Fort Monmouth Radar-Visual — General's Alert

On September 10, 1951, Signal Corps student operators at Fort Monmouth, New Jersey, were running a radar exercise when they tracked an unidentified target moving at an estimated 700 mph at approximately 93,000 feet — far above any known aircraft of the era. The object made course reversals that the equipment could not track in automatic mode, requiring manual operation. The following day, a T-33 jet trainer pilot flying near Red Bank, New Jersey reported observing a bright, round metallic disc at high altitude that quickly departed. Fort Monmouth's intelligence officer sent a classified report up the chain of command. The report reached General Charles Cabell, Air Force Director of Intelligence, who was sufficiently alarmed to fly to Wright-Patterson Air Force Base and personally confront the Project Grudge officers, demanding to know why the program had failed to take such cases seriously. The Fort Monmouth incident is directly credited in declassified Air Force documents as the catalyst that led to Project Grudge being replaced by the more rigorous Project Blue Book in early 1952.