Remote Sensing and GeosynchronousOrbitSatellites, since theirinception, have been one of the greatest boons to mankind. Hundreds ofsatellites circle the earth, all with very different missions. A satellite’smission determines a great deal about it, its orbit for example.
The correctpositioning of a satellite in space is paramount for mission success. Ageosynchronous orbit is an example of where one might place a satellite toachieve a specific goal. This orbit was popularized by Arthur Clarke in 1945,it revolutionized how satellites are positioned to better collect anddistribute data. While Clarke focused on this orbit for communications it isalso useful for remote sensing. Whatis Remote Sensing?Remote sensing isgathering information without making physical contact with that object.Detecting the energy reflected from Earth is how most sensors gatherinformation. Aircraft and satellites are the main vehicles used to conductremote sensing.
There are two types of remote sensors: active and passive.Active sensors will project something, such as a laser, onto the earth and thenrecord how much time it takes to return to the sensor. A passive sensor willcollect data based on outside stimuli, such as radiation from the sun. Remotesensing is used for many reasons: terrain mapping, tracking weather, observingpatterns in wildlife, monitoring land use, and many other types of observation.
1 GeosynchronousOrbitMost remote sensingsatellites reside in geosynchronous orbit also called GEO orbit. This orbit isideal for telecommunications, monitoring weather patterns, and continuousobservation over a given area. To achieve geosynchronous orbit a satellite willorbit the earth at a distance of 35,786 kilometers and have a speed of aboutthree kilometers per second. At this altitude and speed its orbit will take 24hours to complete matching that of the earth’s rotation making the satelliteappear to be stationary.
2 A geosynchronous orbit isadvantageous for a number of reasons. One reason is the amount of groundcoverage achieved; over 40 percent of the equatorial plane is covered by onesatellite. This means that only three satellites are needed to provide fullcoverage of the planet, with the exception of the poles. Ground stationsbenefit from this orbit as well; not having to track a moving object reducescosts. Currently, 402 satellites reside in geosynchronous orbit, a testament tohow useful this orbit for different satellite operations.3 One satellite that utilizes GEO is theGeostationary Operational Environmental Satellite Program (GOES).
GOES is aconstellation of satellites used by NASA and the NOAA for the remote sensing ofweather patterns. GOES sensors provide worldwide coverage to aid meteorologistsin predicting local weather such as: hurricanes, tornadoes, dust storms,volcanoes and many other weather phenomena. GOES can monitor solar activity aswell, enabling scientists to predict space weather as well as terrestrial.While the GEO orbit is incredibly useful for remote sensing it can greatlyimprove communications as well.4 Communicationssatellites are used for common daily activities such as television and radio orthey can be used for military purposes. If the military wants to observe anarea of the world a satellite in GEO can take constant pictures and collectother data on a particular region, or be used for global communications. Wideband Global SATCOM (WGS-5) is one example of a communicationssatellite used to benefit the military. WGS-5 launched in 2013, it is the fifthsatellite in a constellation that provides the military a protected widebandcommunication network.
These five satellites in GEO allow the military to havefocused coverage of a particular region of the world; WGS-1 covers the Pacific,WGS-2 covers the Middle East, 3 covers Europe and Africa, 4 looks at SoutheastAsia, and 5 will be used to cover the United States. The WGS constellation isjust one example of a satellite based in GEO that benefits us.5Using geosynchronous orbitfor communications and remote sensing has benefited all of mankind. This orbit changedthe way we focus satellites for data collection and distribution. The way we predictweather and map the surface of the Earth has been revolutionized by remote sensingGEO satellites. Arthur Clarke made an observation that changed how we position satellitesin space to maximize their capabilities. Satellites continue to be launched intoGEO, some for communications, others for remote sensing, making it one of Earth’smost popular orbits. 1.
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5.Ray, Justin. “Powerful New US Military Satellite Launches IntoOrbit.” Space.
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