We consider the problem of data dissemination in a satellite network. In contrast to previously studied models, broadcasting is among peers, rather than client server. We introduce a cost model for data dissemination in peer to peer satellite networks. The model quantifies the tradeoff between the inconsistency of the data, and its transmission cost; the transmission cost may be given in terms of dollars, energy, or bandwidth. Using the model we first determine the parameters for which eager (i.e. consistent) replication has a lower cost than lazy (i.e. inconsistent) replication. Then we introduce a lazy broadcast policy and compare it with several naive or traditional approaches to solving the problem.