Improvements in radiation shielding materials are needed to support NASA's human and robotic exploration programs. Shielding for both electromagnetic radiation (gamma and x-rays) and particles (protons and neutrons) are critical. Ideally, the shielding should be part of a multifunctional, structural composite material to maximize mission payload. To meet this need, ASI will develop structural composites enhanced by novel carbon nanofiber (CNF) materials. One version is CNF whose hollow cores are filled with heavy elements for electromagnetic by a novel intercalation technique. Another is hydrogenated CNF for particle shielding. The enhanced CNF will then be included in the resin of a standard carbon fiber reinforced structural composites where they will add radiation blocking functionality and enhance strength properties. In addition, the intercalated nanofibers will be compounded into polyethylene, a known proton absorber, to create a shielding material that simultaneously blocks all relevant forms of radiation. Materials will be tested for gamma, x-ray, and proton shielding, as well as multifunctional structural and electrical properties.