Artemis II Team Completes Full Launch Day Rehearsal, Simulates Cutoff

NASA and its partners conducted a Countdown Demonstration Test for the Artemis II crew at Kennedy Space Center on December 20 and 21, 2025, executing a near complete launch day timeline and rehearsing procedures with hardware in the loop. The drill involved the four astronauts, hundreds of launch, flight and recovery personnel, and integrated Orion and Space Launch System hardware to exercise communications, boarding, closeout and contingency flows ahead of the mission's first crewed lunar test flight.

The crew for Artemis II consists of Reid Wiseman, Victor Glover, Christina Koch and Jeremy Hansen, a team made up of three Americans and one Canadian. The agency said the participants and ground teams entered the CDDT having already completed more than 30 prior mission simulations together, reflecting a long lead up of coordinated training and systems checks.

Over the two day rehearsal the astronauts donned survival and flight suits, departed the Neil Armstrong Operations and Checkout Building O&C, rode through the Vehicle Assembly Building and boarded the Orion spacecraft while it remained inside the VAB. Mission managers deliberately included Orion and SLS hardware in the integrated test environment so teams could walk procedures with real interfaces rather than only data driven simulations. Ground to crew communications checks, closeout flows and a full terminal countdown timeline were carried out as if for a real launch, including rehearsals for weather and propellant contingencies.

The simulated launch sequence reached the terminal countdown and concluded with a planned cutoff 29 seconds before liftoff, occurring at 5:51 p.m. Eastern Standard Time on December 21, 2025. That scripted halt let teams verify abort and response processes at a critical final moment, and will inform refinements to routines ahead of live fueling and rollout operations.

Following the CDDT, program managers are preparing a wet dress rehearsal that will fully fuel the SLS core stage and upper stage with cryogenic liquid oxygen and liquid hydrogen. The wet dress is expected to practice loading more than 730,000 gallons of propellant and to run a complete countdown sequence with the rocket on the pad. Additional pad activities planned before that test include an emergency egress exercise for the crew and final communications verifications prior to rollout to Pad 39B.

Artemis II is slated as the program's first crewed flight, a roughly 10 day test mission that will send the crew around the Moon and back to Earth. The flight is intended as a human systems and ground systems checkout ahead of later missions that will seek to return humans to the lunar surface. Work on related exploration systems continues in parallel, including partner efforts to develop a new spacesuit that has seen testing at the Neutral Buoyancy Laboratory for use in training and future missions.

Enthusiast communities have characterized the December drill as the last major rehearsal before crewed launch, and some community projections list a potential launch window in February through April 2026, a timeframe that has not been presented as an official agency launch date. NASA officials will provide formal schedules for the wet dress rehearsal and pad rollout as plans are finalized.