As for VSS Unity itself, Virgin Galactic confirmed at 16:14 UTC that the spacecraft had landed safely at Mojave Airport, a little over 10 minutes after touching space.
"SpaceShipTwo, welcome to space", Virgin Galactic representatives said via Twitter during today's flight.
That means VSS Unity could reach space as soon as Thursday, but Virgin admits that it could take much longer to reach that milestone.
On the ground, a gaggle of press, space enthusiasts, including Branson and his guests watched the flight, tilting their heads skyward.
That's "space" by the USA definition, which awards astronaut wings to anyone who goes above 50 miles. That differs from a long-held view that the boundary is reached at 100 kilometers. But Whitesides cited new research that favors the lower altitude and said that as a USA company it will use the US standard.
"This is a test flight, a no-kidding test flight, with all the novelty and excitement and risk", said Mr Whitesides, on the eve of the flight.
In the meantime, a commercial space race is underway as companies rush to build spacecraft that can carry astronauts and tourists into microgravity. "There is no guarantee that everything will work perfectly first time and, like all programs seeking to take bold steps, we will inevitably have times when things don't go as planned".
Virgin Galactic's carrier airplane WhiteKnightTwo carrying a space tourism rocket plane SpaceShipTwo takes off from Mojave Air and Space Port in Mojave, California, U.S.in a still image from video December 13, 2018.
The aircraft reached an altitude of 271,268ft as it made its rapid ascent into space and clocked up a velocity equivalent to 2.9 times the speed of sound. The FAA plans to formally honor the pilots of Thursday's flight by awarding them astronaut wings at a ceremony in Washington next year.
"It was a great flight and I can't wait to do it again", said Mr Sturckow, who flew on the space shuttle four times.
After reaching 43,000 feet, VSS Unity dropped from the aircraft, coasting for a few seconds before firing up its engines.
Virgin Galactic says about 600 people have reserved tickets, priced between $200,000 and $250,000, to ride aboard its supersonic plane. The twin tails temporarily rotate upward to increase drag, then return to a normal flying configuration before the craft glides to a landing on a runway.
Funded by the late billionaire Paul G. Allen and created by maverick aerospace designer Burt Rutan, SpaceShipOne won the $US10 million Ansari X Prize.
Virgin Galactic's SpaceShipTwo made a little bit of history today.
But a series of delays has grounded the firm, which suffered a disaster four years ago, when the VSS Enterprise broke apart in midair, killing co-pilot Michael Alsbury and seriously injuring pilot Peter Siebold. Also, SpaceX founder Elon Musk recently announced plans to take a wealthy Japanese businessman and his friends on a trip around the moon.
A personal record: This was the fourth powered test flight of the company's SpaceShipTwo suborbital spaceplane (called VSS Unity) and its first since July.