NASA delays Artemis 2 mission after hydrogen leak in heavy-lift rocket

NASA has pushed back the Artemis 2 launch from its original February 8 date to no earlier than March, following issues with fueling its Space Launch System (SLS) heavy-lift rocket. The same technical glitches had previously delayed the Artemis 1 mission back in 2022.

• The Artemis 2 launch target has shifted from February 8 to March 2025 due to liquid hydrogen leaks
• The problems emerged in the same SLS components that troubled the uncrewed Artemis 1 launch in November 2022
• The four astronauts will exit their two-week quarantine and return to it 14 days before the new launch date

NASA conducted a two-day “wet dress rehearsal”-a full launch simulation including fueling-at Kennedy Space Center in Florida. The test began on January 31 at 8:13 pm EST as the launch control team settled into their stations. Over the next day and a half, engineers powered up both stages of the Space Launch System, charged the Orion capsule’s batteries, and completed most of the prep checklist. But the critical fueling step exposed serious issues.

Leak resurfaces in the same spot as two years ago

On February 2, over 2.65 million liters of cryogenic liquid hydrogen and oxygen were loaded into the SLS fuel tanks. During hydrogen loading into the core stage, a leak appeared at the supply interface. Engineers spent hours troubleshooting, pausing the hydrogen feed, warming up seals for reseating, and adjusting flow rates. They managed to fill and maintain the tanks, but near the end of the countdown simulation, the leak intensified sharply, forcing NASA to abort the test just five minutes before the planned liftoff.

The hydrogen leaks were eerily similar to those that dogged Artemis 1 ahead of its November 2022 launch. All occurred at the same spot-the interface between the tail service mast umbilical and the hydrogen feed line running from the mobile launcher tower to the SLS. Due to multiple leaks, the Artemis 1 mission was postponed from spring 2022 to November. That flight ultimately succeeded, with the unmanned Orion capsule circling the Moon and returning safely to Earth.

Besides the leak, the rehearsal revealed several minor anomalies. Audio communications dropped out several times-a problem that had surfaced in the weeks before testing. A valve related to sealing the Orion crew module hatch had recently been replaced and needed readjustment. Procedures for closing the capsule and preparing it for crew ingress took longer than expected. The four astronauts weren’t involved in the rehearsal, as wet dress rehearsals do not include boarding.

Crew exits quarantine after launch delay

NASA astronauts Reid Wiseman, Victor Glover, Christina Koch, and Canadian Jeremy Hansen have been in quarantine in Houston since January 21. They were scheduled to fly to Florida on February 4 for final launch preparations ahead of the February 8 liftoff, but that trip is now canceled. The crew will exit isolation and return to quarantine two weeks before the new targeted launch date.

There are five launch windows open for Artemis 2 in March: March 6-9 and March 11. If the mission misses these slots, the next windows are in April-on April 1, April 3-6, and April 30. “Engineers overcame several challenges over two days of testing and completed many planned objectives,” NASA said in a February 3 statement. “To give teams time to analyze data and conduct a second wet dress rehearsal, the agency is moving the launch to March as the earliest possible date.”

NASA will hold a press conference on February 4 at 1:00 pm EST (9:00 pm MSK) to provide more details from the wet dress rehearsal. Whenever Artemis 2 finally lifts off, it will mark a historic moment: no human has left low Earth orbit since December 1972, when Apollo 17’s crew returned from the Moon.