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Path: utzoo!watmath!clyde!burl!ulysses!allegra!mouton!karn
From: karn@mouton.UUCP
Newsgroups: net.ham-radio,net.columbia
Subject: Challenger orbital elements
Message-ID: <164@mouton.UUCP>
Date: Fri, 28-Sep-84 20:18:34 EDT
Article-I.D.: mouton.164
Posted: Fri Sep 28 20:18:34 1984
Date-Received: Sat, 29-Sep-84 09:39:07 EDT
Organization: Bell Communications Research, Inc
Lines: 32

Here is a predicted element set for orbit 23 of the upcoming Challenger
mission. Note, however, that it was based on an October 1 launch and needs
to have its RA (right ascension) of the ascending node adjusted for the
actual launch time, which I believe is currently scheduled for October 4.

Epoch time:      84276.85138889
   Tue Oct  2 20:26:00.0   1984 UTC
Inclination:       57.2007 deg
RA of node:        68.7538 deg
Eccentricity:    0.0010544
Arg of perigee:   346.2766 deg
Mean anomaly:      14.1415 deg
Mean motion:   15.97849766 rev/day
Decay rate:          0.046 rev/day^2 [incredibly high! -- prk]
Epoch rev:              23
Semi major axis:  6658.131 km
Anom period:     90.121113 min
Apogee:            287.857 km
Perigee:           273.816 km
Ref perigee:      2466.84893045
   Tue Oct  2 20:22:27.590 1984 UTC

The high inclination of this mission will make the orbiter visible at much
higher latitudes than most shuttle missions. It will also make it possible
for more amateurs to receive the 435 mhz transmissions of a Getaway Special
experiment that will be mounted in the cargo bay.  Tracking the shuttle,
however, has always proven to be extremely difficult due to the unpredictable
drag effects of the low orbit and the constant perturbations of maneuvering
rockets. As we found with STS-9, predictions made from element sets which
were only a day old could be off by minutes.

Phil Karn