Elon Musk’s Space Exploration Technologies Corp. launched its Falcon Heavy rocket for the U.S. military early Tuesday, a spectacular night time liftoff that Musk described as the company’s toughest yet.

The rocket and payload rumbled aloft at 2:30 a.m. local time from NASA’s Kennedy Space Center in Florida after a three-hour delay. SpaceX then recovered the rocket’s two side boosters -- which flew in April as part of the Arabsat-6A mission -- at Cape Canaveral Air Force Station in Florida. The center core failed to land on a droneship in the Atlantic Ocean.

Falcon Heavy is carrying 24 satellites for the space agency, Department of Defense research labs and other partners. SpaceX fought for the right to compete for Air Force launches, and Tuesday’s liftoff marks a huge milestone for the company’s relationship with the U.S. military.

"It’s the first multi-mission, multi-payload deployment for the Falcon Heavy and that’s really exciting for everybody," Col. Robert Bongiovi, Director of the Launch Systems Enterprise Directorate at the U.S. Air Force Space Command, said in a statement before the launch.

The mission, known as STP-2, will place the 24 spacecraft in three different orbits. The payload includes an Air Force Research Laboratory Demonstration and Science Experiments (DSX) satellite; the National Oceanic and Atmospheric Administration-sponsored Constellation Observing System for Meteorology, Ionosphere and Climate-2 (COSMIC-2) and four NASA experiments, according to the SpaceX website. The final deployment will take place more than three and a half hours after the launch. Shortly before 3 a.m. local time, SpaceX’s Twitter feed began confirming deployment of the first satellites.

SpaceX set a company record last year with 21 launches for customers. Last month, the Hawthorne, California-based company sent up the first batch of its own satellites, a key step toward creating a space-based constellation that beams broadband to under-served areas across the globe.

Much of the focus in 2019 has been on the first flight with humans on board. SpaceX and Boeing Co. have contracts with NASA to ferry American astronauts to the International Space Station as part of the agency’s Commercial Crew program.

SpaceX completed the Demo-1 flight of its “Crew Dragon” in March without humans on board. But in late April, the capsule was engulfed in flames and destroyed during a test, a mishap that probably will push back the commercial crew schedule. NASA and SpaceX are reevaluating target test dates.

--With assistance from Tony Capaccio.