The Netherlands Aerospace Centre (NLR) together with Toray Advanced Composites and 12 other parties take part in the Netherlands liquid hydrogen (LH2) composite tank consortium which is funded by the Netherlands research & development mobility (RDM) Fund. The goal of the RDM project NLR takes part in is to develop a long-life, fully composite LH2 tank for civil aviation. Microcracking and the subsequent hydrogen permeation remain the biggest challenges. This study encompasses three fundamental facets to test and select composite materials: a comprehensive investigation into material behavior, the formulation of a Finite Element Method (FEM) model, and a partial experimental verification of said FEM model. The latter integral component involves an extensive testing system that includes room temperature and cryogenic tensile tests, permeability assessments, and microcrack evaluations facilitated by optical microscopy. During the experiments there is focussed on the critical microcrack density and material selection criteria such as ply thickness.