In this letter, we consider a rate-splitting multiple access (RSMA)-based uplink satellite network and propose a dynamic power allocation and decoding order scheme depending on the channel coefficients. The exact outage probability expression of the considered system is derived for the shadowed Rician fading channel. The asymptotic outage probability expression is also obtained, and the coding gain and diversity order of the system are found. Simulation results validate the derived expressions, and it is shown that full diversity can be achieved using the proposed channel-dependent power allocation and decoding order scheme. Furthermore, the proposed scheme is compared with the conventional decoding order and power allocation schemes, and its superior performance is demonstrated.