Space radiation health: a brief primer.

The goals of space radiation health research are to understand qualitatively and quantitatively the ionizing radiations present in the space environment, identify qualitatively and quantitatively the risks associated with these radiations, and discover countermeasures to mitigate these risks. The articles that follow address each of these three components of space radiation health research. This article introduces the basic science and definitions underlying radiation health research and protection. Space radiations consist of energetic protons from the sun, protons and electrons from the sun that are trapped in the Earth's magnetic field, and cosmic rays that include energetic nuclei of H, He, C, N, O and Fe atoms. The risks presented to space travelers by these radiations include cancer due to protons and cosmic-ray exposure, immune failure due to high-dose solar proton storms, and possible neurological effects caused by single tracks of cosmic-ray heavy nuclei. Potential countermeasures include shielding, medication consisting of radical scavengers, anti-oxidant consumption, cytokines, and cell transplants.