Generally, in space, astronauts & cosmonauts are in a constant state of free fall--the same feeling when you go down a large hill in a roller coaster--but for several hours/days/weeks/months.
So primarily, motion sickness.
But also, the human circulatory systems has evolved to exist with gravity. In orbit, these mechanisms malfunction, and fluid tends to accumulate in the head--causing puffy eyes and faces.
Typically, people adjust to these changes in a day or two. Some unfortunate people never adapt, and have a miserable time in space.
They can get bored, loss of muscle and bone mass, space sickness.
Ego.
Astronauts are important because they advance our knowledge on space, and space exploration. They find cures for diseases or sickness's such as bone cancer or motion sickness. They can also tell what the temperature or weather is. They can also report to other countries if something bad is coming toward them like, a worldwide flood.
Fred Haise experienced Space Adaptation Sickness, a condition similar to motion sickness and caused by gravitational changes affecting the body's spatial orientation.
Fred Haise the lunar module pilot of Apollo13 experienced travel sickness in space.
It is a disease the causes a sickness.
protozoan
"emotions".
Space Adaptation Syndrome
helium
trypanosoma
stds, Plants, Sickness,
Why astronauts are not allowed to eat beans
Altitude sickness is caused by changes in the distribution of oxygen and pressure. The symptoms of altitude sickness resemble those of a cold.
Sleeping sickness is an infection of the brain that causes frequent sleep, among other symptoms.
Sickness.
stds, Plants, Sickness,