NASA’s Artemis II SLS (Space Launch System) rocket with the Orion spacecraft atop a mobile launcher is seen at Launch Complex 39B, Thursday, Jan. 29, 2026, at NASA’s Kennedy Space Center in Florida.
NASA/Jim Ross
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 oxygen chilled to minus 297 degrees Fahrenheit.
The chilldown process ensures the hardware is conditioned for the extreme temperatures of cryogenic propellants, reducing thermal shock and safeguarding system integrity.
A 24/7 live stream of the rocket at the pad remains online, as well as a separate feed to capture wet dress activities.
