Path: utzoo!utgpu!tmsoft!dptcdc!dpmizar!swrinde!cs.utexas.edu!rutgers!bellcore!jupiter!karn
From: karn@jupiter..bellcore.com (Phil R. Karn)
Newsgroups: sci.space.shuttle
Subject: Re: Sun synchronous orbits
Message-ID: <12484@bellcore.bellcore.com>
Date: 9 Dec 88 23:51:39 GMT
References: <684@pyuxd.UUCP> <1988Dec4.225033.18207@utzoo.uucp> <6464@polyslo.CalPoly.EDU> <12418@bellcore.bellcore.com> <8143@dasys1.UUCP>
Sender: news@bellcore.bellcore.com
Reply-To: karn@jupiter.UUCP (Phil R. Karn)
Organization: Bell Communications Research, Inc
Lines: 16

>I understand why the sun synchronous orbit is desirable for spy photography,
>but wouldn't there be exploitable weakness in it too?  If all your pix
>of the Leningrad shipyard show it at 2PM local, aren't there games they
>can play with light and shadow to camouflage stuff?

There undoubtedly is. I'm not an expert on photoreconnaissance; I'm more
familiar with remote sensing when you don't have humans actively trying
to defeat what you're doing.  But you might well have multiple satellites
that come over at different local times, e.g., one morning satellite and
one afternoon satellite, as is done with the low altitude polar orbiting
weather satellites.  You can also get multiple pictures of a site during
a single pass from a variety of perspectives, even when the lighting is
(essentially) constant. See the KH-11 pictures of the Soviet shipyard
in Deep Black (an excellent book, by the way).

Phil