NASA@NASA·39mDid you know......that the @NASAArtemis II Moon rocket is 322 feet tall? That’s just a few yards shy of the length of a football field.Bet you thought we were going to say something else about #SBLX. 😉
NASA's Kennedy Space Center@NASAKennedy🏈 Go Long! When a spacecraft needs a ride to space, NASA's Launch Services Program has commercial rockets of all shapes and sizes to choose from as part of the NASA Launch Services II contract.Here's how some of these rockets stack up against a football field!
Ryan Caton@dpoddolphinpro·4h.@NASA has provided an update on the progress towards the next Artemis II Wet Dress Rehearsal:Repairs- Two seals have been replaced where the high hydrogen gas concentrations were- Reconnecting interfaces expected by Monday 9th- Testing will happen at Stennis to "evaluate additional dynamics of the plates"- "Engineers are reviewing options to test the repair work prior to the next wet dress rehearsal to ensure the seals are performing as expected."Changes for next WDR- Orion hatch will be closed prior to next WDR.- Closeout Crew NOT going to pad.- CAA not retracted during terminal count.- 30 mins extra time added to the planned hold before fuelling, and the planned hold after fuelling, allowing more troubleshooting time.These changes are interesting, considering the Orion closeout operations caused a significant amount of the delays & difficulties on the first wet dress.
NSF - NASASpaceflight.com@NASASpaceflightArtemis II: Preliminary information points to a second WDR (Wet Dress Rehearsal) target of next Friday.Interestingly, there's talk of a NET launch date of March 3 (not previously in the windows), which could result in a daylight launch T-0. All subject to change of course, and hydrogen behaving.
NASA Updated on work performed on Artemis II H2 leakNASA Conducts Repairs, Analysis Ahead of Next Artemis II Fueling Testby : Rachel H. KraftEntire Text:QuoteSince concluding a wet dress rehearsal Feb. 3 ahead of Artemis II, technicians have replaced two seals in an area where operators saw higher than allowable hydrogen gas concentrations during the test. Engineers are analyzing the removed seals and developing plans to address all issues ahead of the next rehearsal.Once the SLS (Space Launch System) rocket’s tanks were drained of cryogenic propellant following the previous test, technicians immediately began work to access the tail service mast umbilical on the mobile launcher and detach rocket and ground-side interface plates to inspect the area of the elevated gas levels, and replace seals around two fueling lines.Two tail service masts, each about three stories tall, provide cryogenic propellant lines and electrical cable connections to the SLS core stage. The tail service masts tilt back before launch and include “quick disconnects,” mechanisms that instantaneously disconnect at liftoff to ensure a safe and reliable retraction at launch.While teams continue evaluating the cause of the leak, reconnecting the interfaces is expected to be complete on Monday, Feb. 9.
Since concluding a wet dress rehearsal Feb. 3 ahead of Artemis II, technicians have replaced two seals in an area where operators saw higher than allowable hydrogen gas concentrations during the test. Engineers are analyzing the removed seals and developing plans to address all issues ahead of the next rehearsal.Once the SLS (Space Launch System) rocket’s tanks were drained of cryogenic propellant following the previous test, technicians immediately began work to access the tail service mast umbilical on the mobile launcher and detach rocket and ground-side interface plates to inspect the area of the elevated gas levels, and replace seals around two fueling lines.Two tail service masts, each about three stories tall, provide cryogenic propellant lines and electrical cable connections to the SLS core stage. The tail service masts tilt back before launch and include “quick disconnects,” mechanisms that instantaneously disconnect at liftoff to ensure a safe and reliable retraction at launch.While teams continue evaluating the cause of the leak, reconnecting the interfaces is expected to be complete on Monday, Feb. 9.
The real reason is because doing vehicle checkout in the VAB is the entire point of the VAB. The pad isn't a good environment to be out at doing highly technical work.They might change the procedure if it really is necessary, but if it isn't, doing that work at the pad doesn't make sense and just complicates the pad flow.
Has Crew-12 delay any impact on WDR-2 ?
Feb 9, 2026NASA explains the procedure astronauts will undertake to shield themselves in case of a solar storm hitting the spacecraft during flight. Credit: NASA Johnson Space Center
Was it the cold that did the seals in?
