The North American X-15 was an experimental Air Force and NASA Hypersonic Rocket powered aircraft that was used to ...

Since 1951, NASA (known in those pre-space days as NACA ... The best known of these vehicles, such as the X-1 and X-15, were used to study flight at extreme altitude and speed.

At the height of the Cold War during the 1960s the U.S. Air Force and NASA tested an experimental rocket-powered research aircraft code-named X-15.The X-15 experiments were conducted at Edwards ...