Object observed from recent Titan 4 launch

Ted Molczan (molczan@fox.nstn.ca)
Mon, 30 Dec 1996 02:07:07 -0500

Over the past few days, Anthony Beresford has provided me
with several observation reports of an object that I believe
originated with the Titan 4 launched from VAFB on 20 Dec 1996
at 18:04 UTC.

The object is precisely in the standard KeyHole western orbital 
plane, but its orbital dimensions are not standard, and it 
appears to be much brighter than a KeyHole (approx std mag = 3,
1000 km range, 50 percent illuminated).

The orbit is visible in the S. hemisphere at latitudes south
of about 35 S. One purpose of this message is to encourage 
other S. hemisphere observers to obtain accurate positional
measurements and estimates. (See search orbit at end of this
message.) 

Another purpose is to provide other analysts besides myself an 
opportunity to contribute to understanding this object, especially 
its orbit. This analysis could benefit greatly from an understanding
of high-drag orbits. I begin with a summary of Anthony's observations, 
NASA's NORAD catalogue information, and conclude with my own analysis, 
preliminary orbital elements, and comments.

Observations by Anthony Beresford
---------------------------------
Anthony did attempt to post his initial report to SeeSat-L,
but for some reason it did not appear. Since then, we have
corresponded directly, and have copied several other Southern
Hemisphere observers. For the benefit of analysts on SeeSat-L,
here the relevant excerpts from Anthony's sighting reports.

24 Dec 1996
-----------
>On the evening of Dec 24 (local time) I observed a high object
>coming up from the South and bisecting the line between Archenar and Canopus.
>Overhead at 1254 UT ( + or - 1 minute). Disappeared into shadow at
>50 degrees elevation in the North. Calculations reveal shadow height overhead
> was 710Km. Brightness steady at mag 2.5-3 .

>The time on Dec 24 came from reading my wristwatch, when
>I came back into ligt Ted. Its 17 seconds slow on UTC at momemnt
>and only varies by about a 1.5 seconds a month. I read the watch
>when it said 23:26:30 [=12:56:30 UTC] or so, and worked backwards, so
>timimg errors cant be late. I was wondering the identification myself. 
>Last night I stayed outside till 13:00 just to see if something else turned

26 Dec 1996
----------- 
>Tonite saw similar object in similar path. Timed at RA 4 h 25min, dec -58.5,
>at 12h 56m 17s UT .Sowhat objects in polar orbit or higher inclination
>do we know with nodal periods very close to 13.5 or 14.5 revs /day.
>Could it be the Titan-4 launch of a few days ago.
> Observer situated at 34.96S, 138.66 E ( cospar 8597)

27 Dec 1996
-----------
>Saw it again tonite Ted had binoculars, but
>I didnt press stopwatch hard enough to start it.
>So apart from saying it was 1251 UT overhead,
>I cant say much more. It was 7 minutes earlier than 
>predictions based on the elements you sent me.
>If anything its maximum brightness tonite was
>mag 2.0, an easy naked eye object.


28 Dec 1996
-----------
>object tracked reached mag 2.5 high (70 deg in Eastern sky)
>Postion near Canopus timed at 12h 46 min 13.8 sec UTC
>                   RA 6h 10.0 min     )
>                   Dec -55deg 05 min  )  Epoch 2000
>After getting time. I continued watching orbit
>pane till 1302UTC and saw nothing more.


29 Dec 1996
-----------
>I saw the usual bright ( mag 2.5)
>object at 1238UT RA 7h 08.0 min, dec -49.2 degs. The postion is
>accurate but the time is only  + or - 20secs. 
>After getting back out at 1248 I watched till 1311 UT. Only other
>object I saw was Lacrosse 2 heading S.


NORAD Catalogue	
---------------
NORAD has catalogued two objects from the 20 Dec launch, as would be
expected. Presumably, the second object is the Titan 2nd stage.

Also, I note that there is an 18 object gap immediately after the
second Titan-launch object. Most likely, this will turn to be debris
from an unrelated launch. If it turns out to be from this launch, then
that would be significant. I am not aware of any debris having been
catalogued from a KeyHole sun-synchronous launch.

1996 072A  USA 129     24680     US    20 DEC      ELEMENTS NOT AVAILABLE
1996 072B              24681     US    20 DEC      ELEMENTS NOT AVAILABLE

      OBJECTS 24682 THROUGH 24699 HAVE NOT BEEN CATALOGED BY USSPACECOM.

1995 062C              24700    ESA    17 NOV      ELEMENTS NOT AVAILABLE
1996 073A  BION 11     24701    CIS    24 DEC    90.4   62.8      378    217
1996 073B              24702    CIS    24 DEC      ELEMENTS NOT AVAILABLE


My Analysis
-----------
Using the observations of 24, 26 and 27 Dec, I derived my first preliminary 
orbit:

99999A          15.0  3.0  0.0  3.0 v
1 99999U 99999  A 96361.53908565  .02800000  00000-0  95384-3 0    01
2 99999  97.9100  61.6000 0575000 152.0000 168.4000 15.05000000    01

This is a pretty good fit to the data. The times of the observed events are
reproduced to the observed precision, typically one minute. On the 24th, the 
shadow entry occurs at about 50 deg elevation, as observed, but the azimuth
is about 10 deg east of the observation. Also, the bisection of Canopus-Archenar 
is not exact, also somewhat east of the observation. Anthony advises that
those angles were not very precise.

