Why do astronauts need spacesuits? Astronauts must wear spacesuits whenever they leave a spacecraft and are exposed to the environment of space. In space, there is no air to breath and no air pressure. Space is extremely cold and filled with dangerous radiation. Without protection, an astronaut would quickly die in space. Spacesuits are specially designed to protect astronauts from the cold, radiation and low pressure in space. They also provide air to breath. Wearing a spacesuit allows an astronaut to survive and work in space.