载人航天是一项艰巨的事业。因为太空环境十分艰苦恶劣,人在航天过程中要经受巨大的加速度、噪音、振动、失重、宇宙射线等不良因素的影响,而且宇航员在这样的环境中还要完成复杂的驾驶、操纵、实验和观测任务,甚至还可能遇到一些意想不到的情况,需要正确、及时和果断地进行处理。 正因如此,对宇航员的选 Manned space is a difficult undertaking. Because the space environment is very harsh, people are subject to enormous acceleration, noise, vibration, weightlessness, cosmic rays and other adverse factors in the course of spaceflight, and astronauts have to complete complex driving, maneuvering and experimenting in such an environment And observation tasks, and may even encounter unexpected situations that need to be dealt with correctly, promptly and decisively. Because of this, the selection of astronauts