If all goes well on April 30, Elon Musk’s Dragon spaceship will become the first private space vehicle to rocket off into space and dock with the now-completed International Space Station.

It will be yet another major milestone for Musk, who seems to make a career of them.

The 40 year-old entrepreneur runs not one, not two, but three major businesses revolving around his two of his key interests: renewable energy and space travel. Musk is also keenly interested in the Internet and began his entrepreneurial career by building, running and then selling PayPal over a decade ago.

Today, he’s chief designer and CTO of the private space company Space Exploration Technologies (better known as SpaceX), Co-Founder of Tesla Motors, which makes electric cars, and Chairman of Solar City, the U.S.’s largest solar power company, which Musk told me may IPO later this year.

Still, with the launch date nearing, Musk will have to turn more of his attention to SpaceX.

Mashable wanted to understand what led Musk to take on this high-risk enterprise. Was Musk a space junkie as a child?

Not so much. In fact, Musk, who was born two years after the first lunar landing had trouble pinpointing the first space mission he witnessed on TV.

To be fair, he lived in South Africa at the time, which had terrible television options. “We literally had one channel and it was only on for half a day,” Musk says.

Musk said his interest in space came not so much from witnessing the work NASA had done before, but from his own firm belief that “we should be a multi-planet species.”

Even so, he never thought he’d be working on space-related projects — because “I thought that was the province of large governments."

Musk started pitching the idea of a small greenhouse on Mars (“Mars Oasis,” he calls it), mainly so he could get people excited about traveling to and beyond the Red Planet.

As NASA wound down its manned space missions in the early part of this century, Musk began to ramp up. Eventually SpaceX, which also makes the Falcon 1 rocket, was competing to be the first private business to ferry astronauts to and from the International Space Station, potentially taking over from the Russian Soyuz capsule. SpaceX’s Dragon is currently the only cargo option, according to Musk.

Musk, by the way, is not a manned-mission purist. He said that most space travel will be unmanned and even this first Dragon test mission will be guided not by human hands, but by Dragon’s own robotic mind.

“The thing that's interesting and slightly scary is that Dragon is a robotic spaceship, automatically navigating itself to the space station,” Musk explained. "It does pause at various points and ask if everything is OK. So it asks permission to proceed.”

Musk paused and added with a laugh, “But who knows, it could be like Hal 9000, 'Open the pod bay doors,’ and it doesn't do it.”

Not everyone is on board with privatized space travel. Astronaut Neil Armstrong and Buzz Aldrin have reportedly criticized NASA's increasing reliance on Musk’s company, claiming it threatens U.S. space dominance.

Still, Musk’s SpaceX is all but embedded within NASA — and vice-versa, since the company has both ex-NASA employees and actual NASA employees hard at work on the Dragon project.

“It’s important to acknowledge the role of NASA," says Musk. "I would not have been able to start SpaceX without what the amazing work NASA has done in the past. Nor would SpaceX be where it is today without the help of NASA."

For as much as Musk respects NASA, he’s quick to acknowledge one of the key benefits of SpaceX’s vehicle: It costs eight times less to fly the Dragon than it did the Space Shuttle.

So what does the future hold for the billionaire entrepreneur? Space, of course. Musk says that five years from now he’ll make the journey himself.