Viking, say, casting copper base (5,5)
I believe the answer is:
space probe
'viking' is the definition.
(thesaurus)
'casting copper base' is the wordplay.
'casting' indicates an anagram.
'copper'+'base'='copperbase'
'copperbase' anagrammed gives 'SPACE PROBE'.
'say' acts as a link.
(Other definitions for space probe that I've seen before include "highflying investigative unit" , "NASA craft" .)