Branson, a brash, charismatic London native who founded Virgin Atlantic Airways in 1984 and Virgin Galactic 20 years later, had planned the flight for later this summer. He moved it up after competitor Blue Origin and its founder, Jeff Bezos, announced plans to ride their rocket into space from West Texas on July 20.
Blue Origin, which in recent days has launched a social media campaign disparaging of Virgin Galactic, softened its tone in the hours before the flight, tweeting: "Wishing you a great flight tomorrow @virgingalactic!"