Elon Musk reigns over an entrepreneurial landscape of epic proportions. With Tesla Motors, the cherub-faced CEO wants to wean us off fossil fuels with electric cars for the masses. With SolarCity, he envisions panels blooming on a million rooftops.

Elon Musk reigns over an entrepreneurial landscape of epic proportions.

With Tesla Motors, the cherub-faced CEO wants to wean us off fossil fuels with electric cars for the masses.

With SolarCity, he envisions panels blooming on a million rooftops.

He is laying the groundwork for the world�s biggest battery factory.

Yet this 42-year-old planet-saving, big-dreaming engineer has his sights on a celestial prize: Mars.

With SpaceX, the rocket company he founded in 2002, Musk hopes to employ recyclable rockets to save humanity, blasting earthlings into space to one day build settlements on the Red Planet.

�Mars is what drives him,� said Louis Friedman, an astronautics engineer who has known Musk for a decade. �From a psychological point of view, if you�re stuck on Earth, humankind has limits � and Elon isn�t the kind of guy who likes to live with limits.�

Silicon Valley�s most-intrepid CEO already has employed his potent combination of vision, determination and attention to detail to accomplish two tasks widely thought impossible: creating a viable American car company with Tesla and starting a successful private space venture with SpaceX.

His vision springs from a childhood in South Africa, where he devoured comics and science fiction and flew with his swashbuckling dad in a small plane over the African bush. Now, thanks to the fortune he amassed as co-founder of PayPal and the risk he took on rockets, Musk has a shot at opening up the universe.

�The moment he was out of PayPal and could do something else, it was, �Let�s see if we can launch a rocket,�??� Errol Musk, Elon�s 68-year-old father, said in a rare interview. �The cars and solar power are side issues, really � though big ones! I have no doubt that he will get man to Mars in his lifetime.�

Alexandra Musk, Elon�s 20-year-old half sister, said he sees Mars as humanity�s only viable refuge.

�With all the environmental problems on Earth, the next step is to move to a planet that we can live on,� she said. �He wants to go up into space himself, but with his own kids being so young, he can�t really do that. He�d be gone for a quite a while.�

Although he declined to comment for this story, Musk has described Mars as a �fixer-upper� planet that over time could sustain human life. Mercury is too close to the sun; Venus is too hot.

But even to Friedman, Musk�s initial proposal to launch a rocket seemed ludicrous. �I said, �Are you crazy? Everybody who tries to get into the rocket business quickly learns that it costs a lot more money than they thought.� He said to me, �I know, but I can do it.�??�

SpaceX�s Falcon 9 rocket, carrying its Dragon cargo spacecraft, was launched on Friday from Cape Canaveral for a fourth trip to the International Space Station.

Musk was born in Pretoria, South Africa, to Maye and Errol Musk in June 1971, the oldest of three children. His parents divorced in 1980, and he lived mostly with his father. Both sides of the family had means � and wanderlust, so Musk and his family traveled extensively. He was reared with household responsibilities, despite his family�s means, and he was a bright and interested student, adept at chess and computers.

In the late 1980s, when South Africa was in political turmoil, he moved to Canada to continue his college education and then transferred to the University of Pennsylvania, studying finance, management and physics before heading to Silicon Valley in 1995.

He had a summer internship at Pinnacle Research, an energy-storage startup. He planned to pursue graduate work in applied physics at Stanford University but instead joined the Internet boom.

Entrepreneurial successes soon followed. Musk co-founded Zip2, which was sold to Compaq in 1999. Then he launched the financial-services company X.com, which morphed into PayPal.

The pay dirt from selling PayPal to eBay for $1.5 billion in 2002 enabled a now-wealthy Musk to embrace his true love: space travel. He left Silicon Valley for Los Angeles, long an epicenter of the aerospace industry, and started SpaceX, where he is both CEO and chief technology officer. He now shuttles back and forth between SpaceX and Tesla, based in Palo Alto, Calif.

Aerospace engineer Robert Zubrin, president of Pioneer Astronautics, has watched Musk�s passion for Mars grow since they met in 2001 during a Mars Society fundraiser. Zubrin said Musk�s most-striking qualities are a self-deprecating sense of humor and his uncanny ability to master arcane and complex subjects that accomplished aeronautical engineers have required decades to learn.

�When I first met him, he knew absolutely nothing about rockets, though he clearly had a scientific mind,� Zubrin said. �By 2004, he had learned a fair amount, and by 2007, he knew everything. This guy had gone and educated himself in this entire art. If you sat down with him and asked a bunch of technical questions about rocket engineering, he could answer them all.�

But Musk didn�t stop with rockets. As an early investor in Tesla Motors, he risked his newly acquired fortune to keep the company afloat. As CEO and product architect (his signature is on the sun visors of the first Model S sedans), Musk oversees more than 6,000 employees.