The Scaled Composites Model 316 SpaceShipOne is an experimental air-launched suborbital spaceplane that uses a hybrid rocket motor. The design features a unique "shuttlecock" reentry system whose half-delta wing folds upward at the center of its twin tail booms; this increases drag while remaining stable. It was developed by Scaled Composites, Burt Rutan's aviation company, in their Tier One program, without government funding. On June 21, 2004, it made the first privately-funded human spaceflight, and on October 4, it won the $10-million Ansari X Prize, by reaching 100 kilometers in altitude twice in a two-week period with the equivalent of three people on board, with no more than ten percent of the non-fuel weight of the spacecraft replaced between flights.