New developments of space launch systems often rely heavily on proven technologies from the last seven decades. One reason for this are the enormous development costs and the relatively small production quantities over which these investments must amortize themselves to be economically viable. Another reason is the customer’s trust in proven technologies and a restraint attitude towards new technologies. After all, the safe transportation of payloads that cost billions of dollars is at stake. To support new development processes and to study different geometry concepts for cryogenic launcher stages, this work presents a coupled method based on thermodynamic mission analysis and structural optimization. From the thermodynamic simulations, the thermodynamic state of the propellant, evaporation rates, pressure changes, and propellant residuals can be derived for an entire mission scenario. For a given tank geometry and the expected loads during the mission, the structural optimization tool calculates a mass-optimal solution for a variety of stiffening concepts and wall thicknesses. Coupling of both methods and the overarching global optimization of specific sets of parameters opens new possibilities to evaluate the qualification of different tank concepts for a specific mission profile. Parameter studies for targeted analyses of component properties, tracking, and manipulation of heat flows with insulation materials are just a few features. Low computational requirements as well as easy parallelization of the convoluted optimization loops allow time-efficient analyses of a wide range of parameters and allow for the search of global optima. The obtained solutions form the base for subsequent development steps. The applicability of the presented methods is illustrated with two tank concepts, a solution with two separate tanks and a combined tank with a common bulkhead for separation of propellant and oxidizer compartment, and their optimizations for an Ariane 6 upper stage equivalent mission to the geostationary Earth orbit. Assets and drawbacks of both tank concepts are evaluated, the properties of a sandwich common bulkhead investigated, and the technology put to the test.    «

New developments of space launch systems often rely heavily on proven technologies from the last seven decades. One reason for this are the enormous development costs and the relatively small production quantities over which these investments must amortize themselves to be economically viable. Another reason is the customer’s trust in proven technologies and a restraint attitude towards new technologies. After all, the safe transportation of payloads that cost billions of dollars is at stake. To...    »