In 1968, a Saturn V rocket secretly containing a nuclear warhead was launched from the McKinley Rocket Base on April 4th. It suffered a serious malfunction, went off course and exploded. The true details regarding this mishap at the time was "never generally revealed." (TOS: "Assignment: Earth")
Images of the missile in space shown on the Beta 5 computer screen was taken from film shot during the Apollo 4 interstage separation sequence.