Two came back to touchdown zones on the Florida coast just south of Kennedy. Their landing legs made contact with the ground virtually at the same time.
"That was epic," said Mr Musk. "That's probably the most exciting thing I've ever seen, literally."
The third booster was due to settle on a drone ship stationed several hundred kilometres out at sea. Unfortunately, it was unable to slow its descent by re-igniting sufficient engines, missed the target vessel and was destroyed as it hit the water at some 500km/h.
By then, the upper-stage of the Falcon Heavy, with its Tesla cargo, was heading on a trajectory that would hopefully take it towards Mars' orbit.
That required the engine on the upper-stage to fire on three separate occasions, with the third and final ignition only occurring after a long cruise phase - something which was confirmed some six hours after the launch.