Carbon Radiation Shielding for the Habot Mobile Lunar Base

Abstract

Radiation is the leading showstopper for long duration human exploration of the lunar surface. The need for an effective and safe radiation shielding material has become the "Holy Grail" of radiation protection research. This paper reports the results for one material in particular-carbon-in the "Bioshield" particle accelerator test of candidate radiation shielding at Brookhaven National Laboratory, sponsored jointly by NASA and the Italian Space Agency. Shielding samples were bombarded by both Iron and Titanium nuclei beams at1 GeV/n relativistic energy. This paper reports the results for Fe. The target behind the shielding was a lymphocyte culture; created using advanced cytogenetic techniques (premature chromosome condensation and fluorescence in situ hybridization). The shielding samples included aluminum, PMMA acrylic/Lucite, polyethylene, and lead. The Habot Mobile Lunar Base Project at NASA-Ames Research Center provided the carbon-shielding sample because of its potential to provide a suitable shielding material to apply to the exterior of the Habot. The specific material tested is "CCAT CC-1, Carbon-filled carbon." This particular formulation has the advantage that the manufacturer controls the density to .01 g/cm 3. The density of this sample is 1.65 gm/cm 3. The carbonfilled carbon performed successfully, providing the second best dose reduction after polyethylene and the best overall reduction in radiobiological damage to the lymphocyte culture. This experiment suggests that carbon composites present important advantages for space habitat construction.