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From: ke4zv!gary@gatech.edu (Gary Coffman)
Newsgroups: sci.military
Subject: Re: Pegasus
Message-ID: <1991Apr22.072403.26403@amd.com>
Date: 21 Apr 91 15:30:08 GMT
References: <1991Mar30.020340.27985@amd.com> <1991Apr12.055442.14741@amd.com> <1991Apr17.055545.13756@amd.com> <1991Apr18.032927.22679@amd.com>
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From: ke4zv!gary@gatech.edu (Gary Coffman)


This is in response to Henry and John Prentice who question the need for
detailed pictures from the proposed small tactical satellites.

prentice%triton.unm.edu@ariel.unm.edu (John Prentice) writes:
>launched cheap and dirty satellite.  Also, you don't necessarily need
>high resolution.  For example, to see a convoy you don't need to be able
>to read their license plates.

The is probably true, but you *do* need to be over the target area when
the convoy is there. My primary objection to tactical satellites is that
they are over the target area for no more than twenty minutes a day in
two ten minute passes separated by 12 hours.

No quick launch satellite seems likely to be as useful to a tactical
commander as a directed overflight with a recon aircraft would be.
Nor would the quick looks by the small satellite be more useful than
continous surveillance from a high orbit satellite system. Catching 
convoys on the ground seems a better mission for GSTARS aircraft than 
for a satellite that you may have to wait as much as twelve hours to 
access.

Depending on the satellite design and the geography, you might have
to wait for the satellite to pass over your location in order to 
program it to look at the area that you are interested in, wait for
it to pass directly over that area maybe 12 hours later, then wait
for it to return over your position another 12 hours later for the
data dump. A 24 to 36 hour reaction time certainly seems less than
timely for tactical data. Contrast this to the 1 hour or so turnaround
from a ready recon aircraft or the near realtime info from a GSTARS
aircraft or data relayed from a coordinated series of strategic high 
orbit satellites.

It seems to me that the best system for satellite tactical recon
would require a series of satellites in relatively high, >1000 mile,
orbit where they would get a near hemispheric view. A target area
could be handed off from one satellite to the next in such a fashion
that the target area could be under near continous realtime surveillance.
This type of system would require national strategic control centers
rather than being operated at a field commander's whim.

A use once and throw away system would still likely require one orbit
to stablize the satellite and check out the cameras followed by another
orbit to acquire the data and access to a global high data rate satellite 
communications network to relay the data back to the commander in the
field. All of this would require coordination with national centers.
It would be hardly as cost efficient or timely as simply ordering up
a recon aircraft.

This all sounds more like Pegasus and litesat proponents looking for
a mission rather than an actual operational niche that needs to be
filled.

Gary