VSS Unity VP-03 (also referred to in some sources as PF04) was a sub-orbital spaceflight of the SpaceShipTwo-class VSS Unity piloted by Mark P. Stucky and co-piloted by Frederick W. "CJ" Sturckow. VSS Unity was carried aloft by the White Knight Two carrier plane before being released. The spacecraft reached an apogee of 82.7 km (51.4 mi), the flight satisfied the United States definition of spaceflight (50 mi (80.47 km)), but fell short of the Kármán line (100 km (62.14 mi)), the internationally accepted standard. It was the first crewed spaceflight from U.S. soil since the Space Shuttle mission STS-135 in 2011.