For SpaceUpClose.com & RocketSTEM
KENNEDY SPACE CENTER, FL – Repairs are in progress on NASA’s first ever Space Launch System (SLS) Mega Moon rocket and ground systems required to carry out the next attempt at the critical countdown and fueling test – known as the Wet Dress Rehearsal (WDR) – after the 32 story tall stack rolled off the launch site at Launch Complex 39B at NASA’s Kennedy Space Center (KSC) and rolled back to the Vehicle Assembly Building (VAB) overnight on April 25 to April 26.
The WDR cryogenic fueling and practice countdown test was halted after 3 attempts in April due to technical problems mostly with the ground systems.
The WDR must be successfully completed before NASA can proceed forward with the launch of the maiden SLS on the unpiloted Artemis 1 lunar mission now slated for no earlier than (NET) this summer.
Due to the huge volume of work ahead being compounded by another time consuming back and forth trip between the VAB and pad 39B after a hopefully successful WDR as soon as June, launch of the uncrewed Artemis 1 test flight is likely to slip to either the early or late August launch windows.
The 4.2 mile (6.8 km) journey of NASA’s Space Launch System (SLS) rocket integrated with the Orion spacecraft for the Artemis I mission from pad 39B to the VAB took about 10 hours -beginning at 7:54 p.m. ET Monday evening, April 25 and concluding just before dawn at approximately 6 a.m. ET on Tuesday morning, April 26.
Enjoy our gallery of up close photos of the SLS stack move taken from the KSC Press Site by the Space UpClose team of Ken Kremer and Jean Wright.
After arriving inside the VAB and securing the stack the team extended the work platforms to allow access to SLS and Orion from top to bottom.
The top priorities for technicians inside the VAB were to replace a faulty upper stage check valve and find and fix a small hydrogen leak within the tail service mast umbilical (TSMU) ground plate housing, and perform additional checkouts before returning to the launch pad for the next wet dress rehearsal attempt.
Furthermore, Air Liquid, the commercial supplier for the gaseous nitrogen (GN2) system, will make and verify upgrades to their pipeline configuration to support Artemis I testing and launch which twice delayed the WDR attempts by several hours when it was not operational in time during the countdown prior to the start of cryogenic fueling.
Following a serious leak of hazardous hydrogen NASA was forced to halt the 3rd attempt to complete the critical countdown and fueling test of cryogenic propellants known as the Wet Dress Rehearsal (WDR) on Thursday, April 14, for the maiden Space Launch System (SLS) Mega Moon rocket planned to launch on the unpiloted Artemis 1 lunar mission as soon as this summer.
NASA decided the SLS rocket would have to be rolled back to the VAB to locate, fix and repair the source of the hydrogen leak discovered in the tail service mast umbilical at the base of the mobile launcher during loading of liquid hydrogen (LH2) propellent into the SLS core stage Thursday afternoon April 14 – and resolve other significant problems as well such as the faulty upper stage Helium (He) check valve.
NASA officials said they hope to roll the SLS stack back out to pad 39B by late May if repairs are satisfactorily completed, at a media briefing.
If that happens then the launch term is aiming to conduct the next WDR test attempt in the early to mid-June timeframe.
To date engineers working inside the VAB have “replaced the faulty helium check valve on the interim cryogenic propulsion stage (ICPS) that was identified after the second wet dress rehearsal attempt.”
After inspecting the valve they “found a small piece of rubber that prevented the valve from sealing correctly. Teams are looking at possible sources of the debris, but did not see any issues with the valve itself, and plan to test the newly installed valve later this week to confirm it is operating as expected,” officials said at the My 5 media briefing.
“Engineers also performed tests to address a hydrogen leak on one of two tail service mast umbilicals between the mobile launcher and the rocket. These umbilicals provide liquid oxygen and liquid hydrogen propellants, as well as electrical connections, from the mobile launcher to the rocket’s core stage during the launch countdown. Teams conducted leak checks on all the joints and tightened several flange bolts, or fasteners that act as a washer to increase the compression strength, that can loosen over time and were the most likely source of the leak. Teams re-tightened the flange bolts on the liquid hydrogen, liquid oxygen, and core stage intertank umbilicals. Engineers have not detected leaks in subsequent testing at ambient air temperature, and will continue to monitor for leaks when loading the super cold propellants at the launch pad.”
The supplier that provides gaseous nitrogen for operations during tanking is upgrading its facility to meet the requirements for the next wet dress rehearsal attempt and the Artemis I launch. Teams are on track to complete the work early next week, followed by testing to ensure the system is ready for tanking. During the test, teams pump gaseous nitrogen into dry structures to protect avionics during propellant loading.
After all major work is completed and verified, teams will retract the working platforms and prepare the integrated SLS rocket and the Orion spacecraft for the second journey to the launch pad, likely late May.
More precise dates for roll to the pad and the next WDR attempt will only be announced after work is nearing completion inside the VAB.
Watch Ken’s commentary about NASA SLS WDR demo test, NASA Crew-3, Crew 4 and SpaceX AX-1 missions and Starlink.
Apr 29: WKMG CBS 6 with my commentary about the record setting Falcon 9 turnaround of 21 days since the Axiom-1 launch
Apr 22: Fox 35 Orlando features my analysis of the busy week ahead in space with weather delayed Earth return of AX-1 crew this weekend, launch of 4 NASA/ESA Crew-4 astronauts on SpaceX Crew Dragon NET Apr 26 & rollback of NASA SLS to VAB for repairs
Apr 20: WFTV ABC News Orlando features my commentary about the SpaceX static fire and impact of weather induced delays to departure of Ax-1 and launch of Crew-4.
Apr 15/16 & Apr 12/13: WFTV ABC News Orlando and WKMG CBS 6 Orlando featured my comments about NASA SLS WDR wet dress rehearsal countdown and fueling demo test and human launches to ISS:
Apr 6: WFTV ABC 9 Orlando featured my comments about 1st fully private astronaut launch to ISS by SpaceX on AX-1 mission:https://www.wftv.com/news/local/brevard-county/first-all-private-astronaut-mission-iss-set-liftoff-kennedy-space-center-this-week/FYE5QAT735BA7G42O6IVCJGB4Q/
Apr 4 & 5: WFTV ABC News Orlando and Fox 35 Orlando featured my comments about NASA SLS WDR wet dress rehearsal countdown and fueling demo test and human launches to ISS
Watch Ken’s continuing reports about Artemis, SLS, Orion and NASA missions, SpaceX Crew and Cargo Dragons, SpaceX Axiom-1, JWST, IXPE, DART, Lucy Asteroid mission, GOES, SpaceX Starlink, Commercial Crew and Starliner and Crew Dragon, Blue Origin and Space Tourism, and onsite for live reporting of upcoming and recent SpaceX and ULA launches including Crew 1 & 2 & 3 & 4, ISS, Solar Orbiter, Mars 2020 Perseverance and Curiosity rovers, NRO spysats and national security missions and more at the Kennedy Space Center and Cape Canaveral Space Force Station.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news: www.kenkremer.com –www.spaceupclose.com – twitter @ken_kremer – email: ken at kenkremer.com
Dr. Kremer is a research scientist and journalist based in the KSC area, active in outreach and interviewed regularly on TV and radio about space topics.
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