Project Blue Book: Seventeen Years of UFO Investigations and 701 Cases Left Behind

On June 24, 1947, private pilot Kenneth Arnold was flying near Mount Rainier in Washington State. He reported seeing nine bright objects moving in formation at a speed he could not match to any aircraft he knew. Arnold said they moved like saucers skipping across water. Newspapers shortened the description to "flying saucers," and Americans began looking at the sky with a new kind of fear.

Within months, the U.S. Air Force ordered officers to collect reports of airborne objects that might affect national security. This was not a hobby group. Investigators were expected to record dates, times, direction, speed, altitude, shape, witnesses, and any marks left at a site. The public mission was to determine whether Soviet aircraft, new weapons, or another threat was crossing American airspace.