If you're thinking you might want to be an astronaut, don't forget to consider all the uncomfortable aspects of the job. Sure, seeing the Earth from orbit can be exciting, but eating freeze-dried food can get old after a while. And living in close quarters for months on end might get a little trying. An astronaut's work life can be tough, which is why only the most mentally and physically fit candidates are chosen.
Health Issues
Astronauts have a host of physical issues to deal with when living in microgravity. Their faces may puff up as body fluid flows upward, and they lose bone density the longer they're away from Earth's gravity. When they first get into space, they have to relearn how to walk, how to keep their balance and how to not feel like they're always upside down. Many astronauts suffer space adaptation syndrome, which means they throw up quite a bit before they adjust to the new environment.
Typical Workday
Astronauts, whether on a space shuttle or the International Space Station, perform experiments during their workdays, check systems to make sure they're working properly, work with satellites and help fix broken parts of the space station. When an astronaut is living on the ISS, he typically works a long day, from 6 a.m. to 9:30 p.m., Greenwich Mean Time. He'll eat three meals a day and work out for two to 2.5 hours a day so he doesn't lose muscle tone from the microgravity.
Sleep
Sleeping is an unusual feat for astronauts. The sun sets 16 times a day when they live on the ISS, so astronauts may need earplugs and eye masks to help mimic the feeling of night. Due to weightlessness, astronauts don't need to sleep on a mattress; a bed feels the same as the floor or even a wall. But their limbs may float in microgravity, so astronauts typically restrain their arms and legs. Astronauts can sleep in a designated sleeping compartment that includes a sleeping bag, a light and a vent. But they can also take their sleeping bag out of the compartment and anchor it anywhere they want to sleep, even on a wall.
Eating
The low-gravity work environment also affects an astronaut's eating habits. Astronauts can't risk having crumbs and other dry foods floating around the ISS or shuttle and contaminating the environment, so they typically have to eat stickier foods that will stay on their forks, like oatmeal. Salt has to be suspended in water to be eaten. They have a choice of foods, including fresh food they have to eat within days of arrival, dried fruits and dried meat, foods they have to rehydrate, like oatmeal and certain vegetables, certain soups and foods whose natural form is suitable for low-gravity environments, like tortillas.
