At launch-plus-four-minutes, as Starship was losing altitude, a large explosion ripped across the blue sky, the result of computers, or someone on the ground, triggering the vehicle's Flight Termination System (FTS).
"With a test like this, success comes from what we learn, and we learned a tremendous amount about the vehicle and ground systems today that will help us improve on future flights of Starship," SpaceX said in a statement.