LONDON — Richard Branson is set to blast off to space on Sunday aboard his own rocket ship. The thrill-seeking billionaire joined five Virgin Galactic employees also assigned to the test flight to the edge of space high above the southern desert of New Mexico.

Take-off was delayed by an hour and a half, Virgin Galactic announced early Sunday morning, because of the weather conditions on site. It is now scheduled for 8.30 a.m. local time (16:30 CET).

It will be broadcast live on the Virgin Galactic website.

"My mission statement is to turn the dream of space travel into a reality — for my grandchildren, for your grandchildren, for everyone," Branson wrote on Twitter ahead of lift-off.

The London-born founder of the Virgin Group, who turns 71 in a week, wasn't supposed to fly until later this summer. But he assigned himself to an earlier flight after Blue Origin's Jeff Bezos announced plans to ride his own rocket into space from West Texas on July 20.

Virgin Galactic doesn't expect to start flying customers before next year. Blue Origin has yet to open ticket sales or even announce prices, but late last week boasted via Twitter that it would take clients higher and offer bigger windows.

Unlike Blue Origin and Elon Musk's SpaceX, which launch capsules atop reusable booster rockets, Virgin Galactic uses a twin-fuselage aircraft to get its rocket ship aloft.

The space plane is released from the mothership about 44,000 feet (13,400 meters) up, then fires its rocket motor to streak straight to space. Maximum altitude is roughly 55 miles (70 kilometers), with three to four minutes of weightlessness provided.

The rocket plane — which requires two pilots — glides to a runway landing at its Spaceport America base. — Euronews