NASA has targeted Thursday, February 19, 2026, at 8:30 p.m. EST for the Artemis II wet dress rehearsal — the most comprehensive ground test short of an actual launch, and the final major systems hurdle before the agency sends humans beyond low-Earth orbit for the first time since 1972.

Launch controllers began the nearly 50-hour countdown sequence at Kennedy Space Center, Florida, on the evening of February 17. A successful rehearsal would open the door to an earliest crewed launch opportunity of March 6, 2026.

So what exactly is a wet dress rehearsal? The "wet" refers to cryogenic propellants — in this case, liquid hydrogen and liquid oxygen — being loaded into the Space Launch System rocket's core stage and upper stage tanks. It is, in short, a full-scale countdown simulation: the launch team runs through every procedure up to the point of ignition, pausing at T-minus 1 minute 30 seconds and again at T-minus 33 seconds before recycling the clock back to T-minus 10 minutes. The team will execute two terminal count sequences within a four-hour test window. The rocket does not leave the pad. But every system that would be live on launch day is exercised under real propellant load.

Notably, the four Artemis II crew members — Reid Wiseman, Victor Glover, Christina Koch, and Canadian Space Agency astronaut Jeremy Hansen — will not board Orion for the rehearsal. Ground teams will conduct spacecraft closeout and hatch operations in their place.

The test comes after a minor but significant setback: a February 12 fueling test was halted when engineers identified a suspected filter problem in ground support equipment affecting liquid hydrogen flow. Technicians replaced the component within days and proceeded to the full rehearsal attempt — a contrast worth noting.

For context: the Artemis I uncrewed test flight in 2022 required multiple scrubbed wet dress rehearsal attempts over several months before NASA finally launched in November of that year. Hydrogen leaks, ground equipment faults, and a hurricane forced repeated delays, turning the pad operations into a prolonged public demonstration of the program's struggles. That the Artemis II team diagnosed and resolved a similar hydrogen flow issue in under a week reflects meaningful operational progress.