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Tuesday, February 17, 2026

A small Artemis II story - next WDR is on NOW

Because I really can't find anything new to write about.

NASA to fuel up for a full Wet Dress Rehearsal until Friday, Feb. 20

The headline is basically the story.  We all knew it was going to happen just not the official date. 

The agency plans to load more than 700,000 gallons (2.65 million liters) of liquid hydrogen (LH2) and liquid oxygen (LOX) into Artemis 2's Space Launch System (SLS) rocket on Thursday (Feb. 19), wrapping up a crucial two-day-long test called a wet dress rehearsal.

This will be the second wet dress for Artemis 2, the first crewed moon mission since the Apollo era. The first rehearsal, which began on Jan. 31, ended prematurely due to an LH2 leak detected during propellant loading.

There was an attempt to repeat the test last week (Feb. 12) that didn't actually pass, but enough indications of improvement were present to make the team think they made progress. 

Artemis 2 teams replaced two seals in the aftermath of the first wet dress. Then, on Feb. 12, they partially filled SLS' tanks with LH2 in a "confidence test" designed to assess the efficacy of that fix. A problem with ground support equipment restricted the flow of LH2 during that test, but the team nonetheless was "able to gain confidence in several key objectives."

Artemis 2 team members soon tied the ground-support issue to a filter, which they replaced over this past weekend. They now feel ready to conduct another wet dress rehearsal, which will run through the key operations leading up to launch.

The test countdown clock officially started this evening, Feb. 17 at 6:50 p.m. EST (2350 UTC) and is scheduled to run until approximately 12:30 a.m., Friday, Feb. 20 (2530 UTC).  

The full Moon is seen behind the Space Launch System rocket at NASA’s Kennedy Space Center in Florida. Yeah, I ran this picture the other day, but it's pretty. NASA/Ben Smegelsky



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9 comments:

  1. Dave SFebruary 17, 2026 at 10:31 PM

    Why no comment on the SpaceX pivot from Mars to the moon? Love to hear your take on that.

    ReplyDelete
  2. BeansFebruary 17, 2026 at 11:17 PM

    So... I wonder what the percentage of Hydrogen leakage is 'acceptable' and 'safe' for this WDR?

    Everyone else's shift to Methane/Oxygen as a fuel mixture seems to be much more sensible.

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    Replies
    1. IgorFebruary 18, 2026 at 4:25 PM

      Well, di-hydrogen is a slippery little molecule (literally), but it gives more energy output per liter thus giving more thrust. Theoretically, anyway. Methane is a much larger molecule and is easier to handle, but less energy content per gram. Not by much, and the Raptors seem to be wringing out every erg they can with the V3 Raptors.
      So, Methalox is the way to go. Until we develop a NERVA... ;P

      Delete
    2. BeansFebruary 18, 2026 at 11:25 PM

      The side effect of H2 is the need for larger fuel tanks, therefore eliminating some of the energy-positive benefits of H2. Larger tanks need more insulation, more framing or stiffening and are subject to pressure changes more than smaller tanks.

      And the sealants needed to mostly hold the H2 in adds... more weight and reduces volume more than the sealants needed for O2 or CH4.

      H2 is vastly over-rated as fuel as the issues more than outweigh the benefits.

      Delete
    3. SiGraybeardFebruary 19, 2026 at 8:56 AM

      "H2 is vastly over-rated as fuel as the issues more than outweigh the benefits." THIS...

      The more difficulties they go through in these WDRs, the more I think it's a 1960s (or 50s!) decision. Get the absolute best specific impulse they could get because they knew nothing about the practicalities of something that had never been used at this scale before.

      Now we have 60 years of experience with it and have to ask if it's really worth all the extra work it requires for the extra problems it gives us.

      Delete
  3. jerseygirlangieFebruary 18, 2026 at 7:42 AM

    " It didn't pass the test, but we're pretty sure it's good enough ... " Yeah, I wouldn't want to be up top when they light THAT candle !

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    Replies
    1. SiGraybeardFebruary 19, 2026 at 9:01 AM

      Absolutely.

      Add in that if this mission fails, especially in that worst possible way, the "second moon race" is over. It's possible it even takes out NASA - once lots more people understand what a fustercluck the entire SLS has been.

      Delete
  4. bravokiloFebruary 19, 2026 at 5:32 AM

    What are they filtering out of the fuel supply? Dog hair? I would hope that such an engine could handle some impurities.

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  5. digital marketing serviceFebruary 19, 2026 at 6:36 AM

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