1. A method of mitigating interference occurring between two different communications systems, each system comprising a constellation of communications satellites orbiting the earth, said satellites each comprising a satellite antenna for transmitting and receiving information, and a plurality of earth-based stations, each of said earth-based stations comprising at least one earth-based antenna for transmitting information to and receiving information from one or more of said satellites, said satellite and earth-based antennas transmitting information utilizing the same frequency spectrum, said method comprising the steps of: (a) positioning satellites of a first communications system relative to satellites of a different communications system, said satellites of said first communications system being positioned at altitudes above the earth, said altitudes being determined to provide sufficient spatial diversity to minimize interference from adjacent satellites of said different communications system; and (b) positioning said satellites of said first communications system relative to said satellites of said different communications system, said satellites of said first communications system being positioned at orbital inclinations with respect to the earth's equator, said orbital inclinations being determined to provide sufficient spatial diversity to minimize interference from adjacent satellites of said different communications system.