Driving down the east coast of Florida, you'll eventually reach Cape Canaveral. It's honestly a toss-up whether Leonida has a space-launch equivalent - we hedge our bets either way.
What we know
No official word. The trailer flyovers don't clearly show a launch-pad-style location. Guessing is done by fans.
Why it's interesting if it exists
GTA San Andreas had Easter Basin and the Aircraft Carrier. Something space-coded would be a massive content drop: story missions, set pieces, maybe even aerospace gameplay.
It's actually questionable whether Rockstar would go that far with fictional infrastructure. They could. They might not, though.