Conference 7.286::space

I'm sure the sat. watchers can fill in the details, but there is at
least one (and I thought 3) "constellation" satellites up there.

I've seen them on various elements lists, but never bothered to try
and watch them myself.

All are military in nature.  I thought the most well-known had over 5
parts.   I doubt they were KH's (unless the nature of KH's have changed).


- dave

    GPS?

RE: <<< Note 946.2 by skylab.zko.dec.com::FISHER "How may I be honest with you today?-Tuvok" >>>

>    GPS?

I'm almost positive that the DoD's GPS satellites orbit alone.
						-- Tom

    re .3
    
    Correct, the GPS satellites orbit alone. The term constellation is used
    to describe any related group of satellites, not necessarily orbiting
    in close proximity.
    
    I do recall reading about some sigint satellites that were grouped
    together in orbit, perhaps to do some type of interferometry. It would
    take me a long time to track down the reference though.
    
    gary

    If .0 can supply the date and time along with his site location at
    the time of the observation, I'll take a shot at running it through
    my satellite tracking program I have on my PC at home. 
    I may be able to determine what it/they was/were.
    
    Bob

Re GPS:  Are you saying that no two GPS satellites are in the same orbit (except
for time)?  I somehow had the impression that there were two or 3 of them all in
the same orbit.  Or did you just mean that they are not close together?

Burns

RE: <<< Note 946.6 by skylab.zko.dec.com::FISHER "How may I be honest with you today?-Tuvok" >>>

I wouldn't be surprised if there were one or two on-orbit GPS satellite spares.
I don't know what a likely orbit would be for them, since (assuming that they
exist) they would need to be able to maneuver substantially to replace an
in-operative satellite. In any case I doubt that they'd be parked very close to
one of the other satellites in the constellation.
						-- Tom

    I didn't say that GPS birds are not in the same orbit, just that they
    do not orbit together (or at least that is what I was trying to say).
    
    There are several GPS orbits, basically the same but different orbital
    planes. Each orbit has several satellites, spaced equally around the
    orbit.
    
    I don't know what they do for spares. I suspect changing orbital planes
    requires more delta-V than the satellite propulsion system can provide.
    I'd be more inclined to design some redundancy into the system so that
    it can remain operational after point failures. I think a GPS receiver
    only needs to see 2 birds to fix location.
    
    If there are on orbit spares, there would be no reason to have them
    in close proximity to active satellites.
    
    gary

    From my recollection of three separate web sites I have visited
    in recent months, and also by parsing through the visual.tle
    file found at the space archives maintained by TS Kelso, the
    GPS satellites are going to be pretty difficult to be seen by the
    naked eye or even in binoculars. So whatever it was that was seen,
    it wasn't GPS birds. It's more likely that it was an old COSMOS
    rocket booster. There are a lot of these in orbits with inclinations
    greater than 80�. Alot of these COSMOS upper stage rockets & boosters
    are in the visual magnitude range of between magnitude 3-8, according
    to some information I seen.
    
    Bob
    

    I'll await Brian's posting of his observation site used when he
    made his observation, and then I should be able to narrow down
    what it was that he may have seen.
    That way I can enter his observing location along with the date
    & time into my satellite tracking program, and something should
    pop up.
    
    Bob

    re .1
    
    I think you are thinking of the NOSS (Whitecloud) series. See 360.8 et seq.

      FTP from archive.afit.af.mil/pub/space the file visual.tle for most 
    visual orbiting objects. Plug this into a satelite tracking 
    program(PCTRACK or WINORB) to calculate passes. Also try on the WWW 
    the following; http://ssl.berkeley.edu/isi_www/ 
    for the MIR, Shuttle(When it's up) and a few others.
    
    
    
    	Terry