**13. Space medicine and medical astrosociology**

#### **13.1 The healthcare system**

The healthcare system is an extremely important social institution briefly described in an earlier subsection. Relatedly, space medicine is vital for the health and safety of settlers on Mars. Traditionally, space medicine has focused on the effects of spaceflight on the human body, which strongly involves the biological and life support issues. It is defined more broadly as the "practice of all aspects of preventive medicine including screening, health care delivery, and maintaining human performance in the extreme environment of space preserving the long-term health of space travelers [64]." Thus, preventive and reactionary efforts are involved, as countermeasures are not always effective.

These types of definitions apply mainly to living in a spacecraft and they focus on human factors rather than social-scientific principles. Human factors and ergonomics are important although not all practitioners are also social scientists. The two are complementary, however. This is important during the voyage to Mars though social science should apply more strongly even in weightlessness. However, when the focus extends to the settlement where the gravity field changes from zero gravity to one-third of Earth's, Martian medical practice will change in order to adapt to yet unknown biological effects. It will depend on the specific conditions of the planetary environment that will differ from weightlessness in outer space. Intensive research will be necessary at that point.

Before that point, the trip to Mars will likely involve a considerable time spent in near zero gravity (although artificial gravity is only a slight possibility because this option adds additional cost and difficulties in the solving engineering issues for the spacecraft). This means that the same problems faced by astronauts within the cislunar environment will be experienced by the settlers during the voyage although it may well be worse due to going from microgravity to zero gravity unless preventive actions are taken. It will be vital to keep each individual as physically fit and healthy as possible in order to reduce the physiological problems that could exist upon landing.

Some of the well-documented health issues that affect humans during space travel include radiation poisoning, DNA damage, cardiovascular stress, bone density loss, swelling of the optic nerve head, dehydration, cognitive decline, increased risk of mutations and cancer, and various molecular, behavioral, and physiological changes compared to those who continue to live on Earth. These types of detrimental effects were confirmed as a result of the NASA twin study involving Scott Kelly who stayed aboard the International Space Station (ISS) and Mark Kelly, also an astronaut, who remained on Earth [65] (see **Figure 5**). Living and working on the ISS for up to 6 months presents measurable health risks and problems, but this is mild compared to what can happen during a voyage to the fourth planet.
