Author: Tiffany Fairley

Engineers and technicians at NASA’s Kennedy Space Center are conducting final preparations for next week’s roll out of the Space Launch System (SLS) Moon rocket and Orion spacecraft. Currently scheduled for Monday, June 6, the rocket will depart the Vehicle Assembly Building (VAB) and head to Launch Pad 39B for the Artemis I wet dress rehearsal.

Teams successfully completed all major planned objectives identified during the previous wet dress rehearsal attempts, as well as some forward work previously planned for after the tanking test. The removal of the final set of platforms is complete and the crawler transporter sits underneath the massive rocket, spacecraft and mobile launcher.

First motion is scheduled for 12:01 a.m. EDT on June 6, and the launch team will closely monitor weather conditions and use the best window to complete the journey. The four-mile trek will take approximately 8-12 hours to arrive at the launch pad, after which the crawler transporter will make its way back down the pad surface and rest outside the pad gate.

Engineers will then connect the rocket and spacecraft to the ground systems and conduct check-outs in preparation for the tanking test, planned for approximately two weeks after the rocket arrives back at the pad. NASA will provide a live stream at 5 p.m. EDT, Friday, June 3 with an exterior view of the VAB ahead of the rollout of the SLS rocket and Orion spacecraft as well as the arrival at launchpad 39B  on the Kennedy Newsroom YouTube Channel.

The Space Launch System (SLS) rocket and Orion spacecraft are targeted to return to launch pad 39B at NASA’s Kennedy Space Center in Florida on June 6, for the next wet dress rehearsal attempt ahead of the Artemis I mission.  First motion is currently slated for 12:01a, the morning of the 6^th   with tanking operations to begin no earlier than June 19.

The rehearsal is the final test needed before launch and calls for NASA to load propellant into the rocket’s tanks, conduct a full launch countdown, demonstrate the ability to recycle the countdown clock, and drain the tanks to practice the timelines and procedures that will be used for launch.

While inside the Vehicle Assembly Building (VAB), teams completed several major objectives, including assessing the liquid hydrogen system leak at the tail service mast umbilical, replacing the interim cryogenic propulsion stage (ICPS) gaseous helium system check valve and support hardware, and modifying the ICPS umbilical purge boots. The addition of hazardous gas detectors above the upper stage allows for additional visibility into any potential leaks during cryogenic operations.

The hatches, or access points, of the crew module and launch abort system are now closed in preparation for rollout. Engineers installed rain gutters on the crew access area to help prevent moisture from entering the crew module while the spacecraft and rocket are at the launch pad. Teams have started retracting the service platforms that surround the Moon rocket and spacecraft in the VAB for rollout configuration ahead of their return to the launch pad.

NASA will provide livestream views the rollout of the SLS rocket and Orion spacecraft from VAB and arrival at launch 39B. For more information about the launch availability, click here.

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.

Final preparations on the umbilicals to ensure connectivity between the mobile launcher, the Space Launch System rocket and Orion spacecraft were completed this evening.

The umbilicals provide power, communications, coolant, and fuel to different parts of the rocket. Additional accessories provide access and stabilize the rocket and spacecraft. During launch, each umbilical releases from its connection point, allowing the rocket and spacecraft to lift off safely from the launch pad.

Teams have also completed a final walkdown at the pad to verify the rocket and ground equipment are in the correct configuration for tanking operations checking to ensure no foreign object debris is present near the rocket that could present a hazard during the test.

The next update will be provided in the morning of April 14, prior to the mission management team’s pre-tanking briefing where they will review the status of operations and determine if they are “go” to proceed toward tanking operations.

Real-time updates will be provided on the Exploration Ground Systems Twitter account with “go” for tanking targeted on April 14. NASA is also streaming live video of the rocket and spacecraft on the Kennedy Newsroom YouTube channel.

At approximately 5 p.m. EDT today, the launch team arrived at their stations inside the Launch Control Center at NASA’s Kennedy Space Center in Florida. The countdown will begin 30 minutes later at 5:30 p.m. or L-45 hours, 10 minutes before the initial target T-0 for the wet dress rehearsal test for NASA’s Artemis I mission. Teams are proceeding with a modified test, primarily focused on tanking the core stage and minimal propellant operations on the interim cryogenic propulsion stage (ICPS) with the ground systems at Kennedy. Tanking operations are scheduled to occur on Thursday, April 14.

