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29-399: The Satellite Data System ( SDS ) is a system of United States military communications satellites . At least three generations have been used: SDS-1 from 1976 to 1987; SDS-2 from 1989 to 1996; SDS-3 from 1998 to the present. It is believed that these satellites were known by the code name Quasar . The first generation was named simply 'SDS', the second generation was named 'Quasar' and

58-663: A K-band downlink. Two dishes are 4.5 m (15 ft) in diameter, while the third is 2 m (6 ft 7 in) in diameter. The solar arrays generate 1238 watts of power. It is believed that the Space Shuttle has been used to launch several satellites, possibly on missions STS-28 , STS-38 , and STS-53 . Other launches have used the Titan IV launch vehicle . Military satellite The first military satellites were photographic reconnaissance missions. Some attempts were made to develop satellite based weapons but this work

87-816: A British member of the Government Communication Headquarters, had contacts with the KGB and funneled various information regarding US satellite intelligence, which may have included details on Canyon. The Canyon satellites were eventually replaced with the next generation of COMINT satellites, the Vortex/Chalet series, whose maiden flight took place in June 1978. Seven Canyon satellites were launched from 1968 to 1977, all with Atlas SLV-3A (extended Atlas tanks for longer burn time) Agena D vehicles from LC-13 at Cape Canaveral rather than Vandenberg Air Force Base, due to

116-542: A degree from one another in geosynchronous orbit . The first satellite navigation system, Transit , used by the United States Navy , was tested in 1960. It used a constellation of five satellites and could provide a navigational fix approximately once per hour. During the Cold War arms race , the nuclear threat was used to justify the cost of providing a more capable system. These developments led eventually to

145-557: A ground controller sent an erroneous command that sent it into an unrecoverable tumble. The second Canyon ( OPS 3148 ) was launched in April 1969, followed by the third ( OPS 7329 ) in September 1970. Both satellites performed erratically, with their transmissions often cutting out or becoming intermittent. Despite these problems Canyons 2 and 3 returned much useful intelligence information, particularly regarding Chinese military maneuvers during

174-484: A mass of 630 kg (1,390 lb) and was launched on Titan-3B rockets. The SDS-1 satellites had similar orbits to the Air Force's Jumpseat ELINT satellites. It has been speculated that the early satellites served as data relays for the first KH-11 Kennen reconnaissance satellites. The SDS-2 is significantly more massive at 2,335 kg (5,148 lb), with three separate communication dishes, including one for

203-543: A mass of 700 kg and were launched from Atlas/Agena D rockets into near- geosynchronous orbits . They carried large parabolic reflecting dishes, estimated at 10 m in diameter, and signals were transmitted to a center in Bad Aibling , West Germany . Unlike contemporary photo-reconnaissance satellites, Canyon was not a bus satellite integrated into the Agena stage and it separated once placed in geostationary orbit. The program

232-528: A number of subsequent programs including Magnum and Trumpet , but these remain classified and therefore many details remain speculative. The Soviet Union began the Almaz ( Russian : Алмаз ) program in the early 1960s. This program involved placing space stations in Earth orbit as an alternative to satellites. Three stations were launched between 1973 and 1976: Salyut 2 , Salyut 3 and Salyut 5 . Following Salyut 5,

261-778: Is a constellation of military satellites managed by the United States Space Force . Six spacecraft were launched between 1994 and 2003, of which five are operational, with the sixth lost in a launch failure. They are deployed in geostationary orbit and provide wideband, narrowband and protected military communication systems. Wideband systems support high-bandwidth transfers. Protected systems offer more sophisticated security protection like antijam features and nuclear survivability, while narrowband systems are intended for basic communications services that do not require high bandwidth. The United Kingdom also operates military communication satellites through its Skynet system. This

290-406: Is a major concern in satellite communications, so geographic and meteorological factors play an important role in choosing teleports. Since some of the major military activities of the U.S. army are in foreign territories, the U.S. government needs to subcontract satellite services to foreign carriers headquartered in areas with favorable climate. Military Strategic and Tactical Relay, or Milstar ,

319-508: Is currently operated with support from Astrium Services and provides near worldwide coverage with both X band and Ultra high frequency services. Skynet 5 is the United Kingdom's most recent military communications satellite system. There are four Skynet satellites in orbit, with the latest launch completed in December 2012. The system is provided by a private contractor, Astrium, with

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348-451: Is still classified. The Air Force did not acknowledge the existence of the program at all until 1990, thirteen years after the last Canyon was launched. However, the Soviets found out about it as early as 1975 and began taking preventative measures to stop their radio communications from being tapped into, including the replacement of satellite dishes with landlines. In addition, Geoffrey Prime,

377-540: The Space-Based Infrared System (SBIRS). In the United States, research into satellite based weapons was initiated by President Dwight D. Eisenhower in the 1950s. In 1958, the United States initiated Project Defender to develop an anti- ICBM solution launched from satellites. The satellites would have deployed a huge wire mesh to disable ICBMs during their early launch phase. The project floundered due to

406-579: The Soviet Ministry of Defence judged in 1978 that the time consumed by station maintenance outweighed the benefits relative to automatic reconnaissance satellites. In 2015, United States military space units and commercial satellite operator Intelsat became concerned about apparent reconnaissance test maneuvers by the Russian satellite Olymp-K , launched in September 2014, when it maneuvered between Intelsat 7 and Intelsat 901 , which are located only half

435-536: The UK government paying service charges based on bandwidth consumption. Canyon (satellite) Canyon was a series of seven United States spy satellites launched between 1968 and 1977. Also known by its program number AFP-827, the satellites were developed with the participation of the Air Force . The Canyon project is credited as being the first American satellite system tasked for COMINT . The satellites each had

