Being alone in outer space can be frightening. That is one reason why astronauts on solo（单独的） space flight were given plenty of work to keep them busy. They were also in constant communication with people on the earth,However, being with people from whom you cannot get away might be even harder than being alone. This is what happens on long submarine（潜水艇） voyages. It will also happen on long space flights in the future. Will there be special problems of adjustment under such conditions?
Scientists have studied the reactions of men to one another during long submarine voyages. They have found that the longer the voyage lasts, the more serious the problem of adjustment is. When men are shut up together for a long period, they begin to feel uneasy. Everyone has little habits of speaking and behaving that are ordinarily acceptable. In the limited space over a long period of time, however, these little habits may become very annoying.
Apparently, although no one wants to be alone all the time, everyone needs some degree of privacy. When people are enclosed together, they are in what is called a stress situation. That means that they are under an unusual amount of pressure or stress.
People who are well-adjusted are able to handle stress situations better than others. That is one reason why so much care is taken in choosing our astronauts. These men undergo a long period of testing and training. One of the things tested is their behaviour under stress.

一个人独自呆在外太空会让人害怕，这是为什么宇航员在太空飞行时要让他（们）忙个不停的一个原因，他们还要与地面的人保持通讯；然而，与他人长时间呆在一起而无法拥有自己的隐私（私密空间和时间）比独自一人呆着更为可怕。这就是在潜艇长时间航行时发生的情况，以后也将会发生在长时间的太空飞行中。在这种情况下，有什么特殊问题要调整吗？
科学家对长时间潜艇航行时人与人相互之间的反应做了研究，他们发现旅途时间越长，要调整的问题越严重。当人被长时间封闭在一起之初，他们就开始不自在。每个人的在说话和行为方面的小习惯通常是可以接受的，但长时间封闭在有限的空间里时，这些小习惯会变得非常恼人。
很显然，没有人会想老是一个人呆着，但人人也都需要一定的隐私，当人们被封闭在一起时，他们就处在一个被称之为压力的状态，就是说他们受到的压力或紧张的程度非同寻常。
会很好地进行调节的人比那些不会调节的人更能应付这种压力。这就是为什么在挑选宇航员要特别小心的一个原因，这些宇航员要经过长期的考验和训练，其中要考验的事情之一就是身处压力环境时的行为。