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A military satellite is an artificial satellite used for a military purpose. The most common missions are intelligence gathering, navigation and military communications.
The first military satellites were photographic reconnaissance missions. Some attempts were made to develop satellite based weapons but this work 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 the sky, half of which are owned by the US, followed by Russia, China and India. [1]
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. [2] Within this program a number of sub-programs were developed including Corona. [2] Satellites within the Corona program carried different code names. The first launches were code named Discoverer. This mission was a series of reconnaissance satellites, designed to enter orbit, take high-resolution photographs and then return the payload to Earth via parachute. [2] 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. [3] Corona was followed by other programs including Canyon (seven launches between 1968 and 1977 [4] ), Aquacade [5] and Orion (stated by US Government sources to be extremely large [6] ). There have also been a number of subsequent programs including Magnum and Trumpet, [7] 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, the Soviet Ministry of Defence judged in 1978 that the time consumed by station maintenance outweighed the benefits relative to automatic reconnaissance satellites.[ citation needed ]
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 a degree from one another in geosynchronous orbit. [8]
The first satellite navigation system, Transit, used by the United States Navy, was tested in 1960. [9] 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 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. [10] The USAF had requirements for a more accurate and reliable navigation system, as did the United States Army for geodetic surveying [11] 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 was launched in 1969. [12]
In 1978, the first experimental Block-I GPS satellite was launched [13] 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). [14] Full Operational Capability (FOC) was declared by Air Force Space Command (AFSPC) in April 1995, signifying full availability of the military's secure Precise Positioning Service (PPS). [14]
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 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 the lack of any mechanism to protect the satellites from attack resulting in the cancellation of Defender in 1968. [15]
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 the treaty with a further 27 pending full ratification. [16] [17]
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 Ka band) frequency bands.
The US Armed Forces maintains international networks of satellites with ground stations located in various continents. Signal latency 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. [18]
Military Strategic and Tactical Relay, or Milstar, 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 is currently operated with support from Astrium Services and provides near worldwide coverage with both X band and Ultra high frequency services. [19]
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. [20] The system is provided by a private contractor, Astrium, with the UK government paying service charges based on bandwidth consumption. [20]
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The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radio navigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite systems (GNSS) that provide geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. It does not require the user to transmit any data, and operates independently of any telephone or Internet reception, though these technologies can enhance the usefulness of the GPS positioning information. It provides critical positioning capabilities to military, civil, and commercial users around the world. Although the United States government created, controls and maintains the GPS system, it is freely accessible to anyone with a GPS receiver.
The militarisation of space involves the placement and development of weaponry and military technology in outer space. The early exploration of space in the mid-20th century had, in part, a military motivation, as the United States and the Soviet Union used it as an opportunity to demonstrate ballistic-missile technology and other technologies having the potential for military application. Outer space has since been used as an operating location for military spacecraft such as imaging and communications satellites, and some ballistic missiles pass through outer space during their flight. As of 2018, known deployments of weapons stationed in space include only the Almaz space-station armament and pistols such as the TP-82 Cosmonaut survival pistol.
Nuclear weapons delivery is the technology and systems used to place a nuclear weapon at the position of detonation, on or near its target. Several methods have been developed to carry out this task.
Space Systems Command (SSC) is the United States Space Force's space development, acquisition, launch, and logistics field command. It is headquartered at Los Angeles Air Force Base, California, and manages the United States' space launch ranges.
GPS satellite blocks are the various production generations of the Global Positioning System (GPS) used for satellite navigation. The first satellite in the system, Navstar 1, was launched on 22 February 1978. The GPS satellite constellation is operated by the 2nd Space Operations Squadron (2SOPS) of Space Delta 8, United States Space Force.
USA-54, also known as GPS II-7 and GPS SVN-20, was an American navigation satellite which formed part of the Global Positioning System. It was the seventh of nine Block II GPS satellites to be launched, which were the first operational GPS satellites to fly.
USA-83, also known as GPS IIA-5, GPS II-14 and GPS SVN-26, is an American navigation satellite which forms part of the Global Positioning System. It was the fifth of nineteen Block IIA GPS satellites to be launched.
USA-84, also known as GPS IIA-6, GPS II-15 and GPS SVN-27, is an American navigation satellite which forms part of the Global Positioning System. It was the sixth of nineteen Block IIA GPS satellites to be launched.
USA-91, also known as GPS IIA-11, GPS II-20 and GPS SVN-37, was an American navigation satellite which formed part of the Global Positioning System. It was the eleventh of nineteen Block IIA GPS satellites to be launched.
USA-92, also known as GPS IIA-12, GPS II-21, GPS SVN-39, and NAVSTAR 39, is an American navigation satellite which forms part of the Global Positioning System. It was the twelfth of nineteen Block IIA GPS satellites to be launched.
USA-94, also known as GPS IIA-13, GPS II-22 and GPS SVN-35, was an American navigation satellite which formed part of the Global Positioning System. It was the thirteenth of nineteen Block IIA GPS satellites to be launched.
USA-126, also known as GPS IIA-17, GPS II-26 and GPS SVN-40, is an American navigation satellite which forms part of the Global Positioning System. It was the seventeenth of nineteen Block IIA GPS satellites to be launched.
USA-135, also known as GPS IIA-19, GPS II-28 and GPS SVN-38, is an American navigation satellite which forms part of the Global Positioning System. It was the last of nineteen Block IIA GPS satellites to be launched.
OPS 5111, also known as Navstar 1, NDS-1, GPS I-1 and GPS SVN-1, was an American navigation satellite launched in 1978 as part of the Global Positioning System development program. It was the first GPS satellite to be launched, and one of eleven Block I demonstration satellites.
OPS 5112, also known as Navstar 2, NDS-2, GPS I-2 and GPS SVN-2, was an American navigation satellite launched in 1978 as part of the Global Positioning System development programme. It was the second of eleven Block I GPS satellites to be launched.
OPS 5118, also known as Navstar 6, GPS I-6 and GPS SVN-6, was an American navigation satellite launched in 1980 as part of the Global Positioning System development programme. It was the sixth of eleven Block I GPS satellites to be launched.
Navstar 7, also known as GPS I-7 and GPS SVN-7, was an American navigation satellite which was lost in a launch failure in 1981. It was intended to be used in the Global Positioning System development program. It was the seventh of eleven Block I GPS satellites to be launched, and the only one to fail to achieve orbit.
OPS 9794, also known as Navstar 8, GPS I-8 and GPS SVN-8, was an American navigation satellite launched in 1983 as part of the Global Positioning System development program. It was the eighth of eleven Block I GPS satellites to be launched.
USA-1, also known as Navstar 9, GPS I-9 and GPS SVN-9, was an American navigation satellite launched in 1984 as part of the Global Positioning System development programme. It was the ninth of eleven Block I GPS satellites to be launched, and the first satellite to receive a USA designation.
While the United States Space Force gained its independence on 20 December 2019, the history of the United States Space Force can be traced back to the beginnings of the military space program following the conclusion of the Second World War in 1945. Early military space development was begun within the United States Army Air Forces by General Henry H. Arnold, who identified space as a crucial military arena decades before the first spaceflight. Gaining its independence from the Army on 18 September 1947, the United States Air Force began development of military space and ballistic missile programs, while also competing with the United States Army and United States Navy for the space mission.