Elon Musk may be the world's richest rocket scientist.

The 47-year-old CEO of Tesla and SpaceX and cofounder of OpenAI has said he won't be happy until we've escaped Earth and colonized Mars . Luckily, he has the mind and the money to make it happen.

Despite a massive net worth hovering around $23.6 billion , Musk has never taken a paycheck from Tesla, refusing his $56,000 minimum salary every year.

Back in March, Tesla shareholders approved a plan awarding Musk$2.6 billion in stock options, reports CNBC , which will vest in 12 tranches, or portions, as the company hits key milestones over the next decade. The $2.6 billion amount was March 21 current stock value. U.S. News notes that if Musk meets the goals and the stock value rises during that time period, it "could net him more than $50 billion."

In January, Tesla announced it would pay Musk nothing for the next 10 years no salary, bonus, or stock until the company reaches a $100 billion market cap. If and when that happens, Musk could potentially overtake Amazon CEO Jeff Bezos as the richest person in the world.

A notorious workaholic , Musk doesn't spend cash on lavish vacations or expensive hobbies. Instead, the entrepreneur spends most of his time at the office or in factories, retreating to one of his four Los Angeles mansions at the end of the day.

Scroll through to find out what we know about how Musk, a father of five, amassed his fortune and how he spends it.

As a child growing up in South Africa, Musk taught himself to code. By the time he was 12, he sold the source code for his first video game for $500.

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OnInnovation/Flickr

Source: MONEY

Just before his 18th birthday, Musk moved to Canada and worked a series of hard labor jobs, including shoveling grain, cutting logs, and eventually cleaning out the boiler room in a lumber mill for $18 an hour an impressive wage in 1989.

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OnInnovation/Flickr

Sources: MONEY , Esquire - Elon Musk: Tesla, SpaceX, and the Quest for a Fantastic Future

Musk got a pay cut to $14 an hour when he started a summer internship alongside his brother, Kimbal, at the Bank of Nova Scotia after cold-calling and impressing a top executive there.

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Aaron P. Bernstein/Reuters

Sources: MONEY , Esquire - Elon Musk: Tesla, SpaceX, and the Quest for a Fantastic Future

After he arrived for his freshman year at Queens University in 1990, Musk quickly picked up a side hustle selling computer parts and full PCs to other students. "I could build something to suit their needs like a tricked-out gaming machine or a simple word processor that cost less than what they could get in a store," Musk said.

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Larry Busacca/Getty Images for The New York Times

Sources: MONEY , Esquire - Elon Musk: Tesla, SpaceX, and the Quest for a Fantastic Future

Within two years, Musk transferred to the University of Pennsylvania on a partial scholarship.

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f11photo/Shutterstock

Sources: MONEY , Esquire - Elon Musk: Tesla, SpaceX, and the Quest for a Fantastic Future

To cover the rest of his tuition, Musk and a buddy would turn their house into a speakeasy on the weekends, charging $5 at the door. "I was paying my own way through college and could make an entire month's rent in one night," Musk said.

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AP Photo/Mark Lennihan

Sources: MONEY , Esquire - Elon Musk: Tesla, SpaceX, and the Quest for a Fantastic Future

Musk graduated with a bachelor's degree in physics and an economics degree from the Wharton School and moved to Stanford to pursue his PhD.

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REUTERS / Phil McCarten

Source: MONEY

He left the program within days to found an internet startup with his brother. They started Zip2, a city guide software for newspapers, with $28,000 in seed money from their father.

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Fred Prouser/Reuters

Source: MONEY

Four years later, in 1999, they sold Zip2 for $307 million, earning Musk $22 million. He invested more than half of his earnings to cofound X.com, an online banking service.

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Reuters/Mike Blake

Source: MONEY

The company quickly merged with its rival and became PayPal with Musk as the majority shareholder. In 2002, eBay bought PayPal and Musk walked away with $180 million.

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Reuters/Lucas Jackson

Source: MONEY

Musk turned his attention to his new space exploration company, SpaceX, after leaving PayPal. A few years later he cofounded electric-car maker, Tesla, and then SolarCity, a solar power systems provider. The success of these companies eventually launched him into the billion-dollar club but not before he went broke.

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Reuters

Source: VentureBeat

In late 2008, Musk divorced his first wife and it took a toll on his finances. A year later, Musk said he "ran out of cash" and had been living off loans from friends while trying to keep his companies afloat.

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Brendan McDermid/Reuters

Sources: VentureBeat , Forbes , TechCrunch

But when Tesla debuted on the stock market in 2010, Musk's fortune sky rocketed. By 2012, he appeared on Forbes' richest list for the first time with a net worth of $2 billion.

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Tesla

More than five years later Musk has amassed a $23 billion fortune and he's not shy when it comes to spending it.

