Biological Effects of Cosmic Radiation in Low-Earth Orbit

Space exploration poses health hazards to the crews of manned missions. Exposure to cosmic radiation and loss of bone density are considered the two most important risk factors for long-term missions. Stochastic risk deriving from cosmic radiation exposure can be estimated by physical dosimeters, using appropriate conversion factors. Recent measurements of space radiation fluence and energy spectra will improve current estimates. Biological dosimetry can be used as a tool to determine the risk directly from biological damage. Chromosomal aberrations in astronauts' peripheral blood lymphocytes have been used as a biomarker of cancer risk. In this paper we will also discuss countermeasures to radiation damage, focusing on the problem of shielding in space.