Re: Drones and sensing passively IR

"Thomas.Barclay" wrote:
> 
> IR Detection:
> 
> Whereas I will agree that a modern IR telescope can pick out small
changes
> from ambient, I must ask a couple of questions as this discussion
pertains
> to detecting ships: How many objects are there in the scan of a scope,
and
> how many exhibit non-ambient IR? I don't know. But if dust and
meteorites
> and whatnot do, then you have a lot of things to watch.
> 
> Also, is there not a focal distance for the telescope? a band of range
it
> can monitor? I'm assuming it doesn't "see" all the IR from location of
the
> ship to the next solid object... or if it does, how does it
distinguish
> between dust, a close in meteor, a far away ship, etc that all may be
> superposed to produce the composite IR reading for that bearing and
azimuth?
> If it has any sort of focal radii or focal band, then it has to sweep
> repeatedly (and I assume in order to be as sensitive as we discuss, it
has
> to do so *very slowly*) so it might well be VERY hard to detect a ship
from
> IR signature given the volume of space the scan array has to examine.

	Well, having read the most part of the thread pointed out by
Nyrath,
there doesn't seem to be a clear consensus on this. Mostly, it seems to
come down to how much scanning work you need, how much processing work
you need, how quickly you can do the work, and, of course, how many
detectors you have (you need at least two for triangulation if you want
to calculate distance). One point which was pretty much conceeded (and
backed up by calculations) was that, using current technology, you could
detect the Space Shuttle's manuvering thrusters in the asteroid belt,
and its main engines out beyond Pluto. Thus, if you're using thrust, you
can't hide. ( <
http://x34.deja.com/[ST_rn=ps]/getdoc.xp?AN=500531705&CONTEXT=955891876.
1444610054&hitnum=4>
for a reference article).
	Regardless of strategic detection (which this concentrates on),
by the
time you're in tactical weapons range (say a few light-seconds, which is
almost certainly WAY beyond weapons range, but will work for
comparison), no one can hide. If you have two ships (for triangulation),
you can detect position VERY precisely (even more so, and including
velocity, if the opponent's using thrust), so detection is (IMO) more an
issue for campaigns than for tactical games. Pretty much, by the time
you have a chance of hitting each other, you'll know enough about your
opponent's ships (mass, acceleration, position, velocity, appearance,
etc.) to fight them effectively.

> Of course, it might not. Noam, Mark? Somebody know the answer to how
these
> IR telescopes work and care to make some projections about if a ship
is
> easily/quickly detectable from IR or if it will remain (for some
> physical-law type reason) a slow task to scan for IR passively?
> 
> OTHER:
> 
> Someone pointed out they'd find it hard to imagine a hull 250 C lower
than
> the inside of a ship. And yet they can envision gravitic compensators
and
> jump drives... <heh>. That's funny.

	That was me. Yes, a bit strange, but then I don't play with
gravitic
drives (or reactionless drives of ANY type - they violate too much in
the way of conservation laws). As for jump drives, there's plenty of
theory that suggests that they're impossible, but there's also some
theory that says "maybe not." I'm willing to accept their existence
provisionally, as long as they DON'T appear to violate too many physical
laws (I'm willing to allow people to get around relativity for the sake
of the game).

> I believe the comment made about lasers and hull penetration is spot
on.
> Ship lasers probably have to hit a bunch of times or stay on the same
spot
> for a period to burn through. Missiles with bomb-pumped lasers are of
course
> a different matter.

	Not THAT different, and even less likely to hit initially. You
can see
the designer's notes for "Brilliant Lances" (url provided earlier,
findable through www.grognard.com) for problems with laser focussing, as
for targetting, it's essentially a matter of how quickly you can move a
distance equal to your cross-section, versus how quickly your opponent
can detect you, fire, and have the shot arrive. STL weapons are, of
course, even harder to hit with....

-Brian Quirt