BUSAN, South Korea — NASA rolled out the second core stage for the Space Launch System rocket July 16 to ship it to Florida for the Artemis 2 mission next year.

The core stage, built at the Michoud Assembly Facility in New Orleans, rolled out of the manufacturing facility there and onto the Pegasus barge moored nearby. The barge will transport the stage to the Kennedy Space Center.

“The delivery of the SLS core stage for Artemis 2 to Kennedy Space Center signals a shift from manufacturing to launch readiness as teams continue to make progress on hardware for all major elements for future SLS rockets,” said John Honeycutt, NASA SLS program manager, in a statement.

The stage, while largely complete, will undergo some additional outfitting once at KSC. It will then be attached to its two solid rocket boosters and interim cryogenic upper stage inside the Vehicle Assembly Building, followed by the Orion spacecraft for the Artemis 2 mission. That mission is currently scheduled for launch no earlier than September 2025.

The second core stage had a smoother assembly than the first core stage, said Dave Dutcher, SLS program manager at Boeing, the vehicle’s prime contractor, in an interview before the rollout. “This is our second one and there are a lot of lessons learned. It’s a much cleaner vehicle throughout the build and test than the first one.”

He said Boeing had “fully implemented” lean manufacturing, an approach that attempts to optimize production and management of supply chains. “We’re constantly looking at where’s the waste in that build.”

Examples of that, he said, include eliminating duplicate testing of items and streamlining work that needs to be done in clean rooms. “We’ve also learned along the way that the most effective way to build this vehicle is doing as much as we can in the vertical,” he said, because it provides 360-degree access.

There are lessons learned from building the Artemis 2 core stage as well, such as changing the sequencing of work and addressing supply chain challenges. “Some of the parts didn’t come in in the order that we would have preferred,” he said. For the Artemis 3 core stage in development, “more of our hardware is coming in in the right sequence.”

Dutcher said Boeing and NASA are continuing with plans to do some final assrmbly work of the core stage at the Kennedy Space Center, starting with Artemis 3. The engine section will be built at KSC in a clean room, along with more vertical assembly. “That’s a tremendous amount of time savings with just those two examples.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...