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From: b-davis@utah-cs.UUCP (Brad Davis)
Newsgroups: net.sci,net.space
Subject: Re: Re: Would a candle burn ...
Message-ID: <3429@utah-cs.UUCP>
Date: Fri, 2-Aug-85 11:56:23 EDT
Article-I.D.: utah-cs.3429
Posted: Fri Aug  2 11:56:23 1985
Date-Received: Sun, 4-Aug-85 08:13:46 EDT
References: <53@ssc-vax.UUCP> <1206@sjuvax.UUCP> <1816@aecom.UUCP> <612@ttidcc.UUCP>
Reply-To: b-davis@utah-cs.UUCP (Brad Davis)
Distribution: net
Organization: University of Utah VCIS Group
Lines: 30
Xref: watmath net.sci:398 net.space:4389
Summary: 

In article <65@ssc-vax.UUCP>:
>The current space program uses a 100% O2 atmosphere.  If you lit a
>flame in such an atmosphere, would all the dust and other random
>particles ignite in the presence of the flame?
>
>In article <1816@aecom.UUCP> werner@aecom.UUCP (Craig Werner) writes:
>>	You'd have to ask the Russians. As long as the Americans use a pure
>>Oxygen atmosphere (they did thru Skylab, and I believe they still do), this
>>is one experiment that is not going to be done on the shuttle.
>
>I thought we stopped using 100%  O2  after  the  Apollo  13  disaster.  Can
>someone confirm the current state of such?
>

Are you sure about this?  At the beginning of the Apollo program
we were using close to a 100% O2 atmosphere (90+%) and lost 3 
astronauts during a test when a fire swept through the capsule.  
(I think it was Apollo 3.)  NASA decided that they might have 
been saved had the atmosphere been less O2.  I think that the 
Russians used a He - O2 mixture at the time.  I also think that 
NASA changed after that.  

A 100% O2 mixture would burn the astronauts lungs.  The biggest 
reason for using a high concentration of O2 is that the pressure
of the cabin can be kept lower, simplifing sealing the cabin.
-- 

			Brad Davis
			{ihnp4, decvax, seismo}!utah-cs!b-davis
			b-davis@utah-cs.ARPA