SpaceX's Falcon Heavy roared to life for the first time on Wednesday.
Elon Musk's rocket company performed its long-awaited static fire test around 12:30pm today at Kennedy Space Center's launch pad 39A.
All 27 of the Falcon Heavy's Merlin engines fired up for the first time simultaneously, creating huge, billowing clouds of white smoke, according to the Daily Mail.
The test created monstrous booms that could be heard up to three miles away. Everything appeared to go as planned - meaning the massive rocket is now ready to launch "in a week or so."
The billionaire tech mogul said in a tweet on Wednesday that the Heavy will launch by the end of January.
"Falcon Heavy hold-down firing this morning was good," Musk said. "Generated quite a thunderhead of steam."
"Launching in a week or so," Musk added.
SpaceX has called the Falcon Heavy the "most powerful rocket in operation," with over 5 million pounds of thrust and the ability to lift more than 140,000 pounds of cargo.
Now that SpaceX has shown that the Heavy's engines can fire up properly, the megarocket will be on step closer to liftoff.
The test comes after SpaceX has grappled with months of delays, tied to this week's government shutdown, as well as operational issues.
SpaceX relies on personnel from NASA's Kennedy Space Center and the U.S. Air Force's 45th Space Wing to oversee operations.
The Falcon Heavy "megarocket" will fire beyond orbit from the former Apollo 11 moon rocket launchpad at the Kennedy Space Centre near Cape Canaveral, Florida.
Musk said the launch vehicle will blast off at the "end of the month" on an unmanned mission with a unique payload - the billionaire's cherry red 2008 Tesla Roadster, which will be fired toward Mars.
The rocket will use 27 engines and three separate re-usable cores that will return to Earth after liftoff during the test flight, which is set to be one of the firm's most technically complex challenges to date.
Before the maiden launch, a full test firing of the rocket's engines was required, Musk said.
"Falcon Heavy now vertical on the former Apollo 11 moon rocket launchpad," he wrote on Instagram last week.
"At 2,500 tons of thrust, equal to 18 Boeing 747 aircraft at full throttle, it will be the most powerful rocket in the world by a factor of two. Excitement on launch day guaranteed, one way or another.
"Hold-down test fire next week. Launch end of the month."
When it lifts off for the first time in late January, the Falcon Heavy will become the most powerful rocket in the world thanks to its 5.1 million pounds of thrust generated through 27 Merlin engines.
The vast rocket, which is ultimately three Falcon 9 rockets linked together, will have the combined thrust to eventually launch 140,000 pounds (63,500kg) of cargo into orbit.
The mission marks SpaceX's most ambitious project to date.
Musk founded SpaceX in 2002, with the aim of reducing space transportation costs and enabling the colonisation of Mars.
The 46-year-old South African is also the CEO of Tesla, and predicts Falcon Heavy's payload will stay in deep space for a while.
A photo of the unusual cargo - Musk's cherry red 2008 Tesla Roadster - was released last month.
Images released by SpaceX show an original Roadster perched on a large cone inside the Falcon Heavy on what appears to be a secure mount to keep it stationary as the rocket makes its maiden flight.
"Test flights of new rockets usually contain mass simulators in the form of concrete or steel blocks. That seemed extremely boring," Musk said in December.
"Of course, anything boring is terrible, especially companies, so we decided to send something unusual, something that made us feel.
"The payload will be an original Tesla Roadster, playing Space Oddity, on a billion year elliptic Mars orbit."
If all goes according to plan, the Falcon Heavy will off and enter Earth's orbit.
"At liftoff, the boosters and the center core all operate at full thrust," according to SpaceX.
"Shortly after liftoff, the center core engines are throttled down."
"After the side cores separate, the center core engines throttle back up,' the firm continued."
Eventually, the main module will continue its trajectory into "deep space", the billionaire said, with a destination set for the orbit of Mars 140 million miles (225 million kilometres) away.
Musk has said the payload "will be in deep space for a billion years or so if it doesn't blow up on ascent."
In a Washington, D.C., speech last July the Tesla founder which said Falcon Heavy is one of the most difficult and technically complex projects SpaceX has ever undertaken.
"There's a lot of risk associated with Falcon Heavy," he said during the 2017 International Space Station Research and Development Conference.
"Real good chance that the vehicle doesn't make it to orbit. I want to make sure to set expectations accordingly."
Musk has spent the proceeding months building up hype for the historic launch with a series of social media posts.
Last month he posted an image to Twitter of people stoof next to a landed Falcon Heavy rocket to give an idea of the vehicle's scale.
He tweeted: "Falcon Heavy launching from same @NASA pad as the Saturn V Apollo 11 moon rocket.
"It was 50% higher thrust with five F-1 engines at 7.5M lb-F.
"I love that rocket so much."
He also confirmed the rocket will have a "max thrust at lift-off is 5.1 million pounds or 2300 metric tons," adding the first mission will run at 92 per cent capacity.
"Falcon Heavy to launch next month from Apollo 11 pad at the Cape.
"Will have double thrust of next largest rocket. Guaranteed to be exciting, one way or another," Musk originally posted.