Explanation:

 LEO- Low Earth Orbit
With Low Earth Orbit extending from 200 km to 1200 km it means that it is relatively low in altitude, although well above
anything that a conventional aircraft can reach. However LEO is still very close to the Earth, especially when compared to other
forms of satellite orbit including geostationary orbit.
LEO characteristics
• Orbit times are much less than for many other forms of orbit.
• Less energy is expended placing the satellites in LEO than higher orbits.
• The lower orbit means the satellite and user are closer together and therefore path losses a less than for other orbits such as
GEO.
• LEO satellites have shorter life spans than others
• Some speed reduction may be experienced as a result of friction from the low, but measurable levels of gasses, especially at
lower altitudes.
• Radiation levels are lower than experienced at higher altitudes.
Applications for LEO satellites
A variety of different types of satellite use the LEO orbit levels. These include different types and applications including:
• Communications satellites - some communications satellites including the Iridium phone system use LEO.
• Earth monitoring satellites use LEO as they are able to see the surface of the Earth more clearly as they are not so far
away. They are also able to traverse the surface of the Earth.
• The International Space Station is in an LEO that varies between 320 km (199 miles) and 400 km (249 miles) above the
Earth's surface.
Space debris in LEO
• Apart from the general congestion experienced in Low Earth Orbit, the situation is made much worse by the general level of
space debris that exists.
• There is a real and growing risk of collision and major damage - any collisions themselves are likely to create further space
debris.
Medium Earth Orbits-MEO
• They are in between LEO and GEO orbits. Operate about 8000-20000km above the earth that is lower than GEO and higher
than LEO.
• Basically used for navigation satellites
• They are placed in an elliptical orbit.
• Examples include GPS and Global Communication and Orblink