- Historical Background (Geostationary, LEO, MEO, HEO Orbits 4/7/2002)
- Usage of GEO satellites
- Communication Satellite
There are more than 100 communication satellites orbiting Earth. It acts as a relay station in space. People use them to bounce messages from one part of the world to another. It takes the voice communications that long to travel all the way up to the satellite and back to Earth. These messages can be telephone calls, television pictures and Internet. Communication satellites such as the EchoStar 3 move in a geosynchronous orbit (TheTech 30/3/2002).
Pic 2: EchoStar 3 (TheTech 30/3/2002)
- Weather Satellite
Weather satellites are used for earth observation purpose (remote sensing system). Before the advent of GEO satellite technology, all weather predictions were base on information from ground reporting system, reports from pilots of aircrafts and from ships at sea, and from high altitude balloons. Satellite images showing the advance of weather fronts are regular elements of the evening news. This meteorological information is also available to anyone with a persona computer and relatively inexpensive hardware and software. In addition to weather, a network of American, European, Japanese and Russian satellites orbits the Earth in various configurations to purpose “real-time” monitoring of our environment. Usage of GEO imaging satellites for civilian purposes and scientific research include monitoring of ocean temperature, rainfall amounts, desert encroachment, rainforest disappearance, air quality levels, updated maps and daily weather reports (Geostationary, LEO, MEO, HEO Orbits 4/7/2002).
- Advantages and Disadvantages of GEO satellite
GEO are positioned at a high altitude in the spatial resolution of their images (typically 2.5km per pixel). It tends to be not good as some polar orbiting satellites (typically 1 km to 50m per pixel), which are much closer to the Earth. However, GEO have an advantage of their height. It can view the whole earth disk below them rather than a small subsection. They can scan the same area very frequently (about 30-60 minutes). This makes them ideal as weather satellites. It also brings the world closer to one another through communication and television. These satellites can also be used to predict natural disasters.
Since GEO satellites are always positioned above the equator, they cannot see the north or south poles and are of limited use for latitudes greater than 60-70 degrees north and south. The further it is from the equator, the lower the spatial resolution of each pixel and the greater the possibility of being hidden by the Earth’s curvature. So, the satellite would provide less information such as temperature and wind speed nearer to the north and south poles. GEO satellites in the highest orbits are susceptible to burst of high-energy particles that are infrequently emitted from he sun. These particles may cause memory upsets, dielectric charging and radiation damage to the components. This can result in operational glitches, degradation of service or in extreme cases, loss of the satellite (Dundee Satellite Receiving Station Geostationary Satellites 4/7/2002)
In conclusion, the GEO satellite plays an important part in our lives. It helps us to communicate and to predict the weather. It is important to know how the satellite works as it saves our time, our lives, provide us with important information and for entertainment purposes.
1) TheTech, 30/3/2002
2) Dundee Satellite Receiving Station 4/7/2002
3) Introduction to Satellites and Orbits 4/7/2002
4) Geostationary, LEO, MEO, HEO Orbits 4/7/2002
Conclusion for the whole thing
There are 3 main types of satellites, which are the LEO satellites, GEO satellites, and polar orbiting satellites. With these satellites, communication, entertainment, information, weather forecast, prediction of natural disasters, rescues and many more benefits can be easily obtained.