The Falcon Heavy rocket launched early Tuesday, two cores made it back safely.

SpaceX’s Falcon Heavy rocket launched at 2:30 am ET from Launch Complex 39A at the Kennedy Space Center in Florida on Tuesday morning. It sent its payload of 24 satellites into space. Less than three minutes after the launch, the rocket’s two side-mounted boosters separated as planned from the first stage’s center core and subsequently returned to make a safe landing near KSC. Over the next 3 hours and 30 minutes, the Falcon Heavy’s upper stage separated from the center core and flew onward, into the first of several orbits. One of its missions was to drop off 24 satellites into three different orbits.

Then the center core attempted to make landing more than 1,200km downrange on a drone ship in the Atlantic Ocean. SpaceX founder Elon Musk had warned earlier that the chance of landing on the drone ship was about 50% because of the core’s exceedingly high energy it accumulates during its return to Earth. It didn’t make it, making a visible explosion as it hit the water nearby.

The mission marks the first time the Air Force has flown payloads on a Falcon Heavy rocket. It was also the first time the US Air Force allowed any of its payloads to fly on previously used rockets. The two side-mounted Falcon 9 cores previously flew on the Arabsat-6A Falcon Heavy launch in April while the center core is new.

The two side-mounted cores will attempt to return to a landing site along the Florida coast shortly after launch, and the center core will attempt to land on a drone ship more than 1,200km downrange.

According to ArsTechnica.