The most common and most likely answer to this crossword clue is the 7 letter word MIRANDA
I've seen this crossword clue in The Guardian
M
I
R
A
N
D
A
More clues leading to the result MIRANDA
- Girl missing in action outside border
- Artificial satellite along with a — natural one?
- Girl married at island golf club
- Space station with a satellite
- Space station with a name
- Country besieged by mad, reckless Shakespearean character
- Satellite with a moon
- Girl collapsing in Drama
- Marina is swimming around Duke and Prospero’s daughter
- She made her name in drama
Buddy explains!

The straight part
We know that "moon" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case moon = miranda.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.