Brave man in the rocket (4)
I believe the answer is:
hero
'brave man' is the definition.
(I've seen this before)
'in the rocket' is the wordplay.
'in' indicates the answer is hidden within the clue.
'HERO' is hidden in the letters of 'the rocket'.
(Other definitions for hero that I've seen before include "Man of great courage and deeds" , "Man admired for courage and achievement" , "Person lauded for bravery" , "Chief good guy in a book or film" , "Exceptionally courageous person" .)