The commercial spacecraft will aim to provide suborbital spaceflights to space tourists who will also experience short periods of weightlessness.
The service’s maiden flight has been repeatedly delayed over the years, its original SpaceShipTwo vehicle broke apart during an October 2014 test flight that killed the co-pilot, although successful flights have taken place since then.
In front of 100 guests who have put down deposits for Virgin Galactic’s first flights, Branson said three or four test flights will be conducted from New Mexico, beginning this autumn, before engineers allow him to fly.
The two suborbital test flights to date – conducted in December and February over California’s Mojave Desert – provided several minutes of weightlessness.
He declined to say when his flight might happen.
“My track record for giving dates has been so abysmal that I’m not giving dates anymore. But I think months, not years,” he told The Associated Press.
The company is in the process of moving from Southern California to Spaceport America in the New Mexico desert near Truth or Consequences, which has set everything back four months, according to Branson. The test pilots need to practice landing there, he said, before passengers tag along.
“I certainly won’t go into space before brave test pilots feel 100 per cent comfortable that we’ve checked every box,” he said.
The winged spaceship is dropped in flight from a custom-designed plane. Once free, it fires its rocket motor to hurtle toward space before gliding back to Earth like Nasa’s old space shuttles.
The latest test flight by VSS Unity reached an altitude of 56 miles while travelling at three times the speed of sound.
About 600 people, ranging from their teens to early 90s, have reserved a seat, according to a company spokeswoman. Tickets are $250,000.
Maryann Barry bought a ticket less than a month ago. She grew up near Cape Canaveral during the 1960s, and her late brother worked on Nasa’s Saturn V Moon rockets. “This is my life coming full circle actually,” said Barry, 58, who works for the Girl Scouts in Orlando.
When asked if she will be afraid, Houston violinist Debbie Moran, 62, said she is trying to do everything she has ever wanted to do in life before her spaceflight in another few years.
“We all know it’s not the safest thing in the world,” she said. “I still have not told my mother.”
“Everybody is fearful. But the point is you have to overcome the fear to get the excitement,” said Arvinder Bahal, 73, a real estate investor from Boston