
The first powered flight of the X-15, piloted by Scott Crossfield.
The episode was converted into a 32 page comic book ("Dell Comics" (#716)) in 1956. Under the title Walt Disney's Man in Space: A Science Feature from Tomorrowland.
It was also made into a "Tomorrowland adventure" book for classroom use in 1959 as Man in Space: A Tomorrowland Adventure.