Becoming an astronaut was his grail.
Origin of grail
- Middle English greal from Old French graal from Medieval Latin gradālis flat dish, of unknown origin
From American Heritage Dictionary of the English Language, 5th Edition
- From Old French grael, ultimately from Latin graduale.
- Old French graal (“cup”), from Medieval Latin gradalis.
- Origin uncertain; perhaps a reduced form of gravel.
- Compare Old French graite slender.