Dog star gets a ship into position (6)
I believe the answer is:
lassie
'dog star' is the definition.
(I've seen this in another clue)
'a ship into position' is the wordplay.
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'into' is an insertion indicator.
'position' becomes 'lie' (lie can mean to place or position).
'a'+'ss'='ass'
'ass' placed within 'lie' is 'LASSIE'.
'gets' is the link.
(Other definitions for lassie that I've seen before include "Screen mutt - Scottish girl" , "Screen canine" , "Young Scottish female" , "dog in pictures" , "girl found" .)