Titan 4 payload not seen tonight - major manoeuvre seems to have occurred.

Ted Molczan (molczan@fox.nstn.ca)
Wed, 10 Jul 1996 02:35:38 -0400

I had two opportunities to observe 96038A tonight, but it failed
to appear. The first was at 3:23 UTC on 10 July. I looked for it
from 3:21 until 3:27. The second was at 4:56 UTC, and I looked from
4:53 through 5:06.

Both passes were less than ideal, in that the phase angle was poor,
with less than 20 percent illumination, and the elevation was low:
10 deg on the first pass, and about 15 deg on the second pass. The
sky was very clear, and I was using mounted 11x80 binoculars, so
I believe that I should have seen the object on at least one pass.
I have plenty of experience observing very poor passes, mostly with
success, so I am inclined to believe that the object has made a
major manoeuvre. I was prepared for that possibility, given that
U.S. medium inclination spysats have in recent years spent about 
one week in their initial parking orbit, before manoeuvring to
a higher orbit, and this was one was launched one week ago.

I believe that the manoeuvre occurred sometime after Pierre 
Neirinck's obs of 8 July 22:43 UTC, and western Canada observer's
non-obs of 9 July 6:14 UTC. If it went into a Molniya transfer
orbit, then we would be looking for a small perigee kick stage in
a 300 km by >8000 km, 55 deg orbit, with perigee at 55 S latitude. 
That would make for a rather difficult search in the N. hemisphere. 
For tonight, I decided to check whether or not it moved to a somewhat 
higher parking orbit. Based on past history, I selected a circular 
460 km orbit, and set the epoch and RAAN mid-way between the last known sighting, and the first non-sighting:

96040A          10.0  3.0  0.0  5.0
1 96040U 96040    96191.10312500  .00000000  00000-0  00000-0 0    09
2 96040  55.0000 158.0500 0000001   0.0000   0.0000 15.37000000    07

I searched in and near this orbit from 10 July 2:33 through 4:20 UTC,
except between 3:21 and 3:27, when I looked in the last known orbit,
epoch 96190. None of the satellites I saw moved in the correct
direction, nor did they resemble 96038A.

I could have missed the object while checking my star charts, or it 
might have moved to a significantly different parking orbit, outside
the area I searched. I will consider searching again tomorrow, weather
permitting, and assuming nobody else has found it, either in the 
original or some other orbit. There is a small possibility that the
object is still in the last known orbit, but was simply too faint
to see on my passes.

Bye for now