Quote from: hektor on 02/09/2026 02:52 pmHas Crew-12 delay any impact on WDR-2 ?Nothing has been announced, but the two missions are completely independent of each other. Different pads, crews, control centers, and staffs.
One of the areas where NASA is trying to separate the missions is concerning the suit up room in the Neil Armstrong Operations and Checkouts building at the Kennedy Space Center in Florida. That’s where crews don their flight and entry suits and perform leak checks prior to heading out to the launch pad.Another area for deconfliction is in the Department of Defense assets that are positioned in the unlikely event that there were an in-flight abort during ascent. Both the Artemis program and the Commercial Crew Program use similar capabilities provided by the DoD before reaching orbit.
Quote from: RocketFan1959 on 02/09/2026 05:37 pmQuote from: hektor on 02/09/2026 02:52 pmHas Crew-12 delay any impact on WDR-2 ?Nothing has been announced, but the two missions are completely independent of each other. Different pads, crews, control centers, and staffs.They are NOT "completely independent of each other". They use some of the same unique range and marine recovery assets that cannot be replaced or reallocated in short order: https://spaceflightnow.com/2026/01/30/cold-weather-delays-earliest-artemis-2-launch-opportunity/QuoteOne of the areas where NASA is trying to separate the missions is concerning the suit up room in the Neil Armstrong Operations and Checkouts building at the Kennedy Space Center in Florida. That’s where crews don their flight and entry suits and perform leak checks prior to heading out to the launch pad.Another area for deconfliction is in the Department of Defense assets that are positioned in the unlikely event that there were an in-flight abort during ascent. Both the Artemis program and the Commercial Crew Program use similar capabilities provided by the DoD before reaching orbit.
Feb 9, 2026NASA had heat shield on the Orion capsule with Artemis 1, and they are flying the same heat shield design with astronauts on Artemis 2.
Echo@Echo5550·14mLooks like the scaffolding that was previously on the Tail Mast has been removed! Good sign that repairs have been finished and it has been reconnected like NASA has said in a blog post.Up Next WDR!
The spokesperson did not immediately provide any additional details, including the amount of hydrogen to be loaded aboard the rocket or if the propellant tank would be pressurized to duplicate the conditions that interrupted the WDR.
Ryan Caton@dpoddolphinpro·Interesting note that @NASA has changed its mind about sending the Closeout Crew to LC-39B during Wet Dress Rehearsal #2: "a team of personnel will go to the launch pad to practice Orion closeout operations, including closing the spacecraft’s hatches."Alongside the troublesome hydrogen TSMU, the closeout crew faced a number of difficulties & delays during WDR #1 - hopefully their learnings will make this process easier this time around.
QuoteRichard P. Gallagher@rpg571·1hThe Hydrogen Leak Puzzle: Why SLS's Keeps Springing Leaks—and NASA's Plan to Seal ItWhy Hydrogen Plays Hard to Seal: The Tiny Molecule That Won't Stay Put[delete much for clarity]But here's where it bites: thermal contraction. "Steel shrinks one way, aluminum another, PTFE a third—everything's fighting at -423°F," Honeycutt explained. "Add vibration from the 4-mile rollout, a speck of debris, or a fast-fill surge, and poof—tiny leak path" (Feb. 3 briefing). During the WDR, leaks hit 12-14% H2 concentration in the TSMU cavity, spiking to abort levels when the core stage pressurized at T-5:15. "As we began that pressurization, we did see that the leak within the cavity came up pretty quick," said Charlie Blackwell-Thompson, Artemis launch director (Feb. 3 briefing).