Spaceflight radiation carcinogenesis Spaceflight radiation carcinogenesis Astronauts are exposed to approximately 50-2,000 millisieverts (mSv) while on six-month-duration missions to the International Space Station (ISS), the Moon and beyond. The risk of cancer caused by ionizing radiation is well documented at radiation doses beginning at 50 mSv and above. Related radiological effect studies have shown that survivors of the atomic bomb explosions in Hiroshima and Nagasaki, nuclear reactor workers and patients who have undergone therapeutic radiation treatments have received low-linear energy transfer (LET) radiation (x-rays and gamma rays) doses in the same 50-2000 mSv range. While in space, astronauts are exposed to radiation which
Ionizing radiation radiation is always ionizing, but only extreme-ultraviolet radiation can be considered ionizing under all definitions. As noted, the biological effect of ionizing radiation on cells somewhat resembles that of a broader spectrum of molecularly damaging radiation, which overlaps ionizing radiation and extends beyond, to somewhat lower energies into all regions of UV and sometimes visible light in some systems (such as photosynthetic systems in leaves). Although DNA is always susceptible to damage by ionizing radiation, the DNA molecule may also be damaged by radiation with enough energy to excite certain molecular bonds to form thymine dimers. This energy may be