NASA's Shuttle-derived super heavy-lifter stands 98 meters tall and has flown twice. NASA cancelled Block 1B and Block 2 upgrades in February 2026 and is standardizing on the flying Block 1 vehicle. The Artemis III core is in the Vehicle Assembly Building, with RS-25 installation and booster stacking underway for an Earth-orbit docking demo.
01 / 06
Configurations
NASA is standardizing on the Block 1 vehicle that already flew twice. Block 1B and Block 2 upgrades — including the Exploration Upper Stage and Mobile Launcher 2 — were cancelled in February 2026.
95 tto LEO
ICPS upper stage, four RS-25s, and five-segment boosters. Flew Artemis I and II. Artemis III stays on this block, with an inert spacer instead of ICPS because the mission remains in Earth orbit.
105 twas LEO
Would have replaced ICPS with the Exploration Upper Stage. NASA cancelled EUS, the Universal Stage Adapter, and Mobile Launcher 2 in February 2026 and is standardizing on Block 1.
130 twas LEO
Advanced-booster upgrade that would have pushed TLI past 43 metric tons. Cancelled with the Block 1B upgrades. NASA is not funding this configuration.
02 / 06
Pipeline
A single SLS flight draws on four NASA centers and contractors. Artemis III hardware is already at Kennedy; Michoud is building what comes after.
Core stage build
Friction-stir welding joins barrel sections into the 212-foot core stage. The Artemis III core left here in April 2026; later cores continue down this line.
Green Run (first article)
The Artemis I core fired all four RS-25 engines on the B-2 stand. Later cores have not repeated that full-duration Green Run before shipping to Kennedy.
Booster casting
Five-segment solid motors are cast in pairs. Each booster produces about 3.6 million pounds of thrust at liftoff — not each segment.
Stack & launch ops
Booster stacking is in the VAB: three of five segments were up as of August 31, and RS-25 installation began August 24. Core mate, the spacer, and Orion are still ahead of rollout to 39B.
03 / 06
Program milestones
5 of 6 tracked gates cleared — the Artemis III core is in the VAB, with RS-25 installation and booster stacking underway.
The Artemis I core stage fired all four RS-25 engines together at Stennis for a full-duration eight-minute hot fire.
The 98-meter rocket rolled out and stood fully stacked on pad 39B for its first launch campaign.
SLS Block 1 lifted off on its debut, sending Orion toward the Moon with margin to spare.
The rocket's first crewed flight carried four astronauts around the Moon and back.
The next core is in the VAB. RS-25 installation began August 24, and three of five booster segments were stacked as of August 31.
NASA cancelled the Exploration Upper Stage, Universal Stage Adapter, and Mobile Launcher 2 in February 2026.
04 / 06
What gates the next flight
This is not a NASA launch probability. It scores public SLS production and test signals — Kennedy stacking, Michoud manufacturing, booster supply, and the cancelled Block 1B path — against what the next flight requires.
III core in the VAB
The Artemis III core is in the VAB. NASA began installing RS-25s E2054, E2057, E2048, and E2052 on August 24 and has not posted that the install is finished. Michoud continues later cores; those articles are not the III stack.
New engines in production
Flights draw from the 16 reused Shuttle-era RS-25Ds plus new-build RS-25E engines entering certification at Aerojet Rocketdyne.
3 of 5 segments stacked
Northrop Grumman said on August 31 that three of five Artemis III segments were stacked on the mobile launcher and the forward assemblies had been delivered. The crew viewed that integration on September 2. Each booster produces about 3.6 million pounds of thrust.
First-article path only
The Artemis I core completed a full-duration Stennis Green Run in March 2021. Later cores, including Artemis III, have not repeated that campaign before shipping to Kennedy.
Cancelled Feb 2026
NASA cancelled the Exploration Upper Stage, Universal Stage Adapter, and Mobile Launcher 2. The agency is standardizing on Block 1.
VAB stacking underway
Booster segments and the core are in the VAB, and engine installation has started. Wet dress and countdown rehearsals still wait on a complete stack and a committed launch period.
05 / 06
References
Primary program records used for this tracker. Readiness figures are editorial estimates from public signals — not an official NASA launch probability.
06 / 06
Related missions
Recent catalog entries flying on the Space Launch System.
