我们在谈到航天的话题时,总要问“人类为什么要航天”?一般说来,人们都是从积极的方面去论述。的确,载人航天可以提高国家的威望,发挥巨大的军事应用潜力,开发空间产品和促进空间科学技术的发展,载人航天的积极作用是不可抹煞的。但是,载人航天有没有副作用呢?回答也是肯定的。 宇航员是一项危险性很高的职业,失重条件对人体 When we talk about the topic of space flight, we always ask “why humans want space?” Generally speaking, people all talk about the positive aspects. Indeed, manned space flight can enhance the prestige of the country, exert enormous potential for military applications, develop space products and promote the development of space science and technology. The positive role of manned space flight can not be ignored. However, there are no side effects of manned space? The answer is yes. Astronaut is a dangerous job, weightlessness on the human body