Of course, the most serious physical injury in space is the change of chromosome results, and the high radiation environment is beyond human adaptation for a long time. Even if you do a physical examination in the hospital, it won't take more than a minute, and the hospital also has warnings to remind patients to stay away from the ct room. This is because radiation will do serious harm to people's health in a subtle way.
After many astronauts returned to Earth from space, their blood vessels were blocked and blood clots appeared. Because of sudden changes, their bodies have not adapted. Above the earth, blood flows downward due to gravity. But there is a vacuum in space and there is no gravity, so blood will flow back. If people stay in space for a long time, their blood will go up to six, which will lead to poor blood circulation, swollen astronauts' faces and insufficient blood supply to their hearts.
Therefore, astronauts will definitely feel uncomfortable when they return to the earth, which is just like acclimatization, but a little farther away, it is just acclimatization from space to the earth. The astronauts who just got off the spaceship were all carried down and couldn't even walk. Some astronauts may recover later, but the radiation damage is irreversible.
Some astronauts can't adjust their state, and may even be unable to take care of themselves. Coupled with the psychological burden, it is easy to collapse at any time. Therefore, although space is novel and eager to explore for human beings, it is also a very scary and dangerous existence, and human beings have also paid a lot in the process of exploring the universe.