From: jdunning@phoenix.Princeton.EDU (John Alan Dunning)
Subject: Re: Still WASTE HEAT? (actually, it's more about sentinels now)
Originator: news@nimaster
Keywords: surveillance stealth detectors computers aesthetics
Organization: Princeton University
Date: Thu, 17 Dec 1992 15:46:28 GMT

In article <BzByDF.7Cv@bunyip.cc.uq.oz.au> scooper@kepler.physics.uq.oz.au (Steven Cooper) writes:
>pksuk@rodan.acs.syr.edu (Peter K. Suk) writes:
>>You and those ice-cream licking sentinels!  Those check-writing, AI,
>>IR-telescope-looking, waterlogged sons of Baal are going to save
>>everything, right!?  WRONG!  I'm gonna BLOW THEM UP!  :)
>>
>>*maniacal laughter!*
>
>Don't you like my sentinels? :(
>
>>But seriously now, wouldn't they be the first target?
>
>Yes, of course they would, but the mere act of destroying them would alert the
>owners of the sentinels that something was up. As such they would still have 
>served their purpose. 
>
>Steven Cooper
>scooper@kepler.physics.uq.oz.au

Clearly, trashing the sentinels as you're driving into the system
isn't very stealthy.  But what if you could jam the sentinels in some
way, or fake them out?  Then you might be able to drive a whole fleet
of warships by without giving your opponents any early warning.

To do this, you'd first have to know where the sentinels are.  How
stealthy can a sensitive sentinel be?  Obivously they're going to have
be very cold so their own heat doesn't interfere with their sensing
abilities.  But the heat from their power source and electronics
(photonics, whatever) has to be radiated somewhere, presumably in a
direction directly opposite the sensor end.  This is going to make it
somewhat difficult to detect them if you're approaching their sensor
end, as you probably will be if you're coming from outsystem.

But the sentinels will inevitably occlude stars, and perhaps you can
catch them then.  So let's say you know where all the sentinels are,
either through espionage(?) or long, careful observation.

You have two choices for evading the sentinels: either camouflaging
your ship or physically compromising the sentinels.

For camouflage, what if, instead of having a single, large radiator,
you had lots of tiny ones, all over the ship, with their total surface
area equaling that of the larger one?  Does it matter,
thermodynamically speaking, that the radiating surface is not
contiguous?  (Of course, the internal plumbing is going to be tricky.)
Let's also say you can turn these radiator ports on and off at will,
very quickly, that you can point them in any direction, and that you 
can tune the radiation to any wavelengths that you like.

So if you know where the sentinels are, you can figure out which stars
in their field of view you're occluding at any given time.  Then as
you're moving in front of a star, you point a radiator at the proper
sentinel(s) and beam a simulation of that star's light it.

The more I'm thinking about it, the more I'm realizing how difficult
it would be to deliver exactly the same number and wavelength of
photons from exactly the same point, without interruption, that the
sentinel is expecting.  If you don't, the sentinel is going to see the
star twinkling, or change in brightness.

In any case, would you be able to dispose of enough waste heat this
way?  Since today's telescopes count individual photons, I'm assuming
any one star isn't radiating much heat.  Keep in mind, though, that you may
be in the field of view of a number of sentinels, so you're going to
have several radiators going at once, and that you're
pumping out as much heat as you can get away with in the direction
opposite them.  You're probably not going to be able to have the
engines running, but if you're trying to silently drift into the
system?  Or am I completely off?

The other option is physically sabotaging the sentinels.  To do this,
you might fire a bunch of very cold, marble-sized spaceships at them.
They might use the maneuver someone mentioned previously for
overshooting the target and decelerating behind it, so they don't hit
the sentinels with their exhaust.  But in this case, you're talking
about scales of kilometers, rather than A.U., so the extra time
involved would probably be negligible.

Assuming the sentinels don't have sensors for detecting little
spaceships attaching to it, the microships should have do difficulty
rendezvousing with them.  Once there, they could just sit and watch
what is being transmitted back to space traffic control and figure out
how what the sentinel is seeing is encoded in the signal.  If the
signals are encrypted, it might be very difficult to crack the code.
But even though the individual ships are small, and thus carry small
computers, you could network a bunch of them and get a fairly powerful
computer.  Once you know what the right signals are, the microships
just send some nano into the guts of the sentinel and (carefully) tap
into the transmitter.  Then it doesn't matter how loud the attacking
ships are.

John