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From: mmd@zuaxp0.star.ucl.ac.uk (Michael Dworetsky)
Subject: Re: Ariane 5 failure
Date: 1996/10/01
Message-ID: <1996Oct1.093107.47351@ucl.ac.uk>#1/1
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sender: news@ucl.ac.uk (Usenet News System)
references: <agrapsDy4oJH.29G@netcom.com> <52a572$9kk@goanna.cs.rmit.edu.au>
 <843845039.4461.0@assen.demon.co.uk>
organization: University College London
newsgroups: sci.astro,sci.math.num-analysis,comp.lang.pl1,comp.lang.ada
Date: 1996-10-01T00:00:00+00:00
List-Id: <comp.lang.ada>


In article <843845039.4461.0@assen.demon.co.uk> john@assen.demon.co.uk (John McCabe) writes:
>rav@goanna.cs.rmit.edu.au (@@           robin) wrote:
>
><..snip..>
>
>Just a point for your information. From clari.tw.space:
>
>	 "An inquiry board investigating the explosion concluded in  
>July that the failure was caused by software design errors in a 
>guidance system."
>
>Note software DESIGN errors - not programming errors.
>

Indeed, the problems were in the specifications given to the programmers, 
not in the coding activity itself.  They wrote exactly what they were 
asked to write, as far as I could see from reading the report summary.

The problem was caused by using software developed for Ariane 4's flight
characteristics, which were different from those of Ariane 5.  When the
launch vehicle exceeded the boundary parameters of the Ariane-4 software,
it send an error message and, as specified by the remit given to
programmers, a critical guidance system shut down in mid-flight. Ka-boom. 


-- 
Mike Dworetsky, Department of Physics  | Haiku: Nine men ogle gnats
& Astronomy, University College London |         all lit
Gower Street, London WC1E 6BT  UK      |   till last angel gone.
   email: mmd@star.ucl.ac.uk           |       Men in Ukiah.