PDL@MIT-XX@sri-unix (12/01/82)
From: PDL at MIT-XX (P. David Lebling) This is summarized from the "Bioastronautics Data Book" (2nd Edition), a NASA publication. It refers to several animal studies which show a similar response in several species to decompression to near-vacuum conditions (1-2mm Hg). It then says, extrapolating those results to humans: "Some degree of consciousness will probably be retained for 9 to 11 seconds. In rapid sequence thereafter, paralysis will be followed by generalized convulsions and paralysis once again. During this time, water vapor will form rapidly in the soft tissues and somewhat less rapidly in the venous blood. This evolution of vapor will cause marked swelling of the body to perhaps as much as twice its normal volume unless it is restrained by a pressure suit. (It has been demonstated that a properly fitted elastic garment can entirely prevent ebullism at pressures as low as 15mm Hg absolute). ... Venous pressure will meet or exceed arterial pressure within 1 minute. There will be virtually no effective circulation of the blood." "...survival was the rule if recompression occurred within about 90 seconds." "...some animals have died within seconds of decompression and a few others have had severe, lasting central nervous system damage." The qualifier "some" is not too encouraging, but I'd call it possible if unlikely. Note also the remark about preventing ebullism (vaporization of body fluids) with an "elastic garment". It looks like the non-bulky spacesuit has been tried and works, but only to a point. Dave -------