RE: Delta IV-H under performance

From: Ted Molczan (molczan@rogers.com)
Date: Wed Dec 22 2004 - 10:16:02 EST

  • Next message: Kevin Fetter: "RE: Delta IV-H under performance"

    Thierry Marais wrote:
    
    > From: "Ted Molczan" <molczan@rogers.com>
    > 
    > > They confirm that the upper stage compensated for the 
    > > under-performance of the CBC stages, to achieve very nearly the 
    > > intended 27.3 deg, 275 km X 36,394 km orbit.
    > 
    > These TL show that there's 'only' 530 m/s missing at apogee, 
    > what a manoeuvring payload could compensate, but it also 
    > represents the loss of many years of its life. (~50 m/s/year 
    > for geosationary stabilization)
    > 
    > I am probably wrong but I feel the flames were very orange 
    > for a LH-LO mix... or my video player distorted the colorimetry ! :-)
    
    I have been wondering about that too. I know that in terrestrial combustion
    processes, even a few percent insufficient oxygen results in a severe loss of
    efficiency, and one of the telltale signs is a yellowing of the flame. I know
    next to nothing about the norms of rocket combustion. Do those concepts apply
    equally there?
    
    Spaceflight Now reports that the outer CBC rockets appeared to shut down 8 s
    early:
    
    http://www.spaceflightnow.com/delta/d310/
    
    "Nearly four minutes after liftoff, tracking cameras following the launch showed
    the starboard and port boosters shut down their engines and peel away from the
    rocket's core. But the engine cutoff and subsequent booster separation came
    about 8 seconds prematurely, based on the advertised timeline."
    
    Would such an early shut-down be consistent with insufficient oxygen?
    
    Ted Molczan
    
    
    
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