From: mooregr@deletethisgreenms.com   
      
   "William Elliot"  wrote in message   
   news:Pine.NEB.4.64.2103190119300.7640@panix5.panix.com...   
   >   
   >On Thu, 18 Mar 2021, JF Mezei wrote:   
   >   
   >> Does the SLS core stage tank use the same foam as for the Shuttle's   
   >> ET? Would all the post-Columbia research and refinements still be   
   >> considered to be "current" or would much progress have been made   
   >> since resulting in new significantly different foam formulation?   
   >   
   >For what is the foam used?   
   >   
   SOFI - Spray on Foam insulation.   
   Two purposes (though I suspect less so on SLS) but basically to keep the LH2   
   and LOX insulated from the atmosphere so there's less boil-off.   
      
   On ascent, especially with the STS ET, to keep the additional heat load from   
   friction off.   
      
   >> In terms of the Shuttle ET, it was mostly smooth except for perhaps 1/5   
   >> that had ridges on the surface. What was the purpose/reason for only   
   >> that portion having ridges? SLS doesn't appear to have such a zone.   
   >>   
   >> Does the foam have an expiry date? Since SLS has been delayed and   
   >> delayed and delayed, I wonder if at one point they would have to ditch   
   >> the tank/core because the foam has started to decompose?   
      
   --   
   Greg D. Moore                   http://greenmountainsoftware.wordpress.com/   
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