[more deletions]The system allows it by design: The TSMU cavity is continuously purged with helium or nitrogen to dilute and vent any H2 gas, keeping concentrations safe. NASA monitors via sensors; the old Shuttle limit was a conservative 4% H2, So for Artemis II, they raised the allowable to 16%—"an appropriate leak limit for LH2 in that cavity," per Honeycutt (Feb. 3 briefing). "At 16 percent, you could not [ignite it]," he added, based on ignition tests (Ars Technica, Feb. 16, 2026).During WDR, spikes to 12-14% were managed until the final pressurization push. The purge and sensors act like a safety net—if it hits the limit, the Ground Launch Sequencer aborts automatically. This tolerance is why leaks don't doom the mission outright; it's baked into cryo ops, from Shuttle to SLS.NASA's Fix-It Plan: Swap, Test, and Redesign for the Long Haul[more deletions]This isn't defeat—it's the rocket "talking to us," as Honeycutt put it. With data piling up, NASA eyes March, honing the system for crewed flights. For the TSMU, fixing the leaks could be what transforms, stuck on the pad forever into launching from the pad and going to the Moon.https://twitter.com/rpg571/status/2023459060788375692
Richard P. Gallagher@rpg571·1hThe Hydrogen Leak Puzzle: Why SLS's Keeps Springing Leaks—and NASA's Plan to Seal ItWhy Hydrogen Plays Hard to Seal: The Tiny Molecule That Won't Stay Put[delete much for clarity]But here's where it bites: thermal contraction. "Steel shrinks one way, aluminum another, PTFE a third—everything's fighting at -423°F," Honeycutt explained. "Add vibration from the 4-mile rollout, a speck of debris, or a fast-fill surge, and poof—tiny leak path" (Feb. 3 briefing). During the WDR, leaks hit 12-14% H2 concentration in the TSMU cavity, spiking to abort levels when the core stage pressurized at T-5:15. "As we began that pressurization, we did see that the leak within the cavity came up pretty quick," said Charlie Blackwell-Thompson, Artemis launch director (Feb. 3 briefing).[more deletions]The system allows it by design: The TSMU cavity is continuously purged with helium or nitrogen to dilute and vent any H2 gas, keeping concentrations safe. NASA monitors via sensors; the old Shuttle limit was a conservative 4% H2, So for Artemis II, they raised the allowable to 16%—"an appropriate leak limit for LH2 in that cavity," per Honeycutt (Feb. 3 briefing). "At 16 percent, you could not [ignite it]," he added, based on ignition tests (Ars Technica, Feb. 16, 2026).During WDR, spikes to 12-14% were managed until the final pressurization push. The purge and sensors act like a safety net—if it hits the limit, the Ground Launch Sequencer aborts automatically. This tolerance is why leaks don't doom the mission outright; it's baked into cryo ops, from Shuttle to SLS.NASA's Fix-It Plan: Swap, Test, and Redesign for the Long Haul[more deletions]This isn't defeat—it's the rocket "talking to us," as Honeycutt put it. With data piling up, NASA eyes March, honing the system for crewed flights. For the TSMU, fixing the leaks could be what transforms, stuck on the pad forever into launching from the pad and going to the Moon.
hopefully i simply do not understand what i am reading. The above post seems to me to indicate that the hydrogen will not ignite at a 16% concentration. So far so good. However, there is no indication as to how close to the ignition point this concentration is. Therefore it seems to me that for design purposes one needs to assume that ignition can occur at any concentration above 16%. Also, to nit-pick, the hydrogen concentration will not be exactly uniform throughout the gas concentration in the vicinity of the sensor, etc., etc., etc.My question is: is it accurate that there is no buffer or safety margin by setting the allowable concentration to be 16% when it is claimed that based on one test that the hydrogen does not exist at 16% concentration. It seems like a factor of 2 would mean the concentration should be limited to 8% or approximately 11.5% if a safety factor of 1.4 is used.Could someone give me a better perspective. Thanks.For emphasis from the original quoted post:"but tests showed the flammability threshold here is closer to 16%". Is that "closer to" greater than or less than 16%? Not clear to me which is the correct intrepretation. How close to 16% is it? What is the margin? Another portion from the original uncut post:"fixing the leaks could be what transforms, stuck on the pad forever into launching from the pad and going to the Moon"Going from memory, this reminds me of the Challenger debate about whether to launch and someone asked if "we should wait to April to launch' [ok, paraphrased from memory].Translation: Based on the original quoted post, I would not be asking what I am asking if the cutoff had been set to12% or less.
Shouldn't the WDR be after the Call to Stations?
