From: snidely.too@gmail.com   
      
   David Spain submitted this gripping article, maybe on Tuesday:   
   > On 1/25/2021 9:39 PM, JF Mezei wrote:   
      
   >> Isn't the landing done using separate header tanks and those are   
   >> indepedant of main tanks, so different filling of main tanks at launch   
   >> shouldn't change anything at the time the engines perform final burn to   
   >> land.   
   >   
   > There might be different amounts of residual propellant left in the main   
   > tanks during testing to get a profile on how well the header tanks perform   
   > under different structural loads. Seems to be a relevant issue based on SN8   
   > results.   
      
   SN8's pressurization system may have relied on gas from the generators   
   /beginning with propellants from the main tank/ (either charging during   
   ascent or using residualt).  I'm not sure how much detail was revealed   
   about this part.  SN9 will use helium (in COPDs, apparently) as an   
   interim fix; long term fix has not been revealed (and wasn't settled on   
   at the time of Elon's tweet about SN9+helium).   
      
   /dps   
      
   --   
   Killing a mouse was hardly a Nobel Prize-worthy exercise, and Lawrence   
   went apopleptic when he learned a lousy rodent had peed away all his   
   precious heavy water.   
   _The Disappearing Spoon_, Sam Kean   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)