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From: miq@psuvm.bitnet.UUCP
Newsgroups: sci.space.shuttle,sci.space
Subject: Re: Things aint so bad
Message-ID: <20769MIQ@PSUVMA>
Date: Thu, 24-Sep-87 09:17:34 EDT
Article-I.D.: PSUVMA.20769MIQ
Posted: Thu Sep 24 09:17:34 1987
Date-Received: Sat, 26-Sep-87 13:49:38 EDT
References: <7405@sri-unix.ARPA>
Organization: The Pennsylvania State University - Computation Center
Lines: 29
Xref: utgpu sci.space.shuttle:344 sci.space:2938

In article <7405@sri-unix.ARPA>, larson@sri-unix.ARPA (Alan Larson) says:
     
>>The shuttle, when it flies again, will be safe.
>>It will *not* be cost-effective, and will *not* be able to fly often enough.
     
>Am I the only one who is having trouble with this first claim?  There
>were a large number of items (I think they called them criticality-1
>items) which, if any one of the failed, would lead to catastrophe.
>
>I don't have a list of these items, but I did have the impression that
>there was very little being done them.
     
     The question is not the number of these items, but the likelihood
of them going bad.  Even if there are thousands of such items, if the
odds of any one going bad were less than a million to one, the risk
would still be acceptable.  Further, there's little being done about
them because there's little that *can* be done.  There will always
be some systems for which failure means disaster.  This is true of
any vehicle or device, not just the Shuttle.
     
     The human body has *loads* of criticality-1 items (ask a nursing
or a med student), but it averages over 70 years before catastrophic
failure (assuming proper maintenance).  :-)
     
-------
James D. Maloy                  The Pennsylvania State University
Bitnet: MIQ@PSUECL, MIQ@PSUVM   Aerospace Engineering, '87
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