Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site ucbcad.UUCP Path: utzoo!linus!decvax!tektronix!ucbcad!moore From: moore@ucbcad.UUCP Newsgroups: net.space Subject: Re: Re: sattelites - (nf) Message-ID: <42@ucbcad.UUCP> Date: Fri, 22-Jul-83 07:28:49 EDT Article-I.D.: ucbcad.42 Posted: Fri Jul 22 07:28:49 1983 Date-Received: Sat, 23-Jul-83 02:07:24 EDT Sender: notes@ucbcad.UUCP Organization: UC Berkeley, CAD Group Lines: 25 #R:sri-arpa:-301500:ucbcad:9900001:000:851 ucbcad!moore Jul 21 14:19:00 1983 Just to put a silver spike through this topic: if you have two objects orbiting at radii of R1 and R2 over a planet of radius r, then the maximum angle the two objects can be separated and still see each other is given by Theta_Max = arccos(r/R1) + arccos(r/R2) For r = 4000 miles (Earth radius?), R1 = 26300 miles (geosynchronous radius), R2 = r + 100 miles (shuttle radius?), we get Theta_Max ~= 94 degrees, so the shuttle will be within line of sight of the communication satellite 2*94/360 or ~52% of the time. BTW, a geosynchronous satellite covers 45% of the equator and 42% of the earths surface. This is what COULD be covered, according to the geometry of the problem; I don't know if the reception is at all acceptable at the fringes of the covered region. Peter Moore ...!ucbvax!moore (USENET) moore@berkeley (ARPANET)