An issue with the SLS rocket's helium pressurization system is prompting the move. It can only be worked on while inside NASA's Vehicle Assembly Building.

NASA has conducted two wet dress rehearsals for Artemis II, the latest of which concluded Feb. 19. Having resolved a hydrogen fuel leak that stymied the first practice countdown, NASA on Feb. 20 set March 6 as its targeted launch date.

NASA vs SpaceX rockets compared on cost, technology, and performance, revealing how reusability and innovation reshape modern spaceflight missions.