Let star liner make such a voyage (12)
I believe the answer is:
interstellar
'such a voyage' is the definition.
'let star liner make' is the wordplay.
'make' is an anagram indicator.
'let'+'star'+'liner'='letstarliner'
'letstarliner' with letters rearranged gives 'INTERSTELLAR'.
(Other definitions for interstellar that I've seen before include "Occurring between stars" , "In deep space" , "realm of Star Trek" .)