When the message you're trying to give someone is, "I dig your smarts," and also, "I like other stuff about you, too," then the right gift to give is this matte black onyx bracelet. The onyx says that you care about their well-being and about protecting them from shitty vibes (if you're into that kind of thing). The NASA charm says that you respect and celebrate their nerdiness.
You've a pendant choice of sterling silver or an 18K gold plating; decisions, decisions. Personally, I think you should get one of each so you can match, but hey, you gotta do you.