One of the most interesting uses for pen occurred during the Apollo 11 mission. Apollo 11 was the mission when man first landed on the moon. On July 20th, 1969 Neil Armstrong and Edwin "Buzz" Aldrin, Jr landed upon the surface of the moon. But during their mission, Buzz Aldrin accidentally broke the circuit breaker that was responsible for arming the main engine used to lift the capsule off of the moon. Without this switch, the two astronauts could be stranded. Fortunately, a pen came to the rescue.