SpaceX test-fired the booster engines in Texas Thursday on its giant next-generation Starship rocket. Company founder Elon Musk said the test was a success successfully igniting 31 of 33 engines.

Starship is the name for the deep space rocket and booster SpaceX is developing for moon missions with NASA and ultimately missions to Mars. The booster fired Friday is called Super Heavy and makes up roughly half of Starship’s size. “One day Starship will take us to Mars,” Musk said on Twitter after the test.

Starship is designed to be reusable. It is 390 feet tall and twice as powerful as the Saturn V that took Americans to the moon. Its height is comprised of the booster and rocket.

SpaceX plans to use a variant of Starship to land astronauts on the moon as part of NASA’s Artemis program. The company has a fixed-price, milestone-based $2.89 billion contract to develop its human landing system. “SpaceX’s HLS Starship, designed to land on the Moon, leans on the company’s tested Raptor engines and flight heritage of the Falcon and Dragon vehicles,” NASA said when the contract was awarded in 2021. ”Starship includes a spacious cabin and two airlocks for astronaut moonwalks. The Starship architecture is intended to evolve to a fully reusable launch and landing system designed for travel to the Moon, Mars, and other destinations.”

The human lander is being developed through NASA’s Marshall Space Flight Center in Huntsville directed by program manager Lisa Watson-Morgan.