Health threat from cosmic rays radiation resulting from particle interactions within the vitreous humor. This phenomenon has been replicated on Earth by scientists at various institutions. As the duration of the longest Apollo flights was less than two weeks, the astronauts had limited cumulative exposures and a corresponding low risk for radiation carcinogenesis. In addition, there were only 24 such astronauts, making statistical analysis of any potential health effects problematic. In the above discussion dose equivalents is units of Sievert (Sv) are noted, however the Sv is a unit for comparing cancer risks for different types of ionizing radiation. For CNS effects absorbed doses in
Ionizing radiation nuclear transmutation and induced radioactivity. The relevant mechanisms are neutron activation, alpha absorption, and photodisintegration. A large enough number of transmutations can change macroscopic properties and cause targets to become radioactive themselves, even after the original source is removed. Ionization of molecules can lead to radiolysis (breaking chemical bonds), and formation of highly reactive free radicals. These free radicals may then react chemically with neighbouring materials even after the original radiation has stopped. (e.g., ozone cracking of polymers by ozone formed by ionization of air). Ionizing radiation can disrupt crystal lattices in metals, causing them to become amorphous, with consequent