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 […]
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 […]
As teams continue to fuel the SLS (Space Launch System) rocket’s core stage with liquid oxygen and liquid hydrogen, teams began propellant loading operations for the rocket’s interim cryogenic propulsion stage (ICPS), or upper stage. The launch control team is filling the ICPS with liquid hydrogen. The core stage liquid hydrogen and liquid oxygen tanks, meanwhile, are currently in fast fill. A 24/7 live stream of […]
Teams began chilling down the liquid hydrogen lines for the interim cryogenic propulsion stage of NASA’s SLS (Space Launch System) rocket. This critical step cools the propellant lines ahead of loading super-cold liquid hydrogen, chilled to minus 423 degrees Fahrenheit, into the SLS’s upper stage tank. The chilldown process ensures the hardware is properly conditioned for cryogenic temperatures, reducing thermal shock and […]
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 […]
Teams have started chilling down the liquid hydrogen (LH2) and liquid oxygen (LOX) lines for the SLS (Space Launch System) rocket’s core stage. This critical step cools the propellant lines ahead of loading super-cold liquid hydrogen and liquid oxygen into the core stage tanks, which will eventually hold hundreds of thousands of gallons of liquid hydrogen chilled to minus 423 degrees Fahrenheit and liquid […]
At approximately 11:25 a.m. EST, the Artemis launch director, in coordination with the mission management team chair, gave the “go” to begin loading cryogenic liquid propellant into the SLS (Space Launch System) rocket for wet dress rehearsal. While teams continue to monitor cold weather that would impact launch day, they are not tracking weather constraints to Monday’s tanking operations. NASA teams have completed final preparations and closeouts of the umbilicals […]
The Artemis II wet dress rehearsal countdown continues as teams at NASA’s Kennedy Space Center in Florida began configuring the SLS (Space Launch System) rocket and Orion spacecraft with gaseous nitrogen, an important step to mitigate fire hazards, protect spacecraft systems, and ensure mission safety. Technicians are currently replacing the ambient air in the SLS and Orion crew module with gaseous nitrogen, which is an inert […]
