RE: EUVE reentry probabilities

From: Matson, Robert (ROBERT.D.MATSON@saic.com)
Date: Wed Jan 30 2002 - 14:28:13 EST

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    Hi Bjoern and List,
    
    > The area of a band around a latitude is R*R*width * 2 * pi * cos(lat),
    > not considering oblateness.  So between two latitudes, it is the
    > integral, or 2*pi*(sin(lat1)-sin(lat2)), or for your example
    > 4*pi*0.3987. For the whole sphere it is 4*pi, so 40% is your
    > answer.
    
    The more interesting (and far more difficult) calculation is the
    land-to-water ratio as a function of satellite inclination.  Because
    of the irregular boundaries of continents and islands, there will
    be two extreme cases:  the inclination with maximum land-to-water
    ratio, and the inclination with the corresponding minimum ratio.
    Since the computation encompasses more and more area as the
    inclination increases, both extremes are likely to be found at
    fairly low inclinations.  The 90-degree-inclination case simply
    reduces to the global land-to-water ratio, which is known (though
    I don't recall the figure).
    
    Of course, for this list ~observation~ of the reentry is of more
    interest than actual recovery of debris; the two are obviously
    related, but the probability of observation is much improved
    over probability of being within the debris field boundary
    (somewhat akin to the difference between seeing a partial solar
    eclipse and a total one).
    
    Best,
    Rob
    
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