National Aeronautics and Space Administration X-15 Transparency Collection

This collection consists of 13 glass-mounted 70mm (2.75 x 3.5 inch) color transparencies of National Aeronautics and Space Administration (NASA) North American X-15 hypersonic research aircraft operations and pilots.

First flown in 1959, the North American X-15 hypersonic research aircraft bridged the gap between human flight in the atmosphere and spaceflight. Three airframes were built by North American Aviation, Inc. for the X-15 program (serial numbers 56-6670, 56-6671, and 56-6672) each using liquid rocket engines built by the Reaction Motors Division of the Thiokol Chemical Corporation. Based at the National Aeronautics and Space Administration (NASA) Flight Research Test Center at Edwards Air Force Base, California, the X-15 was the first winged aircraft to fly Mach 4, 5, and 6 and to operate at altitudes above 30,500 m (100,000 ft). Eight of the twelve test pilots received astronaut wings for X-15 high-altitude flights. Film slides were used extensively in the 20th century for illustrated talks and presentations. The same still picture images were often reused for multiple presentations in business, education, and scientific settings. While cardboard (and later plastic) mounts were the most common, metal-edged glass slide mounts such as those found in this collection helped protect the film in high-use slides from both frequent handling and the high heat generated by the high-intensity incandescent light bulbs used in film projectors.