Interplanetary communication networks operate in harsh environments where space protocols must deal with huge propagation delays, scanty resources, and regular link disrup- tions. The Licklider Transmission Protocol (LTP) serves as a convergence layer for the transmission of bundles in the form of data blocks, and offers reliable delivery through segment retransmissions. To prevent waste of resources, LTP can stop a block transmission at either side of a communication after a certain number of timeout events or control segment transmis- sions. We analyze the method employed in the current reference implementation of LTP that sets values for these parameters and suggest an alternative method that provides enhanced control over the expected block loss ratio. Simulation results provide evidence of the efficacy of the proposed approach. Outputs of this research potentially benefit the performance of space networks and challenged terrestrial networks.