pjs@aristotle.JPL.NASA.gov (Peter Scott) (04/07/90)
In article <1990Apr5.163338.3198@uokmax.uucp>, jabishop@uokmax.uucp (Jonathan A Bishop) writes: > > Above, Robert writes that if the Shuttle deviates to far > > from course, the Range Safety Officer would blow it up. > > Correct if I'm wrong, anybody, but didn't Apollo 12, after the lightning > strike, develop a high enough roll rate that the RSO had his finger on the > button? Somewhat different situation, though; I imagine they would have suggested to the crew that they fire the escape tower in advance of the abort :-) No such option for the shuttle while the SRBs are attached :-( This is news. This is your | Peter Scott, NASA/JPL/Caltech brain on news. Any questions? | (pjs@aristotle.jpl.nasa.gov)
ddj@hpfinote.HP.COM (Doug Josephson) (04/09/90)
In article <1990Apr6.024706.15843@utzoo.uucp> henry@zoo.toronto.edu (Henry Spencer) writes: >I don't recall hearing of this, and several of the usual references don't >mention it. The Apollo spacecraft's electrical systems were really knocked >for a loop, but the (completely separate) computers of the Saturn V were >better protected and were not bothered by the lightning hit. From "Apollo: The Race to the Moon" by Murray & Cox, pg. 379: (quoted without permission) "In the case of the IU (Instrument Unit), induced currents reached the guidance system's circuits but the computer software kept the platform from tumbling. In addition, the incident on Apollo 12 dramatically vindicated the decision early in the 1960s to have separate guidance systems for the spacecraft and the launch vehicle." However, the CM did lose its guidance platform, since the fuel cells were disconnected from the power distribution buses. The fuel cells were reconnected when telemetry established they had been disconnected, and the CM platform was re-aligned using star sightings in Earth orbit. Now, IMHO, if the IU platform was not affected, the launch vehicle should not have been rolling excessively. I think the major concern was whether or not to abort the ascent - if they had, then the RSO might have come into play. BTW, the above book has great technical details about the various Apollo flights - I recommend it highly! Doug Josephson ddj@hpfinote.HP.COM Fort Collins, CO