Re: ISS solar cells

From: Tony Beresford (aberesford@iprimus.com.au)
Date: Sun Dec 03 2000 - 18:00:58 PST

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    At 12:09 4/12/00 , Ron Lee wrote:
    >I am not sure this is correct.  The Iridium antennaes are more vertical
    >than earth facing and we see reflections from other satellites like
    >Superbird-A.
    >
    >Ron
    Ron, we see reflections off the Solar panels of abandoned geostationary
    satellites BECAUSE the solar panels are no longer pointing at the Sun,
    as they are on working satellites. If you work out the numbers ,
    knowing the solar panel areas , you will see that the solar panels
    are not very reflective. In fact to respond to a remark of Alexander,
    they have always been so. The gain in efficiency comes from improvments
    in converting photons to hole-electron pairs, not any changes in the
    bulk reflectivity ( 12.5%) which is governed by the refractive index
    change from vacuum or air, to silicon( gallium arsenide).
    The Iridium MMA's are pointed downward at about 30 degrees off the 
    vertical, to receive transmissions.  As has been discussed several
    times a surface pointing sraight down, like the antennae backplane
    of the globalstar satellites cant produce solar reflections either.
    Tony Beresford
    
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