Stationkeeping of a constellation of geostationary communications satellites

Three possibilities are examined for increasing the number of direct broadcast satellites in one geostationary orbital location. Six satellites could be maintained within one overall allocation of 0.6 deg total width in longitude and 0.2 deg latitude by dividing it into sub-boxes. The single-satellite sub-box scenario is contrasted with plans for sub-boxes containing two and three satellites. For multiple-satellite sub-boxes, careful phasing of the eccentricity and inclination vectors of the spacecraft is used to guarantee separation in two directions. This latter method is more efficient than the single-satellite sub-box in terms of East-West stationkeeping velocity requirements. The three-satellite sub-box is most efficient, and provides more separation than does the plan for two satellites. A stationkeeping schedule is given which avoids simultaneous maneuvers on satellites within the sub-box.