TL;DR: NASA finished stacking the Artemis III solid rocket booster segments and installed all four RS-25 core-stage engines at Kennedy Space Center, setting up a short-stack tanking test at Launch Pad 39B.
Booster work finished for tanking configuration
According to NASA, teams at Kennedy Space Center in Florida completed integration of the final solid rocket booster motor segments onto the mobile launcher for the "short stack" arrangement planned for a tanking test.
The agency reported the milestone on Oct. 13, 2026, in an update titled "NASA Completes Artemis III Booster Stacking, Shares Status Update." That update said work on the Space Launch System rocket continues at Kennedy.
According to The Florida Press report titled "Artemis III Boosters Fully Stacked at Kennedy Space Center," the formal close of booster stacking occurred Sept. 30, 2026, with integration of aerodynamic nose cones atop the left and right forward assemblies inside High Bay 3 of the Vehicle Assembly Building.
Each forward assembly combines an aerodynamic top, a forward skirt containing avionics, and a frustum containing motors that enable separation of the boosters from the core stage after launch.
The twin solid boosters supply more than 75 percent of total SLS thrust during liftoff from Launch Pad 39B, while also supporting remaining rocket elements and the Orion spacecraft during final assembly.
Four RS-25 engines installed on core stage
Teams also completed installation of all four RS-25 engines on the SLS core stage, according to NASA.
The next core-stage task is installation of the systems tunnel. The tunnel extends along the length of the stage and routes pyrotechnic cabling.
That wiring system permits a single-use, quick disconnect for controlled movements during liftoff. NASA described the tunnel installation as the immediate next step on the massive stage.
In the coming weeks, the stage is scheduled to be joined with the solid rocket boosters. That mating operation will complete the rocket's "short stack" configuration.
The short stack does not include the full upper-stage complement planned for a later flight configuration. It is the vehicle arrangement designated for the upcoming propellant-loading demonstration.
Rollout and propellant-loading rehearsal planned
NASA plans to roll the short-stack SLS rocket from the Vehicle Assembly Building to Launch Pad 39B for a tanking test in the coming months.
During that test, the Artemis launch team will practice procedures and timelines for loading propellant into the rocket.
While the vehicle is at the pad, the Artemis III crew will conduct a launch-day rehearsal and emergency-exit walkdown.
The assigned crew members are NASA astronauts Randy Bresnick, Frank Rubio and Andre Douglas, along with European Space Agency astronaut Luca Parmitano.
The rehearsal sequence includes suiting up in astronaut crew quarters, driving to the launch pad, ascending the mobile launcher, and walking through the exit route designated for the unlikely event of an emergency during the launch countdown.
Pad 39B flame deflector work continues
At Launch Pad 39B, teams continue refurbishment of the flame deflector. According to NASA, the deflector sustained minimal damage following the Artemis II launch.
Bricks on the flame trench itself were not affected by that launch. The agency attributed that outcome to ground-support improvements informed by lessons learned after Artemis I in 2022.
The flame deflector and trench are part of the ground systems that manage exhaust and energy released at liftoff. Continued refurbishment is occurring in parallel with vehicle assembly inside the Vehicle Assembly Building.
Pad readiness and vehicle readiness are proceeding as linked efforts ahead of the planned tanking demonstration.
Orion power and propulsion checks advance
Teams are continuing testing on the Orion spacecraft. Recently, engineers with ESA and Airbus inspected the solar-array wings.
Those wings deliver power to the service module. The service module provides propulsion, thermal control and electrical power to the spacecraft.
It also supplies air and water for the crew. The inspection is part of ongoing integrated checks before further spacecraft processing.
The solar-array inspection follows continued umbilical and systems work on Orion at Kennedy. NASA's October update placed Orion testing alongside booster, core-stage and ground-systems work as parallel paths toward the tanking test.
Spacer and adapters move toward shipment
At Marshall Space Flight Center in Huntsville, Alabama, the forward and aft rings were welded on the Artemis III spacer, completing its primary structure.
The spacer will represent upper-stage dimensions during the mission. Dimensional checks on the hardware are now underway.
Engineers also are converting two existing structural test articles into flight-ready hardware. The items are the Orion stage adapter and the launch vehicle stage adapter.
Exterior painting on the Orion stage adapter was recently completed at Marshall. Cables and brackets are scheduled to be installed soon.
The launch vehicle stage adapter has undergone detailed inspection and preparation. Corrosion removal is nearly complete, and nondestructive evaluation is scheduled to begin this fall.
After that evaluation, technicians will apply conversion coating to the interior, prime and paint the exterior, and apply thermal-protection spray foam to the cone-shaped adapter.
The spacer and both adapters remain on track to ship to Kennedy early next year, according to NASA.
Crew training covers fitness, food and recovery
The Artemis III crew has continued training activities for the mission. Recently, crew members completed lessons on the flywheel exercise device.
They practiced hardware setup, anticipated exercises and equipment disassembly. The compact device is about the size of an extra-large shoe box.
It uses pulleys and a torque limiter to mimic a rowing machine. The design allows aerobic, resistive and rowing exercises with straps attached to either a bar or harness.
Nutrition work has also advanced. At the Space Food Systems Laboratory in Houston, crew members sampled nearly 200 menu items to select favorites for the mission. The selections are intended to support health and performance throughout the flight.
The crew concluded helicopter underwater-egress training. That work involved escape from a submerged, upside-down mock helicopter cabin in a controlled pool environment.
The training prepares the astronauts for potential off-nominal water crash-landings. It focused on controlled exit procedures from an inverted cabin while submerged.
Last week, members of the Artemis III crew traveled to San Diego for recovery training with NASA and military partners. The sessions included water lifts by U.S. Navy helicopters.
They also completed several suited training activities in Orion Crew Survival System suits this week. The work covered post-insertion operations, deorbit procedures and emergency responses.
Those suited activities included communication-system checks, suit operations, emergency-equipment handling, contingency drills and cabin configuration with stowage. NASA described the work as preparation for scenarios that may arise during flight phases.
Crew visits spacecraft and lander providers
In September, the full Artemis III crew and backup astronauts visited Florida together for the first time since their crew announcement earlier this year.
The astronauts visited their Orion spacecraft. They saw the integrated solid rocket boosters atop the mobile launcher.
They also viewed the core stage during final processing ahead of integration. The visit gave the crew a direct look at flight hardware in different stages of assembly.
The crew also visited commercial partners SpaceX and Blue Origin. The purpose was to become more oriented with progress by the lunar-lander providers.
NASA characterized the September visits as another milestone in preparation for the Artemis III mission. The agency provides additional mission information through its Artemis program pages.