Low Earth Orbiter (LEO) is the orbit of low-flying, fast-orbiting telecommunications satellites that orbit the Earth in circular or elliptical orbits. The altitude of Low Earth Orbit satellites is between 700 km and 1,500 km, and the Earth orbital period is between 1.5 h and 2.5 h. An example of such a satellite constellation are the orbiting satellites in the Iridium project
initiated by Motorola. Low Earth Orbiter satellites have the advantages of shorter signal propagation times, which can be estimated at about 20 ms, and lower transmission power with which LEO satellites can be reached from Earth. A disadvantage, however, is the limited lifetime of
about 7 years.
bits Satellite services based on low-earth-orbit satellites are called LEO-SAT, and more than a dozen operators of global satellite services offer such services. In addition to voice services, data, multimedia and video services are also offered withtransmission rates of up to 64 Mbit/s.
Well-known LEO-SAT services are Iridium, Teledesic, Globalstar, Skybridge and Leosar.