Virgin Galactic's tourism spaceship climbed more than 50 miles high above California's Mojave Desert on Thursday, reaching for the first time what the company considers the boundary of space.

The rocket ship hit an altitude of 51 miles (82 kilometers) before beginning its gliding descent, said mission official Enrico Palermo.

"We made it to space!" Palermo exclaimed.

The supersonic flight takes Virgin Galactic closer to turning the long-delayed dream of commercial space tourism into reality. The company aims to take paying customers on the six-passenger rocket, which is about the size of an executive jet.

Virgin Galactic founder Richard Branson said there will be more test flights and if all goes well he will take a ride before the public gets its chance.

"I believe that sometime in the second half of next year that we will start being able to put regular people up into space," he said, describing Thursday as one of the best days of his life.

Virgin Galactic considers 50 miles (80 kilometers) the boundary of space because that is the distance used by the U.S. Air Force and other U.S. agencies. That differs from a long-held view that places the boundary at 62 miles (100 kilometers.) But Virgin Galactic CEO George Whitesides cited new research that favors the lower altitude.

At the start of the test flight, a special jet carrying the Virgin Space Ship Unity flew to an altitude near 43,000 feet (13,100 meters) before releasing the craft. The spaceship ignited its rocket engine and it quickly hurtled upward and out of sight of viewers on the ground. The spaceship reached Mach 2.9, nearly three times the speed of sound.

The two test pilots – Mark Stucky and former NASA astronaut C.J. Sturckow – will be awarded commercial astronaut wings, Federal Aviation Administration official Bailey Edwards said.

"It was a great flight and I can't wait to do it again," said Sturckow, who flew on the space shuttle four times.

"People have literally put their lives on the line to get us here," Branson said. "This day is as much for them as it is for all of us."

More than 600 people have committed up to 250,000 U.S. dollars for rides in the six-passenger rocket that include several minutes of weightlessness and a view of the Earth far below.

The development of Virgin's spaceship takes far longer than expected

The endeavor began in 2004 when Branson announced the founding of Virgin Galactic in the heady days after the flights of SpaceShipOne, the first privately financed manned spacecraft that made three flights into space.

When Branson licensed the SpaceShipOne technology, he envisioned a fleet carrying paying passengers by 2007, launching them from a facility in southern New Mexico called Spaceport America.

But there were significant setbacks. Three technicians were killed in 2007 by an explosion while testing a propellant system at Scaled Composites LLC, which built SpaceShipOne and was building the first SpaceShipTwo for Virgin Galactic.

Then, in 2014, SpaceShipTwo broke apart during a test flight by Scaled Composites when the co-pilot prematurely unlocked the "feathering" braking system and it began to deploy. The co-pilot was killed but the injured pilot managed to survive a fall from high altitude with a parachute.

Branson isn't alone in the space tourism business: Jeff Bezos' Blue Origin is planning to take space tourists on suborbital trips, using the more traditional method of a capsule atop a rocket that blasts off from a launch pad. SpaceX's Elon Musk recently announced plans to take a wealthy Japanese entrepreneur and his friends on a trip around the moon.