The US have literal tons of lunar soil and rock samples. Why does China want or need the Chang'e 5 mission to return soil from the moon?

美國已經有好多噸的月壤和巖石樣本了。為什么中國還要發起嫦娥5號任務去月球自己帶回月壤呢?



(當年美國贈送的“國禮”——放大鏡下的1克月巖。)