Documents / FOIA release
This is a 1992 CIA History Staff monograph by Gregory W. Pedlow and Donald E. Welzenbach, originally classified Secret NOFORN and approved for release in 2013. It covers the CIA's manned overhead reconnaissance program from 1954 to 1974 and the two aircraft it developed, the U-2 and the A-12 OXCART. The history covers the U-2 overflights of the Soviet Union, the 1960 downing of Francis Gary Powers and later operations in Asia and Latin America. It also includes a section on U-2s, UFOs and Operation BLUE BOOK.
“US Navy”15 pages
Secret NOFORN
Chapter 2
Although the photo intelligence gained from Project GENETRIX was limited in quantity, it was still some of the best and most complete photography obtained of the Soviet Union since World War II. It was referred to as "pioneer" photography because it provided a baseline for all future overhead photography. Even innocuous photos of such things as forests and streams proved valuable in later years when U-2 and satellite photography revealed construction activity.
Of still greater importance to the U-2 program, however, was the data that US and NATO radars obtained as they tracked the paths of the balloons—whose average altitude was 45,800 feet-over the Soviet Bloc. This data provided the most accurate record to date of high-altitude wind currents, knowledge that meteorologists were later able to put to use to determine optimum flightpaths for U-2 flights.
One completely fortuitous development from Project GENETRIX had nothing to do with the cameras but involved a steel bar. This bar served a dual purpose: the rigging of the huge polyethylene gasbag was secured to the top of the bar and the camera-payload and automatic-ballasting equipment was attached to the bottom. By sheer chance, the length of the bar—91 centimeters—corresponded to the wavelength of the radio frequency used by a Soviet radar known by its NATO designator as TOKEN. This was an S-band radar used by Soviet forces for early warning and ground-controlled intercept. The bar on the GENETRIX balloons resonated when struck by TOKEN radar pulses, making it possible for radar operators at US and NATO installations on the periphery of the Soviet Union to locate a number of previously unknown TOKEN radars.
These radar findings, coupled with other intercepts made during the balloon flights, provided extensive data on Warsaw Pact radar networks, radar sets, and ground-controlled interception techniques. Analysis of these intercepts revealed the altitude capabilities and tracking accuracy of radars, the methods used by Warsaw Pact nations to notify each other of the balloons' passage (handing off), and the altitudes at which Soviet aircraft could intercept the balloons. All of this information could be directly applied to future U-2 missions. $ ^{72} $ Not linked to a story yet.
FOIA release, from the cia-readingroom collection. The PDF is mirrored here; the original link is under it. The text was read from the page images by an OCR model; expect the odd misread word. 406 pages are in the text index: search them above, or from the library's search.