Re: Super tracking device at SpaceCom?

From: tlj18@juno.com
Date: Tue May 16 2000 - 23:12:55 PDT

  • Next message: Ron Lee: "Simsat 1 Obs, 17 May 2000"

    >Concerning the physics on acceleration due to drag I checked the 
    >excellent
    >book 'Fundamentals of Astrodynamics and Applications' from David A. 
    >Vallado
    >(1997). 
    >
    >He gives a formula for the acceleration which depends from:
    >- coefficient of drag (c_D), a dimensionless value which reflects the
    >satellites susceptibility to drag forces (known from aerodynamics)
    >- cross-sectional area (A), the area which is normal to the sattelites
    >velocity vector
    >- mass (m)
    >- atmospheric density (rho)
    >- velocity relative to the atmosphere (v_rel)
    >
    >Problems to calculate accurate accelarations due to drag is that most
    >reentering objects are tumbeling with the result, that A is 
    >continuously
    >changing. Furthermore it is difficult to estimate accurate atmospheric
    >denisity in the upper atmosphere due to the limited knowledge of the
    >interactions of the solar wind and Earth's magnetic fields. This is 
    >also (in
    >my oppinion) the main reason, why predictions on decaying objects are 
    >cursed
    >with larger errors.
    >
    >I would like to avoid further mathematics and physics, otherwise i am 
    >going
    >off topic on this list.
    
    Hello,
    
    Are such formulas like the above on the web somewhere?
    
    Also, can anyone refer me to some reference where I can make satellite
    predictions with nothing more than paper, a pencil, and a TLE data set
    (no computer being used)?
    
    ================================================================
    Jonathan T. Wojack                                                
    tlj18@juno.com
    
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