The launch director halted today’s Artemis I launch attempt at approximately 8:34 a.m. EDT. The Space Launch System rocket and Orion spacecraft remain in a safe and stable configuration. Launch controllers were continuing to evaluate why a bleed test to get the RS-25 engines on the bottom of the core stage to the proper temperature range for liftoff was not successful, and ran out of time in the two-hour launch window. Engineers are continuing to gather additional data.
Teams Continue to Hold While Data Gathering Continues
Teams are in a hold in the countdown at T-40 minutes while engineers evaluate why the bleed test to condition the engines was not successful. Engineers are looking at options to gather as much data as possible. The Artemis I rocket and spacecraft are in a stable, safe condition.
Engineers Troubleshooting Engine Conditioning Issue
While liquid oxygen loading into the interim cryogenic propulsion stage continues and core stage tanks continue to be replenished with propellants, engineers are troubleshooting an issue conditioning one of the RS-25 engines (engine 3) on the bottom of the core stage. Launch controllers condition the engines by increasing pressure on the core stage tanks to bleed some of the cryogenic propellant to the engines to get them to the proper temperature range to start them. Engine 3 is not properly being conditioned through the bleed process, and engineers are troubleshooting.
Teams also are assessing what appears to be a crack in the thermal protection system material on one of the flanges on the core stage. The flanges are connection joints that function like a seam on a shirt, are affixed at the top and bottom of the intertank so the two tanks can be attached to it.
Core Stage Fueling in Replenish, Go for Upper Stage LOX Loading
The Space Launch System’s core stage liquid oxygen (LOX) and liquid hydrogen (LH2) tanks are fully fueled and both are being replenished. During replenish, the propellant that naturally boils off is being replaced to ensure the tanks are at full capacity for launch. A “go” has been given for liquid oxygen loading into the interim cryogenic propulsion stage.
Core Stage Propellant Loading Continues, Teams Go for Upper Stage Tanking
As teams continue to fuel the Space Launch System (SLS) rocket’s core stage with liquid oxygen (LOX) and liquid hydrogen (LH2), teams have been given a go to begin propellant loading operations for the rocket’s interim cryogenic propulsion stage (ICPS). The ICPS is the upper stage of the rocket responsible for giving the Orion spacecraft the big push it needs to head toward the Moon.
The core stage LOX tank is more than 80% filled, and the core stage LH2 tank is more than 61% filled. Although the LH2 tank is larger than the LOX tank, LOX is denser than LH2 and takes longer to load.
Teams continue to work toward a two-hour launch window that opens at 8:33 a.m. EDT, from Launch Pad 39B at NASA’s Kennedy Space Center in Florida.
Coverage of tanking operations continues on NASA TV and the agency’s website and the NASA app. A full launch broadcast will begin at 6:30 a.m. EDT.
Liquid Hydrogen Fast Fill Resumes, Monitoring Continues
Teams continue to troubleshoot a liquid hydrogen leak at the mating interface with the core stage. After manually chilling down the liquid hydrogen as part of troubleshooting efforts, they are in fast fill operations.
Engineers Troubleshoot Core Stage Liquid Hydrogen Leak in Mating Interface
During the transition from slow fill of liquid hydrogen into the Space Launch System rocket’s core stage to fast fill operations, launch controllers saw a spike in the amount of hydrogen that is allowed to leak into the purge can, a housing covering the tail service mast umbilical’s quick disconnect, or mating interface with the rocket. Engineers started reverse flow of liquid hydrogen into the core stage and are currently troubleshooting.
Although a similar issue was identified in an earlier wet dress rehearsal, it may not necessarily be the same cause.
Core Stage Propellant Loading Underway
After chilling the lines for liquid oxygen (LOX) and beginning with slow fill of the Space Launch System (SLS) rocket’s core stage, the team has now transitioned to LOX fast fill. Teams have also completed chilldown of the liquid hydrogen (LH2) lines and started LH2 slow fill.
Launch Director Gives “Go” to Begin Cryogenic Operations, NASA TV Coverage Underway
Artemis Launch Director Charlie Blackwell-Thompson has given the “go” to officially begin loading propellants into the Space Launch System rocket. The launch weather officer now reports there are no indication of lightning within five nautical miles of Launch Pad 39B. Tanking begins with chilldown of the core stage liquid oxygen transfer line.
NASA TV coverage is underway at http://www.nasa.gov/live.
NASA TV coverage underway, Propellant loading on hold due to weather
The launch team is ready to begin loading propellant into the rocket, but they are holding due to a small weather cell that is producing lighting. Weather criteria for tanking stipulate that the probability of lightning must not exceed 20% in the first hour of tanking. The team is prepared to proceed with tanking as soon as the weather issue is no longer a concern.
NASA TV coverage is underway at http://www.nasa.gov/live.