But “air-launch” comes with several advantages, says Chuck Rogers, a deputy branch chief at NASA’s Armstrong Flight Research Center in California. Launching a rocket plane from mid-air might sound like a complex way to get humans into space. SpaceShipTwo then drops from the bigger plane’s underbelly, ignites its rocket engine, and flies toward the edge of space at a steep incline, traveling roughly three and a half times the speed of sound. A mothership called WhiteKnightTwo carries the SpaceShipTwo rocket plane to an altitude of more than 40,000 feet (~12 km). Unlike traditional crewed rockets that launch from the ground, SpaceShipTwo launches from mid-air. The spaceship was unveiled on 19 February 2016, as Virgin Galactic founder Sir Richard Branson had projected in November 2015 ground and flight testing commenced thereafter. On, Unity reached the milestone of bearing the weight of the airframe on its own wheels. As of April 2015, initial ground tests of Unity were projected to be able to begin as early as late 2015. As of early November 2014, the build of Unity was about 90 percent structurally complete, and 65 percent complete overall.

The spacecraft's registration, N202VG, was filed in September 2014. VSS Unity (image credit: Virgin Galactic) Figure 1: SpaceShipTwo 'Unity' at rollout event on 19 February 2016 in Virgin Galactic FAITH hangar, Mojave, California, USA.

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