Radiation-Hardened Composites for Space Applications

Physical Sciences, Inc. (PSI) and our subcontractor Textron Systems Division (TSD) propose to develop multifunctional, compact (thin), yet low-mass, composites for applications to space systems on small satellites. In addition to providing mechanical strength for structural enclosures, these materials will be significantly more effective in shielding against ionizing space radiation than traditional composites on a unit volume basis and traditional metals on a unit mass basis. Starting with graphite-epoxy composite as the baseline (control) material, our idea is to embed into the epoxy powders of materials which efficiently increase the attenuation (scattering and absorption) of protons and electrons. For EMI shielding, we will consider high electrical conductance metal foils (or vapor deposits) on the inner face of the composite panel. The outer, space-exposed face of the panel, coated with proper surface treatments, will provide thermal control as well as protection against atomic oxygen. Phase I program will include stopping power calculations for representative embedded composites, and for selected cases, Monte-Carlo modeling of proton an electron scattering to determine their radiation absorption characteristics. We will process and fabricate of samples of radiation-hardened composites; measure proton beam attenuation through the samples at the Harvard Cyclotron Laboratory, and conduct preliminary high frequency EMI attenuation testing.| Benefits: Compare, low mass radiation hardened shields, made of high strength-to-weight ratio composites, have wide application as structural enclosures for spacecraft and payload systems on military and commercial satellites, resulting in substantial reductions in total spacecraft weight. The technology can be directly and effectively adapted to commercial applications which require shielding against neutrons, e.g. hazardous nuclear environments.|