The four crew members of the Artemis 2 mission exit the Neil Armstrong Operations and Checkout Building during the Countdown Demonstration Test, a launch day rehearsal for the Artemis 2 mission. Image: Michael Cain/Spaceflight Now
In a prelude to the real deal, the four astronauts of the Artemis 2 mission boarded their Orion spacecraft inside the Vehicle Assembly Building at the Kennedy Space Center on Saturday afternoon.
The three Americans and one Canadian participated in a launch day rehearsal referred to as the countdown demonstration test or CDDT. It was the first opportunity for everyone involved with the mission to be on hand and to go through the motions of the big day with the fully integrated rocket in the loop, instead of just data simulations. The test appeared to reach its conclusion with a cutoff of the simulated countdown at the T-29 seconds point at 5:51 p.m. EST (2251 UTC).
Astronauts Reid Wiseman, Victor Glover, Christina Koch and Jeremy Hansen departed the Neil Armstrong Operations and Checkout Building at around 12:20 p.m. EST (1720 UTC), sporting their orange pressure suits, for a 5.5-mile journey to the Vehicle Assembly Building where the Space Launch System rocket and their Orion Capsule was waiting for them. After a few minutes of remarks to stand-ins for their family members and other NASA officials gathered outside, the crew boarded their transport vehicle and hit the road.
Canadian Space Agency astronaut Jeremy Hansen speaks with a NASA employee during the Countdown Demonstration Test on Dec. 20, 2025. Image: Michael Cain/Spaceflight Now
Originally, the astronauts were to be driven in new electric vehicles from a company called Canoo Technologies. However, that company went bankrupt earlier this year and according to a NASA statement to Spectrum News 13, in October, the agency instead leased Boeing’s Astrovan — used to transport astronauts for CST-100 Starliner missions — to serve as the transport vehicle.
The crew departed the building about three hours later than planned. A NASA spokesperson blamed the delay on communications issues, but could provide no further details other than that the issues were resolved and the test proceed.
The rehearsal is already running at least a month behind schedule. It was scheduled for November 19 but NASA postponed that, eventually blaming “a blemish” on a thermal barrier surrounding the Orion crew access hatch which prevented its closure.
The test was rescheduled for Dec. 17, but that too was abruptly delayed without explanation.
The four members of the Artemis 2 crew say farewell to NASA colleagues as they prepared to embark on the next phase of the Countdown Demonstration Test on Dec. 20, 2025. From left to right: Jeremy Hansen, Christina Koch, Victor Glover and Reid Wiseman. Image: Michael Cain/Spaceflight Now
The CDDT is similar to the terminal countdown demonstration tests performed during the space shuttle era. Those launch day rehearsals were done at the pad as they are for SpaceX Crew Dragon missions.
During an Artemis 2 briefing in September, Artemis Launch Director Charlie Blackwell-Thompson said after the crew enters the Orion capsule, they will perform a communications check, strap in, configure the crew module and proceed with the countdown to just before the terminal count before a planned stop.
“As part of that, we’ll also do an egress demonstration and that will be what we call CDDT part one,” Blackwell-Thompson said. “Once that testing is complete, we have some other servicing ops that we’ll take care of in the Vehicle Assembly Building.
“We will go ahead and do our flight termination system test and we’ll start closing out the vehicle compartments as part of our final closeouts of SLS.”
The timing of the rollout of the SLS rocket and Orion spacecraft will be contingent on a smooth CDDT and FTST. The rocket will be travel about four miles from the VAB to the pad at Launch Complex 39B.
The second part of the CDDT will happen shortly after the rocket gets to the pad. Blackwell-Thompson said they’ll use that time to review the emergency egress system, which is a zipline style basket system to get away from the rocket before the launch escape system is armed.
After some additional work, like doing some communications testing at the pad, the astronauts will be brought to the pad to run through the process of using the emergency egress system.
Once all of that is done, the stage will be set for the wet dress rehearsal, where teams will practice loading the SLS rocket with more than 730,000 gallons of liquid oxygen and liquid hydrogen.
The launch of Artemis 2 is currently slated for no earlier than February 6. NASA also says the launch will take place no later than April 2026.