Space medicine is the science in which we do the practice of medication on astronauts in the atmosphere outside the earth. Astronautical hygiene is the application of knowledge and skill to the avoidance of exposure to the risks that may be the origin of astronaut ailing health. These two sciences work jointly to make sure that astronauts work in a secure atmosphere. It is important to know that for how much duration people can endure the space environment without getting a disease and how much time they will take to have the adaptation to the earth’s environment. Environment on space is entirely different from that on the earth. So, human beings have to face harsh environment while in space. There is zero-gravity in space, low atmospheric pressure, radiations, and dust. Due to the strange environment in space astronauts may have problems of bone, muscle, cardiovascular, food and nutrition. They may also have to face immunology and infection risks. So, special care is needed for the better hygiene of astronauts. They should do regular exercise; eat healthy food and cover themselves by space suit.