Nevertheless, the forces that can be felt on the passengers when descending are greater than when ascending and reach six times the force of gravity.

Once the aircraft is back in the atmosphere, the tail booms rotate back down and the aircraft glides off for a landing. The entire flight can take less than two hours.

The pilots are David Mackay and Michael Masucci.

In addition to Mr. Branson, three Virgin Galactic employees will evaluate what the experience will be like for future paying customers. You are Beth Moses, the lead instructor for the astronauts; Colin Bennett, chief operations engineer; and Sirisha Bandla, vice president of government affairs and research operations. Ms. Bandla will also conduct a science experiment provided by the University of Florida.

Virgin Galactic’s design already has an imperfect safety record. The company’s first spaceplane, the VSS Enterprise, crashed during a test flight in 2014 when the co-pilot moved a lever too early in flight, which allowed the tail booms to rotate if they were supposed to stay rigid. The Enterprise broke apart and co-pilot Michael Alsbury was killed. The pilot Peter Siebold survived the parachute jump from the plane.

The controls have been redesigned so that the tail boom cannot be unlocked prematurely.

In 2019, Virgin Galactic came close to yet another catastrophe when a new metal thermal sheet was improperly installed, covering holes that allow air trapped in a horizontal stabilizer – the small horizontal wing on the tail of an aircraft – to be removed when the aircraft emanating from it rises into the thinned layers of the atmosphere. Instead, the pressure of the trapped air ripped a seal along one of the stabilizers.

The mishap was revealed earlier this year in the book “Test Gods” by Nicholas Schmidle, an employee of the New Yorker. The book quotes Todd Ericson, then vice president of security and testing for Virgin Galactic, as saying, “I don’t know how we didn’t lose the vehicle and killed three people.”