Several allocation strategies are investigated for sharing the satellite capacity among user communities requiring circuit-switched or store-and-forward (message-switched) communication service. Teletraffic and queueing models are used to obtain analytical results by which the allocation strategies are compared. It is shown that the capacity required to provide a specified grade of service is strongly dependent upon the particular allocation strategy chosen. Therefore, an allocation strategy can be selected which requires less capacity and hence provides more efficient utilization of the satellite capacity for a specified grade of service.