It's not rocket science is said of something that is really not hard to understand. Come on, it's not rocket science, after all it's not rocket science.
It is faintly impatient, and it is usually said to somebody making heavy weather of a simple thing. Rocket science stands in for the hardest work anybody could name.
1phraseit's not rocket scienceSaid of something that is really not hard to understand.
“Fill in the date and sign it, since it's not rocket science.”
it's not rocket science is a phrase.
Also accepted in games: not rocket science
Practised in Idioms