Earth caught by radio interference over the moon (8)
I believe the answer is:
ecstatic
'over the moon' is the definition.
(I've seen this before)
'earth caught by radio interference' is the wordplay.
'earth' becomes 'E'.
'caught' becomes 'c' (cricket abbreviation).
'by' means one lot of letters go next to another.
'radio interference' becomes 'static' (radio static).
'e'+'c'+'static'='ECSTATIC'
(Other definitions for ecstatic that I've seen before include "Cites act, being deliriously happy" , "Feeling great rapture or delight" , "Cite acts, being overjoyed" , "high!" , "Full of bliss" .)