Secure satellite broadcast (7)
I believe the answer is:
tighten
'secure' is the definition.
(thesaurus)
'satellite broadcast' is the wordplay.
'satellite' becomes 'titan' (I've seen this before).
'broadcast' shows a homophone (sound like) (how the word might sound on the radio or TV).
'titan' sounds like 'TIGHTEN'.
(Other definitions for tighten that I've seen before include "Fasten more firmly" , "Make more taut" , "Make stricter" , "Constrict" , "get tense" .)