"I would like to die on Mars; just ____ impact” (Elon Musk) (3,2)

I believe the answer is:

not on

(Other definitions for not on that I've seen before include "Informally, can't be accepted or tolerated" , "taboo" , "Modern usage for unacceptable" , "Impractical" , "Informally, cannot be permitted or tolerated" .)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.