A major turning point for private spaceflight occurred on June 21, 2004, when SpaceShipOne, the first nongovernmental crewed spacecraft, flew 62.5 miles (100 kilometers) above Earth's surface. In doing so, the vessel crossed a boundary called the Kármán line, the accepted point of entry to space as defined by the International Astronautical Federation.
After two more flights in 2004, one on Sept. 29 and another on Oct. 4, the piloted vehicle won the $10 million Ansari X Prize for repeated flights in a privately developed, reusable spacecraft.
