Testing of the rocket stages, launch platform and ground systems are expected "over the next few weeks" before Vulcan rolls out to the launch pad for fuel loading and countdown practice, ULA officials wrote in a blog post(opens in new tab) on Monday (Feb. 6).

Once that's all done, Vulcan will complete ground testing with a simulated countdown and a brief firing of its main engines to get it ready for its first mission, called Certification Flight-1.

Vulcan Centaur will replace ULA's long-standing Atlas V and Delta IV rockets, which are certified for commercial, government and national security missions by the U.S. Space Force.

The first stage is powered by two BE-4 methane-liquid oxygen engines built by Blue Origin, Jeff Bezos' spaceflight company.

The mission will loft two demonstration satellites for Amazon's Project Kuiper broadband constellation, along with a Celestis Memorial Spaceflight payload and a commercial moon lander called Peregrine.

Elizabeth's reporting includes an exclusive with Office of the Vice-President of the United States, speaking several times with the International Space Station, witnessing five human spaceflight launches on two continents, working inside a spacesuit, and participating in a simulated Mars mission.