NASA's "Artemis 2" Moon mission has been delayed from March to earliest April due to a helium problem detected in the SLS rocket's upper stage following a fueling test. Former German astronaut Ulrich Walter, who experienced similar issues in 1993 with a hydrogen valve delaying a Shuttle launch, explained that helium is a "tricky, hard-to-control gas" essential for pressurizing cryogenic fuels like liquid hydrogen and oxygen. The SLS rocket will now be returned to the Vehicle Assembly Building at Kennedy Space Center for further inspection. This mission, carrying astronauts Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen, aims to orbit the Moon, marking the first human lunar journey since 1972 and the second flight of the SLS rocket. Walter believes an April launch is realistic if no further major complications arise.