NASA astronauts Chris Williams and Zena Cardman, both Expedition 74 flight engineers, work on spacesuit maintenance inside the International Space Station’s Quest airlock on Dec. 16, 2025.Credit: NASA NASA astronaut Chris Williams will connect with students in Pennsylvania to answer prerecorded science, technology, engineering, and mathematics (STEM) questions while aboard the International Space Station. The [...]
Clouds and the Sun illuminate the sky on Wednesday, Jan. 28, 2026, as NASA’s Artemis II SLS (Space Launch System) rocket and Orion spacecraft stand vertical at Launch Complex 39B at NASA’s Kennedy Space Center in Florida. NASA/Cory S Huston Following the vent and relief test on the interim cryogenic propulsion stage (ICPS) liquid hydrogen [...]
NASA’s Artemis II SLS (Space Launch System) rocket and Orion spacecraft, secured to the mobile launcher, are seen on Launch Pad 39B, Saturday, Jan. 17, 2026, at NASA’s Kennedy Space Center in Florida. NASA/Aubrey Gemignani Fueling of the SLS (Space Launch System) rocket is proceeding on all fronts, following earlier pauses on liquid hydrogen flows. [...]
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 [...]
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 [...]
Photo of the Day What part of Orion is this? Just north of the famous Orion Nebula is a picturesque star forming region in Orion's Sword that contains a lot of intricate dust -- some of which appears blue because it reflects the light of bright embedded stars. The region's popular name is the [...]
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 continues to exceed the allowable limits. Liquid hydrogen filling operations on both the core stage and upper stage are paused [...]
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 [...]
The Moon is seen shining next to the SLS (Space Launch System) and Orion spacecraft, atop the mobile launcher on January 28, 2026, at Launch Pad 39B at NASA’s Kennedy Space Center in Florida.NASA/Sam Lott As teams continue to fuel the SLS (Space Launch System) rocket’s core stage with liquid oxygen and liquid hydrogen, teams began propellant loading [...]
