Protection in flying saucer orbiting moon ultimately (9)
I believe the answer is:
insurance
'protection' is the definition.
(insurance is a kind of protection)
'in flying saucer orbiting moon ultimately' is the wordplay.
'flying' is an anagram indicator.
'orbiting' is an insertion indicator.
'ultimately' indicates one should take the final letters.
The last letter of 'moon' is 'n'.
'saucer' with letters rearranged gives 'surace'.
'surace' enclosing 'n' is 'surance'.
'in'+'surance'='INSURANCE'
(Other definitions for insurance that I've seen before include "Protection against a future eventuality" , "Cover against mishaps" , "Indemnity" , "Safeguard" , "Such a policy guarantees" .)