Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!usc!jarthur!dmoore From: dmoore@jarthur.Claremont.EDU (Douglas K. Moore) Newsgroups: sci.space.shuttle Subject: Re: What happened? Could risk be higher? Message-ID: <3573@jarthur.Claremont.EDU> Date: 13 Dec 89 20:50:09 GMT References: <5082@jane.uh.edu> <1989Nov29.163242.1165@utzoo.uucp> <6791@pdn.paradyne.com> <1989Dec1.040218.26158@utzoo.uucp> <6801@pdn.paradyne.com> <2991@viper.Lynx.MN.Org> Reply-To: dmoore@jarthur.UUCP (Douglas K. Moore) Organization: Harvey Mudd College, Claremont, CA Lines: 52 In article <2991@viper.Lynx.MN.Org> dave@viper.Lynx.MN.Org (David Messer) writes: >In article <6801@pdn.paradyne.com> dave@rnms1.paradyne.com (Dave Cameron ) writes: >>>In article <6791@pdn.paradyne.com> dave@rnms1.paradyne.com (Dave Cameron ) writes: >> >>[concerning how fast the Challenger crew would have lost consciousness] >> >>time of useful consciousness (not time to total loss) is: >> >>for 40,000 ft - 15 sec >>above 65,000 ft - < 9 sec >> >>below 40k things improve rapidly, for example at 30k it is 1 1/2 min >>and only 2k lower it is 2 1/2 - 3 min > >I wonder how they define "useful" consciousness... I have >heard that one would stay conscious for thirty seconds or so >in a total vacuum, but I don't know how "useful" it would be. > >Given that they almost certainly lost consciousness, the next >morbid question is whether they regained it once they got below >12,000 feet or so... I wonder why people want to know such >things. The term Useful consciousness refers to the time when you can activly think preform tasks. one can ride in an altitude chamber and experience the effects of this. you rapidly lose motor skills. This is why airplanes have the oxygen system. if the plane loses preasure you will have between 15-30 seconds to get the mask on or you will lose the ability to follow the instructions to put it on. This is one reason why they tell you if your traveling with children to put yours on first. then put the childs on. (if this ever happens to you put one on anyone who dosent have one on too.) Once you are on oxygen things return to normal if it hasnt been too long. for this you have a couple of min. The pilot will also be doing everything he/she can to bring the plane below 15000 ft. you can breath without assistance at or below this altitude. Someone else remarked that one could stay concious in a vacuum. this doesnt seam to make sence to me. if you were say rapidly exposed to a vacuum the preasure diffrential would litterly rip the air from your lungs. secondly you would rapidly freeze, and if all that wasnt bad enough. At that preasure (=0) the water in you body would be very happy to boil and you would explode like something put in a microwave that dosent have a hole in it. (if you have never seen this try it, but in someone elses microwave (it makes a mess)). Sorry to be so grafic, but vacuums are not fun places to be. ... Doug Moore, Harvey Mudd College, sometype of disclaimer implied I am dyslexic so dont anyone flaming me for my spelling or grammer.