SpaceX fired up its prototype Starship rocket on Wednesday evening at the company's facility in southern Texas, CEO Elon Musk confirmed in a tweet.

"Starhopper completed tethered hop," Musk said in a tweet, sharing a video of the apparent test firing.

"All systems green," he added.

Musk tweet: Starhopper completed tethered hop. All systems green.

SpaceX is in the early stages of developing its Starship rocket. Starship, with an enormous booster called "Super Heavy," is being built to transport up to 100 people to the moon, Mars and more.

Designed to be a fully reusable launch system, the "hopper" version of Starship is key to proving the design and mechanics of a rocket that will unlock Musk's vision of making spaceflight more like air travel.

The company is also building a next-generation series of engines for Starship, known as Raptors. The prototype Starship has one Raptor, which is the second "flight ready" version of the engine that SpaceX has tested.