Dynamics of a Multiple Set of Low Orbiting Satellites

There is a growing interest in the use of multiple network of low orbiting satellites for communications and other applications. Unlike the geosynchronous satellites, these will be continuously in motion relative to earth stations. Ideal operation thus will require a deployment that ensures a continuous presence of an average number of satellites over an earth station, achieved by regular replacement of the outgoing satellites in view over the station by an equivalent group of incoming ones. This type of network of satellites requires a systematic selection of the orbital elements taking into account the constraints imposed by the available launch facilities and other resources. Available launch facilities constrain the possible range of orbital inclination selection. The number of planes at each inclination and the mean anomaly distribution remain free parameters for appropriate optimal selection. Sign ficant role is played by the distribution of the available number of satellites among the selected inclinations. Optimum assignment has to take into account the total earth coverage provided by orbits with specific inclinations. A simulation study has been carried out at Contel Spacecom to examine the various orbital deployment schemes taking account of the constraints involved. Results of the simulation study lead to useful practical conclusions pertaining to launch requirements for such a system of satellites as well as the estimates of the earth station to satellite and inter-satellite physical connectivity.