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NASA's SLS delays due to Hydrogen leak

Photo of the Aft umbilicals of SLS // Photo: Ryan Bale

On Saturday, September 3rd, NASA's Space Launch System (SLS) rocket began fueling up for its second attempt at launching Orion around the Moon on the Artemis I mission.

During initial fueling of the Liquid Hydrogen (LH2) tank on the core stage, there was an over pressure event in one of the lines that caused fuel flow to stop automatically. After this, there was a consistently large LH2 leak coming from the umbilical when switching from slow fill into fast fill that would stop fueling again. After trying a couple different methods to try and "re-seat" the seal of the connection, teams were unable to fix the large leak without going out to the pad, and scrubbed the launch for the day.

SLS at LC-39a 24 hours prior to its second launch attempt // Photo: Ryan Bale

The Mission Management Team met in the Launch Control Center (LCC) after the scrub to assess what the next steps are for SLS. They came to the conclusion of sending teams out to the pad to try and fix the seal and maybe attempt another Wet Dress Rehearsal to ensure the issue has been fixed. After this, they will be rolling SLS back to the VAB, scrubbing any more launch attempts for this period, to replace batteries on the Flight Termination System (FTS) and check out the rest of the vehicle as they have access to it.

The next launch period for Artemis I is period #26 that runs from September 19th through October 4th, but it's possible NASA targets the 27th launch period which runs from October 17th, until October 31st. This will avoid any conflicts with SpaceX's upcoming Crew-5 mission, which is currently slated to launch October 3rd. Any activity of SLS fueling or rollout operations stop all work at LC-39a, which SpaceX launches crewed missions from.

Teams will be assessing the launch date as they work through issues and rollback of the vehicle, so there's no for sure date for the next launch as of now. Follow Spaceflight News on Twitter for future updates on launches and SLS.



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