Re: Detection sources

> Definitely. The other (semi)-missing factor here is relative
> temperature. On the Earth, there isn't THAT much of a temperature
> differential, so you need to have a pretty high differential to detect
> anything. In space, though, things are different. The background is
MUCH
> cooler (a random patch of sky is probably going to be within shouting
> distance of absolute zero), and a ship hull just CAN'T be kept at that
> temperature very well (or, at least, I wouldn't really want to try to
> design a ship where the outer hull is more than 250 degrees centigrade
> cooler than the inner hull). Current technology is well able to detect
a
> few degrees divergence from background (not via earth-based
telescopes,
> of course), and I see no reason to suppose that future technology will
> be any LESS capable.
>
> -Brian Quirt

I was trying to set up a spreadsheet to see what kind of heat transfer
you
would get using different temperature differences between an inner hull
at
say 25 C and the outer hull, and a space temperature
of -270 C.  What I was wondering is what are the sizes of some of the
ships?
Since the heat transfer depends on surface area.

Right now I am using a cylinder 100m long with a 20 m diameter, and you
hit
a kilowatt around a 175 degree difference in hull temps with around 58
kW at
no temperature difference.  These are pretty approximate numbers because
radiation is ungodly complex, at least to me.

Christopher K Smith
SR MECH Auburn University
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Homepage http://www.auburn.edu/~smithck
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