This flight followed the first Falcon Heavy test launch in 2018 and involved the Arabsat-6A, a Saudi Arabian communications satellite.
The webcast should begin about 20 minutes before the rocket's anticipated liftoff.
"The Falcons have landed", Musk said in a tweet that included pictures of all three boosters. The auto, which was carrying a space-suited mannequin nicknamed Starman, was vaulted into outer space and is expected to orbit the sun for the foreseeable future.
The Falcon Heavy differs from the Falcon 9 rocket.
Falcon Heavy's debut flight previous year attracted massive attention, in part because CEO Elon Musk made a decision to launch his own luxury Tesla Roadster as the test payload.
The version of the Falcon Heavy that will fly this week will not be exactly the same as the previous mission: The Falcon Heavy's rocket cores will be more powerful, making use of upgrades to SpaceX's smaller workhorse rocket, the Falcon 9.
The rocket is expected to be used primarily for United States military missions, and to launch spy satellites and hefty commercial telecom satellites. That mission was more of a test than anything else, with head man Elon Musk deciding to send his own Tesla as the rocket's payload.
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Thousands of people came to SpaceX's launch site in Florida to watch the spectacle.
Roughly three minutes after clearing the launch pad, Falcon Heavy's two side boosters separated from the core rocket for a synchronised landing at the Cape Canaveral Air Force Station, just like it did for the rocket's debut a year ago.
NASA's Saturn V rockets, used for the Apollo moon shots, are the all-time launch leaders so far in size and might. Last year, SpaceX recovered two Falcon Heavy boosters on land but narrowly missed landing the third on a drone ship in the Atlantic Ocean. It will include coverage of the landing attempts and satellite deploy.
The satellite aims to provide communications to people in the Middle East, Africa, and Europe.
The U.S. Air Force tapped SpaceX in 2018 to launch for $130 million a classified military satellite and in February added three more missions in a $297 million contract.
SpaceX has several paying customers committed to flying on Falcon Heavy, including Inmarsat, Viastat and Arabsat, according to its launch manifest.