Artemis I WDR Update: Third Test Attempt Concluded

Teams concluded today’s wet dress rehearsal test at approximately 5:10 p.m. EDT after observing a liquid hydrogen (LH2) leak on the tail service mast umbilical, which is located at the base of the mobile launcher and connects to the rocket’s core stage. The leak was discovered during liquid hydrogen loading operations and prevented the team from completing the test.

Before ending the test, teams also met test objectives for the interim cryogenic propulsion stage by chilling down the lines used to load propellant into the upper stage. They did not flow any propellant to the stage because of an issue with a helium check valve identified several days ago.

When teams paused propellant loading, the rocket’s core stage liquid oxygen tank was about 49% filled and the liquid hydrogen tank had been loaded to about 5% capacity prior to the hydrogen leak.

Teams are now working to drain propellant from the rocket. They will inspect the umbilical connection, review data, and establish a go-forward plan to address the hydrogen leak.

NASA plans to host a media teleconference April 15 to provide updates on troubleshooting and next steps for the wet dress rehearsal test.

Artemis I WDR Update: Teams Complete Modified Upper Stage Liquid Hydrogen Operations

While loading liquid hydrogen (LH2) on the rocket’s core stage earlier this afternoon, engineers detected a leak on the tail service mast , which is located at the base of the mobile launcher and connects to the core stage.

Though engineers stopped loading LH2 and liquid oxygen (LOX) on the core stage, the launch director gave approval for teams to chill down the ICPS LH2 lines to collect additional data and have completed that activity. Engineers will not load LH2 or LOX into the ICPS tanks, due to an issue with a helium check valve experienced several days ago. When teams paused propellant loading earlier today, there was about 49% of LOX on the core stage and about 5% of LH2 was loaded into the core stage tank prior to the hydrogen leak.

The terminal countdown will also not occur today due to the modified configurations and delays with propellant loading. Teams are reassessing the next steps and will determine a go-forward plan following today’s test.

Artemis I WDR Update: Teams Working Solution to Continue Propellant Loading Operations

Following the completion of slow fill for liquid hydrogen (LH2), teams encountered an issue when they started fast fill operations for LH2. After fast fill on LH2 began, a surge in pressure automatically stopped the flow of liquid hydrogen. Teams are working to troubleshoot this issue and the rocket is in a safe configuration. In the meantime, liquid oxygen flow was paused on the core stage to ensure the tanking operations for LOX and LH2 remain synchronized.

After fast fill resumes for liquid hydrogen to the core stage, teams will load minimal cryogenic propellants on the interim cryogenic propulsion stage. Because of an issue with a helium check valve found several days ago, teams will chill down the lines used to load propellant into the upper stage but not flow any actual propellant to the stage.

The clock is continuing to count down for now, and the team will work to re-synchronize the operations timeline and clock during a planned T-10-minute hold at which point the launch team will establish a new T-0.

Follow along with the countdown on the Exploration Ground Systems Twitter and watch a live stream of the test on the Kennedy Newsroom YouTube channel.

Artemis I WDR Update: Core Stage Liquid Oxygen Loading Operations Resume

After troubleshooting an issue with the temperature of liquid oxygen during early stages of propellant loading into the rocket’s core stage, launch controllers have resumed operations. Teams performed chill down operations again before liquid oxygen began flowing into the tank and adjusted pump speeds as necessary during flow to help ensure temperatures remain below limits. They also opened valves to bleed off any warm liquid oxygen.

Earlier in the count, teams began slow fill operations for liquid oxygen, but were automatically halted when temperature readings on the propellant showed it was warmer than intended. The liquid oxygen is an extremely cold, or cryogenic, propellant that is maintained at minus 297 degrees Fahrenheit and must be kept at super cold temperatures. As the super cold liquid oxygen fills the core stage main propulsion system, some venting may be visible.

Teams have now progressed to fast fill for core stage liquid oxygen and slow fill for liquid hydrogen.

Follow along with the countdown on the Exploration Ground Systems Twitter and watch a live stream of the test on the Kennedy Newsroom YouTube channel.

Artemis I WDR Update: Core Stage Liquid Oxygen Propellant Loading Halted, Expected to Resume 

Liquid oxygen loading into the core stage was automatically halted near the beginning of slow fill operations when temperature readings on the propellant showed it was warmer than intended. The rocket is in a safe configuration while teams troubleshoot and determine a path forward.  

Engineers believe they understand the issue and are working a solution that will allow operations to continue. Teams saw a similar issue during the wet dress rehearsal attempt on April 4, but at a slightly different point in propellant loading operations. 

The slow fill process involves slowly filling the core stage with propellant to thermally condition the tank until temperature and pressure are stable before beginning fast fill operations, which is when you fill the tank at a quicker pump speed. 

Follow along with the countdown on the Exploration Ground Systems Twitter and watch a live stream of the test on the Kennedy Newsroom YouTube channel. 

Artemis I Update: Core Stage Liquid Oxygen Chilldown Underway 

The launch control team has begun chill down operations and resumed the countdown clock ahead of flowing super cold liquid oxygen (LOX) into the core stage tank.  The new T-0 time for today’s test is 3:57 p.m. EDT for the first of the two terminal count runs for the wet dress rehearsal.  

