Vortex (satellite)

DNI depiction of a NRO SIGINT satellite

Vortex, previously known as Chalet, is 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 weigh approximately 1,800 kilograms and are operated from 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 The Chalet/Vortex satellites replaced the older generation of Canyon satellites, and were superseded by the larger, more capable Mercury SIGINT satellites.

Launches

Vortex satellite footprints

Satellite	Launch	NORAD Number	Notes
Chalet 1	10 June 1978	(OPS 9454)	COSPAR ID: 1978-058A
Chalet 2	1 October 1979	(OPS 1948)	1979-086A
Chalet 3	31 October 1981	(OPS 4029)	1981-107A
Vortex 4	31 January 1984	(OPS 0441)	1984-009A
Vortex 5	2 September 1988	(USA 31)	1988-077A
Vortex 6	10 May 1989	(USA 37)	1989-035A

See also

• Magnum SIGINT satellites – a similar, contemporary program run for the Central Intelligence Agency
• Mercury or "Advanced Vortex" SIGINT satellites – replacements for Vortex

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

References

• Richelson, Jeffrey T. ed. U.S. Military Uses of Space, 1945-1991 Vol 1, Guide. National Security Archive. 1991.