NASA’s Space Launch System (SLS) rocket core stage is on the move, the latest step in the Artemis program’s mission to bring the first woman and next man to the Moon by 2024. It will also become the "backbone" rocket for future deep space destinations. The roll out is an "exciting leap forward" – when all is said and done, the SLS will be the most powerful rocket ever built. 

Due to its size, all five core stage structures were assembled separately and then bolted together, measuring 65 meters (212 feet) from end to end. The core stage is considered the "powerhouse" of the rocket, with four RS-25 engines and two massive tanks holding 733,000 gallons of propellant. During liftoff, the core stage will produce 2 million pounds of thrust to send astronauts to the Moon. 

On January 8, 2020, the core stage was loaded onto the Pegasus barge for testing at NASA’s Stennis Space Center near Bay St. Louis, Mississippi. These "Green Run" series will be the final tests before the Artemis launch. The name was given for the green, or new, hardware they plan to evaluate later this year.

"Completion of this first-time build of the Space Launch System rocket’s core stages puts humans on the cusp of a new era of space exploration," said John Honeycutt, the SLS Program Manager at NASA’s Marshall Space Flight Center in Huntsville, Alabama. "NASA’s SLS rocket is designed to evolve so a variety of missions can be accomplished first to the Moon for the Artemis missions and then to Mars and other deep space destinations."

The trip from the Michoud factory to the barge is only 2 kilometers (1.3 miles), but it offered plenty of opportunities to glimpse the SLS rollout. More than 1,100 companies contributed toward the final production of the SLS rocket, with Boeing building the core stage and Aerojet Rocketdyne providing the RS-25 engines.

"This is a historic moment for NASA’s Artemis program and a proud time for the Space Launch System Core Stage team as the first flight article leaves the factory floor," said Julie Bassler, the NASA SLS Stages manager. "Roll out of the core stage to Stennis ahead of the core stage Green Run test series signals an exciting next phase as NASA prepares for the first Artemis launch. The Green Run test series will verify the stage is ready to ship to the launch site."

Since the announcement, the rocket program has been delayed and exceeded initial cost estimates. The Artemis 1 launch date remains tentative, with an estimated launch of November 2020, but with other reports suggesting 2021 from the Kennedy Space Center as more realistic. The first mission will not have a crew on board, instead performing a flyby within 60 miles of the Moon’s surface. 

Artemis 2 will be the program's first crewed mission, with a planned launch date of late 2022. The astronauts will perform a flyby, but not land on the lunar surface  If all goes to plan, Artemis 3 will see the first woman and next man step on the Moon.