This is a wind-tunnel model of the X-20 Dyna-Soar (Dynamic Soaring), the prototype for a single-piloted spaceplane. Originally conceived by German aerospace designer Eugen Saenger as a skip-glide rocket bomber with intercontinental range, the concept was transformed by the U.S. Air Force into a manned reconnaissance platform in space. Designed to be launched by rocket into orbit, the X-20 was a "lifting body" design and would have landed like an airplane. The Dyna-Soar program was cancelled in December 1963, before the first manned test flight took place. This wind-tunnel model was used to test the aerodynamic characteristics of the X-20. It was built by Boeing and donated by the U.S. Air Force Museum in 1966.