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By © Charles P. Vick 2007 All Rights Reserved


CANYON – SIGINT Spacecraft Series – ( NRO/USAF/NSA Program AFP-827)

Code name CANYON was the first in a long series of earth orbit NRO/USAF/NSA, SIGINT (signals intelligence) spacecraft used by the USAF and intelligence Community for a variety of mission. They were launched by the stretched Atlas-3A Agena-D series booster with a total of at least seven launch attempts with only one failure. The spacecraft were actually nothing more than USAF services specific sophisticated earth orbit space based earth receiving stations operating over the entire emitted electro magnetic radio spectrum frequency range. The CANYON introduced the first large fold out deployable gold mesh covered receiving dish antenna design of about 20-28-30 feet in diameter with a total spacecraft mass of between 500-600 pounds. CANYON’s first launch was apparently August 6, 1968 and its last launch was apparently May 23, 1977. They were designed to monitor and pick up from the ground electronic signals intelligence (ELINT), radio, communications intelligence (COMINT) and radar emitters emissions intelligence (RADINT) in addition to the missile test telemetry intelligence (TELINT) acquisitions capabilities all coming under the general SIGINT heading. Its primary mission was COMINT intercepts of Soviet radio and microwave tower communications traffic. They were fully dedicated mission operations that were highly successful in acquiring SIGINT through the larger multi-mission general SIGINT reflector dishes.

The technology for these SIGINT spacecraft were slow in coming on line development wise but later proved out highly successfully once the technology was perfected. Like any new technology program it had its issues that slowed its initial progress. During the era they were developed it literally became a serious chase to just keep up with the developing different kinds of monitor able electronic emissions that these systems were able to monitor crying for larger more sophisticated systems able to do multiple missions at the same time.

Each gravity gradient stabilized spacecraft was about 20-30 feet in diameter and about 28 feet long with the dish attached to gimbals for steering from the command, communication, control and intelligence, power bus. CANYON’s dish did not cover the entire visible surface of the earth and thus the dishes were presumable set on gimbals to monitor specific points or objects of interest such as ballistic missile flight test telemetry. This would thus require several spacecraft to accomplish this monitoring task over the full range of the ICBM’s flight test.

It is presumed that each spacecraft bus carried two solar arrays and one down link communications dish. The launch shroud was 62.26 inches in outside diameter while it’s inside diameter was 58 inches with a total length of 15.67 feet. Part of the nose portion of the shroud was a part of the spacecraft which housed the sophisticated receiving feed horns collecting the earth based signals reflected off the large SIGINT dish.

Circumstantial evidence additionally would tend to indicate that the MIDAS program number 461 IR, BMEUS sensors technology were also placed on the Canyon series. One could also think about the DMSP weather satellites block-4 series as a usable platform for similar sensor deployment. Above the feed horn’s apparatus housing circumstantially there may have been consideration of an early adjunct ballistic missile early warning sensor payload similar to Midas-B new variation of which were later deployed on subsequent SIGINT satellite. This was used by the satellite to help track ballistic missile flights in progress. Examples of this are the Heritage GEM sensor system deployed on the Jumpseat SIGINT satellite and the RADIANT AGATE / COBRA BRSSS system deployed on TRUMPET SIGINT satellites would indicate the early heritage of such adjunct payloads but there is no confirming USAF Space and Missile System Division histories on an otherwise silent program. These examples are all USAF/NRO programs only.

This spacecraft utilized the five foot diameter by 20.86 foot long Agena-D based stage to place it on a geosynchronous transfer orbit that then became a elliptical near geosynchronous orbit once the spacecraft bus housed orbit insertion solid motor was fired to placed it in that figure eight drifting orbital position. They were operated at an inclination that was at approximately 9.9 - 10.3 degrees with a perigee between 31,600-32,700 kilometers and an apogee of between 39,200-39,900-40,800 kilometers with a spacecraft life of five to seven years. The USAF primarily utilized it for monitoring Soviet missile COMINT. The Agena-D rocket stage portion of the SIGINT packages carried the usual assortment of earth, horizon and solar sensors to orient the spacecraft but it did not remain attached to the spacecraft. The constellation of spacecraft was able to receive and send the data to several global ground stations via radio signal operated by NSA/USAF personnel. The data was then processed and analyzed at NSA headquarters for further analysis distribution to the Air Force intelligence community.


 1. Pike, Christopher Anson, “CANYON, RHYOLITE and AQUACADE,” Spaceflight, Vol. 37, November 1995 pp. 381-383.

2. McDowell, Jonathan , U. S. Reconnaissance Satellites Programs, Part 2: Beyond Imaging, Quest, Vol. 4, No. 4.

3. Day, Dwayne A., Ferrets of the High Frontier, Spaceflight, Vol. 46, February 2004, pp. 75-81.


USAF Canyon SIGINT Satellite Concept

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Page last modified: 21-07-2011 13:04:12 ZULU