A 'Sausage-shaped' Radar Echo at 2,500 mph off Okinawa

The AN/CPS-1 radar at the Okinawa ground-controlled intercept site stood on a 750-foot hill a few miles north of Kadena Air Base. At 15:27Z on 3 October 1951, about 00:27 on 4 October local time, it painted a large, solid, sausage-shaped echo 90 miles out on a bearing of 014. Sgt. M. W. Watson on the high beam tracked it over six sweeps to 152 miles. Pvt. Gonzales on the low beam picked up four more returns between 200 and 247 miles, and a radar mechanic agreed with what they saw.

The echo was two and a half to three times the size of a B-29's return. Its long axis stayed at right angles to its direction of travel. Within a single 15-second sweep it turned about 90 degrees. The computed speed was about 2,500 to 3,000 miles an hour at 45,000 to 49,000 feet.

What is on the record

The file is Project Blue Book Unknown no. 984. Closer radar sites and a height-finder did not detect the target. The operators saw no weather or clutter on the scope, though the island echoes had brightened. Heavy CW interference blocked the reporting net.

The experts who looked at it did not agree. A 20th Air Force analysis read the plots as a wide formation in a gradual manoeuvre and sought a natural cause. Frank C. Anton, a Philco engineer, concluded the echo was "not of natural origin" and was probably man-made, possibly a guided missile carrying an S-band transponder. The Air Technical Intelligence Center said that with experts in conflict any further theorising would be "pure conjecture". The record card reads UNIDENTIFIED.

Berliner's list of Blue Book unknowns carries the case and names Watson and Gonzales. NICAP lists it as BB 984. Berliner gives a speed of 4,800 miles an hour and a time of 10:27 p.m. The file's own figures are used here.

Why it sits where it does

L4 · OFFICIAL RECORD: a released government record names who saw it. Watson and Gonzales are named, along with the rest of the site's radar crew on duty. This is a radar-only case. Nobody saw anything with their eyes, and the Blue Book file is the archive's only account of the night. The tier measures sourcing, not truth. What drew that echo across the scope is not resolved here.