Vortex, previously known as Chalet, was a class of spy satellite operated by the United States during the 1980s and 1990s to collect signals intelligence (SIGINT) from high Earth orbit. The Vortex satellites were operated by the National Reconnaissance Office for the United States Air Force and listened to radio transmissions originating from Earth or space. The intercepted data is believed to have been fed into and analyzed by the National Security Agency ECHELON system.
The satellites each had a mass of approximately 1,800 kilograms and are operated from non-stationary geosynchronous orbits. Each reportedly carried a 38-meter-diameter umbrella-like reflecting dish to collect radio signals from Earth. At least six launch attempts were made of Chalet/Vortex satellites between 1978 and 1989. The Chalet/Vortex satellites replaced the older generation of Canyon satellites, and were superseded by the larger, more capable Mercury satellites.
Launches Name COSPAR IDSATCAT No. Launch date(UTC) Launch vehicle Launch site Orbit Remarks OPS 9454 1978-058A10941 10 June 197819:08 Titan III(23)C CCAFS LC-40 OPS 1948 1979-086A11558 1 October 197911:22:00 Titan III(23)C CCAFS LC-40 OPS 4029 1981-107A12930 31 October 198109:22:00 Titan III(23)C CCAFS LC-40 OPS 0441 1984-009A14675 31 January 198403:08:01 CCAFS LC-40 USA-31 1988-077A19458 2 September 198812:05:02 CCAFS LC-40 USA-37 1989-035A19976 10 May 198919:47:01 CCAFS LC-40 * – The rockets used for the first three launches also included Transtages, however it was considered an integral component of the rocket, and an additional upper stage for launches.
See also Magnum SIGINT satellites – a similar, contemporary program run for the Central Intelligence Agency Mercury or "Advanced Vortex" SIGINT satellites – replacements for Vortex
References Richelson, Jeffrey T. ed. U.S. Military Uses of Space, 1945-1991 Vol 1, Guide. National Security Archive. 1991.
External links Vortex satellite drawing SIGINT satellite overeview from Federation of American Scientists List of SIGINT satellites from FAS Jonathan's space report No 369 (1998-08-22) Vortex/Chalet history from Encyclopedia Astronautica Launch log from Jonathan's Space Report