Re: Titan IV launch

Jason Hatton (jason.hatton@etss.u-strasbg.fr)
Sun, 10 May 1998 17:30:55 +0000

Allen Thomson wrote:

> BTW, if Tony Beresford and Jason Hatton would give their permission,
> I'd like to repost this thread on sci.space.satellites.visual-observe
> in hopes of creating interest there.

That's fine by me. Hopefully, someone may come up with some answers to
these questions, particularly the likely target orbit (GEO vs Molniya).
There is some basic info on Titan Centaur launch trajectories &
manoevres on Johnathan's Centaur mission;

http://hea-www.harvard.edu/QEDT/jcm/space/misc/centaur.html

Unfortunately, to my knowledge all Titan-IV centaur launches into GTO or
Molniya orbits have been classified. However, looking at the orbital
parameters in Jonathans table, it looks like most (but not all) launches
to GEO involve three burns which leave the Centaur in an inclined,
almost geosynchronous orbit;

(Data from Jonathans centaur page, altitudes in km)
Centaur TC-13           23713 1995-060B 180? x 180? x 28.5?     MECO1
                                        180? x 35827 x 26.7     MECO2
                                        35700? x 35900? x 10?   MECO3
Milstar DFS 2           23712 1995-060A 35700? x 35900? x 10?   MECO3

Where as for a Molniya orbit :
Centaur TC-8            23610 1995-034B 245 x 255 x 56.1        MECO1
                                        245? x 39200? x 64?     MECO2
                                        1300? x 39200? x 64?    MECO3
USA 112                 23609 1995-034A 1300? x 39200? x 64?    


Although these are high altitude orbits, Titan Centaur's may not be so
difficult to spot if the behaviour of Atlas-Centaurs is anything to go
by. Most of these flash & are quite bright, I regularly observe these
flashing as bright as mag +8 all the way out at apogee (more than
37,000km range). Since the Titan Centaur stage is also metallic & even
larger there is a good chance it would behave much like an Atlas
Centaur. It's flashes should be quite distinctive, ie. regular,
relatively sharp & probably short period.  So perhaps it's feasible that
the recently launched Centaur & other Titan-Centaurs could be spotted &
tracked visually using a telescope. Maybe someone will come across these
when observing the region around GTO?

Some general information on Centaur rocket is on the Visual Satellite
observers home page, including pictures of the Centaur-G which is very
similar to those used on Titan-IV centaur launches;

http://www2.plasma.mpe-garching.mpg.de/sat/centaur.html


Best wishes & clear skies, 


Jason P Hatton
INSERM U311
ETS Strasbourg
67065 Strasbourg Cedex
France

48.538N / 7.731E / 143m