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=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,CP1252 X-Google-Thread: 103376,f039470e8f537101 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2003-07-23 12:24:18 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!headwall.stanford.edu!newshub.sdsu.edu!logbridge.uoregon.edu!arclight.uoregon.edu!wn13feed!wn12feed!wn14feed!worldnet.att.net!204.127.198.203!attbi_feed3!attbi.com!rwcrnsc53.POSTED!not-for-mail Message-ID: <3F1EE0E0.6060603@attbi.com> From: "Robert I. Eachus" User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.0.2) Gecko/20021120 Netscape/7.01 X-Accept-Language: en-us, en MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: Ariane5 FAQ References: <1058799152.775376@master.nyc.kbcfp.com> <1058810510.375902@master.nyc.kbcfp.com> <3f1c374f$0$11375$cc9e4d1f@news.dial.pipex.com> <3f1ce57f$1@news.wineasy.se> <1058900795.12630@master.nyc.kbcfp.com> <3F1DAB65.1090004@attbi.com> <3f1e77c2$1@news.wineasy.se> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit NNTP-Posting-Host: 66.31.71.243 X-Complaints-To: abuse@comcast.net X-Trace: rwcrnsc53 1058988257 66.31.71.243 (Wed, 23 Jul 2003 19:24:17 GMT) NNTP-Posting-Date: Wed, 23 Jul 2003 19:24:17 GMT Organization: Comcast Online Date: Wed, 23 Jul 2003 19:24:17 GMT Xref: archiver1.google.com comp.lang.ada:40720 Date: 2003-07-23T19:24:17+00:00 List-Id: Tarjei T. Jensen wrote: > Robert I. Eachus wrote: > >>Also the SRI software used the Ariane 4 moments of inertia in its >>control laws. The report seems to indicate that there was a 10 Hz >>ocillation building up due to this. If it had gone on would that have >>been sufficient to destroy Ariane 501? Probably. > I believe that I saw a program on Discovery in which it was claimed that the > oscilations would eventually have destroyed the rocket. As I said, probably. But if it didn't, the oscillations would result in the Ariane 5 not reaching the expected orbit. Less dramatic, but just as fatal for the payload. And that is why I keep posting on this topic, hoping that everyone will "get it." The actual failure scenario is interesting, but the fact that there were two others waiting to happen means that you should look at what they all have in commmon: The missing "scrub" of the SRI specifications against the Ariane 5 requirements. We are talking about something that should have taken about a week for three or four people, if there were no major discrepancies. Of course, in this case, the bill would have been higher, but a lot less than the bill for the failure. -- Robert I. Eachus �In an ally, considerations of house, clan, planet, race are insignificant beside two prime questions, which are: 1. Can he shoot? 2. Will he aim at your enemy?� -- from the Laiden novels by Sharon Lee and Steve Miller.