One on Saturn trip, taking in ring and comet's tail? (9)
I believe the answer is:
astronaut
'comet's tail?' is the definition.
The definition and answer can be both people as well as being singular nouns.
Maybe there's an association between them I don't understand?
'one on saturn trip taking in ring' is the wordplay.
'one' becomes 'at' (I can't explain this - if you can you should give a lot more credence to this answer).
'on' means one lot of letters goes inside another (as in clothing 'on' a person).
'trip' indicates anagramming the letters.
'taking in' indicates putting letters inside.
'ring' becomes 'o' (letter resembling a ring).
'saturn' anagrammed gives 'strnau'.
'strnau' placed around 'o' is 'stronau'.
'at' placed around 'stronau' is 'ASTRONAUT'.
'and' is the link.
(Other definitions for astronaut that I've seen before include "For member of high-flying mission" , "Armstrong or Sharman, say" , "Buzz Aldrin, e.g." , "Space explorer" , "Space voyager" .)