Artemis II delayed to March after hydrogen leak during wet dress rehearsal
NASA will target a March launch for Artemis II after hydrogen leaks interrupted Monday's fuel test. Teams plan a second wet dress rehearsal and more data review.
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By Torontoer Staff
NASA announced Tuesday it will now target a March launch for the Artemis II moon mission after hydrogen leaks interrupted a critical wet dress rehearsal at Kennedy Space Center on Monday. The agency said the delay will allow teams to review data and conduct a second wet dress rehearsal before the crewed flight test.
The leaks emerged a few hours into the daylong loading of more than 2.6 million litres of super-cold liquid hydrogen and oxygen into the Space Launch System rocket, forcing controllers to halt fuel loading multiple times. Teams also reported delays in close-out operations and intermittent audio dropouts for ground crew communications during the run.
What happened during the wet dress rehearsal
Engineers began hydrogen loading around midday as part of a full dress rehearsal meant to mimic the final stages of an actual countdown. Excess hydrogen accumulated near the base of the 98-metre rocket, prompting at least two pauses while launch controllers worked through mitigation techniques developed after the 2022 debut of the Space Launch System, which was similarly delayed by hydrogen leaks.
NASA said the wet dress rehearsal was stopped short of engine ignition, with countdown clocks set to end a half-minute before zero. The agency has not named a specific launch date in March, saying teams must first fully review test data, mitigate each issue, and return to testing.
We will allow teams to review data and conduct a second wet dress rehearsal before flight test.
NASA
How the delay affects the crew and the schedule
The four astronauts assigned to Artemis II were taken out of their roughly two-week quarantine after the test. NASA said they will enter quarantine again about two weeks before the next launch window. Before Monday's postponement, the earliest possible launch would have been the coming Sunday, and a cold snap had already shortened February's launch opportunities by two days.
The crew includes commander Reid Wiseman, two other American astronauts, and one Canadian astronaut, Jeremy Hansen. On Monday they monitored the rehearsal remotely from Houston, about 1,600 kilometres from the launch site at Kennedy Space Center.
Technical issues and planned responses
- Hydrogen accumulation near the rocket base halted propellant loading multiple times.
- Delays in close-out procedures increased test duration and complexity.
- Ground crew experienced recurring audio dropouts, complicating communications.
- Teams will analyse data, apply mitigations used after the 2022 SLS test, and run a second wet dress rehearsal.
NASA's focus will be on pinpointing leak sources, validating fixes under test conditions, and ensuring reliable communications during critical procedures. Engineers have precedent for identifying and resolving such problems, but the work can require multiple test cycles.
What Artemis II will do
Artemis II is a nearly 10-day crewed flight meant to send four astronauts past the Moon, around its far side, and back to Earth. The mission will not enter lunar orbit or attempt a landing. Its primary goals are to test the Orion capsule's life-support systems, communications, and other systems with astronauts aboard in deep space conditions.
The flight is a test flight intended to advance the Artemis programme's broader aim of establishing a sustained human presence on and around the Moon. Successful completion would set the stage for future missions that plan to return astronauts to the lunar surface.
Next steps and what to watch
NASA has not announced a definitive March launch date. Engineers will complete a full review of wet dress rehearsal data, implement mitigations, and schedule a second dress rehearsal. Stakeholders will be watching for confirmation that hydrogen venting and communication issues have been resolved under test conditions.
Observers should also track any adjustments to astronaut quarantine timing and how the revised schedule interacts with upcoming launch windows. Cold weather and ground support logistics remain factors that can affect the timing of repeat tests and the eventual launch.
The delay is a reminder that complex crewed missions require multiple test cycles to validate systems. NASA says the additional time will help ensure the safety and readiness of both the rocket and crew before Artemis II departs for its flyby of the Moon.
Artemis IINASAspaceKennedy Space Centerrocket
