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#1
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The best guess now is that the object departing columbia on flight day 2 was
a hunk out of the left RCC panel 8, maybe half a foot across or more. Suppose it had shown up on an exterior PLB camera view, flashing off near the horizon. Would it have looked really different from 'ordinary' debris, different enough to be a recognizable symptom of something worth worrying about? If so, does this imply future shuttle flights should keep a better eye outside? JimO |
#2
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James Oberg wrote:
The best guess now is that the object departing columbia on flight day 2 was a hunk out of the left RCC panel 8, maybe half a foot across or more. Suppose it had shown up on an exterior PLB camera view, flashing off near the horizon. Would it have looked really different from 'ordinary' debris, different enough to be a recognizable symptom of something worth worrying about? It would have been obvious after a few seconds that it was in a similar orbit to columbia. A prompt request for some radar tracking might confirm that it had originated near/came past shuttle. It would not be obvious what it was. What is procedure on strange stuff floating near shuttle? Combined with the foam-strike video, if someone with a clue was aware of both events, then two and two might be put together. What you get when you add two and two is a whole nother question. -- http://inquisitor.i.am/ | | Ian Stirling. ---------------------------+-------------------------+-------------------------- Among a mans many good possessions, A good command of speech has no equal. |
#3
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"James Oberg" wrote in message
.. . The best guess now is that the object departing columbia on flight day 2 was a hunk out of the left RCC panel 8, maybe half a foot across or more. Suppose it had shown up on an exterior PLB camera view, flashing off near the horizon. Would it have looked really different from 'ordinary' debris, different enough to be a recognizable symptom of something worth worrying about? I doubt that its optical characteristics would have helped distinguish it from ordinary debris, but perhaps spotting it on video would have prompted a more timely search for it in USSTRATCOM's radar logs. Did NASA have precudures in place that would have quickly brought the existence of a piece of co-orbital debris to the attention of the people who were concerned about the foam strike? Analysis of its orbital elements would have revealed its ballistic coefficient, which fit well with the densest elements of the shuttle's TPS - the RCC and densest tiles. Regardless of its physical properties, the object appears to have been unique in that no previous shuttle mission that did not conduct an EVA or satellite deployment resulted in the cataloguing of unaccounted debris. Quoting from my web page on the FD 2 object: "Most of the catalogued debris were items confirmed lost by astronauts during EVAs: a screwdriver on STS 51I, a wire carrier and a socket on STS 88, a pad on STS 102. Two pieces of debris were catalogued subsequent to the EVA of STS 106. I am unaware of any reports from NASA linking them to the EVA. Their orbital elements are not sufficiently accurate to confirm that separation occurred during the EVA. Two pieces catalogued from STS 51, appear to be from the anomalous deployment of the ACTS satellite, which resulted in the shedding of debris into orbit. 2003-003B may well be unique; however, it was only found after it had decayed, as a result of an unprecedented post-flight search of archived radar observation logs, motivated by the loss of Columbia and her crew. Would a similar retrospective of previous shuttle missions have turned up other unaccounted debris? What would have been their physical properties? If the archival data exists, it might be worth the effort to find out just how unique 2003-003B may have been." If so, does this imply future shuttle flights should keep a better eye outside? I believe so. Ted Molczan |
#4
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The title of this thread made me think of an old (mostly original cast maybe?)
