[3]

RADIATION DOSIMETRY AND DOSES FROM SPACE RADIATION. WHAT DOES IT MEAN?  F. A. Cucinotta, H. Wu, M. Shavers, and K. George, NASA Lyndon B. Johnson Space Center, Houston TX

    A complicated mixture of high-energy protons and heavy ions, and secondary radiations produced by them, bombards astronauts during space travel. Developing a useful physical parameter to characterize the outcome of such exposures has been and remains a complicated problem because of lack of knowledge of the biological effects of heavy particles. We present an overview of past space measurements of radiation exposure including measurements of absorbed dose, linear energy transfer (LET) spectra, dose equivalent, or charge and energy spectra of particles.  Expectations for future space exploration missions are also discussed.  The approach used by NASA to answer problems related to space radiation risks is to pursue radiobiological research for understanding and mitigating potential health risks. One area of research has been in the development of models of radiation track structure, which provide a description of energy deposition events in biomolecules, cells, or tissues. We discuss progress in the biophysical description of heavy particle tracks that have direct application to the interpretation of space radiation dosimetry.