posted 02-03-2026 04:44 PM               

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Originally posted by Axman:
I believe "historic" is being severely abused here.

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posted 02-03-2026 04:57 PM               

quote:

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Originally posted by Jim Behling:
Artemis II isn't a first...

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Mercury-Redstone 3, Mercury-Atlas 6, Gemini-Titan 3, Apollo 7, Apollo 8, STS-1, Demo-2 and Starliner CFT are all firsts: the first crewed flight of a rocket. How is Artemis II any different?

The four Artemis II astronauts are going to travel farther into deep space than anyone before them. It was historic when the Apollo 13 crew did it, so why is it not historic now?

posted 02-04-2026 09:25 AM            

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Originally posted by Robert Pearlman:
...is going to be historic.

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As someone who followed the Mercury, Gemini, Apollo, Skylab, ASTP and Space Shuttle flights avidly at the time I am still excited by this forthcoming venture. Really pleased for all of those who were not around at the time and this is their time and no one should begrudge them that.

posted 02-04-2026 05:25 PM            

But it isn't a new problem. Liquid hydrogen is currently used on many other rockets, and was of course used in the second and third stages of the Saturn V. I seem to recall hydrogen leaks during Saturn V countdowns (including Apollo 11) but no Saturn V launch was ever delayed or scrubbed because of a hydrogen leak.

posted 02-04-2026 08:05 PM               

In the final hours of the Apollo 11 launch countdown on July 16, 1969, as the crew was getting to board, a major hydrogen leak was detected.

This is Apollo Saturn Launch Control; T minus 2 hours, 45 minutes, 55 seconds and counting...

We have discovered a problem at the launch pad itself as the crew is about to arrive. We have a leak in a valve located in a system associated with replenishing liquid hydrogen for the third stage of the Saturn V launch vehicle. We have sent a team of three technicians and a safety man to the pad and these technicians are now tightening bolts around the valve.

Once the technicians depart, we will send hydrogen again through the system to assure that the leak has been corrected.

... a hydrogen fire, invisible to the naked eye, had broken out at the aft end of the orbiter. Had the crew evacuated at that time, they would have run through the invisible flames.

The pad's fire suppression system came on to deal with the fire, and when the crew did finally egress the shuttle, they received a good dousing of water. The crew returned safely, if a little drenched, to crew quarters.

After ground teams assessed the cause of the abort, they made the decision to roll the stack back to the VAB, demate Discovery from the ET and SRBs and tow it back to the OPF. Workers replaced the faulty engine, and Discovery rolled back out to the launch pad on Aug. 9 for another launch attempt...

posted 02-05-2026 01:53 PM               

During the shuttle era, the threshold was about four percent. After what was learned on Artemis I, NASA raised the allowable concentration level to 10 percent. During the Artemis II tanking test, the first leak reached 12 to 14 percent concentration, approaching but not exceeding the 16 percent limit set by NASA.

It was only the replenish valve leak late in the terminal count that exceeded the limits and called off the count.

posted 02-05-2026 05:12 PM               

quote:

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Originally posted by Blackarrow:
...has that knowledge and experience been lost or is it simply impossible to work with liquid hydrogen without having to expect regular leaks?

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posted 02-09-2026 07:38 PM               

Artemis 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.

posted 02-12-2026 08:30 AM               

The Weather Channel to Deliver Comprehensive, Multi-Perspective Coverage of NASA's Artemis II Moon Mission

The Weather Channel announced today it will deliver comprehensive, multi-perspective, and multi-location special coverage of NASA's Artemis II mission. Ahead of and during the launch, The Weather Channel's meteorologists and leading American space authorities will examine the atmospheric and space-weather conditions critical to launching humans toward the Moon.

For the first time since 1972, NASA is sending humans on a path to the moon with Artemis II. Launching atop NASA's Space Launch System (SLS) rocket, four astronauts will embark on a 10-day mission to orbit the Moon. Artemis II marks the first crewed flight of the SLS rocket and Orion spacecraft, testing modern human deep-space capabilities and paving the way for sustained lunar exploration and science.

