SpaceX

El Segundo, California

Founded: 2002

Employees: 370

Musk's Investment: $100 million

Cost Per Launch: $7.1 million to $35 million

Launches booked: 14

Size of Falcon 9 Rocket:178 feet high; 12 feet wide

"I started SpaceX because I wanted to help reduce the cost of space transportation so it would be feasible to establish life on another planet. We optimize not only the launch costs but also the cost of developing and manufacturing the rocket. We're like a low-cost version of Boeing and Pratt & Whitney, on top of a Southwest."

Tesla Motors

San Carlos, California

Founded: 2003

Employees: 300

Musk's Investment: $37 million

Cars Sold: 600

Price: $98,000

Zero to 60: Four seconds

"Tesla is making the first real production electric car. By real, I mean that the car isn't subsidized in any way--it's valuable on its own merits. Our strategy is to start with a high-price, low-volume car and then move down to a lower price, higher volume. Eventually we're going to be a big American car company with a half-dozen models and hundreds of thousands of cars."

SolarCity

Foster City, California

Founded: 2006

Employees: 180

Musk's Investment: $10 million

Installation cost: $30,000 and up

Jobs Per Month: 90

Typical Yearly Savings: $1,800

"SolarCity installs solar panels, but installation is only one part of what we do. There's the design of the system: What's it going to look like? How's it going to be structured? There's the wiring, the permitting, the monitoring. It's a hairball of elements that need to be put together. What most people don't realize is that SolarCity--not the panel manufacturer--is providing the bulk of the value."