More than reasonable fare to Jupiter or Mars? (8)
I believe the answer is:
ambrosia
'more than reasonable fare' is the definition.
I know that 'fare' relates to this answer.
I don't understand the remainder of the clue.
(Other definitions for ambrosia that I've seen before include "dish fit for the gods when cooked without salt" , "Olympic table to hold this?" , "Food and drink of gods" , "Wonderful food" , "Delicious food" .)