What are the advantages of low earth orbit satellite system?
Low earth orbit (LEO) can have a perigee as low as 100 miles, although 200-900 mile perigees are more common. The lower the perigee, the greater the atmospheric resistance, so, unless the satellite has significant station-keeping fuel, it will have the shortest lifetime in orbit, perhaps 5 years. This orbit is best for listening to low-power transmissions aimed at the satellite or at a constellation, or for eavesdropping on low-power signals meant to stay on Earth. It also has the best view for taking detailed images of phenomena on Earth, for earth resources mapping or military reconnaissance. They are also important for communications where minimizing the round-trip speed-of-light delay to and from orbit is most important, as for satellite-based telephony. Constellations need to have tens of satellites to provide continuous Earth coverage from this orbit. Individual orbits are of short duration, typically of 90 minutes. Low Earth Orbit satellites must travel very quickly to resist th
