Project 10073 Record Card and Related Correspondence — North Truro, Mass., 22 October 1951

This document is an Air Intelligence Information Report (IR-47-51E) regarding unusual radar scope sightings recorded on 22 October 1951 at the radar station in North Truro, Massachusetts. The report details two separate radar contacts, one occurring between 0230Z and 0232Z and another between 0418Z and 0422Z. The radar operators reported a single object with a characteristic 'sausage shape' that moved in a westerly and then southerly direction at an estimated speed of 2400 knots. The observations were made using a CPS-68 radar system operating on frequencies of 2992 and 3014 megacycles. The report notes that the individual echo returns and the track appearance substantiated the probability that the radar 'pick-ups' were of a flying object rather than radar interference or malfunction. However, the report also highlights that the station observed a sharp decrease in the strength of the echo returns, a phenomenon common to highly streamlined aircraft, and that the track faded at a distance of 30 miles north of the station. The document includes extensive meteorological data, such as upper air data, winds aloft, and synoptic situation reports, to determine if atmospheric conditions could explain the radar returns. The official evaluation concludes that there is insufficient data to make a definitive assessment. It explicitly states that the weather information does not support temperature-inverted anomalous propagation, which is a common cause for such radar phenomena. The investigators suggest that the possibility of meteors entering the atmosphere and being detected cannot be disregarded, as a meteor would cause ionization of the air, potentially increasing target detectability. The report is signed by Captain B. J. Ortelt and approved by Lt. Colonel Bruce K. Baumgardner of the Eastern Air Defense Force. The document was later downgraded and declassified in accordance with DOD DIR 5200.10.