On 16 Nov 2000, 9:02 Kyler B. Laird wrote:
Remember the satellite that blew up because of a missed comma? (O.k., something like that. Is it an urban legend?)
"MARINER 1, the first U.S. attempt to send a spacecraft to Venus, failed minutes after launch in 1962. The guidance instructions from the ground stopped reaching the rocket due to a problem with its antenna, so the onboard computer took control. However, there turned out to be a bug in the guidance software, and the rocket promptly went off course, so the Range Safety Officer destroyed it. Although the bug is sometimes claimed to have been an incorrect FORTRAN DO statement, it was actually a transcription error in which the bar (indicating smoothing) was omitted from the expression "R-dot-bar sub n" (nth smoothed value of derivative of radius). This error led the software to treat normal minor variations of velocity as if they were serious, leading to incorrect compensation." (From http://www.asi.org/adb/m/02/probe-history-space-faq.html) It was a kind of standard example in software engineering courses at these times. (Remember RPG? Ahh ...:-) Vol 1 No 1 of the Risk Digest (anno '85) (http://catless.ncl.ac.uk/Risks/1.01.html) claimed "Mariner 1: Atlas booster launch failure DO 100 I=1.10 (not 1,10) " Vol 4 Issue 1 (http://catless.ncl.ac.uk/Risks/4.1.html) claimed "Mariner 1: Atlas booster launch failure DO 3 I=1.3 (not 1,3)? " and the version from 9 November 2000 (http://www.csl.sri.com/neumann/illustrative.html) now states "Mariner 1 Venus probe: HW fault plus programmer missed superscript bar in `R dot bar sub n'. See Paul Ceruzzi, Beyond the Limits - Flight Enters the Computer Age, Smithsonian, 1989, Appendix (S 14 5). (Earlier reports had suggested DO I=1.10 bug (see next item) or a garbled minus sign (or hyphen.)" Funny, eh? -- o ( Wolfgang.Strobl@gmd.de (+49 2241) 14-2394 /\ * GMD mbH #include _`\ `_<=== Schloss Birlinghoven, <std.disclaimer> __(_)/_(_)___.-._ 53754 Sankt Augustin, Germany ________________