The International Space Station radiation design environment

Abstract

The change in orbital inclination from 28.5° to 51.6° which accompanied the transition from Space Station Freedom to International Space Station (ISS) changed the Space Station natural radiation environment. At the new inclination of 51.6°, ISS suffers increased exposure to cosmic rays produced during solar flares. The ISS altitude range of 350 to 460 km is the same as for Space Station Freedom. At these altitudes, the ionizing radiation environment consists primarily of geomagnetically trapped protons and electrons and galactic and anomalous cosmic rays. For Space Station design purposes, this ionizing radiation environment is defined for two types of hardware susceptibilities, absorbed dose effects and single event effects (SEE). The ISS radiation environment is not intended as an exact representation of the natural environment which Space Station will experience. Instead, it represents a credible worst case design environment which is specific and quantifiable for design verification.