Zhè kē tàncèqì shōují le xíngxīngjì kōngjiān de shùjù.
This probe collected data on interplanetary space.
Tips
grammar
Built on the same 际 ('between / among') suffix as 国际 (international) and 星际 (interstellar). 行星际 sits one level smaller than 星际: 'between planets' vs. 'between stars'.