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Getty/Kevork Djansezian

Source: Bloomberg

The CEO owns more than $70 million worth of residential property in the Bel-Air neighborhood of Los Angeles. His fifth and latest home purchase: a $24 million as-of-yet unfinished estate.

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Google Maps

Source: The Real Deal , Variety

Musk initiated his Bel-Air buying spree in late 2012, when the then-bachelor purchased a 1.67-acre estate for $17 million. The 20,248-square-foot mansion has a two-story library, a home theater, a gym, and 1,000-bottle wine cellar.

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Google Maps

Source: Variety

As the leader of one of the preeminent auto-makers, it's no surprise Musk has an affinity for cars. Back in 2013, he paid $920,000 at an auction for the Lotus Esprit submarine car used in a James Bond movie.

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AP

Source: MONEY , CNBC

In addition to driving Teslas, Musk owns two gas-powered cars: a Ford Model T and a Jaguar E-Type Series 1 Roadster.

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DeFacto/Wikimedia Commons

Source: MONEY , CNBC

Despite having funds to spare, Musk isn't a fan of lavish vacations or any vacations for that matter. In 2015, he said he'd only taken two weeks off since founding SpaceX about 12 years earlier.

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Reuters/Bobby Yip; Business Insider/Dave Smith

Sources: Inc. , Quartz

Musk has five young children. In a 2014 tweet, Musk said he takes the kids on an annual camping trip. "I'm a pretty good dad," he said. "I have the kids for slightly more than half the week and spend a fair bit of time with them. I also take them with me when I go out of town."

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AP Photo/Mark Lennihan

Sources: Twitter , Elon Musk: Tesla, SpaceX, and the Quest for a Fantastic Future

But by August 2018, Musk told the New York Times that he has taken to working 120 hours a week. "There were times when I didn't leave the factory for three or four days days when I didn't go outside," he told the Times. "This has really come at the expense of seeing my kids. And seeing friends."

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Getty Images/Joshua Lott

Source: The New York Times

Musk said on an earnings call in 2017 that he doesn't have a desk at the Tesla factory: "I always move my desk to wherever I don't really have a desk actually I move myself to wherever the biggest problem is in Tesla. I really believe that one should lead from the front lines, and that's why I'm here."

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Benjamin Zhang/Business Insider

Sources: Business Insider , Fortune

Musk admitted to spending "many late nights" at Tesla's Nevada Gigafactory re-writing software during a production sprint for the Model 3.

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Marques Browne/YouTube

Source: Fortune

For a story published in August 2018, Business Insider reporters spoke with 42 Tesla employees, who said Musk is a visionary, but also unpredictably demanding.

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Tesla Motors

Source: Business Insider

Musk told CBS' "60 Minutes" that he is, in fact, "somewhat impulsive" and doesn't "really want to try to adhere to some CEO template."

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Getty

Source: Business Insider

Not only does Musk spend a ton of time at Tesla, he spends a lot of his money on the company. In the first six months of 2018, he bought more than $35 million worth of shares in Tesla.

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Kevork Djansezian/Getty Images

Source: CNN

Musk also invests a lot of time, energy, and resources into SpaceX.

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John Raoux / AP Images

Source: Business Insider

In just two years, SpaceX has raised more than $2.2 billion to develop, build, and launch Starlink, an effort to cover Earth in ultra-fast broadband internet and build the prototype of its Big Falcon Rocket (BFR), a gargantuan reusable space vehicle designed to bring people to Mars, reported Business Insider's Dave Mosher.

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SpaceX/Flickr (public domain)

Source: Business Insider

Musk also helms The Boring Company, which he founded in 2016 to develop and construct an underground tunnel in Los Angeles in an effort to mitigate traffic. In December 2018, Musk debuted the first prototype.

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Robyn Beck/Pool via REUTERS

Source: Business Insider

According to the New York Times, the Boring Company has raised over $112 million this year and more than 90% of it has come from Musk.

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The Boring Company

Source: The New York Times

In 2012, Musk signed the Giving Pledge vowing to donate the majority of his wealth during his lifetime. Though he's already in the business of improving our environment and the future during his day job, Musk has made sizable donations to causes he cares about, including a $10 million gift to the Future of Life Institute to regulate artificial intelligence.

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jurvetson / Flickr

Sources: Twitter , Business Insider

At the end of the day, the multi-billionaire enjoys inexpensive hobbies like listening to music, playing video games, and reading books. "Hang out with kids, see friends, normal stuff," he said. "Sometimes go crazy on Twitter. But usually it's work more."

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REUTERS/Stephen Lam

Source: Quartz

See Also:

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DON'T MISS: A look at the demanding schedule of Elon Musk, who works in 5-minute slots, skips breakfast, and largely avoids emails