Project Blue Book Case #1827. On the night of August 5-6, 1952, one of the most compelling radar-visual cases in Blue Book history unfolded at Haneda Air Force Base near Tokyo, Japan. Air Force tower controllers first spotted a brilliant, fluctuating light in the sky northeast of the base. The object appeared far brighter than any star and exhibited a pulsating quality that immediately marked it as anomalous.
Ground radar at the Haneda Ground Controlled Intercept (GCI) station locked onto the target, confirming it as a solid return at the same position as the visual observation. The radar tracked the object executing orbital maneuvers — circling in a tight pattern — before it suddenly divided into three separate targets that moved apart and then reconverged. An F-94 Starfire interceptor was scrambled to investigate.
The F-94 crew obtained both visual and airborne radar contact with the target. As the interceptor closed to pursuit range, the object accelerated away at a speed the F-94 could not match, breaking radar lock. The entire encounter lasted approximately ninety minutes, with multiple independent confirmation sources: tower visual observation, GCI ground radar, airborne radar, and pilot visual contact.
The Haneda case became one of Blue Book's most studied "Unknown" classifications. The convergence of visual and radar evidence from multiple platforms made it nearly impossible to dismiss as misidentification or equipment malfunction. The case was prominently featured in the Battelle Memorial Institute's classified statistical analysis of Blue Book data (Project Stork / Special Report No. 14) as a prime example of a high-quality, multi-sensor unknown.