US and Soviet Union Military Satellites
by Jeanette CainMore articles in Satellites
The earliest satellites were made for the armed forces of the United States and Soviet Union military forces, which are still in use today. The armed forces use these orbiting satellites to research battlefield information, locate known or missing troops, ensure communication, and take pictures. There are certain satellites that keep watch on signs of a possible potential nuclear missile and a nuclear explosion.
The DSP, which stands for Defense Support Program, satellites have been in GEO orbits since the 1970's. These satellites monitor the Earth's surface using sensors for detection of ballistic missiles. Any ballistic missile will be detected within seconds, which has greatly reduced the chances of a surprise attack by an enemy. The ability to detect the missiles so quickly provides enough time for a retaliatory strike.
Spy satellites are owned by several nations. The French Helios satellite can see an object as small as a bike on Earth's surface. For the most part, military satellite functions are not well-known, since they would not be spy satellites if everyone knew their capabilities. A 10 year program was started by the United States Government in the latter years of 1990 to replace DSP satellites with the SBIRS, Space-Based Infrared System. This fleet of satellites will have sensors capable of detecting missile launches and will provide recon information.
The first SBIRS is scheduled to be launched into geostationary and elliptical orbits by the United States Defense Department. The low-Earth orbit satellites will work with satellites in the higher orbit to improve missile warnings. The band frequencies used fall within the infrared and visible radiation areas of the spectrum.
GPS, Global Positioning System is popular for commercial usage. It's original function was to be used for the United States Military. The GPS has served, and still does, as a search and rescue satellite for troops in battle. A hand-held device will receive a signal from each of the four GPS satellites, allowing people to find their surface position to within an accuracy of a few meters. The signals relay latitude, longitude, and altitude. In 1991, during the Gulf War, the GPS satellites aided in the search for Allied troops making their way across the Arabian desert. US Air Force Captain Scott O'Grady was shot down by Serbian forces over Bosnia in 1995. Using the GPS receiver, Captain O'Grady was able to figure out his ground position and signal the coordinates. The signals were picked up by F16 planes flying overhead, and Captain O'Grady was then rescued by the Marines.
One of the most important functions of military satellites is to provide reliable and secure communication links. The Armed forces need safe links to communicate with ships, aircraft, and mobile receivers on the land surface. The majority of the time these links are quiet, but during training exercises and battles the traffic will be heavy. Military satellites differ from commercial satellites in one respect: military communication satellites have periods of less activity than the commercial satellites that need to carry a continuous string of high volume traffic.
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