When we see satellites on the ground, they tend to look very similar – simple shiny boxes or cylinder shapes with solar panel wings attached. However, out in orbit, these machines come into their own – behaving very differently depending on their chosen flight path, altitude, and location.
Separating satellites into classes, therefore, is no easy task. One way to classify them is to look at how they orbit the Earth. There are two types of orbit – elliptical and circular. Some satellites start out on an elliptical orbit and then after some nudging from small rockets, will change to a circular orbit. Other satellites move in a permanent elliptical orbit, known as Molniya orbits. These orbits are normally north to south, traveling over the Earth’s poles and complete the orbit in around 12 minutes.
Satellites that pass over the Earth’s poles do so on each rotation and much of the Earth is covered during a polar orbit. For this reason, they are often used as mapping and photography satellites. Weather forecasting services also rely on a global network of polar satellites as they cover the whole globe every 12 hours.
Satellites can also be categorized in terms of their distance from Earth. There are three main types:
Low-Earth Orbits (LEO) – these sit in an area of space which lies about 111 to 1,243 miles above our planet. These low satellites are perfect for observation, military uses and gathering weather data.
Geosynchronous Orbits (GEO) – these satellites travel around the Earth at a higher altitude of above 22,223 miles and the period of orbit takes 24 hours. Also, in this class are geostationary satellites which remain in a fixed location above Earth. Some GEO satellites follow an elliptical orbit, drifting east and west over a fixed point during the period of a full orbit. Some satellites don’t have an orbit that aligns with the equator, taking it north and south as well. These satellites are often used for communications, television and weather forecasting.
Medium-Earth Orbits (MEO) — as the name suggests, these satellites sit between the GEO and the LEO. These satellites are used for navigation, such as that which you find in your car’s GPS. For more information on the benefits of Vehicle Tracking, visit https://www.vehicle-accessories.net/vehicle-tracking/
Satellites can also be thought of in terms of what they are looking at. The majority of satellites sent into orbit in the last few decades have been looking down towards our planet. As such, they are fitted with cameras and lightwave technology. They are able to see the world through different wavelengths of light, including ultraviolet and infrared. This has provided us with cutting edge views of our changing planet. Nowadays, a small number are looking out into space, capturing images of planets, galaxies and faraway stars, continually scanning for comets or asteroids that could be on our way to collide with Earth!
