Detection by IR

Brian, 

I have to suggest that if your logic for suggesting you'd be detected
anywhere in the system if you went active drive is the 'sector blanking'
that prevents FT ships from shooting out the rear, I must ask:

1) Thrusters can fire without causing this interference. Does this by
inference mean one could manouvre on these without detection? I think
you'd
answer no. 

2) What is the practical range of IR detection? Bradford made some
comments
based off of black body radiation, but didn't say much about what ranges
drives could be detected at. You figure across the system. I have to
wonder
about that. 

I assume drive ejecta would be directional (the particulate component).
The
radiated component might be omni-directional or nearly so. However, I'm
also
sure that the further away I go from a spot in space that is radiating,
the
less likely I am to detect one of the radiated waves. The volume of
space a
wave must travel through grows as the third power of distance from that
source. So presumably the detected density of radiation drops as the
square
of distance? If that is true, then if we take Brad's figures as an
example
of the sensitivity of IR detection (detect 300K at 1 LS surely, 10 LS
probably lost against the background radiation) and assume that drives
emit
more powerful signatures (pick 4800K for a guess - lets say that'd be
doubling the 300K 4 times), then I'd guess they'd be visible at 4^4
times
the original figure... which might be about 256 LS for sure and 2560 LS
they'd be for certain lost to background radiation). 

So, if my idea is right, that means you would for certain detect a
manouvring ship out at 76.8 million km (7600 mu at 10,000 km per mu) .
You'd
for sure not detect it out at more than 750 million km.  Assuming drives
run
that hot.  If your thrusters only ran at 600 degrees Kelvin, you'd only
be
detectable at 16 LS. This is still a long way. 

So it seems that if you could close on a ballistic track with baffling
on
and some method of dropping your hull to 150 K, you could probably close
to
tactical ranges without detection. If you fire up your (presumably) hot
drives, you get picked up wherever you are, if someone is looking. If
you're
a real stealth machine, you might even get under 6 mu, but your ship
would
be storing heat at I imagine a high rate... which you would eventually
have
to dispose of. 

So what this seems to suggest is that comet-tail riders, asteroid
riders,
and stealthed ballistic ships could close in on enemies with good sensor
arrays, but anyone just manouvring would be far more visible at huge
distances. I guess it pays to have your patrol ships take a peek at any
strange objects floating through your space - and check for
"hangers-on".....

Thomas Barclay
Software Specialist 
Defence Systems
xwave solutions
www.xwavesolutions.com
v: (613) 831 2018 x 3008

Alea iacta et pessimo resulto factura est.
 
Ave, Caesar! Te morituiri salutimas!