Elon Musk is an entrepreneur best known in space circles for Space Exploration Technologies (SpaceX), which became the first private company to ship cargo to the International Space Station in 2012.
A long-time advocate of Mars exploration, Musk has publicly talked about ventures such as building a greenhouse on the Red Planet and more ambitiously, establishing a Mars colony.
The South African-born businessman describes himself as "an engineer and entrepreneur who builds and operates companies to solve environmental, social and economic challenges."
Besides his work at SpaceX, Musk is the founder of electric car company Tesla Motors, and is the chair of a solar energy designer/installer called SolarCity.
Musk grew up in South Africa and earned degrees in physics and business from the University of Pennsylvania. His first venture after school was Zip2 Corp., an Internet company that provided software and services for businesses.
"Things were pretty tough in the early going. I didn't have any money – in fact I had negative money [because] I had huge student debts," Musk recalled in a 2003 Stanford lecture.
He showered at a local YMCA and lived in his office, managing to keep expenses very low despite his low revenue stream. "So when we went to VCs [venture capitalists], we could say we had positive cash flow," he said.
After Compaq bought Zip2 for more than $300 million in 1999, Musk turned his attention to online bill payments. That company, later known as PayPal, sold to eBay for $1.5 billion in 2002.
Musk now had a small fortune in hand, and at the tender age of 30 was looking to put his energies into something new. He began SpaceX in 2002 with ambitious plans to launch a viable, privately funded space company. In the face of naysayers, he doubled down and worked on a business plan.
'Ridiculously recalcitrant problem'
Musk has repeatedly said that humans must be an interplanetary species to combat the threat of asteroids, and potential human catastrophes such as nuclear war or engineered viruses.
What is blocking us from doing that, Musk wrote in a 2008 Esquire piece, is "the ridiculously recalcitrant problem of big, reusable reliable rockets."
"Somehow we have to ... reduce the cost of human spaceflight by a factor of 100," he added. "That's why I started SpaceX. By no means did I think victory was certain. On the contrary, I thought the chances of success were tiny, but that the goal was important enough to try anyway."
Musk's primary goal when starting SpaceX was to develop a reliable rocket to send payloads into Earth orbit – which later took shape in the form of Falcon 1.
It took four tries to get Falcon 1 off the ground for a first test flight in September 2008, but it eventually succeeded.
"As the saying goes, the fourth time's the charm," Musk said that day to hundreds of employees at his Hawthorne, Calif.-based headquarters. "This is one of the best days of my life."
Musk followed up that success by developing the Dragon spacecraft for cargo and what he hopes will eventually be human spaceflight.
Aware that Dragon would come under skeptics' fire, Musk kept the development secret for 18 months and named it after the children's song "Puff, the Magic Dragon" to thumb his nose at those who didn't believe private spaceflight was possible.
To lift the heavy spacecraft into orbit, SpaceX developed the Falcon 9 rocket. Dragon's first flight to the International Space Station took place in 2012. It was the first privately developed ship to ever dock with the station.
Musk funded the development through his own money at first, and then gained enough experience to attract millions of dollars for NASA to develop his rockets and spacecraft, and to bring cargo to the ISS. He has also received launch contracts from entities such as the U.S. Air Force. [Infographic: How SpaceX's Dragon Space Capsule Works]
Dreams of Mars
Musk has often said that around 2002, he looked up the schedule for when NASA was supposed to send astronauts there, and was shocked to see there was no timeline. That's when, he told Wired, he came up with an idea to do a simple Mars mission "to spur the national will."
"The idea was to send a small greenhouse to the surface of Mars, packed with dehydrated nutrient gel that could be hydrated on landing. You’d wind up with this great photograph of green plants and red background — the first life on Mars, as far as we know, and the farthest that life’s ever traveled," he said.
"It would be a great money shot, plus you’d get a lot of engineering data about what it takes to maintain a little greenhouse and keep plants alive on Mars."
He eventually turned aside from the idea due to financial concerns, but in 2012 he sketched out plans to establish a Mars colony, along with other entities, with 80,000 people living on the Red Planet. (Musk later tweeted he meant to say 80,000 making the journey per year.)
The settlers would live off the land as much as possible, using equipment to generate methane, fertilizer and oxygen from Mars' atmosphere and subsurface water ice. They would arrive using a fully reusable rocket that will be a next generation to the Falcon 9 booster.
One prototype reusable Falcon 9 currently under development is called Grasshopper. The prototype has landing legs on its first stage and it has already made two short flights on Earth as of late 2012.
Still, the cost for such an ambitious plan would be around $36 billion, Musk told SPACE.com in 2012.
"Some money has to be spent on establishing a base on Mars. It’s about getting the basic fundamentals in place," Musk said.
"That was true of the English colonies [in the Americas]; it took a significant expense to get things started. But once there are regular Mars flights, you can get the cost down to half a million dollars for someone to move to Mars. Then I think there are enough people who would buy that to have it be a reasonable business case."
— Elizabeth Howell, SPACE.com Contributor