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From: gsh7w@astsun8.astro.Virginia.EDU (Greg Hennessy)
Newsgroups: sci.space,sci.astro,sci.space.shuttle
Subject: Re: Shuttle scrubbed again
Message-ID: <1990Sep28.190258.29453@murdoch.acc.Virginia.EDU>
Date: 28 Sep 90 19:02:58 GMT
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In article <1001@dg.dg.com> ahughes@dg-rtp.dg.com (Arch Hughes) writes:
#Why is there such a great gap between the launch limit and the 4% 
#concentration?  If the limit was 2% (20K ppm) wouldn't there be ample
#time to scrub as the limit was exceeded, and vent the gas?

Because the sensors can be several feet, or tens of feet from where
the leak is. The concentration will increase as you get closer to the
leak. NASA is leaving themselves a healthy safety margin. 



--
-Greg Hennessy, University of Virginia
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