When it launches, the Falcon Heavy will be the most powerful rocket in operation with 5 million pounds of thrust, but not the most powerful rocket ever.
The commercial company successfully completed an important engine test this week, firing up all of Falcon Heavy's 27 Merlin engines on the launch pad. He heads up the Tesla electric vehicle company, as well as SpaceX and several other companies. "Easy viewing from the public causeway".
The long-anticipated test flight will carry up a Tesla Roadster belonging to Musk, who heads both the rocket and electric auto companies.
The cargo on board for this mission is a cherry red original model Tesla Roadster - and if things go very well, it'll be put into a long looping Mars orbit, a nod to everything Musk's ventures have accomplished thus far, and also what they hope to achieve in the future.
It will, Musk predicted just over a month ago, "be in deep space for a billion years or so if it doesn't blow up on ascent".
It's also enough thrust to launch payloads to the Moon or Mars, so the Falcon Heavy is the key component in SpaceX's bigger ambitions. Musk said in July that developing the new rocket has proven more challenging than expected.
The megarocket's launch will represent another major first for Musk and his company's pursuit of re-usability.
NASA's Saturn V moon rocket, used during the late 1960s and early 1970s, will still top the charts. After blasting off from NASA's historic Launch Complex 39A at Kennedy Space Center, all three will attempt vertical landings, two on land and one on a floating offshore platform.