Meteorologists with the U.S. Space Force 45^th Space Wing predict favorable weather for propellant loading operations.  Weather constraints stipulate there must be less than a 20% chance lightning within 5 nautical miles of pad during the first hour of tanking. Winds also must not be above 37.5 knots and the temperature cannot be below 41 degrees Fahrenheit.

Overnight, teams will power up Orion and the Space Launch System core stage, charge core stage battery, and prepare the four RS-25 engines, which will not be lit during the test.

During the test, the timing for some events on account of several planned operational demonstrations tied to specific capabilities and test objectives may differ from the day of launch countdown. These demonstrations include tests on the cryogenic systems and an approximately three-minute hold inside the terminal count, which would not normally occur on launch day. If needed, the test team may also hold as necessary to verify conditions before resuming the countdown, or use the test window or extend beyond it, if consumables and resources allow them to complete test objectives.

In addition to updates on this blog, NASA will provide live updates on the Exploration Ground Systems Twitter account. NASA is also streaming live video of the rocket and spacecraft at Launch Pad 39B on the Kennedy Newsroom YouTube channel. Activity at the launch pad will likely not be visible during the majority of the countdown, but some venting may be seen during tanking on April 14.

The next operational update will be posted the morning of April 13.

In continued preparations for the Artemis I wet dress rehearsal  test, with tanking targeted for Monday, teams encountered an issue maintaining helium purge pressure on the upper stage engine after change-out of a regulator on the mobile launcher. The RL10 engine on the upper stage uses helium to purge the engine and also to activate upper stage valves during wet dress rehearsal operations. After initial troubleshooting, the team reestablished normal helium purge, and is continuing work to determine the cause of a restriction in the helium flow. Engineers will conduct troubleshooting tomorrow to confirm and characterize system performance. If needed, the mission management team will meet Sunday to disposition any adjustments in the procedures or modifications in test objectives as necessary. After the wet dress rehearsal test, SLS and Orion will return to the Vehicle Assembly Building, and engineers will conduct additional inspections of the related flight systems to further evaluate system performance. The Space Launch System rocket, the Orion spacecraft, and the supporting ground system elements remain in stable condition.

The countdown for the two-day test is currently slated to begin with call to stations beginning at 5 pm EDT on Saturday, April 9 with T-0 planned for 2:40 pm on Monday, April 11. While engineers investigate the issue, teams continue to refine the test schedule to account for insights gained during the previous runs and activities, or test objectives, that were completed earlier this week and no longer need to be included in the next test run, such as configuring ground support equipment. Pending additional analysis, NASA expects to have a forward plan tomorrow for wet dress rehearsal testing.

Check back at this blog for an update on wet dress rehearsal testing for the Artemis I mission. NASA is streaming live video of the rocket and spacecraft on the Kennedy Newsroom YouTube channel. Real-time updates will be provided on the Exploration Ground Systems Twitter account with “go” for tanking.

Teams are preparing for the next attempt of the Artemis I  wet dress rehearsal, pending range availability and restoration of propellants and gases during the test. Through the past two test runs April 3 and 4, engineers accomplished several test objectives that will prepare the teams and integrated systems for launch:

• • Configuring Launch Pad 39B and the mobile launcher for the test, just as it will have to be prepared for launch
  • Clearing personnel and equipment from the launch pad after configuration in order to proceed with propellant loading
  • Powering up Orion and the SLS rocket systems in launch configuration, including the solid rocket boosters, the core stage, and the interim cryogenic propulsion stage
  • Checking out and verifying the Orion spacecraft countdown and commanding by flight controllers at NASA Johnson Space Flight in Houston
  • Checking out the guidance, navigation and control system and all the integrated software that operates across the rocket, Orion, ground systems and ground support centers including the Launch Control Center
  • Verifying and checking out all the range safety and systems with the range
  • Draining the liquid oxygen and liquid hydrogen after the test
  • Powering down the rocket, the spacecraft and ground systems and putting them in a safe configuration

All these activities are necessary for a successful launch or in the event launch controllers decide not to proceed with launch if a technical or weather issue arises during or prior to the countdown. Completing these objectives will allow the team to use the next test opportunity to focus on executing the remaining objectives during dynamic operations, such as loading the cryogenic propellant and working through the launch countdown.

