gutfreund.umass-coins@UDel-Relay@sri-unix (11/23/82)
From: Steven Gutfreund <gutfreund.umass-coins@UDel-Relay> I'm still not sure I have gotton a definitive answer on this: 1. The linear heuristic that the pilot gave for turning feet to millibars of Hg, was obviously flawed. David.Smith's quotations from the CRC are obviously more correct. 2. The comments about Dave of 2001, are not exactly relevent. I am assuming a pressure helmet with some sort of seal that will work. (BTW, I just saw this film last night again, and the scene is pretty believable, I was just not sure how he positioned the pod so well with no rear window). The two major arguments against pressureless suits at this moment seem to be: (1) without pressured suits, exhaling becomes too hard (2) Blood starts boiling when the body is is exposed to vacuum. Counter-arguments to (1) (1) is a good argument, But humans are pretty good about building up lung power for exhaling. Just look at Tuba players, people who can do artificial respiration for hours, or those incredible bagpipe players. I wonder if one could not train ones lungs to produce enough counter pressure against 3.7 psi. If not, why not an elastic band around the chest. This way, the 3.7 psi air forced into the lung will do work which is stored in the band, which can then help the person exhale. (2) Do you really think that if I put my hand in a vacuum bottle, my blood will start to boil? Forget the misleading stuff about persperation, and concetrate. Why is it that blood boils at lower pressures? Just as David.Smith says: "it is a liquid immersed in a lower pressure ambient environment". This can only be accomplished by the artery and vein walls expanding. Will this really happen if a the body is exposed to a mere 16psi differential? The balloonist falling from 102,000 probably had a severely swollen hand due to frostbite (but I could be wrong). I would not be surprized if pressureless suits are not realistic, but I still think that the evidence has not yet been presented here to shoot it down. - Steven Gutfreund