Second fast bowler to become an astronaut (8)
I believe the answer is:
spaceman
'an astronaut' is the definition.
(I know that astronaut can be written as spaceman)
'second fast bowler' is the wordplay.
'second' becomes 's' (common abbreviation).
'fast bowler' becomes 'paceman' (cricket term).
's'+'paceman'='SPACEMAN'
'to become' acts as a link.
(Other definitions for spaceman that I've seen before include "Armstrong, say" , "Distant traveller" , "Astronaut" , "Out-of-this-world chap?" , "one requiring a supply of oxygen?" .)