From: cdorrough@nortonconsultants.com   
      
    wrote in message   
   news:1112738760.799717.249020@g14g2000cwa.googlegroups.com...   
   > > What I can't figure out is how Beal Aerospace made so much progress   
   > > with peroxide.   
   >   
   > Same way the British did -- they were working on biprop peroxide   
   > rockets.  As I understand it, neither Beal's rocket nor the Black   
   > Arrow relied on catalysts to break down the peroxide.  Instead, the   
   > peroxide was thoroughly mixed with hydrocarbon and raised to a few   
   > thousand degrees in a combustion chamber devoid of metallic bits   
   > that had to stay there.... conditions were much more likely to see   
   > prompt, and thus reliable, combustion.   
   >   
   > What I can't figure out is how the Russians have made so much   
   > progress with peroxide.  They're actually using it to boost the   
   > ISS, right?  They've got all the usual problems: long term storage,   
   > temperature cycling, catalysts, etc.  Wow.   
      
   >From NASA doc TD9702 p7-4:   
   "The primary method for conducting a reboost is using the main engine of a   
   docked transport cargo vehicle, typically a Progress M1. ... If no Progress   
   is currently docked when a reboost is needed, the SM engines can also be   
   used to conduct a reboost. However, it is desirable to limit the firings of   
   SM main engines, since they have a limited burn lifetime."   
      
   I don't imagine it's an easy task to replace them when they burn out - but I   
   suppose they'll just schedule it in like any other maintenance task.   
      
   HTH,   
   Cameron:-)   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)