Project Blue Book Case #1479. On July 17, 1952, a bright object was observed over Rapid City, South Dakota — the second Blue Book unknown near Ellsworth AFB (following Case #1243 from June 1). Ellsworth's B-36 intercontinental bombers were among the most important elements of America's nuclear strike force.
July 17 was during the great wave's peak — two days before the first Washington radar events. Ellsworth's production of two unknowns in six weeks reinforced the pattern of nuclear bomber bases attracting disproportionate attention from unidentified objects.
The case was classified "Unknown."