Artemis II crew boards Orion spacecraft for prelaunch rehearsal

The Artemis II crew boarded the Orion spacecraft as part of a prelaunch rehearsal conducted on December 20, 2025, at NASA’s Kennedy Space Center in Florida.

NASA stated that the event took place on December 23, 2025, during the countdown demonstration test, which was intended to practice launch-day procedures.

As the Space Launch System rocket was still not located at the launch pad, the crew was allowed to enter the Vehicle Assembly Building, where they carried out the last steps of preparing the spacecraft, rocket, and ground systems that were still under the final stages.

The rehearsal covered the entire timeline of launch-day activities, ending just moments before the scheduled time for liftoff.

Artemis II crew completes prelaunch procedures inside the Orion spacecraft

Artemis II crew participation in the rehearsal

The NASA astronauts Reid Wiseman, Victor Glover, and Christina Koch, as well as Canadian Space Agency astronaut Jeremy Hansen, make up the Artemis II flight crew.

The astronauts were in their launch and entry suits on the day of the test and went through the same steps as planned for launch day.

The astronauts stayed in the Astronaut Crew Quarters at the Neil A. Armstrong Operations and Checkout Building before going to the spacecraft.

This practice was a teamwork of the astronauts and NASA launch and mission teams to check the crew-specific procedures within the general launch schedule.

Countdown demonstration test objectives

The countdown demonstration test is meant to confirm the events sequence on launch day.

The rehearsal of Artemis II saw the teams executing the final hours of the countdown, where they did the spacecraft boarding, checked communications, and tested the integrity of the suits.

The test ended around 30 seconds prior to the scheduled liftoff point.

According to NASA, the exercise gave an opportunity for the teams to work on operations as if it were launch day and the spacecraft and ground systems were ready for flight.

Problems happening in the rehearsal were not only noted but also solved in real-time as a part of the standard test objectives.

Boarding Orion inside the Vehicle Assembly Building

As the SLS rocket was not rolled out to Launch Complex 39B yet, the crew entered Orion at the Vehicle Assembly Building's High Bay 3.

The astronauts were transported by the Artemis crew transport vehicle after their departure from the Operations and Checkout Building.

Then they took the mobile launcher elevator to the crew access arm, where the closeout team helped them into the spacecraft.

The closeout crew strapped the astronauts in, finished the hatch closure process, and managed leak and communications checks in line with launch-day plans.

Roles of launch and closeout teams

The Rocco A. Petrone Launch Control Center was where the launch teams worked while the closeout crew was at the spacecraft level.

The activities of the environmental control and life support system checks, the audio communications verification, and the countdown synchronization were handled by these teams.

NASA considered this rehearsal as the first complete end-to-end countdown test with the Artemis II crew in the Orion launching configuration.

Earlier tests were concerned with individual elements, but this one united crew operations, vehicle and ground systems interactions.

Next steps toward the Artemis II mission

NASA mentioned that extra countdown testing will be performed following the transportation of the SLS rocket to the launch pad.

Among the future tests are rehearsals of emergency procedures and further validation of launch operations.

Artemis II is designed as the first mission with humans on board of NASA's Artemis program, which will fly around the Moon.

December 2025 will mark the prelaunch rehearsal as a procedural milestone while NASA keeps on preparing the mission with the help of Orion, the Space Launch System and ground infrastructure.

Stay tuned for more updates.