SpaceShipOne was an experimental air-launched suborbital spaceplane that used a hybrid rocket motor. The design featured a unique "feathering" reentry system where the rear half of the wing and the twin tail booms folded upward along a hinge running the length of the wing; this increased drag while remaining stable. The achievements of SpaceShipOne are more comparable to the X-15 than orbiting spacecraft like the Space Shuttle.SpaceShipOne 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. SpaceShipOne's spaceflights were watched by large crowds at Mojave Spaceport. A fourth suborbital flight, Flight 18P, was originally scheduled for October 13, 2004. However, Burt Rutan decided not to risk damage to the historic craft, and cancelled it and all future flights.On July 25, 2005 SpaceShipOne was brought to the Oshkosh Airshow in Oshkosh, Wisconsin. After the airshow, the aircraft was transported to the Smithsonian Institution's National Air and Space Museum to be put on display.The SpaceShipOne Replica measures 13 3/4" in length and has a 13 1/2" Wingspan.