Overcoming the radiation challenge of space
Radiation is a normal part of the human environment. Most of this is natural, coming from the sun, space, or the decay of radioactive elements in the ground. If an unprotected human exposes their skin to sunshine, then they are being exposed to ultraviolet solar radiation. Some degree of solar radiation exposure is needed for good physical and mental health. However, excessive exposure is known to cause both immediate and long-term damage to the skin, with the long-term damage being possibly fatal. Nature is not necessarily benign even on our “native” planet.
Despite the risks due to excessive radiation exposure, humans routinely use radiation for industrial and medical uses where humans are indirectly or, for medical uses, intentionally exposed to radiation. In terms of indirect exposure, sound engineering principles and practices have been developed to limit this exposure to levels that, over the course of a lifetime, do not cause an unacceptable increase in the potential of death.
The medical use of radiation is a very good example. The initial crude means of using radiation for internal imaging and medical treatment, originated over a century ago, have advanced to the point where these are now common medical procedures used to prolong life and improve health. Almost everyone in America has had some form of intentional radiation exposure for medical imaging.
Compared with terrestrial experience of using radiation, our experience in engineering human operations in space’s radiation environment is still quite limited. Space radiation is often cited as a formidable obstacle to the expansion of human civilization into space. Yet, our terrestrial experience shows that sound engineering and medical principles and practices can be developed to provide protection against harmful radiation exposure.