Efficient Spacing of Synchronous Communication Satellites

Abstract

Satellites in equatorial circular synchronous orbit remain fixed with respect to an observer on the earth, while those in a circular synchronous orbit inclined with respect to the equator appear to move in a figure 8. A number of satellites can move on a given 8. Optimum packing for a single 8 is determined; the number of satellites per 8 increases as the 8 becomes larger and as the allowable closest approach between satellites decreases. Several packing schemes using multiple 8's, regularly spaced, are presented. For potential systems using frequencies above 12 GHz, with perhaps 1° closest approach between satellites, the best scheme described here permits approximately six times as many satellites as an equatorial system. An illustrative system serving North America has space for a total of 477 satellites, compared with 95 satellites if only equatorial orbits are allowed.