Elon Musk says he has a new timeline for his big Mars project — and it's sooner than you might think.

"I'll be surprised if we're not landing on Mars within five years," Musk told Time Magazine, about SpaceX taking humankind to Mars in a story published Monday.

Musk, the 50-year-old SpaceX founder and CEO who was named Time's Person of the Year, has big plans for the Red Planet: namely, a self-sustaining city with solar-powered hydroponic farms where humans can permanently live, 34 million miles away from Earth.

"The next really big thing is to build a self-sustaining city on Mars and bring the animals and creatures of Earth there," Musk told Time. "Sort of like a futuristic Noah's ark. We'll bring more than two, though — it's a little weird if there's only two." 

In February, space policy expert and Arizona State University professor Greg Autry told Business Insider that Musk likely won't reach Mars until at least 2029, with or without NASA's help.

Other space experts say Mars probably can't sustain long-term human settlement at all. Musk himself told nonprofit XPrize in April that some astronauts will "probably die" en route to Mars.

Musk — currently the world's wealthiest person, with a net worth of $247 billion, according to Forbes — also has a track record of setting unrealistic timelines for moonshot tech advances.

In 2016, Musk tweeted that Tesla's fully self-driving cars would be available within roughly two years. In 2019, he promised 1 million Tesla "Robotaxis" by 2020. The Boring Company, which Musk founded in 2017 to build high-speed commuter tunnels in major cities, appears to have abandoned a project in Chicago and postponed another near Washington D.C. and Baltimore.

"Punctuality is not my strong suit," Musk admitted during an earnings call last year.

SpaceX, recently valued at $100 billion, is a major player in today's space race: In April, the company was awarded an exclusive NASA contract to put U.S. astronauts on the moon for the first time since 1972.

But Musk told Time he's not necessarily trying to make money off Mars. Rather, he said, it's more about what feels "exciting," including an overall goal "to make life multi-planetary and enable humanity to become a spacefaring civilization."

SpaceX has redefined sustainability standards in aerospace engineering since it launched in 2002, becoming the first company to reuse a rocket for a NASA mission in 2017. In May, it became the first-ever private company to carry astronauts to and from the International Space Station.

Getting there hasn't been easy. Notably, SpaceX nearly bankrupted Musk in 2008 after a series of failed rocket launches. Last month, Musk sent employees a letter saying SpaceX could be at "genuine risk of bankruptcy" again — but told Time on Monday that the letter was mostly a motivational tactic.

"We cannot lose our edge or get complacent," he said.

SpaceX has other issues, too.

On Tuesday, former SpaceX engineer Ashley Kosak wrote an op-ed in Lioness stating she was sexual harassed throughout her past four years at the company. She wrote that "misogyny is rampant" within SpaceX, and that Musk "uses engineers as a resource to be mined, rather than a team to be led."

Later on Tuesday, at least five more former SpaceX employees spoke out about harassment at the company, according to The Verge.

And last month, CNBC reported that a number of longtime SpaceX employees, including two vice presidents and a senior director, left the company following a purchase offer tied to employees' stock vesting schedules.

A SpaceX spokesperson did not immediately return CNBC Make It's request for comment.

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