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: Info wanted on Atlantis "secret" military satellite payload
Message-ID: <12485@bellcore.bellcore.com>
Date: 10 Dec 88 00:28:05 GMT
References: <684@pyuxd.UUCP> <1988Dec4.225033.18207@utzoo.uucp> <6464@polyslo.CalPoly.EDU> <12418@bellcore.bellcore.com> <1988Dec8.001846.26121@utzoo.uucp>
Sender: news@bellcore.bellcore.com
Reply-To: karn@jupiter.UUCP (Phil R. Karn)
Organization: Bell Communications Research, Inc
Lines: 39

>Frankly, I don't think we have enough evidence to say *what* that thing is.

Henry's points are well taken. However, I can say that the laws of physics
are as yet still unclassified, so I have run an eclipse predictor for the
next six months on the last known orbital elements for STS-27.

At the moment, the satellite is in continuous sunlight, i.e., it is flying
roughly in the plane of the terminator. It reaches its northernmost latitude
at roughly midday local time.  This is consistent with the report we heard
of the astronauts conducting visual observations of the USSR from the
shuttle.

But things are changing. The orbit plane is precessing 4.28 degrees westward
per day, while the terminator is moving eastward about a degree per day.
This means that the local time at a given point on the earth as seen by the
satellite during its passes will slowly change.

Short eclipses start on Dec 12. By the end of December, they will be about
36 minutes long. So far so good; this is less than half of each orbit, which
is how long eclipses typically are in sun-synchronous orbit (unless you are
again flying roughly in the plane of the terminator).  The eclipses stay
more or less at this length for a while until mid February when they stop
(the orbit plane again matching the terminator for a while).

But by mid March 1989, the orbit plane will have precessed (and the
terminator moved by the earth's motion around the sun) such that each day's
passes over Moscow will all find it in darkness; the passes begin after
sundown and end before sunrise. This continues until the plane has again
precessed so that daylight flights can be made, a fairly slow process.  So
if the satellite is an visible-light optical one, it would be useless for
quite long intervals due to its orbit. The evidence that the satellite
does not require daylight over the USSR to function is therefore quite
strong.

Caveat: this is all based on a quick look using my tracking program; to
analyze this properly I should write a program that specifically looks for
the information I want.

Phil