Yes he did. It's clear as day.
The parenthesis refers to the idea preceding it.
What was that idea? A mission to Mars.
Not Mars all by itself. Had he been talking about Mars in general, and not a mission to Mars. You'd be right.
But you are intentionally ignoring the main subject which is the "mission to Mars". And focusing solely on the planet itself to suit your bias.
How do you use parentheses?
Rule #1:
Use parentheses around nonessential information or abrupt changes in thought. When the words in
parentheses form a complete sentence, place the period inside the closing
parenthesis.
The reason he used parenthesis is because of the rule above.
He originally said, he didn't think NASA should focus solely on the moon.
He then added that NASA should focus on a mission to Mars (of which the Moon is a part of).
(Of which the Moon is a part of). Refers to the idea preceding it: A mission to Mars, and because it was an abrupt change of thought he threw it in parenthesis.