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Canyon 1, 2, 3, 4, 5, 6, 7 (AFP-827)

Canyon was the first series of NRO's near geostationary ELINT/SIGINT satellites launched under the designation AFP-827 or Program 7500. They were focussed on communications intelligence (COMINT).

The satellites were primary built to intercept soviet communications transmissions, especially line-of-sight microwave links, but were also able to tap into very high frequency (VHF) communications. Main contractor was Lockheed. Reportedly they consisted of a large (ca. 10 m diameter) antenna and were three axis stabilized. They were deployed into a 24 h orbit, which is not geostationary, so that triangulations of emmiter sources can be made from different points.

As the orbital data reported is not quite consistent, it is unclear, if the Canyons were deployed directly into the final orbit by the Agena-D or if they used a apogee kick motor. Recent analysis by Jonathan McDowell hints to the first theory, with the Agena-D remaining attached to the spacecraft during the first three missions.

The first satellite was successfully launched in August 1968, but was lost soon after reaching it's station due to erroneous commands sent by ground control. The next two satellites became operational in orbit, but suffered both from service outages. The fourth was lost in a launch failure. The final three satellites eventually performed better and produced valuable intelligence data.

They were succeeded by the Chalet / Vortex series.

Nation: USA
Type / Application: ELINT
Operator: NRO
Contractors: Lockheed
Equipment: ?
Configuration: ~ 10 m Dish Antenna, 3-Axis-Stabilization
Propulsion: ?
Mass: ?
Orbit: 30200 km × 40800 km, 9.00 (typical)
Satellite COSPAR Date LS Launch Vehicle Remarks
Canyon 1 (7501, OPS 2222) 1968-063A 06.08.1968 CC LC-13 Atlas-SLV3A Agena-D
Canyon 2 (7502, OPS 3148) 1969-036A 13.04.1969 CC LC-13 Atlas-SLV3A Agena-D
Canyon 3 (7503, OPS 7329) 1970-069A 01.09.1970 CC LC-13 Atlas-SLV3A Agena-D
Canyon 4 (7504) 1971F 04.12.1971 CC LC-13 F Atlas-SLV3A Agena-D
Canyon 5 (7505, OPS 9390) 1972-101A 20.12.1972 CC LC-13 Atlas-SLV3A Agena-D
Canyon 6 (7506, OPS 4966) 1975-055A 18.06.1975 CC LC-13 Atlas-SLV3A Agena-D
Canyon 7 (7507, OPS 9751) 1977-038A 23.05.1977 CC LC-13 Atlas-SLV3A Agena-D


  • Jeffrey T. Richelson, "Eavesdroppers in Disguise". in Air Force Magazine (August 2012) (Air Force Association)
  • Jonathan McDowell's Space Report #501 (JSR)
Further high orbit ELINT missions:

Geostationary orbit (Canyon-Chalet-Vortex-Mercury series) Geostationary orbit (Rhyolite-Aquacade-Magnum-Orion series) High elliptical orbit (Jumpseat-Trumpet series)