Project Blue Book Case #5003. On October 8, 1957, witnesses in Seattle, Washington, observed a bright object in the sky over the city. Seattle was the headquarters of the Boeing Company, manufacturer of the B-47 and B-52 bombers that formed the backbone of SAC's nuclear strike force, and the commercial 707 jetliner that was revolutionizing air travel.
Boeing's facilities sprawled across the Seattle metropolitan area, from the original Plant 1 on the Duwamish River to the massive Renton factory where 707s rolled off the assembly line. Test flights of military and commercial aircraft were daily occurrences, and Boeing's engineers and test pilots constituted one of the most aviation-literate populations on Earth.
October 8, 1957, was just four days after the Soviet Union launched Sputnik — the first artificial satellite — on October 4. The Sputnik shock was transforming American military and scientific priorities, and the skies were suddenly an object of intense public attention. Any unusual object seen in the days following Sputnik drew heightened interest and scrutiny.
The object over Seattle could not be identified as any Boeing test flight, military operation, or Sputnik-related object. The case was classified "Unknown."