HyPerComp Engineering, Inc. (HEI) proposes to continue the characterization of the cryogenic evaluation of irradiated composite materials for use in composite overwrap pressure vessels COPVs. The intent of the proposed effort is to study the constituent raw composite material properties that result from radiation exposure and tested at cryogenic temperatures. HEI and Mississippi State University (MSU) have recently completed a Phase I STTR (contract #NNM05AA61C) through NASA/MSFC. The intent of this effort is to further the development of that key building block technology for lightweight composite structures suitable for cryogenic fuel storage or human in-space habitats. This effort will incorporate and expand previous work by the participants in the cryogenic performance of composite materials exposed to radiation environments.