Some of the Many Uses of Satellites Today

Michael H. / Physics 336 / 7 April 1997
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Sometimes an object you come across can have many different uses for many different people. The same holds true for satellites. For many different companies use them for many different purposes and reasons. For instance, you can use a satellite for communications, observation, and navigation just to name a few.

Purpose of Unmanned Satellites

Unmanned satellites have six primary functions. First, to investigate the characteristics of the upper atmosphere as well as the exosphere. Second, to study the nature of the earth's space including energetic particles, interplanetary matter, and electromagnetic radiation. Third, to study celestial objects from a vantage point beyond the atmosphere. Forth, to carry out biological experiments. Fifth, to perform non-scientific tasks in applied technology. Such as communications, observation, and navigation. And lastly they are used in support of manned operations. The functions listed here are the satellites primary functions, not their only functions.


One use of satellites is in the field of communications. Communications is a wide topic. It includes television, phones (cellular as well as others), the Internet, beepers, etc.. So, how do satellites work in these devices? Well, lets take television first. By using a satellite dish and a satellite television network, a satellite can beam down as many as 200 crisp, clear channels with CD quality sound. The use of satellites with the Internet would make access faster and cheaper. This would allow consumers to link their home computers to the Internet. The special two-way satellite connections promise fiber-optic-like speeds. And now there are plans to combine satellite television and the Internet into a single dish. On to the phones. The phones that will use satellites are called Globo-Phones. They are expected to come as early as 1998. These phones will provide global hand-held wireless service. Which will provide executives with a cellular-like phone that they could take anywhere they travel. Recently, the company Motorola has released a plan consisting of a network of 72 low-orbit satellites to provide businesses with broad bandwidth communication links around the globe.


Another use of satellites is in the field of observation. Like communications, observation is another wide topic because there are many different types and uses. For instance, one type of observation is espionage or what is commonly called the "spy" business. Between the years 1960 and 1972, 95 Corona satellites conducted espionage successfully. Another area would be geology, or the study (observation) of the earth. Satellites are used by the United States Geological Survey to take extensive photographs of the country. Satellites also allow geologists to make long-duration measurements over many different latitudes and longitudes. They (geologists) also use satellites to monitor natural phenomena, such as clouds, glaciers, sea ice, deserts, and tropical rain forests. The geologists use this information gathered by the satellites to collect clues about long-term global climatic change and ecological threats.


A third use of satellites is in the field of navigation. Like communications and observations, navigation is a large topic because of the many different kinds of transportation. One form of transportation is via automobile or car. The automobile satellite navigation system, called the Guidstar Global Positioning Satellite (GPS) system. This system keeps an eye on you by taking signals from four satellites to triangulate (a process to determine where you are) your position. Next it compares the information from the satellites with directional signals from a car-mounted gyroscope and the odometer. Then it plots all the information gathered against a map encoded on a computer disk in the trunk. Under the automobile category, the National Highway Safety Administration announced a two-year study of an in-vehicle unit that would log on to the Defense Department's 24 global positioning satellites and automatically alert emergency medical services and give then the place and location when a severe accident occurs. The system would be able to differentiate between a fender-bender and a serious accident. Another area would be aerial transportation. In this area satellites are used with the landing systems. One type is the microwave landing system, which uses microwave signals to help land the plane. However, this type of landing system is expensive. Another type of landing system uses the global positioning satellite system. This system is used in poor visibility landings and is inexpensive. The microwave and GPS systems are expected to replace ground based navigational systems.


Satellites have many different uses and purposes for many different people. They are used in the fields of communications, in the areas of television, the Internet, and phones; observation, in the areas of espionage, and geology; and navigation, in the area of transportation as well as many topics and sub-topics.


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