When expanding triletterisms, I guess my brain first reaches for computer-related terms, then taxes, then a very limited list of other things. I didn't think of the Hubble Space Telescope either, which I'm considerably more ashamed about. The only people I would reliably recognize by initials are JFK, GLS, and RMS (the latter two being Guy L. Steele and Richard M. Stallman, both Notable Computer Scientists). And if anyone here used RMS without expanding it, I would still ask if they meant the famous RMS or the local one (Robert M. Schroeck).