title: Compatible atmospheres for a space suit, space station, and shuttle based on physiological principles.
abstract: Fundamental physiological principles have been invoked to design compatible environments for a space suit, space station, and the space craft used to transport the astronauts from Earth. These principles include the long-term memory of tissues for a bubble-provoking decompression, the intermittent nature of blood flow in the tight connective tissues(s) responsible for the bends whose incidence in aviators has been shown to be related to bubble volume by the Weibull distribution. In the overall design an astronaut breathing a mixture of 30% O2 in N2 for 4-5 h in a space craft at 11.9 psia can transfer to a space station filled with the same mix at 8.7 psia and, after a further 4-5 h, go EVA at any time without any oxygen prebreathing at any stage. The probable incidence of decompression sickness has been estimated as less than 0.5% using the present suit operating at 4.3 psia but the risk could be reduced to zero if the suit pressure were increased to 6.5 psia.
mesh_terms: D000337:Aerospace Medicine; D000818:Animals; D001272:Atmosphere; D003664:Decompression; D003665:Decompression Sickness / Q000453:epidemiology / Q000209:etiology; D005118:Extraterrestrial Environment; D006706:Homeostasis; D006801:Humans; D008297:Male; D008433:Mathematics; D009584:Nitrogen / Q000378:metabolism; D011312:Pressure; D011481:Protective Clothing; D013026:Space Flight / Q000295:instrumentation*
chemical_list: D009584:Nitrogen