One aims for space playing cricket in tests, bagging duck (6,9)
I believe the answer is:
rocket scientist
'one aims for space' is the definition.
(rockets go into space)
'playing cricket in tests bagging duck' is the wordplay.
'playing' is an anagram indicator.
'bagging' is an insertion indicator (I've seen this in other clues).
'duck' becomes 'o' (resembles zero - 'duck' in cricket).
'cricket'+'in'+'tests'='cricketintests'
'cricketintests' anagrammed gives 'rcketscientist'.
'rcketscientist' placed around 'o' is 'ROCKET SCIENTIST'.
(Other definitions for rocket scientist that I've seen before include "A high achiever" , "brain" , "Mastermind" , "Clever chap" , "I launch farreaching studies" .)