Space Ionizing-Radiation Environment

The space ionizing-radiation environment is dominated by energetic, highly-penetrating ions and nuclei. These particles constitute the primary radiation hazard for both microelectronic systems and humans in space. The primary components of this environment are:

• Galactic Cosmic Rays
• Anomalous Cosmic Rays
• Solar Energetic Particles
• Geomagnetically Trapped Particles

With these varied sources, the space radiation environment is quite complex. It contains all the naturally-occurring nuclei, from protons (atomic number Z=1) to uranium (Z=92). The energy range of these combined sources extends over fifteen orders of magnitude, from less than 1 MeV (= 10⁶ eV) to more than 10²¹ eV. The intensities, energy spectra, and arrival directions also depend upon location in space. Because of this complexity, numerical models are required to provide an accurate description of this environment.