Ten years ago Saturday (Oct. 4), the era of commercial spaceflight really started taking off.

On that day in 2004, the privately built SpaceShipOne reached space for the second time in less than a week, winning the $10 million Ansari X Prize for the team that built the suborbital spacecraft and giving a nascent industry a huge shot in the arm.

"That was a very important event," Michael Lopez-Alegria, president of the Commercial Spaceflight Federation and a former NASA astronaut, told Space.com. "I would not be surprised if, 50 years from now, people look back and that will be identified as the moment that the era of commercial spaceflight started." [Now Boarding: The Top 10 Private Spaceships]

Pilot Brian Binnie stands atop SpaceShipOne, which won the $10 million Ansari X Prize by reaching space twice within the span of two weeks in 2004.
Pilot Brian Binnie stands atop SpaceShipOne, which won the $10 million Ansari X Prize by reaching space twice within the span of two weeks in 2004.
Credit: X Prize Foundation

The Ansari X Prize was the first competition organized by the nonprofit X Prize Foundation, which seeks to spur technological progress by offering big-money purses.

The competition launched in 1996 as simply the "X Prize," and was renamed in 2004 following a large donation from the Ansari family — including Anousheh Ansari, who made history in 2006 by becoming the first woman to take a privately funded trip to the International Space Station.

The Ansari X Prize challenged private teams around the world to build a reusable, manned vehicle capable of carrying three people to an altitude of 62 miles (100 kilometers) — the generally accepted boundary marking where outer space begins — and back twice within a two-week span.

Twenty-five teams competed in the challenge. One of them was Mojave Aeropace Ventures, which was led by famed designer Burt Rutan and his firm, Scaled Composites, and bankrolled by billionaire Microsoft co-founder Paul Allen.

Rutan's team came up with a 28-foot-long (8.5 meters) vehicle called SpaceShipOne, which was lofted to an altitude of about 50,000 feet (15,000 m) by a carrier plane and then released, using its onboard rocket engine to blast into suborbital space.

SpaceShipOne made history on June 21, 2004, becoming the first privately created manned vehicle to reach space, after flying to an altitude of 62.5 miles (100 km). The spacecraft then won the Ansari X Prize by repeating the feat on Sept. 29 and Oct. 4 of that year, with Mike Melvill piloting the first of these two flights and Brian Binnie at the controls for the second. [SpaceShipOne Pilot Brian Binnie Recalls Historic Flight]

The Ansari X Prize was designed to help get commercial human spaceflight off the ground, and it succeeded in doing so, experts say.

"I think it was tremendously important," George Whitesides, CEO of the commercial spaceflight company Virgin Galactic, told Space.com. "It showed that a small, nongovernment team could carry off a major human spaceflight program. And that was a really important existence proof for a lot of the work that has come in those intervening years."

The X Prize wasn't solely responsible for the rise of commercial spaceflight, of course. Whitesides and Lopez-Alegria cited other spurs as well, including Dennis Tito's first-ever privately funded flight to the space station in 2001. Also important was the entry into the industry of wealthy and successful people, such as billionaire entrepreneur Elon Musk, who founded SpaceX in 2002, and Amazon.com founder Jeff Bezos, who established the under-the-radar aerospace firm Blue Origin in 2000.

But the Ansari X Prize got the world's attention, Whitesides said.

"There was a big picture in almost every [news]paper in the world of that achievement," he said. "It sort of rang the bell of the world. And I think what came after that was an even bigger outflow of private capital, which has been the rocket fuel for all this work that's happened over the last 10 years."

Indeed, the very existence of Virgin Galactic is a testament to the long-term impact of the Ansari X Prize: British billionaire Sir Richard Branson licensed the SpaceShipOne technology and built his spaceflight company around it.

"Richard had been looking for an investment in space and, I think, hadn't found it until the X Prize happened," Whitesides said. "While I think the brand Virgin Galactic had been registered before the X Prize, the substance of the company was essentially formulated by the success of the competition, and Scaled's entry."

Virgin Galactic unveiled SpaceShipOne's successor, the six-passenger SpaceShipTwo, in 2009. The vehicle has successfully completed a handful of rocket-powered test flights and should begin ferrying customers to suborbital space and back — at a current price of $250,000 per seat — sometime in 2015, Branson has said. [Rise of SpaceShipTwo: Virgin Galactic's Test-Flight Photos]

And other companies are in the mix, too. For instance, XCOR Aerospace is developing a one-passenger suborbital rocket plane called Lynxthat may get up and running around the same time SpaceShipTwo does.

Virgin Galactic has repeatedly pushed back its commercial operations over the years. In 2004, for example, Branson predicted that the spaceliner would be flying by 2007.

But such delays are understandable, Lopez-Alegria said, stressing that getting people to space and returning them safely remains a difficult technical challenge.

"They're doing it the right way," he said of Virgin Galactic. "They're taking their time. They're being safe. They're making sure they have all the t's crossed and the i's dotted."

And Virgin Galactic is building a commercial spaceline, not just a spaceship, Whitesides said. So the company has had to develop strategies and solutions in many different areas, from the design of SpaceShipTwo's seats to flight-training programs for their customers to Federal Aviation Administration licensing requirements.

"There are a thousand different things that we're working on," he said.

Lopez-Alegria said he expects 2015 to be a big year for commercial suborbital spaceflight. But regardless of when SpaceShipTwo and Lynx get off the ground, he said, the private spaceflight industry as a whole has made great strides.

For example, SpaceX and Orbital Sciences Corp. are already making robotic cargo runs to the International Space Station under billion-dollar deals with NASA. And the space agency recently tapped SpaceX and Boeing to fly American astronauts to and from the orbiting lab, with a targeted start date of 2017. Boeing got $4.2 billion in this latest commercial crew deal, while SpaceX received $2.6 billion.

"The industry is really here," Lopez-Alegria said. "This is no longer somebody's wishful thinking or dream. This is reality, and now it's just churning it out, making it work and making money at it."

 Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @Spacedotcom, Facebook or Google+. Originally published on Space.com.