Space radiation is a type of high-energy radiation that originates from the sun, other stars, and other sources in space. It includes a variety of particles, such as protons, neutrons, and electrons, that can cause damage to living tissue.

Space radiation can cause a range of health problems for astronauts, including cancer, cataracts, and damage to the central nervous system. It can also increase the risk of heart disease and other conditions.

Microgravity is the condition in which objects appear to be weightless in space. This is because they are in a state of freefall, which cancels out the effects of gravity. However, microgravity can also cause physiological changes in the human body, such as muscle and bone loss, changes in fluid distribution, and alterations to the cardiovascular system.

Microgravity can cause a range of health problems for astronauts, including muscle and bone loss, changes in vision, and alterations to the immune system. It can also lead to cardiovascular changes, such as a decrease in heart size and function.

Astronauts are protected from space radiation through the use of shielding materials on spacecraft and spacesuits. They also undergo medical screening and are monitored for radiation exposure. To mitigate the effects of microgravity, astronauts participate in exercise routines and are given special diets to maintain their bone and muscle mass.