ehartwell writes "It's official. This morning, after WhiteKnightTwo released SpaceShipTwo at an altitude of around 50,000 feet, pilots Mark Stucky and Mike Alsbury ignited the engine for a roughly 16-second blast. After the engine cutoff, the plane coasted back to its landing back at the Mojave airport. Virgin Galactic tweeted that the pilots confirmed 'SpaceShipTwo exceeded the speed of sound on today's flight!' Its predecessor, SpaceShipOne, first went supersonic December 17, 2003."