Last night, SpaceX, a private rocket company based in Southern California, propelled a mass of aluminum to a speed of nearly 12,000 miles per hour, far above the Earth's surface. It was the first time in recent history that a private company successfully launched a rocket into orbit and a vindication for SpaceX founder Elon Musk. "Wow, this is a great day for SpaceX and the culmination of an enormous amount of work by a great team," he wrote in a brief blog post immediately after the launch.

Musk, who was Inc.'s entrepreneur of the year, has been working towards this moment since starting SpaceX in 2002. He invested more than $100 million of his own fortune thanks in part to the $1.5 billion sale of PayPal, which he co-founded in 1999. Amazingly, Musk is a self-taught rocket designer—when I asked him last year how he did it, he replied simply, "I read a lot of books"—which makes yesterday's coup all the sweeter. The company had missed three previous attempts at reaching orbit, leaving his dream of making space travel economical in doubt—or rather, in doubt for everyone but Musk.