Late on Saturday night, technicians at Kennedy Space Center in Florida repositioned the core stage of NASA’s second Space Launch System (SLS) rocket between its two solid-fueled boosters. Within the iconic 52-story Vehicle Assembly Building (VAB), ground teams employed heavy-duty cranes to lift the butterscotch-orange core stage from its cradle in the VAB’s vast transfer aisle, a central passageway that connects the building’s four rocket assembly bays. Utilizing the cranes, the structure was rotated vertically, allowing workers to disengage one of the cranes from the rocket’s base.
Subsequently, the rocket was suspended by a 325-ton overhead crane, which elevated it over the transom into the building’s northeast high bay. The core stage, constructed by Boeing, weighs approximately 94 tons (85 metric tons) and stands about 212 feet (65 meters) tall. At liftoff, it will house 730,000 gallons of cryogenic propellant. It is the largest component of NASA’s Artemis II mission, intended to transport a crew of astronauts around the far side of the moon as early as next year.
Ultimately, ground crews stationed the rocket between the Space Launch System’s paired solid rocket boosters, which were already positioned on a mobile launch platform inside High Bay 3—where NASA previously assembled Space Shuttles and Saturn V rockets for the Apollo lunar missions.
On Sunday, teams in the VAB connected the core stage to each booster at forward and aft load-bearing attachment points. Following the completion of electrical and data connections, engineers plan to stack a cone-shaped adapter on top of the core stage, followed by the rocket’s upper stage, another adapter ring, and finally the Orion spacecraft, which will be home to the four-person Artemis II crew during their 10-day deep space mission.
The launch system’s core stage is currently sandwiched between the rocket’s twin solid-fueled boosters inside the Vehicle Assembly Building at NASA’s Kennedy Space Center in Florida. This core stage is powered by four RS-25 engines, leftover from NASA’s Space Shuttle program.
Artemis II marks the first crewed flight of NASA’s Artemis program, which aims to land astronauts on the lunar south pole and establish a sustainable human presence on the moon, with eventual aspirations of reaching Mars. The first crewed lunar landing is anticipated during the Artemis III mission, which will again utilize the SLS and Orion, but with the inclusion of SpaceX’s large Starship rocket as a lunar lander. Although Artemis II will not execute a lunar landing, it will transport humans close to the moon for the first time since 1972.
The core stage for Artemis II was delivered from its manufacturing site in Louisiana last year, and NASA began stacking the SLS solid rocket boosters in November. Recent progress toward Artemis II includes the installation of the solar panels on the Orion spacecraft and the completion of the spacecraft’s service module closeouts at Kennedy Space Center, equipped with aerodynamic panels that will be jettisoned during launch.
The Orion spacecraft is expected to move to another facility at Kennedy for fueling by next month. It will then proceed to another building to be integrated with its Launch Abort System before being transferred back to the VAB to be stacked atop the Space Launch System. Prior to the uncrewed Artemis I mission in 2022, these activities took approximately eight months to complete before Orion was delivered to the VAB. Therefore, skepticism exists regarding NASA’s target launch date for Artemis II in April 2026, as it is already several years behind schedule.
