Though the Falcon Heavy’s outer cores successfully landed after launch this afternoon, the middle core of SpaceX’s huge rocket missed the drone ship where it was supposed to land, a source tells The Verge. SpaceX later confirmed The Verge’s reporting in a press conference.

The center core was only able to relight one of the three engines necessary to land, and so it hit the water at 300 miles per hour about 300 feet from the drone ship. As a result, two engines on the drone ship were taken out when it crashed, SpaceX CEO Elon Musk said in a press call after the rocket launch. “[It] was enough to take out two thrusters and shower the deck with shrapnel,” he said.

It’s a small hiccup in an otherwise successful first flight. The Falcon Heavy rocket took off from NASA’s Kennedy Space Center in Cape Canaveral, Florida, at 3:45PM ET on Tuesday and made a beautiful arc to space. About two and a half minutes after liftoff, the two outer boosters of the rocket broke away and returned to Earth. The pair then touched down just seconds apart on SpaceX’s two ground landing pads at the Cape called Landing Zone 1 and Landing Zone 2.

At about three minutes after liftoff, the center core broke away from the upper stage — the top portion of the rocket that is carrying the Falcon Heavy’s payload, Musk’s Tesla Roadster. It then attempted to land on SpaceX’s drone ship, but live video of the landing stalled just before the core was slated to make its touchdown. “We lost the center core,” someone said on a separate, unlisted live stream of the launch.

Meanwhile, the upper stage seems to be doing just fine. After launch, Musk tweeted that it had successfully ignited its engine and raised its orbit as intended. Now, the upper stage will spend about six hours coasting through space — a move by SpaceX to demonstrate a tricky orbital maneuver for the US Air Force. That coast will take the rocket through regions of intense radiation that surround Earth called the Van Allen belts, where it will be pelted by high-energy particles. If the vehicle is still operating as it should by then, the upper stage will do another engine burn, putting the car on its deep space path to Mars’ orbit.

Update February 6th, 7:10PM ET: Added SpaceX confirmation of our reporting, and details on what went wrong.