From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: ffc1e,a48e5b99425d742a X-Google-Attributes: gidffc1e,public X-Google-Thread: fac41,a48e5b99425d742a X-Google-Attributes: gidfac41,public X-Google-Thread: 1108a1,5da92b52f6784b63 X-Google-Attributes: gid1108a1,public X-Google-Thread: 103376,a48e5b99425d742a X-Google-Attributes: gid103376,public X-Google-Thread: f43e6,a48e5b99425d742a X-Google-Attributes: gidf43e6,public From: Chris Beer Subject: Re: Papers on the Ariane-5 crash and Design by Contract Date: 1997/04/04 Message-ID: <5i2poh$84@gcsin3.geccs.gecm.com>#1/1 X-Deja-AN: 230644570 References: <01bc3603$f9373d40$b280400a@gavinspc> <01bc4021$607eea80$b280400a@gavinspc> Organization: EASAMS Ltd Newsgroups: comp.lang.eiffel,comp.lang.ada,comp.object,comp.programming.threads,comp.software-eng Date: 1997-04-04T00:00:00+00:00 List-Id: Robert I. Eachus wrote: > > This is the point that Robert Dewar, Ken and myself I have been >emphasizing again and again--there was no error in software >development (for the Ariane 4), and ANY reasonable approach to reuse >would have found the potential problems. Agreed. > Remember the actual failure >sequence involved deflecting the engines beyond the acceptable >stresses for the Ariane 5, which were apparently less than for the >rocket the system was designed for. > Remember that the flight control software, not the Inertial Navigation System software, was attempting to steer the vehicle with a 'non-real' problem, i.e. the measured data it was receiving (from both INS) was (identically) false. If the problem had been real, i.e. a gust of wind, or a propulsion problem, then such engine deflections would be perfectly acceptable if maintaining the vehicle with minimum (zero) incidence. There is no criticism in the 501 report of the requested engine deflections. Chris Beer Opinions are my own...etc..