Abstract：The throughput performance degrades under high traffic loads where massive bursty users access to the satellite. A random access protocol with unequal protection was introduced. Several replicas of a packets were created and sent during different time slots according to a selected degree distribution. The access procedure could be described by a bipartite graph. By using successive interference cancellation (SIC), collided packets can be recovered instead of abandoned. In addition, a portion of time slots in the frame were exclusively for high priority users to improve the decoding performance. An analysis using standard “and-or trees” arguments was introduced. Further, our work was verified with simulations. Simulation results show that the proposed multiple access protocol with unequal protection enhances high priority users’ throughput under high traffic loads.