Elon Musk has been likened to the real-life counterpart of fictional billionaire industrialist Tony Stark. But the CEO of Tesla Motors hasn't always lived a storybook life.

Musk, 42, explained today the crazy journey that brought him from showering in the local YMCA in Silicon Valley while living in his small PayPal startup office to thinking about how to build a civilization on Mars.

In an interview today with Henry Blodget, CEO and editor-in-chief of Business Insider, at the website's annual conference, "Ignition: Future of Digital," Musk talked about his electric car company Tesla Motors, saying he is puzzled about fire concerns for the Model S, which has had "zero deaths" and "zero serious injuries."

With 25,000 cars on the road worldwide, Musk said the company's overriding concern is safety

"If fire is your concern, you could not be in a safer car," said Musk, a father of five.

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"If we thought a recall was warranted, we would do that for sure, if we thought the threat was important," he said, adding that the three recent highly publicized fires were the result of "very high speed impact.

The second fire, which took place in Mexico, resulted from hitting a roundabout and a tree, with the wheels being ripped from the car; but the driver and passenger were able to walk out of it, Musk noted.

"The amazing thing was that he lived, not that there was a fire in the car," he said.

"I won't say the exact speed, but it was four times more impact energy than the most strenuous regulatory test anywhere in the world," he said. "You're not supposed to survive an impact of this magnitude."

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Just after Tesla Motors provided a weak earnings forecast but better-than-expected third-quarter income, the electric car company defended its safety record after a third electric car fire, this time near Smyrna, Tenn.

Musk said the company is working on ramping up production to eliminate or at least shorten its waiting list for cars. Tesla also plans to have a third-generation car in about three years, "about half the price of the Model S ," Musk said.

With better technology, "it will become over time relatively more expensive to own a gasoline car than an electric car," he added.

Blodget also asked Musk about the pressures of being an Internet entrepreneur for PayPal to building private rockets when his companies were bleeding money. Before starting Tesla, Musk said he tried to get a job at Netscape but didn't get any response. He also tried showing up at Netscape's offices but was "too shy" to talk to anybody, he said.

When he co-founded PayPal, the money was slow in the making.

"Our goal was literally, how do we make enough money to pay the rent?" he said. He and his co-founders rented a small office because it was cheaper than an apartment, so they showered at the local YMCA on Page Mill Road in Silicon Valley.

Though PayPal made him a rich man, he invested so much of his personal wealth in Tesla and Space-X that there were, financially, "multiple near-death experiences," he said.

"At the start of both Tesla and Space-X, I thought we would most likely fail," Musk confessed, but still, "I thought this was worth a try."

Now, while running Space-X and Tesla, Musk said he spends most of his time on email.

"I do a lot of email - very good at email. That's my core competency," he joked.