cjh@CCA-UNIX@sri-unix (11/21/82)
(a) When I was taking flying lessons we were taught that the pressure dropoff is about 1 inch of mercury per thousand feet at low levels. 3.7 psi (1 psi ~= 2 iom) sounds like a lot less than 60K feet, even allowing for tapering. (b) Clarke specifically states (e.g. in "Take a Deep Breath") his assumption that short-term survival in airless conditions would require venting oneself as effectively as possible---emptying the lungs, leaving the mouth wide open, and hoping that the eustachian tubes are clear so you don't lose an eardrum; his guesstimate was that you could survive this way for about a minute. (c) Skin as a barrier shouldn't stand anywhere near 15 psi for any length of time. First, skin is quite porous; the surfaces that have the fewest hair follicles (e.g., palms and soles) have the highest possible rate of water loss through sweating. Consider that the cross-sectional area of major arteries, which withstand a peak pressure of ~200 torrs (~4 psi), is mostly wall---which in turn is much solider tissue than skin. I'd like to see evidence countering this, but I doubt there will be any; I don't remember enough physiology to explain clearly but I seem to recall other mechanical reasons why non-coverall pressure suits wouldn't work.