Credits - © Mark Wade
The Dyna-Soar (short for DYNAmic SOARing) orbital “spaceplane” (originally designed as the X-20) was conceived by the U.S. Air Force in 1957 as the next step after the X-15 experimental aircraft. Planned to investigate high-altitude flight at hypersonic speeds, it was to be a piloted, delta-wing glider launched into space by a rocket. The design was based on the World War II-era “Silver Bird” idea of German Eugen Sänger, which was of a bomber that could “skip” and glide around the Earth in the upper atmosphere. It was the first American spacecraft to have reached the mockup stage, and was only eight months away from its first “drop tests” from a B-52, when it was canceled in 1963 in favor of the Manned Orbiting Laboratory.
The air force had planned several versions of the spacecraft. During its development by Boeing, the design gained weight and its launch vehicle was changed from a Titan I to a Titan II and eventually the Titan III, which could carry a heavier load into orbit. The craft would have been covered with a ceramic heat-resistant material, similar to the material that was used later on the Space Shuttle.