Technicians inside the Vehicle Assembly Building at NASA’s Kennedy Space Center began a delicate, multi-day task Thursday to lift the 94-ton core stage of the first Space Launch System heavy-lift rocket for mounting between two solid-fueled boosters already stacked for a test flight to the moon.

But NASA plans to use the government-owned Space Launch System rocket and Orion capsule for the round-trip flight between Earth and the vicinity of the moon, where astronauts will transfer into a lunar lander, such as the Starship, for descent to the surface.

The lifting of the SLS core stage onto its mobile launch platform moves NASA closer to launch of the Artemis 1 test flight.

Before dawn Friday, teams maneuvered the core stage vertical to allow ground crews to disconnect one of the cranes attached to the aft end of the rocket.

The rocket’s twin solid rocket boosters, each standing 177 feet (54 meters) tall, are already stacked inside High Bay 3 on a mobile launch platform.

During launch, the core stage’s RS-25 engines and twin solid rocket boosters will generate 8.8 million pounds of thrust.

The hoisting of the SLS core stage comes about six weeks after the rocket rolled into the Vehicle Assembly Building at Kennedy, following an ocean journey aboard a NASA barge from the Stennis Space Center in Mississippi.

After connecting two cranes to each end of the rocket, ground crews removed one of the two transporters underneath the core stage Thursday, leaving the rocket partially suspended over the floor of the transfer aisle.

Once teams rolled the other transporter out from under the rocket, the cranes lifted the core stage farther off the ground before rotating it vertical.

With the core stage in place, Lanham said the pace of stacking will be be “fairly quick.” Next will be the Launch Vehicle Stage Adapter, or LVSA, the interstage structure that will connect the main stage with the rocket’s upper stage.

The hydrogen-fueled upper stage is derived from the second stage of United Launch Alliance’s Delta 4-Heavy rocket.

Once the upper stage is installed, ground teams will lift another adapter designed to connect the Orion capsule.

That will set the stage for a test to verify the propellant lines, fluid connections, and other umbilicals running between the mobile launch platform’s tower and the rocket can safely release and retract as they will at liftoff.

Ground teams begin process to hoist SLS core stage onto its launch platform