mrgofor@mmm.UUCP (Michael Ross) (01/31/86)
While watching my VCR replay of the shuttle disaster, I noticed something that others may not have caught. The TV people kept showing slow motion footage of the explosion itself - but they didn't think to go the other way and speed up the tape rather than slowing it down. Using the fast scan on my VCR, I watched the whole flight in fast motion. Just before the camera cut to the chase-plane's view, Challenger seemed to be wobbling back and forth a little bit. It's too slow to notice at normal speed - but I thought it was fairly easy to see at the faster speed. You people out there who have it on tape - try it and see. Is it my imagination? Could it hold a clue? --MKR
mrgofor@mmm.UUCP (Michael Ross) (01/31/86)
I posted this article the other day: * While watching my VCR replay of the shuttle disaster, I noticed * something that others may not have caught. The TV people kept showing * slow motion footage of the explosion itself - but they didn't think * to go the other way and speed up the tape rather than slowing it down. * * Using the fast scan on my VCR, I watched the whole flight in fast * motion. Just before the camera cut to the chase-plane's view, Challenger * seemed to be wobbling back and forth a little bit. It's too slow to * notice at normal speed - but I thought it was fairly easy to see * at the faster speed. You people out there who have it on tape - try * it and see. Is it my imagination? Could it hold a clue? Several people mailed me responses asking if it couldn't have been the camera wobbling. I obviously did not speak clearly the first time. I am an amateur photographer, and I know about camera shake - that wasn't what I saw. The wobbling was more like skewing (what do they call it when the rear tries to overtake the front - yaw? pitch?) Anyway, it looked as if it started to steer to the left, then the guidance system compensated and it steered to the right, then back to the left, etc., as if the pilot were driving a car and turning the steering wheel back and forth. It might be my imagination, but look at it yourself, if you can, in sped-up mode. You can't see it at normal speed. It's sort of like applying a "speed filter" - the speed lets you see patterns that would normally be too slight to notice. --MKR
irwin@uiucdcs.CS.UIUC.EDU (02/03/86)
Last night, (Feb 1) our local CBS TV station showed some footage of the launch, that had been withheld from the press by NASA until Feb 1. Two things were very obvious in that footage, there WAS a plume of flame from the right SRB, it was facing the particular camera that took the footage, so it was very visable. The second thing that was apparent, was a zig-zag in the <con trail> of the shuttle, shortly before the explosion. This would not be camera wobble, but a slight change in the attitude or direction of the shuttle and/or the shuttle motor gimbals. Also, in our local newspaper, (Feb 2) there were four photos shown, taken by a 70MM NASA camera, that takes 40 frames per second. The article states that the four frames start at 58.3 seconds into flight, and also said that the plume first showed up in the footage, in those frames. This could be the same footage shown on our TV station, transfered to video tape. In a newscast on the same CBS station this evening, (Feb 2) it was stated that a slight loss in thrust WAS detected in the right SRB. If this is true, and if the loss was due to the plume, then at around 58.3 seconds into the flight, if a loss of thrust occured in the right SRB, the attitude control in the shuttle could have made a correction because of the thrust unbalance. This could account for the "wobble" detected by "MKR" as he viewed the footage on his VCR at high speed. This could also account for the zig-zag in the shuttle con trail. In the footage I saw, this appeared to be several lengths of the shuttle behind it, at the time of the explosion. If it occured at 58.3 seconds and the shuttle exploded at 72 seconds, at some 1900 plus miles per hour, 14 seconds time lapse could well be the distance between the zig-zag and the point of explosion. One could say, maybe wind speed differences at the different altitudes caused the zig-zag in the con trail, but the possible correction for thrust differences in the two SRBs is also a good hypothisis. The one question that may be hard to answer, did the plume of flame from the SRB burn through the liquid fuel tank, or was it in direct line with a distruct charge on the large tank and as a result, caused a detonation of the charge? I am sure that NASA can eventually come up with the answer to that, they know where the charges are located in relation to the plume of flame. The final question, what leaked flame or burned through on the SRB to cause the plume of flame?
cushner@ttidcb.UUCP (Jeffrey Cushner) (02/03/86)
NASA should hire you! The shuttle DID actually wobble as the SRB
lost thrust for 12 seconds or so before the blast. The 3 main
engines and the other SRB swiveled to maintain the proper trajectory.
Unfortunately, the crew members had no idea that this was happening.
This was read in today's LA Times.
--
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*********************************************************************franka@mmintl.UUCP (Frank Adams) (02/04/86)
In article <439@mmm.UUCP> mrgofor@mmm.UUCP (Michael Ross) writes: >* Using the fast scan on my VCR, I watched the whole flight in fast >* motion. Just before the camera cut to the chase-plane's view, Challenger >* seemed to be wobbling back and forth a little bit. It's too slow to >* notice at normal speed - but I thought it was fairly easy to see >* at the faster speed. You people out there who have it on tape - try >* it and see. Is it my imagination? Could it hold a clue? > >Several people mailed me responses asking if it couldn't have been >the camera wobbling. I obviously did not speak clearly the first time. >I am an amateur photographer, and I know about camera shake - that wasn't >what I saw. The wobbling was more like skewing (what do they call it when >the rear tries to overtake the front - yaw? pitch?) Anyway, it looked >as if it started to steer to the left, then the guidance system compensated >and it steered to the right, then back to the left, etc., as if the pilot >were driving a car and turning the steering wheel back and forth. Have you (or anyone) compared this with a successful shuttle launch? This may be just the normal operation of the guidance system. Frank Adams ihpn4!philabs!pwa-b!mmintl!franka Multimate International 52 Oakland Ave North E. Hartford, CT 06108
sean@ukma.UUCP (Sean Casey) (02/04/86)
In article <437@mmm.UUCP> mrgofor@mmm.UUCP (Michael Ross) writes: >While watching my VCR replay of the shuttle disaster, I noticed >something that others may not have caught. The TV people kept showing >slow motion footage of the explosion itself - but they didn't think >to go the other way and speed up the tape rather than slowing it down. Just before the explosion, there was a 10% loss of thrust in one of the SRBs. I suggest that what you are seeing is perhaps the loss of thrust and the compensation applied. Sean -- ------------------------------------------------------------------------------- Sean Casey UUCP: sean@ukma.uucp CSNET: sean@uky.csnet University of Kentucky ARPA: ukma!sean@anl-mcs.arpa Lexington, Kentucky BITNET: sean@ukma.bitnet "Wherever you go, there you are."