The mission reached a key milestone on January 17, when the Artemis II SLS rocket and Orion spacecraft arrived at Launch Pad 39B following a nearly 12-hour rollout from Kennedy Space Center's Vehicle Assembly Building. The earliest launch opportunity opened and passed on February 6, 2026, with additional windows extending through April 2026. Launch windows are determined by Earth-Moon alignment, lighting, communications requirements, and strict weather-related GO/NO-GO criteria essential to crew safety and mission success.

Once NASA confirms a launch date, The Weather Channel will deploy its veteran broadcast teams to provide live reporting and expert analysis from key mission locations:

• Kennedy Space Center, Fla.: Jen Carfagno will report from the launchpad, delivering real-time analysis of lightning risk, upper-level winds, cloud cover, and other GO/NO-GO launch criteria.

• Johnson Space Center, Houston: Paul Goodloe will report from Orion Mission Control, tracking progress and examining weather considerations affecting the crew.

• Cocoa Beach, Fla.: Stephanie Abrams will report from Florida's Space Coast, capturing on-the-ground conditions and the public experience surrounding the launch.

• The Weather Channel IMR studio: Alex Wilson will anchor from the network's Immersive Mixed Reality studio, using advanced visualization technology to explain conditions, timing, and other variables in real time. Science communicator and influencer, Astro Alexandra, will join Alex in studio to break down complex aspects of the launch in engaging, easy-to-understand ways for viewers of all ages

• Splashdown, San Diego, Ca.: Approximately 10 days after launch, Paul Goodloe will cover the Artemis II splashdown, reporting on coastal weather conditions critical to Orion recovery operations.

Ahead of the launch, The Weather Channel's meteorologists will be available for interviews to discuss atmospheric and space-weather factors that could affect launch and splashdown timing, including lightning constraints, wind shear, cloud ceilings, solar activity, and more.

Live Artemis II coverage will air across The Weather Channel and The Weather Channel TV streaming app, with continuous reporting throughout the launch window and mission lifecycle.

posted 02-16-2026 11:22 AM               

Engineers will examine findings before setting a timeline for the next test, a second wet dress rehearsal this month. March remains the earliest potential launch window for Artemis II.

posted 02-16-2026 02:54 PM               

Launch controllers will arrive to their consoles in the Launch Control Center at NASA's Kennedy Space Center in Florida at 6:40 p.m. EST on Feb. 17 to begin the nearly 50-hour countdown. The simulated launch time is 8:30 p.m., Feb. 19, with a four-hour window for the test.

While NASA will not set a formal launch date until after a successful rehearsal and data reviews, the agency has been evaluating in recent weeks if the there are additional days that would be suitable for launch and found an extra opportunity the first week of March. However, managers have determined March 6 is the earliest opportunity for launch that allows for a second wet dress rehearsal, sufficient time for data review, and time to transition the launch pad, rocket, and spacecraft to launch operations.

posted 02-19-2026 09:50 AM               

Engineers at NASA's Kennedy Space Center are conducting a prelaunch test to fuel the Artemis II Space Launch System—a vital step in ensuring this rocket is ready for its upcoming trip around the Moon.

During the rehearsal, teams will demonstrate the ability to load more than 700,000 gallons of cryogenic propellants into the rocket, conduct a launch countdown, and practice safely removing propellant from the rocket without astronauts inside the spacecraft. This is the second "wet dress rehearsal" test, following a previous rehearsal on Feb. 2.

Teams are counting down to the opening of a simulated launch window at 8:30 p.m. EST on Feb. 19 (0130 Feb. 20 UTC), which could extend to up to four hours.

posted 02-20-2026 09:49 AM               

Agency leaders give updates on Artemis II after the second fueling test for the mission around the Moon.

posted 02-20-2026 06:30 PM               

The liquid hydrogen tank shrinks about 6 in. (15 cm) in length and 1 in. (2.54 cm) in diameter when filled with cryogenic fuel. The liquid oxygen tank shrinks approximately 1.5 in. (3.8 cm) in length and 0.5 in (1.3 cm) in diameter when filled.

