United Launch Alliance (ULA) has rolled out its brand-new Vulcan Centaur rocket to the pad for the first time ever, marking a significant milestone in the development of the rocket.

On March 9th, the rocket was moved from the Vertical Integration Facility to Space Launch Complex-41 at Florida’s Cape Canaveral Space Force Station. This move is part of the preparation for the Vulcan Centaur’s first launch, which is expected to take place no earlier than May 4.

At the launch pad, ULA is conducting a series of “pathfinder tests” to assess the performance of the heavy-lift rocket’s first and second stages, its huge launch platform, and ground support systems, among other equipment. These tests include fueling trials, which have already begun.

ULA tweeted on Friday that the fueling demonstrations for the Vulcan Rocket had started at Cape Canaveral, which includes loading liquefied natural gas and liquid oxygen into the first stage. These tests will also verify countdown steps, procedures, and timelines for the inaugural launch.

After the current testing is complete, the 202-foot-tall Vulcan Centaur rocket will be rolled back to the Vertical Integration Facility, where additional work will be done, including the integration of payloads and their protective fairing.

The debut flight of the Vulcan Centaur will carry a handful of payloads, including the Peregrine, a robotic moon lander built by Astrobotic. Also, two demonstration satellites for Amazon’s Project Kuiper internet constellation and a memorial capsule provided by space-burial company Celestis will be on board.

The Vulcan Centaur will replace both of ULA’s currently operational launchers, the Atlas V and the Delta IV Heavy, and the rocket is capable of delivering 60,000 pounds of payload to low Earth orbit in its burliest configuration, featuring six attached solid rocket boosters. This is comparable to the lift capacity of the Delta IV Heavy but considerably greater than the most powerful variant of the Atlas V.