SpaceShipTwo VSS Unity, with its hybrid rocket motor firing, pulls upwards towards space in December 2018.

Earth as viewed from SpaceShipTwo in December 2018 when the vehicle reached an apogee of 51.4 miles.

Virgin Galactic’s WhiteKnightTwo mothership VMS Eve lifts SpaceShipTwo from Mojave; it takes about an hour to reach the altitude at which the spaceplane is released.

The WhiteKnightTwo carrier aircraft and SpaceShipTwo spaceplane combination is Virgin Galactic's two-stage solution for commercial spaceflight.

SpaceShipTwo returns to Mojave after its re-entry and glide back to Earth; its hybrid rocket engine is only engaged for the ascent to space.

SpaceShipTwo's 'feathering' tails rotate to adjust the spacecraft's shape in its suborbital operating environment to enable the crew to control its rate of deceleration.