Astronauts practice space walk under water as the underwater condition is similar to that in space. [CRI]
![Astronauts practice space walk under water as the underwater condition is similar to that in space. [CRI]](http://images.china.cn/attachement/jpg/site1007/20080923/001109b42f980a42e42d32.jpg "Astronauts practice space walk under water as the underwater condition is similar to that in space. [CRI]")