Hi Alan, I am reading a book about the Apollo computer, they bet their life on it not failing (everything related to spacecraft maneuvering went through the computer, there were no mechanical or other backups whatsoever). They only had a single computer per spacecraft! The book states that based on the entire Apollo program, they later estimated the units MTBF to be in excess of 50,000 hours (which is actually not a lot compared to what typical GPSDO's can achieve today). A single transistor, ROM bit, solder-joint, or resistor failure could have killed them. Scary considering they went for 2 week+ missions.. bye, Said In a message dated 11/18/2009 14:38:57 Pacific Standard Time, [email protected] writes:
Sorry Mike , unless, as someone else said, the figures are derived from field failures over at least a good porton of the expected like the MTBF tells you absolutely nothing!! The statistics used on the usual 1000hour test will only tell you the probability of failure in the first 1000hours of use!! It cannot tell you anything mathematically about the extrapolated life....this has become another urban myth. If it works it is more by luck that by mathematical probability. Alan G3NYK _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