To compensate, everything that attaches to them – ducts, vent lines, systems tunnel, brackets, etc. – is connected by accordion-like bellows sections, slotted joints, telescoping sections, or ball joint hinges.

posted 02-21-2026 05:15 AM               

An average passenger jet shrinks and then reexpands by about a quarter of an inch on every flight cycle as it reaches 35,000 feet and then lands, and as every aircraft goes through about 50,000 flight cycles in its lifetime, the metal fatigue endured is greater than the maximum stress placed upon the rocket tanks by over a 100 times.

posted 02-21-2026 05:58 AM               

quote:

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Originally posted by Axman:
It would be a sad state of engineering indeed if the cryogenic shrinkage of fuel and oxidiser tanks caused any sort of mission problem.

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posted 02-21-2026 08:36 AM               

Another related, reasonable question was asked recently of Artemis II launch director Charlie Blackwell-Thompson regarding the effect (if any) of the unusual cold front that the Cape experienced in recent weeks. Her reply:

One of the things about having space hardware is that tank is rated for hydrogen at –423 degrees. So, when you stack that up against the local forecast of 25 to 27, there's certainly things we take into account as it relates to flying, but sitting out at the pad it's in pretty good shape.

quote:

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Originally posted by perineau:
Why do we always say "no earlier than" when giving a launch date, isn't that obvious?

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Although the date set by the FRR often aligns with the opening day of the launch window, sometimes the mission's managers decide more time is needed to address a technical concern or to wait out a poor weather forecast, for example.

posted 02-21-2026 09:49 AM               

Teams are actively reviewing data, and taking steps to enable rollback positions for NASA to address the issue as soon as possible while engineers determine the best path forward.

In order to protect for troubleshooting options at both Pad B and the VAB, teams are making preparations to remove the pad access platforms installed yesterday, which have wind-driven constraints and cannot be removed during high winds, which are forecasted for tomorrow. This will almost assuredly impact the March launch window.

posted 02-21-2026 10:36 AM               

More details from Jared Isaacman, who has said a more extensive briefing will be scheduled for later this upcoming week:

• The ICPS helium bottles are used to purge the engines, as well as for LH2 and LOX tank pressurization. The systems did work correctly during WDR1 and WDR2.

• Last evening, the team was unable to get helium flow through the vehicle. This occurred during a routine operation to repressurize the system.

• We observed a similar failure signature on Artemis I.

• The Artemis II vehicle is in a safe configuration, using ground ECS purge for the engines versus the onboard helium supply.

• Potential faults could include the final filter between the ground and flight vehicle, located on the umbilical, though this seems least likely based on the failure signature. It could also be a failed QD umbilical interface, where similar issues have been observed. It could also be a failed check valve onboard the vehicle, which would be consistent with Artemis I, though corrective actions were taken to minimize reoccurrence on Artemis II.

Regardless of the potential fault, accessing and remediating any of these issues can only be performed in the VAB.

As mentioned previously, we will begin preparations for rollback, and this will take the March launch window out of consideration.

posted 02-21-2026 10:44 AM            

quote:

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Originally posted by Axman:
Metal contracting and expanding due to temperature fluctuation is well understood in engineering...

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posted 02-21-2026 10:53 AM               

The Saturn V also had a mobile servicing tower that allowed greater access to the vehicle on the pad than the SLS has with just a mobile launcher tower.

posted 02-21-2026 06:29 PM            

quote:

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Originally posted by Blackarrow:
As I recall, those ancient Saturn V vehicles were stacked, tested, transported to the pad, tested again, fuelled and launched, almost always on the appointed date without repeated refuelling and returns to the VAB.

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