Following successful chilldown of the liquid hydrogen and liquid oxygen lines, teams started slowly filling the SLS (Space Launch System) rocket’s core stage with super-cold liquid hydrogen, chilled to minus 423 degrees Fahrenheit, then with liquid oxygen chilled to minus 297 degrees. This marks the official start of propellant loading for the Artemis II wet dress rehearsal.
Slow fill is a deliberate process that allows the tanks and associated hardware to thermally condition before transitioning to fast fill. This step minimizes thermal stress and ensures the integrity of the system as hundreds of thousands of gallons of cryogenic propellant flow into the core stage.
A 24/7 live stream of the rocket at the pad remains online, as well as a separate feed to capture wet dress activities.
February 2, 2026
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