SpaceX chief Elon Musk says the centre booster of the Falcon Heavy slammed into the Atlantic at 480km/h, missing the floating landing platform.
Musk says it hit the water with such force that shrapnel flew onto the droneship's deck and took out two engines.
Despite the loss, Musk reveled in Tuesday's successful launch of the powerful Falcon Heavy and the recovery of the two side boosters.
He said watching the simultaneous side-by-side touchdowns of those two boosters at Cape Canaveral Air Force Station was probably the most exciting thing he's ever seen.