NASA's Artemis II leadership, including John Honeycutt, manager of SLS at Marshall Space Flight Center, discuss its first wet dress rehearsal at a press conference Feb. 3. Photo: Courtesy Joe Raedle/Getty Images
Artemis II is now looking at a potential April launch window.
Why it matters: NASA is preparing to send humans on a trip around the moon for the first time in half a century.
Catch up quick: On Feb. 21,following the mission's second wet dress rehearsal on Feb. 19, NASA observed an interrupted flow of helium to the Space Launch System rocket.
"The systems worked during NASA's Artemis II wet dress rehearsals, but teams were not able to properly flow helium during normal operations and reconfigurations," NASA said in an announcement.
Teams are reviewing the data and potential causes, including the interface between ground and rocket lines used to transport helium, a valve in the upper stage, and a filter between the ground and rocket.
Zoom in: Weather permitting, NASA will roll back Artemis II to the Vehicle Assembly Building (VAB) as soon as today, a four-mile trek that will take hours.
NASA says rolling back to the VAB "is required to determine the cause of the issue and fix it."
The issue follows a hydrogen fuel leak during the mission's first wet dress rehearsal a few weeks ago that delayed the launch from February to March.
What we're watching: Pending the reviews, NASA hopes to preserve the April launch window, and will hold a media event to discuss the rollback and more plans.
