From: snidely.too@gmail.com   
      
   On Saturday, Alain Fournier exclaimed wildly:   
   > On Sep/10/2022 at 12:21, JF Mezei wrote :   
   >> Not sure if there is anoyone left in the group, but just in case.   
   >>   
   >> Consideirng SLS has been in development for over 10 years, considering   
   >> they already had quick disconnect experience for H2 refueling on   
   >> Shuttle, I am curous on what constraints would have prevented them from   
   >> developping a reliable H2 fill line quick disconnect for SLS ?   
   >>   
   >> I take it that they can't test it at VAB because they don't have LH2   
   >> lines there.  (and leaking H2 indoors, not a great idea).   
   >>   
   >> But when this quick disconnect was designed, wouldn't it have had some   
   >> real testing with LH2 to ensure it works well and that any limitations   
   >> and maintenance requiremenmts (eg: change rubber seals every X refills)   
   >> would be well known.   
      
   AIUI, the GSE (which is a whole separate set of contractors) wasn't   
   done much sooner than the Green Run, which used different GSE.   
      
   But a nice little test tank would have been handy, wouldn't it?   
   Something like the 7.1 test tank, except validating the GSE in stead of   
   tank welds.   
      
   >> And considering the number of tests they did of this rocket, how come   
   >> this quick disconnect problem didn't get noticed before ?   
      
   It came up in the WDRs, and they thought they had it fixed.  The first   
   launch attempt actually got past this point.   
      
   > It's normal on a new system to have some bugs.   
      
   Yeah, like the Shuttle ... it only had at least 1 scrub for every   
   launch thanks to how easy it is to work with LH2.   
      
   > The real question, in my opinion, is why didn't they disconnect the whole   
   > programme years ago. Why not buy rides from SpaceX and Blue Origin to go to   
   > the moon. It would be much cheaper than the SLS boondoggle.   
      
   Well, of course you know the answer is political, and that SLS is a   
   giant jobs program.   
      
   /dps   
      
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