From: Doug Jones (random@qnet.com)
Date: Fri Dec 03 1999 - 23:19:57 MST
EvMick@aol.com wrote:
>
> In a message dated 12/3/99 11:13:29 PM Central Standard Time,
> zharadon@inconnect.com writes:
>
> > there are
> > still the issues of air pressure and temperature - any ideas?
>
> full body panty hose...
>
> really. very tight ....support against low pressure...
Yeah, Mitch Clapp did the most recent work on counterpressure garments
(specifically gloves) back in 1983. He was the Wunderkind of Case for Mars
II- he singlehandedly took 2nd lace in the Mars Prize contest (it took me a
five person team to beat him), and presented papers on a high resolution
film mapper, dirigibles, and the skinsuit gloves. The guy is annoying :)
> And does vacumn have a tempeture? Is the "fridgid depths of space'
> real or a bogus holiwood meme?
Partially true- in the absence of sunlight, an object radiates into the 3
Kelvin universe. Near Earth, though, 1300 watts/m2 of sunlight is *real*
toasty.
> What is the tempeture of a vacumn? how come it keeps my coffee hot
> in the thermos?
A thermos has low thermal emissivity walls, so the radiative heat transfer
is slow. Spacesuits such as the ones used on the moon and the space
shuttle are deliberately made white (to reflect sunlight) and high
emissivity (to radiate heat)- this because most of the time the problem is
to get rid of the astronaut's metabolic heat.
> Would sweat in a vacumn cool you?
Yes, this is a strength of the skinsuit concept, particularly for Mars.
Since the insolation is much lower, the active cooling system on a moon
suit can be dispensed with, and radiative cooling will suffice most of the
time. Heavy work will cause sweating which will cool *very* well (think of
rubbing alcohol evaporating), and an insulated overjacket and trousers can
be added or removed for colder "weather". One thing which does concern me
is the severe cooling that could arise from a nervous sweat- in an
emergency getting chilled would not be helpful.
> EvMick <------thinks cooling might be more of a problem in space than
> heating..
Perzacktly so- think of the harsh sunlight in the desert on a clear day,
then multiply by 1.5 for all that is absorbed or scattered by the
atmosphere. *And* there is no convection to carry heat away- this is why
near-earth spacesuits have water sublimators for cooling, and use far more
water than oxygen.
-- Doug Jones Rocket Plumber, XCOR Aerospace http://www.xcor-aerospace.com
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