Project Blue Book Case #2219. On November 12, 1952, an unidentified object was observed over Los Alamos, New Mexico — the second Blue Book unknown from America's premier nuclear weapons design laboratory (following Case #1538 from July 22). Los Alamos was actively developing thermonuclear weapons, with the first hydrogen bomb test (Ivy Mike) having been conducted just eleven days earlier on November 1.
The timing is remarkable. The most powerful weapon in human history had just been detonated in the Pacific, and eleven days later, an unidentified object appeared over the laboratory that designed it. Whether coincidence or something more, the juxtaposition was deeply unsettling to the security apparatus protecting Los Alamos.
The laboratory's restricted airspace and comprehensive security monitoring made conventional intrusions extremely unlikely. The pattern of repeated unknowns over Los Alamos — combined with similar patterns at Oak Ridge, Hanford, and other nuclear facilities — constituted one of the most troubling threads in the entire Blue Book record.
The case was classified "Unknown."