Unity took off from the Mojave test centre in California and climbed 51 miles (82km) before beginning its descent early on Thursday.
George Whitesides, chief executive of Virgin Galactic, said after this flight that a full-duration burn would last approximately five seconds longer. That's about a mile and a half past what the USA government recognizes as the edge of space. That differs from a long-held view that the boundary is reached at 100 kilometers. Slung from the WhiteKnightTwo carrier aircraft, the rocketplane was hauled to 46,500 feet and then released. The VSS Unity then fired up its rocket engine and quickly traveled up and out of sight from a group of watchers on the ground.
Short sightseeing trips to space aboard Blue Origin's New Shepard rocket are likely to cost around $200,000 to $300,000, at least to start, Reuters reported in July.
The spacecraft was piloted by Mark Stucky and former NASA astronaut Frederick "CJ" Sturckow.
The pilot, Mr Sturckow, said: "It was a great flight and I look forward to doing it again". It burned for a total of 60 seconds and drove the vehicle directly upward at almost three times the speed of sound. In addition to the two pilots, SpaceShipTwo was also carrying a dummy to simulate a passenger and four unspecified research payloads that are part of the NASA Flight Opportunities Program.
This marked the fourth test of Virgin Galactic's SpaceShipTwo.
"Today we have shown Virgin Galactic can open space to the world", Sir Richard said. Branson met the pilots after the flight and declared "Space is Virgin territory!"
He also stated that, if all goes well, only a few more test flights would be needed before Virgin Galactic would be ready to shift operations to Spaceport America in New Mexico, where the company plans to perform commercial flights. The crash led to major delays in the company's progress in taking tourists to space.
While critics point to Branson's unfulfilled space promises over the past decade, the maverick businessman told a TV interviewer in October that Virgin's first commercial space trip with him onboard would happen "in months and not years". "There have been two people before that have flown winged spacecraft to space and back". Famous people including actor Leonardo DiCaprio and music star Justin Bieber are among them. It returned safely to Earth after the flight.
Richard Branson is not alone in the space tourism business. It was the first spacecraft with humans aboard to be launched from United States soil and reach space since the space shuttle was retired in 2011, and it marked a milestone for the commercial space industry, which also includes companies like Elon Musk's SpaceX, Jeff Bezos' Blue Origin, and Boeing. Bezos's venture will use a more traditional, reusable ground-based rocket, the New Shepard, that lands after returning from sub-orbit similar to SpaceX's Falcon 9 first stages.