Radio set after retuning reaching minor planet (8)
I believe the answer is:
asteroid
'minor planet' is the definition.
(synonyms)
'radio set after retuning' is the wordplay.
'radio set' can be anagrammed to 'ASTEROID'.
Though, I am not clear how this is indicated.
'reaching' is the link.
Can you help me to learn more?
(Other definitions for asteroid that I've seen before include "could be dangerous for astronauts" , "Minor planet" , "circling rock" , "Lump of rock orbiting the sun" , "Any of the small planets revolving around the sun" .)