Project 10073 Record Card and Incoming Message — Arlington Heights, Illinois, 7 November 1961

On November 7, 1961, at approximately 0755Z, personnel from the Martin Company and the US Army 45th Artillery Brigade, operating the Missile Master system in Arlington Heights, Illinois, observed three unusual radar returns. The objects were detected on long-range radar approaching the Chicago area from the east-southeast with a 30-second separation between them. The radar returns were described as very sharp, with the video display tilted approximately 30 degrees, a phenomenon attributed to the high speed of the objects, which were estimated to be traveling in excess of 4,000 knots. Attempts to determine the altitude of the objects were unsuccessful because their speed exceeded the capabilities of the equipment. The first two objects disappeared into ground clutter and did not reappear, while the third object vanished approximately 100,000 yards before reaching the ground clutter. Following the incident, the radar equipment was tested and confirmed to be in perfect operating order. The sighting was reported through official military channels, including a message to the Air Defense Command at Ent Air Force Base. The official conclusion recorded on the Project 10073 record card was that there was insufficient data for evaluation, noting that the radar analyst could not properly assess the returns without specific information regarding the scope's operational characteristics, such as rotation speeds. The report was finalized by 2nd Lieutenant Forrest L. Poska, the Air Defense Artillery Director in Chicago.