In this historical photo from the U.S. space agency, a one-twentieth scale model of the X-15, originally suspended beneath the wing of a B-52, is observed by a scientist as it leaves the bomber model in tests to determine the release characteristics and drop motion of the research airplane.
The test was conducted in the Langley High Speed 7 x 10 Foot Tunnel, around 1957.
The National Advisory Committe on Aeronautics (NACA) was a precursor to NASA. NACA was created by Congress in 1915.
Each weekday, SPACE.com looks back at the history of spaceflight through photos (archive).