"I want to become an astronaut" 是表达“我想成为一名宇航员”的常用说法。

来源：
astronaut 是英语单词，由希腊语 astron（星）和 naut（水手）组成，意思是“星际水手”。

一些例句及其中文翻译：

I have always dreamed of becoming an astronaut. 我一直梦想着成为一名宇航员。
He has been training to become an astronaut for years. 他已经培训了多年，要成为一名宇航员。
She became an astronaut after completing her astronautical engineering degree. 她在完成宇航工程学位之后成为了一名宇航员。