The other half of SpaceX's Starship deep-space transportation system is starting to come out into the light.

Over the past three months, three full-size prototypes of the 165-foot-tall (50 meters) Starship spacecraft have launched on high-altitude test flights, each time with impressive but ultimately explosive results. However, the company hadn't showcased any versions of Super Heavy, the 230-foot-tall (70 m) booster that will launch Starship off Earth — until now.

"First Super Heavy booster," SpaceX founder and CEO Elon Musk said via Twitter on Thursday afternoon (March 18), where he posted a photo of the big rocket at the company's South Texas site, near the Gulf Coast village of Boca Chica.

Booster 1 "is a production pathfinder, figuring out how to build & transport 70-meter-tall stage. Booster 2 will fly," Musk said in another Thursday tweet.

Starship and Super Heavy: SpaceX's Mars-colonizing vehicles in images