What happened
Day says the cruiser's SPY-1 radar showed clusters of unknown tracks appearing above 60,000 to 80,000 ft and dropping to about 20,000 ft or near sea level in seconds. He told History's Unidentified that he saw well over 100 of them across the week. The crew first suspected a fault and recalibrated the radar, but the tracks persisted. Day later persuaded his commanders to send aircraft, which led to entry 3. The raw radar data has never been released.