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http://en.wikipedia.org/wiki/TDRS
--- On Wed, 3/11/09, Nigel Gunn G8IFF/W8IFF [email protected] wrote:
From: Nigel Gunn G8IFF/W8IFF [email protected] Subject: [amsat-bb] Re: NASA predix program To: "Alan Sieg WB5RMG" [email protected] Cc: [email protected] Date: Wednesday, March 11, 2009, 5:08 PM Thanks Alan. I use either Orbitron or InstantTrack. I had always wondered what the range circles over Russia were. Does NASA have an official write up on the 'net. Do we know the object numbers for the TDRS birds? My keps suggest there are 9 TDRS birds up there.
Alan Sieg WB5RMG wrote:
There are several different views you may see, but the
main thing that
we "see" is the background map. Several
"free" programs now utilize the
map made from composite satellite images that looks
natural and cloud-free.
A good example someone pointed out is the default
image in Orbitron.
What sets the NASA maps apart is that they also
usually show the coverage
area of the three primary TDRS relay satellites, and
marks on the future
ground tracks to indicate orbital sunrise and sunsets.
As the shuttle
(or ISS) moves about the orbit, those coverage circles
help visualize the
"TDRSS handovers" where communications will
drop out for a minute or a few.
You may also notice on the ISS map view, the range
circles about the Russian
ground stations. During de-orbit and re-entry the
background goes black and
you'll see blue range circles about the various US
radar tracking sites.
During Joint-Ops with both Shuttle and ISS, they show
Lat/Lon/Alt stats
in the upper corners of the display. Lots of things
they can turn on/off.
The other display (my personal favorite) provides a
multi-view in 3D space.
I've heard it refered to as 'Birds Eye
View' or BEV. I've seen similar
applications running on SGI computers, with a 3 pane
window... the top one
a side view parallel to the velocity vector, with
gravity down. The lower
panes showing 1) a view from above sighting down along
gravity, and 2) a
view from slightly above looking forward along the
velocity vector. These
views are fed by live telemetry data that will include
the vehicles
orientation respective to those vectors. I really like
watching those
during orientation adjustments. If you can watch
before docking, you can
see how the ISS is rotated around to place the docking
port 'in back' so
that the Shuttle's TPS is better protcted from any
orbital debris. If you
see this display before re-entry you can see how they
turn tail-forward
in preparation for the de-orbit burn... I really enjoy
watching this stuff.
Still tho, it is hard to beat the 3D view in
InstantTrack, especially on
one of those Molniya orbits like AO-13, whippin around
perigee - whoosh !
Enjoy /;^)
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-- <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><> Nigel A. Gunn. G8IFF W8IFF (was KC8NHF) 1865 El Camino Drive, Xenia, OH 45385-1115, USA 937 825 5032 e-mail [email protected] www http://www.ngunn.net Member of ARRL, GQRP #11396, QRPARCI #11644, SOC #548, Flying Pig #385, Dayton ARA #2128, AMSAT-NA LM-1691, AMSAT-UK, MKARS, ALC <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><> _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb