NASA’s SLS line: Artemis III–V, Artemis VI hardware underway

In High Bay 3 of the Vehicle Assembly Building, booster segments are stacking for Artemis III. The latest sections carrying NASA’s worm logo went onto the launcher on August 20, leaving two motor segments on each booster; the nosecones and forward skirts are already inside the building. In nearby High Bay 2, teams have started installing four RS-25 engines on Core Stage 3, with at least Engines 2 and 3 visible in the latest images.

The launch vehicle is not the only piece moving. At the Operations and Checkout Building, technicians completed the umbilical connections between the Artemis III Orion crew module and its European Service Module, then powered the crew module through those connections for the first time. At Marshall, teams are also preparing a spacer for Artemis III, which does not need the upper stage used on other SLS configurations.

Behind that immediate launch hardware, NASA’s production flow now includes work for Artemis III, IV, V and VI. The Artemis IV liquid hydrogen tank has completed proof testing at Michoud, and its core stage boattail section has arrived in Florida. For Artemis V, the engine-section barrel is being moved into Michoud’s Vertical Assembly Center, where it will receive the ring that connects it to the liquid hydrogen tank.

Artemis VI is the unresolved piece. NASA has begun work on a connecting ring for Core Stage 6, but the agency is still officially supposed to shift to commercial vehicles after Artemis V. The ring could therefore be long-lead manufacturing for a backup if commercial systems are not ready; whether the vehicle reaches full production remains unclear.

So what changes in practice? NASA is building ahead rather than handling each mission as a separate start, giving Artemis III a visible hardware pipeline while later missions already have tanks, engine sections or adapters in motion. The near-term milestone is still Artemis III, targeted for no earlier than June 2027, when Orion is expected to carry four crew members into Earth orbit. The four-vehicle production flow is real; Artemis VI’s final destination is not yet settled.