SpaceX has finished the “stacking” of its first Super Heavy prototype, the massive next-generation first-stage rocket booster that will ultimately propel its Starship spacecraft to orbit and beyond. The Super Heavy Booster stands about 220 feet tall, or about the same as a Boeing 747’s wingspan, or slightly taller than Walt Disney World’s Cinderella Castle in Florida.

That’s without the addition of the Starship, which would add another 160 feet. However, Super Heavy will go through its own tests before flying with Starship, with much of it focusing on ensuring that its fuel tanks can withstand the pressurization and extreme temperatures necessary to keep all that ignitable material stable before the engines fire.

Super Heavy is powered by the same engines that power Starship — Raptor engines, to be precise, which SpaceX developed specifically for this generation of launch vehicle. The final version will have 28 Raptor engines, but the first prototype will most likely have far fewer, and SpaceX CEO Elon Musk has stated that it will stay grounded, as it is only meant to be used for testing things like build and transportation mechanics.

While he isn’t always accurate about timelines, the Starship upper stage (i.e., the one that looks like a big grain silo with fins) is progressing quickly in its development, including with a recent test flight that ended with a near-perfect landing — minus the subsequent explosion that completely destroyed the prototype rocket just minutes after it had to land.

Musk obviously wants to move quickly with Starship and Super Heavy, in part because of the Artemis program’s ambitious goals of serving as a supplier to NASA for future human lunar landing missions, and in part because the first commercial tourism flight of a Starship is still planned for 2023.