464-818: The deployment of the Global Positioning System (GPS). The US Navy required precise navigation to enable submarines to get an accurate fix of their positions before they launched their SLBMs. The USAF had requirements for a more accurate and reliable navigation system, as did the United States Army for geodetic surveying for which purpose they had developed the SECOR system. SECOR used ground-based transmitters from known locations that sent signals to satellite transponder in orbit. A fourth ground-based station, at an undetermined position, could then use those signals to fix its location precisely. The last SECOR satellite

493-531: The lack of any mechanism to protect the satellites from attack resulting in the cancellation of Defender in 1968. Since October 1967 satellite based weapons systems have been limited by international treaty to conventional weapons only. Art.IV of the Outer Space Treaty specifically prohibits signatories from installing weapons of mass destruction in Earth orbit. The treaty became effective on 10 October 1967 and, as of May 2013, 102 countries are parties to

522-492: The military's secure Precise Positioning Service (PPS). A number of nations have developed satellite based early warning systems designed to detect ICBMs during different flight phases. In the United States these satellites are operated by the Defense Support Program (DSP). The first launch of a DSP satellite was on 6 November 1970 with the 23rd and last launched 10 November 2007. This program has been superseded by

551-480: The necessity of placing them in a geostationary orbit. The first Canyon ( OPS 2222 ) was launched on August 6, 1968. Secrecy surrounding the satellite was tight, and the Air Force would say nothing other than that an "experimental payload" had been launched and it was the first "secret" launch conducted from the Cape since 1963. After a successful launch and orbital deployment, the satellite's mission ended disastrously when

580-569: The sky, half of which are owned by the US, followed by Russia, China and India. The first military use of satellites was for reconnaissance. In the United States the first formal military satellite programs, Weapon System 117L, was developed in the mid-1950s. Within this program a number of sub-programs were developed including Corona . Satellites within the Corona program carried different code names. The first launches were code named Discoverer. This mission

609-743: The system. The SDS satellites were constructed by Hughes Aircraft Company . The primary purpose of the SDS satellites is to relay imagery from low-flying reconnaissance satellites , notably the Keyhole optical reconnaissance and Lacrosse/Onyx radar reconnaissance satellites to ground stations in the United States . Each SDS-1 satellite had 12 channels available for Ultra high frequency (UHF) communication. They were cylindrical in shape, roughly 25 ft (7.6 m) long. 980 watts of electrical power were available from solar panels and batteries . The SDS-1 had

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638-529: The third generation each had their own designations. SDS satellites have a highly elliptical orbit , going from about 300 kilometers at perigee to roughly 39,000 km at apogee in order to allow communications with polar stations that cannot contact geosynchronous satellites. The high apogee meant that the polar regions were visible for long amounts of time, and only two satellites were required in order to achieve constant communications ability. In addition, two geostationary satellites appear to be part of

667-462: The treaty with a further 27 pending full ratification. Communications satellites are used for military communications applications. Typically military satellites operate in the UHF , SHF (also known as X-band ) or EHF (also known as K a band ) frequency bands. The US Armed Forces maintains international networks of satellites with ground stations located in various continents. Signal latency

696-495: The winter of 1970-71 when tensions between China and the USSR were at an all-time high, and also intelligence on North Vietnam for the 1972 Christmas Bombing campaign. The fourth Canyon, launched on December 4, 1971, never made it to orbit. The Atlas booster's sustainer engine shut down early in the launch and the booster drifted off its path, leading to a Range Safety destruct less than two minutes after liftoff. The weather on launch day

725-517: Was a series of reconnaissance satellites , designed to enter orbit, take high-resolution photographs and then return the payload to Earth via parachute. Discoverer 1 , the first mission, was launched on 28 February 1959 although it didn't carry a payload being intended as a test flight to prove the technology. Corona was followed by other programs including Canyon (seven launches between 1968 and 1977 ), Aquacade and Orion (stated by US Government sources to be extremely large ). There have also been

754-552: Was extremely wet, foggy, and overcast, thus the booster had been out of visibility when the failure happened and the Air Force did not make an announcement for three days. The failure momentarily delayed the planned launch of an Atlas-Centaur with an Intelsat satellite until the Air Force Mishap Review Board could complete their investigation and relieve the Atlas-Centaur of guilt by association. A fuel line obstruction

783-499: Was halted in 1967 following the ratification of international treaties banning the deployment of weapons of mass destruction in orbit. As of 2013, there are 950 satellites of all types in Earth orbit. It is not possible to identify the exact number of these that are military satellites partly due to secrecy and partly due to dual purpose missions such as GPS satellites that serve both civilian and military purposes. As of December 2018 there are 320 known military or dual-use satellites in

812-485: Was launched in 1969. In 1978, the first experimental Block-I GPS satellite was launched and by December 1993, GPS achieved initial operational capability (IOC), indicating a full constellation (24 satellites) was available and providing the Standard Positioning Service (SPS). Full Operational Capability (FOC) was declared by Air Force Space Command (AFSPC) in April 1995, signifying full availability of

841-484: Was suspected of having blocked the flow of propellants to the sustainer gas generator, and the way was cleared for the Intelsat launch, which took place on December 20. Three more Canyons were launched in 1972 ( OPS 9390 ), 1975 ( OPS 4966 ), and 1977 ( OPS 9751 ), all of which performed well and gathered considerable intelligence on Soviet activities as well as Arab communications during the 1973 Yom Kippur War . Indeed,

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