T.R | Title | User | Personal Name | Date | Lines |
---|
946.1 | | PRAGMA::GRIFFIN | Dave Griffin | Sat Aug 05 1995 20:24 | 11 |
| 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
|
946.2 | Navigation? | skylab.zko.dec.com::FISHER | How may I be honest with you today?-Tuvok | Tue Aug 08 1995 00:52 | 1 |
| GPS?
|
946.3 | | LHOTSE::DAHL | | Tue Aug 08 1995 13:20 | 6 |
| 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
|
946.4 | | STAR::HUGHES | Captain Slog | Tue Aug 08 1995 16:02 | 11 |
| 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
|
946.5 | Cobe runs in polar & is supposed to be visible naked eye... | NETCAD::BATTERSBY | | Tue Aug 08 1995 16:46 | 6 |
| 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
|
946.6 | | skylab.zko.dec.com::FISHER | How may I be honest with you today?-Tuvok | Wed Aug 09 1995 15:36 | 5 |
| 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
|
946.7 | | LHOTSE::DAHL | | Wed Aug 09 1995 15:41 | 8 |
| 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
|
946.8 | | STAR::HUGHES | Captain Slog | Wed Aug 09 1995 16:21 | 17 |
| 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
|
946.9 | More likely it was a spent COSMOS upper stage rocket/s | NETCAD::BATTERSBY | | Wed Aug 09 1995 17:21 | 13 |
946.10 | Still awaiting Brian's observation site... :-) | NETCAD::BATTERSBY | | Wed Aug 09 1995 17:25 | 8 |
| 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
|
946.11 | | AUSSIE::GARSON | achtentachtig kacheltjes | Wed Aug 09 1995 23:03 | 3 |
| re .1
I think you are thinking of the NOSS (Whitecloud) series. See 360.8 et seq.
|
946.12 | Visual Elements for tracking | WONDER::SKRYPEK | | Wed Aug 16 1995 16:40 | 10 |
| 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
|