From: niklas.holsti@tidorum.invalid   
      
   On 2024-05-25 16:23, Alain Fournier wrote:   
   > On 2024-05-25 5:06 a.m., Niklas Holsti wrote:   
      
       [ snip ]   
      
   >> For IFT-4, they say that there are "operational changes including the   
   >> jettison of the Super Heavy’s hot-stage adapter following boostback to   
   >> reduce booster mass for the final phase of flight." What, so that part   
   >> will fall into the ocean and not be reused? This is a surprising   
   >> departure from earlier principles. Perhaps it is only a temporary   
   >> work-around.   
   >   
   > Indeed, it is a surprising departure from earlier principles. I don't   
   > think that would be only a temporary work-around if they do so to reduce   
   > mass. IFT-4 having no payload, they don't really need to reduce mass, so   
   > they don't need to do it at all now. Perhaps this piece of hardware gets   
   > severely damaged during flight (during hot-staging) and it is easier to   
   > build a new one for each flight than to redesign it to survive intact.   
      
      
   There is some good discussion by "CSI Starbase" in this video:   
      
   https://www.youtube.com/watch?v=Ytl1efG1sBw   
      
   The main suggestion is that fixing other issues by additions to the   
   booster HW increased booster mass so much that the LOX header tank   
   capacity became insufficient for booster recovery. The header tanks are   
   already built for the next few boosters and cannot easily be made   
   larger. Discarding the hot-stage adapter, to reduce mass, may thus be a   
   work-around for this header-tank issue, and may not be needed for future   
   boosters with larger LOX header tanks.   
      
   The video also presents evidence that the hot-stage adapter actually   
   tore itself loose during the last minutes of IFT-3 booster flight. This   
   may have been a factor in the booster's attitude-control problems during   
   its return.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)