips - but also hailed it an "incredible" adventure.

"It would be basically, are you prepared to die? If that's OK, then you're a candidate for going," he said.

Musk dismissed the 1 September explosion of an unmanned SpaceX rocket and its $200m (£150m) satellite payload at Cape Canaveral as "a small thing on a long road".

It followed several successful missions and vertical landings.

He said he was "optimistic" that the first human mission to Mars could leave Earth in 2024, touching down on the Red Planet the following year.

Before that, SpaceX plans to send an unmanned Red Dragon cargo capsule to Mars as early as 2018 to test descent, entry and landing systems.

"I think Earth will be a good place for a long time, but the probable lifespan of human civilisation will be much greater if we're a multi-planetary species," said Mr Musk.

"Ultimately, what I'm trying to achieve here is to make Mars seem possible, make it seem as though it's something that we can do in our lifetimes."

Experts warned reaching Mars, which is around 140 million miles from Earth, required major engineering feats and a massive budget.

John Logsdon, professor emeritus at George Washington University's Space Policy Institute, said Musk's presentation was "long on vision, short on detail".

Chris Carberry, chief executive of Explore Mars Inc, a non-profit corporation promoting the goal of sending humans to Mars within two decades, said the plan was "inspiring", but it would be "challenging to accomplish this in 10 years".