On Sat, Jul 19, 2003 at 10:55:49AM -0400, Robert J. Chassell wrote:
> Presuming the end caps are mostly low-conductive stone or regolith, > the major temperature determiner for the end caps should be, I think, > the air, although indirect light will have an effect.
I think that would be difficult. Heat conduction between air and a surface is usually very small compared to heat conduction by a solid, even a "low conductivity" solid. For example, just a few feet (say, 2m) below ground on earth, the temperature can be quite different than the air temperature. Ground temperature is often quoted as being about 10-15C year round, even during hot summers or cold winters. Presumably this is because the ground conducts heat much better than the air and spreads heat out evenly throughout the ground.
Actually, it is because the soil is a _poor_ conductor of heat, so it doesn't warm up rapidly in the summer or cool off rapidly in the winter, so the temperature a few feet underground stays constant at the average value for the Earth (around 288K when you take into account the luminosity and distance of the Sun, the Earth's albedo, and the greenhouse effect of our atmosphere).
I don't think the possibility of different temperature air around the end caps could be neglected in determining the weather system of a tuna can habitat. Unless, perhaps, there is some form of "super-insulation" on the end caps.
_Vacuum_ is an awfully good insulator, and there's a lot of it outside the habitat. ;-)
The surface temperature of the habitat would be almost entirely determined by radiative equilibrium, taking into account the Sun's luminosity and distance, the albedo of the exterior of the habitat, and the amount of heat in excess of that coming from the Sun generated by the people and equipment inside the habitat.
-- Ronn! :)
Ronn Blankenship Instructor of Astronomy/Planetary Science University of Montevallo Montevallo, AL
Disclaimer: Unless specifically stated otherwise, any opinions contained herein are the personal opinions of the author and do not represent the official position of the University of Montevallo.
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