Final Titan 4 update for tonight

Ted Molczan (molczan@fox.nstn.ca)
Thu, 4 Jul 1996 23:27:44 -0400

I have now updated the payload's elset, using the Moscow observation.
Here are the latest elsets:

96038A          10.0  3.0  0.0  5.0
1 23942U 96038  A 96186.22495718  .00000000  00000-0  00000-0 0    07
2 23942  55.0000 181.5000 0000001   0.0000  76.9000 15.90750000    07
96038A r         9.8  3.0  0.0  5.0
1 23943U 96038  B 96186.22381250  .00120000  00000-0  34213-3 0    02
2 23943  55.0000 181.5000 0000001   0.0000  76.7000 15.92600000    02

Baring a manoeuver by the payload, which could occur at any time,
these elements should be accurate to about 1 minute in time, and 2 deg
in position. I used the Western Canada obs (posted earlier) and the
Moscow obs to derive the elements. The text of the Moscow observation
follows:

On July 4 after 22:00 UTC I've seen two bright objects that may
be related to July 3 Titan 4 launch. Observation was made at 55.63 deg N,
37.47 deg E (Moscow, Russia). Both objects followed the same path
(NW to SE) and passed 2 deg SW of Altair at 02:03:16 and 02:06:13 UTC 
correspondingly (+/- 1 second). The former one had variable brightness
(3-5 seconds), the latter had constant brightness, both approx. 0..+1m.

I will not identify the observer until I have his permission to do so.

I have been studying the RAAN of the past SDS objects, to see if there is an obvious relationship
with this object, i.e. is it going to replace one of them? It is closest to where I believe USA 40 is
located, but it is more than a month away overtaking its RAAN. This is not a particularly high-
confidence analysis because there is some uncertainty in the SDS 2-1 and 2-2 RAANs when
they first moved to their Molniya orbits, and there is even greater uncertainty in the effects of
luni-solar perturbations, which greatly affect the rate of precession of the RAAN.

This launch appears much closer to SDS 2 than any other high-inclination missions we have
seen, such as AFP-731, NOSS and Lacrosse. I do wonder about the 55 deg inclination. Is it due
to some operational limitation of the Titan, such as payload mass? Or, is the object destined to
stay at that inclination, presumably in a higher orbit. The first two SDS 2 payloads were deployed
by shuttle into low 57 deg orbits, then manouevred to a Molniya orbit. The inclination change
takes place near apogee, so the delta V (velocity change) is not all that great. I doubt that the
extra 2 deg change in inclination change from 55 to 63.4 deg would be all that great a challenge.

The first two SDS 2 payloads flashed with a period almost exactly 1 s, indicating, most likely,
a 30 rpm spin-stabilization. We should time this new payload's flash period, to learn whether
or not it matches that of the first two.

I am still a bit concerned by the colour. Two observers have reported a reddish colour. I detected
a faint orange hue in SDS 2-1, but nobody else was able to confirm this. If this new object is
significantly redder than the SDS 2-1, maybe it is not the same. Of course we need more obs
before we can draw any conclusions.

bye for now


bye for now