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The SpaceX Falcon Heavy rocket is getting closer to launching.

SpaceX late on Tuesday tweeted several photos and videos showing the Falcon Heavy rocket sitting on the launchpad vertically, awaiting its ascent. The images aim at showing the progress SpaceX has made at getting the rocket to its first test and illustrate just how big it really is.

“With more than 5 million pounds of thrust at liftoff—equal to approximately eighteen 747 aircraft at full power—Falcon Heavy will be the most powerful operational rocket in the world by a factor of two,” SpaceX tweeted on Tuesday night.

The Falcon Heavy has been in development for the last several years. And although it was expected to make its first test flight in 2013, a host of delays and setbacks forced SpaceX to push back its launch date.

With more than 5 million pounds of thrust at liftoff—equal to approximately eighteen 747 aircraft at full power—Falcon Heavy will be the most powerful operational rocket in the world by a factor of two. https://t.co/NneqPRPr46 pic.twitter.com/oswCUreG6i

— SpaceX (@SpaceX) January 3, 2018

SpaceX has said that the rocket will be capable of carrying 140,000 pounds of cargo into space. It has three cores that work in unison to get the rocket into a low Earth orbit. Most importantly to SpaceX, the cores have been designed to safely come back to Earth, where they can be reused for future missions.

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However, SpaceX and its founder Elon Musk have been quick to toss water on any expectation of a wildly successful launch. Musk has discussed on several occasions the pitfalls his company has faced developing the Heavy Rocket. He’s also said that there’s a “good chance” that in its first launch, which is slated for late-January, it will fail.