Inspections after the second test showed the vent valve that prohibited the team from proceeding with loading liquid hydrogen was configured physically in a closed position, which prevented it from being commanded remotely to an open position. The valve positioning has since been corrected.

Teams were also able to demonstrate their ability to work through several issues, such as severe weather, delays in getting a gaseous nitrogen supply source provided by a commercial vendor up and running, and fixing systems like fans that did not perform as expected.

NASA’s Space Launch System (SLS) rocket, the Orion spacecraft, and the supporting ground system elements are all in excellent condition and in a configuration that supports the next opportunity.

Listen to a replay of the latest briefing, and check back at this blog for an update on the targeted date for resuming WDR testing for the Artemis I mission.

The Artemis I team has ended today’s attempt at the wet dress rehearsal test at 5 p.m. The countdown ended after partially loading liquid oxygen into the Space Launch System core stage tank. This provided the teams a valuable opportunity for training and to make sure modeled loading procedures were accurate. This was the first time using new systems at NASA’s Kennedy Space Center Launch Complex 39B. The team was able to monitor the Artemis I core stage as it was exposed to cryogenic liquids and gather data that will inform updates to propellant loading procedures.

After troubleshooting a temperature limit issue for the liquid oxygen, which delayed the countdown by several hours, the team successfully developed a new procedure for loading the liquid oxygen and filled the tank to 50 percent. Liquid oxygen is an extremely cold, or cryogenic, propellant that is maintained at minus 297 degrees Fahrenheit.

During chilldown of the lines in preparation for loading the liquid hydrogen, the teams encountered an issue with a panel on the mobile launcher that controls the core stage vent valve. The purpose of the vent valve is to relieve pressure from the core stage during tanking. Given the time to resolve the issue as teams were nearing the end of their shifts, the launch director made the call to stop the test for the day. A crew will investigate the issue at the pad, and the team will review range availability and the time needed to turn systems around before making a determination on the path forward.

The wet dress rehearsal is the last major test before launch. This test allows the team to practice propellant loading and thoroughly check out the Artemis I rocket systems as they are exposed to cryogenics.

The launch team is continuing to monitor severe weather in the Kennedy Space Center area surrounding Launch Complex 39B. Earlier this evening one of the lightning towers was struck and teams are currently assessing any impacts.

The lightning protection system consists of three nearly 600 foot tall towers that work together to protect the rocket from lightning strikes. The team will provide an update once a determination has been made on the intensity of the strike and has established a go forward plan.

Meteorologists with the U.S. Space Force Space Launch Delta 45 currently predict favorable weather conditions for tanking on April 3. Forecast for this afternoon slightly improved from yesterday. There is currently less than a 5% chance of lightning within five nautical miles of the launch pad. Weather constraints stipulate there must be less than a 20% chance lightning within 5 nautical miles of pad during the first hour of tanking. Meteorologists are also predicting a 10% chance of winds greater than 23 knots on April 3, when tanking begins. Winds must not be above 37.5 knots and the temperature cannot be below 41 degrees Fahrenheit.

The launch team is monitoring the potential for severe weather in the area later today and adjusting planned outdoor activities to remain on track for the wet dress rehearsal schedule.

While operations at the pad may not be visible during today’s activities at the launch pad, NASA is streaming live video of the rocket and spacecraft on the Kennedy Newsroom YouTube channel.

NASA is also sharing updates on the Exploration Ground Systems Twitter account. Real-time updates from Jeremy Parson, deputy manager of the Exploration Ground Systems Program, will begin on the account when the launch director and mission management team chair give a “go” for tanking operations, expected to occur around 7 a.m. EDT on Sunday, April 3.

The next blog update will be provided after the side flame deflectors are moved into place, which is expected to occur around 5:40 p.m. or L-21 hours.