Six years ago, Elon Musk was on the verge of losing most of his fortune.

His rocket venture, SpaceX, had already experienced three failed launches. Meanwhile, Tesla was losing money fast -- and it was almost impossible to convince investors to pour money into an electric vehicle startup during the 2008 financial crisis. Musk was one setback away from becoming broke.

"I remember waking up the Sunday before Christmas in 2008 and thinking to myself, 'Man, I never thought I was someone who could ever be capable of a nervous breakdown,' but I felt this [was] the closest I've ever come...[because] it...seemed pretty...dark," said Musk, speaking to 60 Minutes reporter Scott Pelley.

Musk appeared on 60 Minutes Sunday evening to talk about his experience building two ambitious startups simultaneously. Although he is now held up as a model of entrepreneurial disruption, Musk admitted that his ventures could easily have turned into spectacular failures.

"I didn’t really think Tesla was going to be successful; I thought we would most likely fail," he said. "But I thought that we’d at least address the false perception that people had that an electric car had to be ugly and slow and boring like a golf cart."

Musk also talked about the role of government support in keeping Tesla afloat. He credited the Department of Energy's $465 million loan guarantee with helping the company scale its production. But he said it was a 2009 investment from Daimler that provided Tesla critical life support.

"There was an investment that was necessary to survive, but it wasn’t actually the federal loan. The federal loan was very helpful, but the loan that was critical to our survival was the investment from Daimler, maker of Mercedes, in May of 2009. And they were the only ones, there was no other company, no other industry of any kind [from] which we could get investments. So what the government loan did was accelerate our progress, but it did not save Tesla," Musk explained.

Watch the full 60 Minutes story on Musk's entrepreneurial saga below. You can also read Eric Wesoff's latest on Tesla's plans for a Giga battery factory here.