The intent of this proposal is to develop key building block technology for lightweight composite structures suitable for cryogenic fuel depot storage as well as human in-space habitat. The effort will incorporate and expand on previous work by the participants in the cryogenic performance of composite materials as well as improved impact technologies for micro-meteor/space debris survivability. It will then develop radiation resistant capabilities. In order to develop reliable composite structures for use as cryogenic fuel storage, human habitation, or other mission critical application a solid understanding of constituent material environmental capabilities is required. While good progress has been made in expanding the knowledge of how composite fibers and matrix systems (resins) react to loads and strains at extremely cold temperatures little to no effort has been made to incorporate radiation exposure such as would be encountered with in-space fuel storage depots. With a view to developing dual-use lightweight composite structures the proposed effort will develop improved composite material resistance to the harsh radiation environment a spacecraft would be expected to encounter during the life of its mission. Our intent is to develop robust light weight composite structures which are cryogenic capable as well as impact and radiation resistant.