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.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.