Outer space is a vacuum with no air or friction. Without protective equipment, humans would quickly die from suffocation as air leaves the lungs and blood cannot carry oxygen, destroying the respiratory and circulatory systems and crashing the nervous system. Astronauts wear pressurized flight suits that contain water vapor and oxygen to regulate body functions and prevent issues like swelling, frost, and loss of consciousness in the extreme conditions of outer space. They undergo extensive training for years to prepare their bodies and minds to survive the dangerous environment.