[amsat-bb] Re: NASA predix program
Alan Sieg WB5RMG
wb5rmg at somenet.net
Wed Mar 11 16:55:17 PDT 2009
> Which satellite prediction program do we see on the big screen
> on the NASA TV broadcasts from mission control in Houston?
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 !
<- Licensed in 1976, WB5RMG = Alan Sieg * AMSAT#20554 ->
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