I guess that you look for a correct Spanish translation for the English sentence "Aim for the moon even if you miss you'll land among the stars", isn't it?
The proposal you provided is not very accurate, it wouldn't be well understood (Disparar means to shoot something, but as the English text says you will land among the stars, obviously you are going up yourself (in a rocket), not aiming / shooting a rifle).
A literal translation would be: "Apunta a la luna; aunque no aciertes vas a aterrizar entre las estrellas"
Of course this idiom is not used in Spanish, but it could be understood by a reader.
If the context is informal speech, a dialogue between two normal people, I would consider also:
"Tú ve a por la luna; si fallas, siempre vas a acabar entre las estrellas"
Of course this isn't used either in Spanish as an idiom, but it sounds like something somebody could say and understand.
Another question is if there is something aequivalent in Spanish which conveyes the same idea as the English idiom, but right now I can't think of anything.
