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
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
carroll@uiucdcsb.CS.UIUC.EDU (02/04/86)
Thinking back to basic flight theory... Taking the Z axis to be vertical, and X to be the direction of motion, Rotation about Z is "yaw" X is "roll" Y is "pitch". So I guess you mean pitch.
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."
cater%mcchi2@MCC.ARPA (John P. Cater) (02/20/86)
It's my guess that what you see on your tape, when speeded up, is nothing more than the normal course and alignment corrections produced by the steerable rocket engines. These adjustable jets make the orbiter- SRB system fly slightly like a bicycle rides (a constant wobbling motion) to maintain positional stability. Remember, that system in not in a maximally stable position when flying vertical and being pushed from the rear (try balancing a pencil on your fingertip -- the only possible way to do it is to wobble your finger back and forth to maintain vertical stability). So I think you are seeing a normal artifact of the guidance control. I may be wrong, but my bet's on normal guidance wobble. John Cater (cater@mcc) Disclaimer: (These are my opinions, and everyone's entitled to them!)
pamp@bcsaic.UUCP (pam pincha) (02/26/86)
In article <8602202058.AA00624@mcchi-proteus> cater%mcchi2@MCC.ARPA (John P. Cater) writes: >It's my guess that what you see on your tape, when speeded up, is nothing >more than the normal course and alignment corrections produced by the >steerable rocket engines. These adjustable jets make the orbiter- >SRB system fly slightly like a bicycle rides (a constant wobbling motion) to >maintain positional stability. Remember, that system in not in a >maximally stable position when flying vertical and being pushed from the >rear (try balancing a pencil on your fingertip -- the only possible >way to do it is to wobble your finger back and forth to maintain >vertical stability). So I think you are seeing a normal artifact of the >guidance control. I may be wrong, but my bet's on normal guidance wobble. > Actually, the information coming out in the time table info at the commission talks seem to indicate that the Shuttle DID WOBBLE just before the accident. In fact the guidence system was trying to correct for the wobble just as everything blew. I suggest you try to correlate the tracking data with the tape. I don't believe that this fellow picked-up just a normal event. (Note: For those interested, CNN and C-SPAN cable networks have been airing the Comission talks. C-Span even showed a whole week's worth of talks the last couple of weekends. I recommend watching. It's rather instructive.) P.M.Pincha-Wagener