A spaceship can travel in space where there is no air.

太空船能在没有空气的太空飞行。

He picks up Travel in Space and reads the first few pages.

他选了一本《在太空旅行》读了前面几页.

Maybe people will be able to travel in space and live on other planets.

也许人们能够在太空上旅行并生活在其他星球上。