Virgin Galactic's manned spaceplane has hit another milestone, breaking Mach 2 as it roared into the mesosphere. With test pilots Dave Mackay and Mike “Sooch” Masucci at the controls, VSS Unity reached 170,800 ft (32.3 miles, 52 km) and a speed of Mach 2.47 (1,832 mph, 2,948 km/h).