NASA teams have transitioned all cryogenic tanks on the SLS (Space Launch System) rocket to replenish mode during the Artemis II wet dress rehearsal. This includes both liquid hydrogen and liquid oxygen tanks for the core stage and the interim cryogenic propulsion stage. Engineers continue to monitor liquid hydrogen concentration levels in the tail service mast umbilical, where a leak […]
Following the vent and relief test on the interim cryogenic propulsion stage (ICPS) liquid hydrogen tank, NASA teams have entered the topping phase of fueling liquid hydrogen. The vent and relief test verifies that the vent and relief valves operate correctly to maintain safe pressure levels inside the upper stage liquid hydrogen tank, while topping ensures the upper […]
Fueling of the SLS (Space Launch System) rocket is proceeding on all fronts, following earlier pauses on liquid hydrogen flows. Liquid hydrogen and liquid oxygen in the core stage are in the replenish phase. Liquid oxygen has also reached the replenish stage on the upper stage. Replenish mode keeps the tank at flight-ready levels by […]
NASA teams have completed filling the core stage of the SLS (Space Launch System) rocket with liquid hydrogen and transitioned to topping mode. Topping ensures the tank reaches its full capacity with super-cold liquid hydrogen chilled to minus 423 degrees Fahrenheit. Engineers continue to watch the leak at the interface of the tail service mast […]
Editor’s note: This blog post was updated at 4:09 p.m. EST on Feb. 2, 2026, to correct the status of liquid hydrogen operations at the time of posting. Ground teams have resumed loading liquid hydrogen operations into the core stage of the SLS (Space Launch System) rocket. Operations were stopped twice after leak rates at […]
The Expedition 74 crew kicked off the week with SpaceX Dragon spacecraft preparations and science hardware maintenance ensuring research continues providing pristine results aboard the International Space Station.
After teams temporarily resumed fast fill of liquid hydrogen operations into the core stage, initial steps to correct the leak proved unsuccessful. The leak rate at the interface of the tail service mast umbilical continued to exceed the allowable limits. Liquid hydrogen filling operations on both the core stage and upper stage are paused as […]
Teams have started chilling down the lines used to feed liquid oxygen into the upper stage. Troubleshooting of liquid hydrogen loading into the core stage continues.
Teams have stopped the flow of liquid hydrogen through the tail service mast umbilical interface into the core stage after leak concentrations exceeded allowable limits. Stopping the flow allows engineers to perform troubleshooting procedures that were developed after Artemis I. Liquid oxygen continues to flow into the core stage, and liquid hydrogen continues to flow […]
