Re: Orbital evolution of object 31572

From: Mike McCants (mmccants@io.com)
Date: Tue Sep 04 2007 - 19:54:08 EDT

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    Igor Lissov posted:
    
    >Has anybody checked the orbital behavior of object 31572 (2007-020B)
    >catalogued as Fregat Deb from the May 31 Globalstar launch, or
    >observed it? I wonder if significant changes in mean motion and
    >a large increase in excentricity can be attributed to natural reasons.
    
    I failed to observe it soon after launch when there was confusion
    over which objects were Globalstar payloads and why there was no
    tle for the fourth payload.
    
    The RCS values have fluctuated - the current value is 0.18 square meters.
    The true value may be much less.
    
    There was another "Fregat Debris" piece cataloged and tracked for a
    while in 2003 (Object 27763).  It was in a high, eccentric orbit, but
    it also shows unusual behavior.
    
    I assume that this object has atmospheric drag even though its perigee
    is at a height of about 900 Km.
    
    I assume that the larger fluctuations in drag (including negative drag
    for some time) are due to solar radiation pressure.
    
    This would indicate some sort of piece of mylar with a large area to
    mass ratio.
    
    I can model solar radiation pressure and come up with an increasing
    eccentricity with the argument of perigee only off about 40 degrees.
    
    I would have to assume that this object rotates slowly and that means
    that the solar radiation pressure varies greatly from time to time.
    I cannot model this behavior.  :-)
    
    So, yes, I believe this is natural behavior.
    
    Mike McCants
    
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