英语翻译Jeffrey Kluger suggested that,the completely closed spac

Jeffrey Kluger suggested(改为suggests) that,the completely closed space is now not the most painful factor for the astronauts to live in the space.As(改为However,) the long-time-exposure under the strong radiation energy can be really dangerous,or even fatal for the astronaut when their（改为they） are on their track around the earth or on their voyage to the moon without the attraction of the magnetic field(18)
Jeffrey Kluger指出,现在对宇航员来说,完全封闭的空间不是生活在太空中最痛苦的因素.然而,当他们处在失去引力的绕地轨道或去往月球的途中时,长时间的暴露在强烈的辐射下,对宇航员来说是非常危险甚至是致命的.
再问： 问一下，密封的空间我写成completely closed space，还有什么好一点的说法么？