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From: CSvax:Pucc-H:Physics:els@pur-ee.UUCP
Newsgroups: net.space
Subject: Re: sattelites
Message-ID: <835@pur-phy.UUCP>
Date: Wed, 20-Jul-83 11:11:05 EDT
Article-I.D.: pur-phy.835
Posted: Wed Jul 20 11:11:05 1983
Date-Received: Thu, 21-Jul-83 20:53:15 EDT
References: sri-arpa.3180
Lines: 13


   I beg to differ, but the shuttle has a line of sight to TDRS-1 LESS than
50% of the time.  I haven't worked it out yet(in the literature they call that
'exercise left for reader'), but geostationary orbit isn't very high compared
to the diameter of the earth.  Common sense tells you that to be visible 50%
of the time, TDRS would have to be infinitely far away.  When the TDRS system
is operational, the three satellites (separated by 120 degrees) will each be
visible from the ground to about 1/3 of the globe.  From its slightly higher
vantage, the shuttle ought to be able to see any given one more than 1/3 of the
time, roughly 40% is my guess.

                                    els{Eric Strobel}
                                    pur-ee!pur-phy!els