The above elset is extremely close to the standard western KeyHole plane, 
moreover, none of the known sun-synchronous objects near this plane coincided
with the observations. The shadow entry helped to determine the eccentricity and 
the argument of perigee, because its elevation was very sensitive to those 
variables. Precessing the argument of perigee 5.8 day back to the time of
launch yields about 173 deg, in close agreement with past launches. A launch 
from VAFB, with insertion into an elliptical parking orbit produces an argument
of perigee between about 160 and 175 deg, depending on the mission.

I am not aware of any previous observations of KeyHole objects so soon after 
launch, so I do not know the typical evolution of the orbits. From U.S. reports 
to the U.N.; and Tass/Itar, I do have the following dimensions of the Titan 2nd 
stage orbits, presumably very soon after launch:

Object  Inc   Per   Apo  Period Source
--------------------------------------
87090B  97.8  143  1018   96.3   U.S.
88099B  97.9  154  1008   96.3   U.S.
92083B  97.7  156   911   96.4   U.S.
95066?  98.7  156   976   95.7   TASS

Heights are in km, and period is in minutes.

The perigee of 92083B, is my revision. The U.N. report stated 256 km, but this
was almost certainly a typo. My value closely fits with the orbital period. 
(The U.S. submissions to the U.N. have been found to have numerous errors of 
this sort.) Regarding 95066, the article implied the payload, but the orbit could 
have been either the Titan 2nd stage or the payload. Also, the period is too low, 
and the inclination was too high. 

So generally, the KeyHoles have entered parking orbits of about 156 x 1000 km,
at nearly 97.9 deg inclination. All that was required to attain the standard
orbit, was to raise the perigee to about 270 km altitude.

My first preliminary orbit had dimensions of about 160 x 957 km, which agrees
closely with these orbits; however, that was 5.8 days after launch. Taking into
account the ndot/2 decay term of 0.028 rev/day^2, the initial orbit would have
been about 160 x 1160 km. The apogee is quite a bit higher than that of a 
standard KeyHole, which I find strange. Why would they launch into such a high
apogee, and then allow drag to eat up nearly 200 km of it?

The observations of the 28th and 29th added their own problems. The first
preliminary orbit does not fit them well, mainly because it predicts much 
earlier passes than were observed. My second preliminary orbit has epoch
on 28 Dec:

99989A          15.0  3.0  0.0  3.0 v
1 99989U 99989  A 96363.53210417  .02300000  00000-0  57503-3 0    09
2 99989  97.9100  63.6600 0570000 145.0000 176.4000 15.07500000    01

This fits the 27, 28 and 29th well, but there are some puzzling aspects:

- the mean ndot/2 since the first preliminary elset is 0.00625 rev/day^2,
  yet actual decay rate has only decreased from 0.028 to 0.023 rev/day^2.
  This suggests a small manoeuvre took place on or after the 26th.

- by the time of the obs on the 29th, the mean motion would have been about 
  15.121 rev/d, implying an orbit of 160 x 913 km. That is a great deal of 
  decay since the initial parking orbit, and much lower apogee than a standard
  Kh orbit.

One argument is that this is really the rocket body, but in that case, why did
it apparently manoeuvre between the 26th and 28th? Also, why is so much brighter 
than a Titan 2nd stage is known to be? The standard magnitude of previous stages 
was about 4.8; this object's is around 3. Also, why is it not flashing? All past 
Titan 2 stages observed by hobbyists (90050B, 91017B, 91076B, 96029B and 96038B) 
flashed, all except 91017B had initial periods between 1 and 6 seconds; 91017B's 
was between 10 and 20 s.

If this is the payload, then why has it been allowed to decay so much since
launch 9 days earlier? Also, why is so bright? Kh's 92083A and 95066A are
not normally magnitude 2 to 2.5 near apogee, even under the best circumstances.
There std mag is about 5; this object's seems to be about 3. Perhaps its 
orientation is unusual.

Finally, I have considered the possibility that the orbit is closer to 14.07
rev/day than 15.07 rev day. In that case, I would expect to be nearly circular.
The following elset roughly fits the obs of 26-29th, but not well enough to
argue that it is correct:

99991A          15.0  3.0  0.0  3.0 v
1 99991U 99991  A 96361.53908565  .00000000  00000-0  00000-0 0    03
2 99991  98.9093  60.8000 0000000   0.0000 321.7000 14.06700000    02

Southern hemisphere observers are advised to use the following orbit 
for searching:

99989A          15.0  3.0  0.0  3.0 v
1 99989U 99989  A 96363.53210417  .02300000  00000-0  57503-3 0    09
2 99989  97.9100  63.6600 0570000 145.0000 176.4000 15.07500000    01

Allow at *least* a 10 minute uncertainty.

Be prepared for anything. If the object suddenly manoeuvres to its standard
orbit of 270 x 1000 km, then it will arrive about 23 min later each day. Also, 
be on the lookout for a second object near this object's orbit. Ideally, should 
consist of precise timings of precise positional sky coordinates. Please include 
time and location of shadow entry. Also, please note colour and magnitude and 
flash period.

Post your observations to SeeSat-L, or e-mail them directly to me.

Clear skies!
Ted Molczan