Weather Favorable for Sept. 3 Launch, Teams Press Ahead with Plan to Address Issues 

Meteorologists with the U.S. Space Force Space Launch Delta 45 predict a 60% chance of favorable weather conditions for an Artemis I launch attempt during a two-hour  window that opens at 2:17 p.m. EDT Saturday, Sept. 3. While rain showers are expected in the area, they are predicted to be sporadic during the launch window. 

 Today, engineers are implementing plans approved at yesterday’s mission management team meeting to address issues that arose during a launch attempt Aug. 29. The mission management team will reconvene Thursday, Sept. 1 to review data and overall readiness — NASA subsequently will hold a status update at 6 p.m. EDT.  

The countdown for launch is scheduled to resume Saturday at 4:37 a.m., at the L-9 hour, 40 minutes planned hold in the countdown where managers receive a weather briefing and conduct a poll on whether to proceed with propellant loading operations. Launch controllers do not need to begin the initial 46 hour, 10 minute countdown again because many of the configurations needed for launch are already in place.   

On Saturday, live coverage of tanking operations with commentary on NASA TV will begin at 5:45 a.m. EDT. Full launch coverage in English will begin at 12:15 p.m. and NASA en espanol broadcast coverage will begin at 1 p.m. EDT. Click here for the latest information on launch briefings and events.  

NASA Targets Sept. 3 for Next Artemis I Moon Mission Launch Attempt

NASA will target Saturday, Sept. 3 at 2:17 p.m. EDT, the beginning of a two-hour window, for the launch of Artemis I, the first integrated test of NASA’s Orion spacecraft, Space Launch System (SLS) rocket, and the ground systems at the agency’s Kennedy Space Center in Florida.

Mission managers met Tuesday to discuss data and develop a forward plan to address issues that arose during an Aug. 29 launch attempt for the flight test. During that launch attempt, teams were not able to chill down the four RS-25 engines to approximately minus 420 degrees F, with engine 3 showing higher temperatures than the other engines. Teams also saw a hydrogen leak on a component of the tail service mast umbilical quick disconnect, called the purge can, and managed the leak by manually adjusting propellant flow rates.

In the coming days, teams will modify and practice propellant loading procedures to follow a procedure similar to what was successfully performed during the Green Run at NASA’s Stennis Space Center in Mississippi. The updated procedures would perform the chilldown test of the engines, also called the kick start bleed test, about 30 to 45 minutes earlier in the countdown during the liquid hydrogen fast fill liquid phase for the core stage.

Teams also are configuring platforms at Launch Pad 39B to enable engineers access to the purge can on the tail service mast umbilical. Once access is established, technicians will perform assessments and torque connection points where necessary.

Meteorologists with the U.S. Space Force Space Launch Delta 45 predict favorable weather conditions for Saturday. While rain showers are expected, they are predicted to be sporadic during the launch window.

The mission management team will reconvene Thursday to review data and overall readiness.

Engineers Assess Data After Scrub, Mission Managers to Meet Tuesday Afternoon  

Engineers are evaluating data gathered during the Artemis I launch attempt Monday, Aug. 29, when teams could not get the rocket’s engines to the proper temperature range required to start the engines at liftoff, and ran out of time in the two-hour launch window to continue. The mission management team will convene Tuesday afternoon to discuss the data and develop a plan forward. 

The Space Launch System’s four RS-25 engines must be thermally conditioned before super cold propellant begins flowing through them for liftoff. Launch controllers condition them by increasing the pressure on the core stage liquid hydrogen tank to route, or “bleed” as it is often called, a portion of the approximately minus 423 F liquid hydrogen to the engines. Managers suspect the issue, seen on engine 3, is unlikely to be the result of a problem with the engine itself. 

During the countdown, launch controllers worked through several additional issues, including storms in the area that delayed the start of propellant loading operations, a leak at the quick disconnect on the 8-inch line used to fill and drain core stage liquid hydrogen, and a hydrogen leak from a valve used to vent the propellant from the core stage intertank. 

 NASA will host a media teleconference Tuesday, Aug. 30, at approximately 6 p.m. EDT to provide an update on data analysis and discussions. The time is subject to change. While managers have not yet set a date for the next launch attempt, the earliest possible opportunity is Friday, Sept. 2, during a two-hour launch window that opens at 12:48 p.m. 


Launch Attempt Scrubbed

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.

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.

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.