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What do satellites do?
"Natural Satellites" Circle around larger, more massive objects (the Earth is technically a satellite of the Sun, and the Moon is a natural satellite of the Earth). Artificial… Satellites Satellites orbit the Earth to provide links between places on the planet (TV, phone, internet) and to study the Earth and space. They provide information to the military, to weather forecasting, to geologists, and more. The orbiting space telescopes examine other planets and stars. Satellites orbit in a variety of directions, but most circle west-tp-east at various heights above the Earth's atmosphere. Geostationary satellites seem to stay in one place, but they only in very high orbits. Geosynchronous satellites orbit exactly once a day, so they stay over the same location on the ground. (see related question) Communications - This includes television, phones (cellular as well as others), and internet. Satellite television providers, for example, broadcast a one-way signal with audio and video programming to their customers. This is of great use for customers who are in areas too remote to use cable or other wired means, or for mobile users in vehicles and boats. Customers simply tune their in-home receivers to the sub-channel they desire and watch digital programming direct from space. Earth Observation and Surveillance - Military reconnaissance satellites and civilian mapping satellites use high-resolution cameras to take photos of the earth's surface for mapping or intelligence purposes. Further, these cameras are not limited to the visible light spectrum, and so some are dedicated to infrared or ultraviolet sensing, which are used by environmental researchers and agriculturists; this can help them determine the temperature, quantity of foliage, chemical composition of the air in different locales, changing height of the polar ice caps, shoreline erosion, or mapping of warm and cold ocean currents. Other uses include popular web applications, surveying, real-time weather observation, and natural resource detection and management. Navigation - Global Positioning System (GPS) satellites function by emitting a specific signal pattern. Variations in this signal can be detected by GPS receivers to determine a GPS user's location relative to the satellite by using a principle called the Doppler Effect. The Doppler effect is the apparent compression or decompression of signals that occurs when the signal source is in motion, relative to a listener, for example, why a train whistle changes pitch when it approaches or departs from the listener. By calculating the amount of compression in the signals for multiple satellites, a GPS receiver can pinpoint the user's location. Because of the large distance between satellites, distances from Earth to distant stars and planets can be determined more accurately (greater parallax). Also, on board cameras can better view objects on Earth in 3 dimensions. There are many purposes for placing satellites in orbit. First and foremost, communications satellites exploit their great distance from the earth to transmit their signals the greatest distance possible. Many modes of communication, chief among them microwave, travel by 'line of sight,' meaning that one must be in a direct, unobstructed sight line in order to receive a signal. The earliest communications satellite received and relayed microwave communications from large ground stations. Today, we have technology to communicate directly through such satellites using satellite phones. Satellite communication permits direct communication beyond the horizon that might not otherwise be possible with conventional VHF (Very High Frequency) communication (ie, radio). Still other satellites are used for assorted experimental purposes, exploiting the lack of vibration, low temperature and low gravity of space as an ideal location for extremely sensitive instruments, such as the Hubble Space telescope and similar projects, which are able to see much deeper and more clearly into the cosmos without having to look through the earth's atmosphere first. A special category of satellite is one that is manned, such as the International Space Station (ISS), and they are used for exploration and research into the effects of long-term low gravity, international cooperation and the promotion of peace, among other purposes. Communication satellites can be used to send telephone messages or TV pictures. A satellite can be used for working out what the weather will be like in a few days. It has a sensor which send a television call to earth telling us what's going to happen. They can also be used for spying and navigation and they can spot forest fires and water pollution. 1st letter is S and ends with E! it transmits radio/ televideo/etc. waves It helps us by like if we atrapped some where and u have afone on u u can call 911 or someone who willhelp u They are used for exploring different planets in our solar system, transmitting radio, telephone, and television signals, and to tell what the weather is going to be like. many sencitest send artifical satalites some revolving around the earth. it is used dish antena The primary uses for an artificial satellite, given our current technology, are: Communication (television and cell phone satellites)Observation (the Hubble Space Telescope, weather satellites, )Location (the GPS system)Habitation (Skylab, Mir, the International Space Station) As our technology continues to expand, it's likely that uses for artificial satellites will as well. For example, a military satellite might provide a way to defend specific nations, or even the Earth as a whole (from a meteor strike, for example). Or, as seen on sci-fi TV shows, a space dock could allow the repair and refueling of space vehicles, without the need to return to our planet's surface. There could eventually be space hotels, low- and zero-gravity tourist attractions, zero-gee factories, controlled-gravity hospitals... The list is bounded only by our imagination, and economic considerations. (MORE)
