Going out into space is not easy, especially because it is something new to the world. Only the most fit and good-with-technology people can go on high tech space shuttles. You must be fit, prepared for emergencies, and be good with equipment since you're riding billions of dollars of technology. Hopefully in the future, when technology improves, people don't need to be so skillful to ride space shuttles.
P.S. The selection is done carefully because organizations and investors don't want to waste money on a rocket that has an increased chance of something bad happening.
The training for the American astronauts is done at N.a.S..A space centers.
Selection and initial training is around 6 months although further parachute and speciality training is done on assignment to a troop.
It is extremely dangerous and stressful to the human body. The actions or inactions of one person could cause instant death. An astronaut becoming ill or incapacitated, could affect the lives of the others. Quick and smart actions, based on training and intelligence, are required to make the mission successful.
artificial selection
Do another selection.
yes it is possible astronauts have done it
Very carefully.
The effects of weightlessness on humans is explored during the work done by astronauts. This helps with advancements in medical and technological fields.
The only country to have sent astronauts to the moon is the United States of America, so it is the largest country to have done so.
natural selection for example is a peppered moth.
First, you enlist in the Army. You pass Basic Combat Training and Advanced Individual Training (or One Station Unit Training, depending on what occupation you enlist for). Then you have to wait until you make the rank of Specialist (E4). At that point, you can request to go to Special Forces Assessment and Selection. If you complete SFAS, then you'll have the opportunity to advance in the selection process to the Q-Course. Once that's done, you'll be assigned to an SF unit.
Astronauts are not necessarily scientists. In fact I'd guess few astronauts are scientists. The original astronauts were test pilots. Some had degrees in engineering. The term rocket scientist is probably a misnomer as most rocket design is done by engineers. Some science specialists are involved.