Transportation accounts for a significant portion of the global use of fossil fuels. A possible solution implies the use of alternative fuels such as hydrogen, which does not produce CO2. This could reduce the environmental of flights by 60/70%. Hydrogen’s low density at room temperature creates the necessity for bigger tanks which critically reduces its efficiency and limits its possibilities for long range flights. A potential solution for this problem is the use of liquid hydrogen (LH2). At the same time, it implies some new challenges due to its cryogenic boiling temperature (20 K). The projects CRYFTO and OVERLEAF consider the use of advanced materials for the design of liquid hydrogen tanks. Currently, there is very scarce knowledge of composite materials behavior at Low Cryogenic Temperatures (LCT). For this reason, this study focuses on the validation process for the structural design of a LH2 tank. The research aims to establish a robust methodology applicable to similar design scenarios, where advanced materials are expected to perform under such LCT conditions. A System Decomposition approach was employed to systematically guide the validation process, starting from a comprehensive characterization campaign across a wide range of temperatures. Finite Element Analysis (FEA) played a critical role throughout this process, not only validating the structural design but also in identifying critical geometries and high-stresses areas that required further investigation. These FEA results were instrumental in tailoring the element and subsystem level tests to the specific structural characteristics of the LH2 tank, ensuring a focused and effective validation campaign. This work demonstrates a systematic approach to the structural validation of composite tanks for cryogenic applications.