From: snidely.too@gmail.com   
      
   Alain Fournier wrote on 12/31/2021 :   
   > On Dec/31/2021 at 05:54, Snidely wrote :   
   >> Thus spake Alain Fournier:   
   >>   
   >>> About 10 hours later both the hot and cold sides have heated up. Why? The   
   >>> sunshield has started to deploy for a few days and deployment should be   
   >>> completed at launch +5.5 days (in a few hours). My guess is that it was   
   >>> launched with a limited stock of coolant that has boiled off and that the   
   >>> sunshield will take care of keeping it cool now.   
   >>   
   >> The coolant is supposed to last for the 10 year mission.  And the limiting   
   >> resource for the 10 year figure is propellant.   
   >   
   > For the most part the telescope is passively cooled. The coolant is used only   
   > for the Mid-Infrared instrument (MIRI). And I doubt the MIRI is cooled yet.   
   > Its operating temperature is -266.5C or 6.7K, not in the same ball park than   
   > the -145C or 131K currently observed on the cold side of the JWST.   
   >   
   > See: https://webb.nasa.gov/content/about/innovations/cryocooler.html   
   >   
      
   But where would that "limited stock of coolant" be that boiled off?   
      
   /dps   
      
   --   
   "This is all very fine, but let us not be carried away be excitement,   
   but ask calmly, how does this person feel about in in his cooler   
   moments next day, with six or seven thousand feet of snow and stuff on   
   top of him?"   
     _Roughing It_, Mark Twain.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)