Previous rockets that are no longer in commission have been more powerful than the Falcon Heavy-including the Saturn V moon rocket, last flown in 1973, which delivered more payload to orbit. It will play David Bowie's "Space Oddity" on loop as it flies toward Mars on a "billion year" voyage.
Here's everything you need to know. The good news for Elon Musk is, the FAA made a decision to approve the payload, which consists of Musk's 2008 midnight cherry red Tesla Roadster with a "Starman" dummy at the wheel.
Many people found it hilarious when they first learnt that was planning to send his Red Roadster on a Mars tour. Elon Musk said on Twitter yesterday that "all systems remain green for launch at 1:30pm EST".
Falcon Heavy, the worlds most powerful rocket, was set to launch as early as 1:30 p.m. from Launch Complex 39A.
No matter what happens - a rocket explosion at the pad or some other calamity - Musk told reporters Monday his company has done everything possible to maximize success and he's at peace at whatever happens.
Last week, the Federal Aviation Administration officially licensed the flight from Kennedy Space Centre. The vehicle has one passenger - Starman - a dummy wearing SpaceX's own spacesuit, with one elbow propped up on the door of the auto and the other holding the steering wheel. On Monday, Musk said the auto would be outfitted with three cameras that should be able to beam back "some epic views".
And, compared to rockets that better rival the Falcon Heavy's power, it's a bargain.
But the Falcon Heavy is essentially three Falcon 9s strapped together, and it'll boast about three times the thrust of the Falcon 9.
Packing five million pounds of thrust at lift-off, it has more punch than any other rocket now operating in the world but less than Nasa's old space shuttles and Saturn V moon rocket. The entire structure is 70m tall, as tall as a 20 storey building.
If the Florida launch is successful, the Falcon Heavy will become the most powerful rocket in and above the world.
This persistence resulted in SpaceX becoming, in 2010, the first private company to launch a spacecraft into orbit and then safely guide it back to Earth, something only large governments had accomplished. In fact, SpaceX plans to try to recover all three of the rocket boosters following Tuesday's launch, two back at Cape Canaveral and one at sea aboard the company's whimsically named drone ship "Of Course I Still Love You".
Using another airplane analogy, SpaceX boasts a Heavy could lift a 737 into orbit, passengers, luggage and all.