Military Communications Satellites |

The military space program is a significant but largely unseen aspect of space operations. Nearly a dozen countries have some kind of military space program, but the U.S. program dwarfs the efforts of all these other countries combined.

Military space operations are divided into five main areas: reconnaissance and surveillance, signals intelligence, communications, navigation, and meteorology . Only the United States and Russia operate spacecraft in all five areas. Several other countries have long used communications satellites for military purposes. In the 1990s, several countries in addition to Russia and the United States began developing reconnaissance satellites.

Reconnaissance and Surveillance

Reconnaissance and surveillance involve the observation of Earth for various purposes. Dedicated reconnaissance satellites, like the United States‘s Improved CRYSTAL and the Russian Terilen, take photographs of targets on the ground and relay them to receiving stations in nearly real time. These satellites, however, cannot take continuous images like a television camera. Instead, they take a black-and-white photograph of a target every few seconds. Because they are in low orbits and are constantly moving, they can photograph a target for only a little over a minute before they move out of range. The best American satellites, which are similar in appearance to the Hubble Space Telescope, can see objects about the size of a softball from hundreds of miles up but they cannot read license plates. The Russians also occasionally use a system that takes photographs on film and then returns the film to Earth for processing. This provides them with higher-quality photos. The United States abandoned this technology in the 1980s after developing superior electronic imaging technology.

Other nations, such as France and Japan, operate or plan on operating reconnaissance satellites that can see images on the ground about one to three feet in length. From the late 1970s until the mid-1990s, China had a film-based system, which is no longer operational. India, Israel, and Brazil also operate satellites capable of making visual observations of the ground. Some private companies operate commercial imagery satellites and sell images on the World Wide Web. These satellites are much less capable than the larger military satellites but their products have improved significantly and are in demand.

Other surveillance satellites, such as the American DSP and Space-Based Infrared System (SBIRS, pronounced “sibirs”) and the Russian Oko (or “eye”), are equipped with infrared telescopes and scan the ground for the heat produced by a missile’s exhaust. They can be used to warn of missile attack and can predict the targets of missiles fired hundreds or thousands of miles away. There are also satellites that look at the ground in different wavelengths to peer through camouflage, try to determine what objects are made of, and analyze smokestack emissions.

Signals Intelligence

Signals intelligence satellites can operate either in low Earth orbit or in extremely high, geosynchronous orbit , where they appear to stay in one spot in the sky. These satellites listen for communications from cellular telephones, walkie-talkies, microwave transmissions, radios, and radar . They relay this information to the ground, where it is processed for various purposes. Contrary to popular myth, these satellites do not collect every conversation around the world. There is far more information being transmitted every day over the Internet than can be collected by even the best spy agency.


Communications satellites operate in several different orbits for various purposes. The most common communications satellites operate in geosynchronous orbit. Some, like the U.S. Navy’s UHF-Follow On satellite, are used to communicate with ships at sea. Others, like the air force’s massive Milstar satellite, are used to communicate with troops on the ground and submarines equipped with small dish antennas. Still other communications satellites are used to relay reconnaissance pictures to ground stations or to troops in the field. Some satellites are used to relay data and commands to and from other satellites.

Russia operates a number of military communications satellites, including some that store messages for a brief period before relaying them to the ground. Several other countries, such as the United Kingdom, Spain, and France, have either military communications satellites or a military communications package installed on a commercial satellite. But few countries have the global military communications requirements of the United States.

Navigation and Meteorology

Navigation satellites are also vital to military forces. Sailors have used the stars to navigate for centuries. Beginning in the early 1960s, the U.S. Navy developed a satellite system to help it navigate at sea. This was particularly important for ballistic missile submarines that stayed submerged for most of their patrols and could only occasionally raise an antenna above the waves to determine their position.

In the 1980s the U.S. Air Force started operating the Global Positioning System (GPS), which allowed anyone equipped with a receiver to locate his or her position on Earth to within about thirty feet or less. GPS uses a constellation of twenty-four satellites that circle Earth every twelve hours. From any point on Earth, there are usually three or four GPS satellites above the horizon at any one time. A handheld receiver detects radio emissions from these satellites.

Commercial receivers are available in sporting goods stores and in many new cars. Using a special civilian GPS signal, they provide less precise location information than the military receivers but still allow a user to navigate accurately. Civilian users can locate their position on Earth to an accuracy of about thirty feet. Russia operates a system similar to GPS, but virtually every military on the planet uses the civilian GPS signal.

Accurate weather information is critical to military operations. The United States and Russia operate meteorology satellites for military use. However, since the end of the Cold War, separate military and civilian meteorology satellites have been viewed as an unnecessary expense, and the military systems have gradually been merged with their similar civilian counterparts.

Antisatellite Defense (“Star Wars“)

Antisatellite (ASAT) and missile defense (Strategic Defense Initiative [SDI] or “Star Wars“) satellites are not currently part of any nation’s arsenal. ASAT weapons are difficult to develop and operate and they have limited usefulness. It is extremely precarious to use a satellite to shoot down ballistic missiles. In the future, satellites may be used to intercept missiles, but it is unlikely that this will happen for a long time.

During the Cold War, both superpowers studied the possibility of placing nuclear weapons in orbit, but neither country did so. A bomb in orbit will spend most of its time nowhere near the target it needs to hit, unlike a missile on the ground, which will always be in range of its target. In addition, controlling a system of orbiting bombs would be difficult.

Military Role of Humans in Space

There has never been a clear military role for humans in space, despite decades of study by both superpowers. During the 1960s, the United States explored several piloted military space systems. One of these was the DynaSoar spaceplane, which was canceled in 1963 after the air force could find no clear mission for it. Another of these was the Manned Orbiting Laboratory (MOL). MOL was to carry a large reconnaissance camera, and two astronauts were to spend up to a month in orbit, photographing objects on the ground. The United States canceled MOL in 1969 after it became clear that humans were not needed for the job and robotic systems could perform the task reliably and in many cases better than humans. The Soviet Union briefly operated crewed space stations similar to MOL but abandoned these for the same reason as the United States.


Around the world, military operations are increasingly using commercial satellites to accomplish their missions. Commercial communications satellites are particularly useful and cheap. In addition, commercial reconnaissance satellites are finding many military uses, enabling countries that cannot afford their own satellites to buy photos of their adversaries.

Satellites are not required for many local military operations. But if a country is operating far from its borders or has global interests, they are a necessity. Only a few countries are willing to pay the expense of operating military space systems, but that number is growing.

see also Global Positioning System (volume 1); Military Exploration (volume 2); Military Uses of Space (volume 4); Navigation From Space (volume 1); Reconnaissance (volume 1); Satellites, Types of (volume 1).

Dwayne A. Day


Richelson, Jeffrey T. America’s Space Sentinels. Lawrence, KS: University of Kansas Press, 1999.

Spires, David. Beyond Horizons: A Half Century of Air Force Space Leadership. Colorado Springs, CO: U.S. Government Printing Office, 1998.

Space Sciences Day, Dwayne A.