The process for the chill down, or cooling, uses the propellant lines to load the Space Launch System rocket’s core stage liquid oxygen in preparation for tanking. The liquid oxygen tank holds 196,000 gallons of liquid oxygen, cooled to minus 297 degrees Fahrenheit. Venting from the super-cold propellant may be visible during this time.  

Liquid oxygen will soon flow into the rocket. Teams will fill the tank slowly at first and then will begin filling it more quickly. As the super cold liquid oxygen fills the core stage tank, some venting may be visible.  

The next blog update will be provided when core stage liquid hydrogen loading begins. 

Follow along with the countdown on the Exploration Ground Systems Twitter and watch a live stream of the test on the Kennedy Newsroom YouTube channel. 

 

Artemis I Update: Launch Director Gives “Go” for Propellant Loading, Countdown Set to Resume 

At approximately 8:05 a.m. EDT, the launch director gave the “go” to start tanking operations.  The countdown will resume at 8:47 a.m. EDT at T-6 hours, 40 minutes.  

Tanking begins with chilling down the liquid oxygen lines for the core stage. In sequential fashion, liquid oxygen (LOX) and liquid hydrogen (LH2) will flow into the into the rocket’s core stage tank and be topped off and replenished as some of cryogenic propellant boils off.  The team also will conduct leak checks to ensure propellant loading is proceeding as expected.  Only minimal cryogenic operations are being conducted on the interim cryogenic propulsion stage because of an issue with a helium check valve found several days ago which cannot be fixed at the launch pad. Teams will chill down the lines used to load propellant into the upper stage but not flow any actual propellant to the stage. 

NASA is streaming live video of the rocket and spacecraft at the launch pad on the Kennedy Newsroom YouTube channel. Venting may be visible during tanking operations. NASA is also sharing live updates on the Exploration Ground Systems Twitter account.   

Artemis I Update: Teams Extending Current Hold, Gaseous Nitrogen Supply Reestablished 

Teams have extended the current hold in the countdown beyond the planned 1.5 hours. Supply has been reestablished of gaseous nitrogen used to purge oxygen from the rocket prior to tanking operations to ensure a safe environment for propellant loading, but teams need additional time to switch supply from air back to the gaseous nitrogen and to discuss confidence in the supply. When the countdown resumes, it will pick up at T-6 hours, 40 minutes. 

Artemis I Update: Mission Management Team “Go” to Proceed with Tanking Pending Resolution of Gaseous Nitrogen Supply Issue 

The mission management team chair has given a “go” to proceed  with tanking the rocket for the Artemis I  wet dress rehearsal test, pending resolution of an issue with an outage at an off-site vendor of gaseous nitrogen used inside the rocket before propellant loading. While a similar issue with a supplier of gaseous nitrogen was experienced during a previous test attempt April 4, teams expect the supply to be reestablished shortly.  Following resolution of the issue, the launch director will give the “go” to officially begin the tanking process. Meteorologists with Space Launch Delta 45 said there were no weather constraints for the test. 

 Tanking begins with chilling down the liquid oxygen lines for the core stage. In sequential fashion, liquid oxygen (LOX) and liquid hydrogen (LH2) will flow into the into the rocket’s core stage tank and be topped off and replenished as some of cryogenic propellant boils off. The team also will conduct leak checks to ensure propellant loading is proceeding as expected.  Only minimal cryogenic operations are being conducted on the interim cryogenic propulsion stage because of an issue with a helium check valve found several days ago which cannot be fixed at the launch pad. Teams will chill down the lines used to load propellant into the upper stage but not flow any actual propellant to the stage. 

 NASA is streaming live video of the rocket and spacecraft at the launch pad on the Kennedy Newsroom YouTube channel. Venting may be visible during tanking operations. NASA is also sharing live updates on the Exploration Ground Systems Twitter account.   

Artemis I Update: Rocket’s Upper Stage and Boosters Powered Up, Countdown On Track

The Space Launch System rocket’s interim cryogenic propulsion stage (ICPS) and boosters were powered up overnight. Teams are in the process of clearing all non-essential personnel from the launch pad area in preparation for propellant loading operations.  

At 6 a.m. EDT, or L-8 hours, 40 minutes, the launch team is expected to reach a planned 1 hour, 30-minute built-in hold. During this time the mission management team will review the status of operations, receive a weather briefing, and make a “go” or “no-go” decision to proceed with tanking operations. 

Tanking milestones include filling the rocket’s core stage with several hundred thousand gallons of liquid oxygen and liquid hydrogen. This will occur over a series of different propellant loading milestones to fill, top off, and replenish the tank. Because of an issue found several days ago with a helium check valve on the rocket which cannot be fixed at the launch pad, cryogenic propellant will not be loaded into the rocket’s upper stage.  

NASA is streaming live video of the rocket and spacecraft at the launch pad on the Kennedy Newsroom YouTube channel. NASA is also sharing updates on the Exploration Ground Systems Twitter account.   

The next blog update will be provided after the “go” or “no-go” decision to proceed with tanking operations.