Radiation risks from space

Radiation from space has many influences on human life, of course in space but also on Earth. This chapter describes the particular structure of the radiation field which consists - contrary to the terrestrial situation - mainly of charged nuclei from protons to nickel nuclei. Their interaction with the Earth's environment is discussed. Understanding the health risks originating from space radiation presents a challenge to biophysical research, some of the current approaches are outlined. Quantitative risk assessment for humans is still very difficult as epidemiological data are riot available for the action of charged particles. The concepts used are based on radiation protection systematics which are described.