Future NASA missions will rely on the use of composite structures as main structural members of space vehicles and composite overwrapped pressure vessels (COPVs) for spaceflight propellant tanks to store fuels, oxidizers, and other liquids for launch and space exploration vehicles. These COPVs must be able to operate at the cryogenic conditions imposed by typical propellants, liquid oxygen (90°K) and liquid methane (110°K). NASA applications for the research proposed herein include: earth-based and space-based cryogenic storage vessels (e.g. cryogenic fuel storage for first stage and upper stage launch vehicles including Crew Exploration Vehicles); long system life cryogenic storage that is both reliable and safe and would perform well beyond the current vessel design life (e.g. orbiting space fuel depots); and space-based habitat structures that are manufactured using fiber-reinforced composite materials. The aerospace and the commercial communities have shown significant interest in using COPVs for cryogenic and non-cryogenic applications. Non-NASA commercial applications for the research proposed include the following: Liquid hydrogen fuel cells in terms of increased safety and reliability; vehicular cryo-compressed gas storage of hydrogen and natural gas which dramatically increases the fuel storage density thus increasing the amount of fuel that can be stored in a vehicle; environmentally-friendly and safer earth-based cryogenic fluid storage where the composite structures will not need painting, stripping, and repainting in order to prevent corrosion as does current metal/steel construction and are also easier to transport due to their light-weight nature; and interest in the marine transport of propane via tanker ships where very large (5300 m3) COPVs will be needed.