RE: NOSS 3-2 - there may yet be a third payload.

From: Ted Molczan (molczan@rogers.com)
Date: Wed Dec 10 2003 - 09:38:22 EST

  • Next message: Mike McCants: "RE: NOSS 3-2 - there may yet be a third payload."

    Sorry for responding to myself, but here are a few additional facts to consider.
    
    > If the Centaur's orbit is being manoeuvred, then what 
    > propulsion system is being used? Can its cryogenic 
    > propellants remain viable for days or weeks after launch?
    
    Even if the cryo propellants could be maintained viable, the main engine is
    overkill for any remaining small orbital changes, i.e. decreasing inclination by
    a fraction of a degree, increasing arg of perigee by several more degrees. It is
    designed for burns no shorter than 10 s. To place that in perspective, requires
    only a 12 to 18 s burn to raise the orbit from 160 x 1200 km to 1000 x 1200 km,
    and increase the inclination by a degree or two.
    
    Could the Centaur's hydrazine thrusters be sufficient to perform small
    manoeuvres? Why would that be better than having the NOSS perform them on its
    own?
    
    > Can Centaurs be provided electrical power to operate in orbit 
    > for days or weeks, instead of the usual less than 12 hours?
    
    There is an Extended Mission Kit, that adds a couple of hours for LEO missions
    requiring a long coast between burns - nowhere close to the 1 - 2 weeks I am
    talking about.
    
    All in all, it does seem improbable for the Centaur to be on a one week plus
    mission, with another NOSS deployment pending. Yet, its slow rise in altitude
    and the nearly ideal geometry of its orbit for a NOSS outlier are tantalizing,
    even if they prove to be meaningless coincidences.
    
    Anyone have any other ideas?
    
    Ted Molczan
    
    
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