Saturday Night Live Sketch involving guest host Kirk Douglas: "What if Spartacus had a Piper Cub at that last battle with the Romans?" Actually, my first thought was that here must be yet another "what if" posting by HallerB. Would it have looked really different from 'ordinary' debris, different enough to be a recognizable symptom of something worth worrying about? Well, we know the real answer to this. The whole left wing could have been seen to come off in orbit, in full view of the crew, and "nothing could have been done about it, anyway", as that was the mantra-mindset of key people on the ground. So why even look? Suppose it had shown up on an exterior PLB camera view, flashing off near the horizon. ...... [snippage] ....... If so, does this imply future shuttle flights should keep a better eye outside? You can't count on “accidentally” visually finding something unexpected has occurred, as any reasonable means of detection. If you really want to guard against undetected damage.... you LOOK for where the actual damage may be. Rather than hoping a piece of debris falling off in orbit just happens to be seen on a camera. Yes, I know that at least once, maybe more, a tile actually has been seen to float by a camera, though ironically IIRC the one I have seen was shot an RMS arm camera, not a payload bay camera. I say ironically since Columbia didn't have an RMS arm on STS-107. And if it had, they'd have used it to look for actual damage on the left wing (to the extent possible anyway, but the gaping hole in the RCC would have been glaringly obvious in the case of STS-107). After all, you can't count on any damage that occurred on launch to have tell-tale debris that just happens to hold on all the way into orbit, then just happens to come loose. Then the chances of cameras happening to spot something coming off. Anything coming off on the belly, the most critical area other than the RCC panels, it would be likely to end up continuing to drift away in the -Z axis. To drift "up", along the +Z axis, first it would have to drift along a Y or X axis parallel to the belly then drift into the +Z axis. In the case of STS-107, you can’t make the assumption that the RCC debris would have been in the field of view of cameras that might have been set to look for anything out of the ordinary. Since the RCC piece might have drifted “down” on the -Z axis, or “aft”. Also, it might have drifted up (or over) into the left bay door then bounced off the door, to the -Z axis. We’re talking something like (admittedly roughly) 50-50 odds that it would have drifted in a direction where a camera could have seen it, again assuming that the cameras were set in a “look for things falling off” mode. Oh, also throw in that it only works for 50% of the orbit too, making the odds roughly 1 in 4. Since anything that came off while orbiting around the night side would go unseen. Unless you want to make the 1 in 4 odds back to 50-50 by adding infra-red capability to all the cameras. Who would really feel comfortable hoping for cameras to find something that fell off in orbit to give a clue to damage, rather than actively looking for damage on launch that likely wasn't going to shed any parts in orbit? - George Gassaway |
#5
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![]() George, here's the secret advantage: any stuff coming off the Orbiter all tends to 'cluster' ahead of and below it, as differential drag drops it into lower faster orbits. Then you look for it, once a rev, at sunset, against the dark Earth background. MCC runs the camera, the crew isn't even involved. Meantime, random axis views also scan -- but don't provide 100% -- the space within 100 meters or so of the Orbiter. And regarding +Z (out-the-belly views), the ET sep camera, in the belly, is being rewired to allow imagery to reach the crew cabin. |
#6
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James Oberg wrote:
George, here's the secret advantage: any stuff coming off the Orbiter all tends to 'cluster' ahead of and below it, as differential drag drops it into lower faster orbits. Then you look for it, once a rev, at sunset, against the dark Earth background. MCC runs the camera, the crew isn't even involved. Meantime, random axis views also scan -- but don't provide 100% -- the space within 100 meters or so of the Orbiter. And regarding +Z (out-the-belly views), the ET sep camera, in the belly, is being rewired to allow imagery to reach the crew cabin. That's a great idea, why do it once an orbit. Just have it looking continuously, with a computer pointing out all the interesting things that are flying formation below and in front of the orbiter. Have two scanning cammeras, the other looking back and above the orbiter, looking for things that have less drag than the Orbiter. If they can identify the debris quickly enough, they could even rendezvous with it to have a look or get whatever it is back. Wouldn't it be better to have the computer doing the scanning onboard the orbiter, and only use bandwidth to send the interesting images down to the MCC. Craig Fink |
#7
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"James Oberg" wrote in
: Orbiter. And regarding +Z (out-the-belly views), the ET sep camera, in the belly, is being rewired to allow imagery to reach the crew cabin. Are they actually talking about leaving the umbilical doors open for an extended period during the flight? They're normally closed fairly soon after ET sep right now, I think. -- Reed |
#8
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![]() "Reed Snellenberger" Are they actually talking about leaving the umbilical doors open for an extended period during the flight? They're normally closed fairly soon after ET sep right now, I think. You're right, of course. My rec would be leave the doors open a day or two to see what shakes loose. |
#9
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"James Oberg" wrote:
"Reed Snellenberger" Are they actually talking about leaving the umbilical doors open for an extended period during the flight? They're normally closed fairly soon after ET sep right now, I think. You're right, of course. My rec would be leave the doors open a day or two to see what shakes loose. Ouch... I totally disagree. I would rather come up with some *other* solution than not closing these potential "plasma entry points" ASAP!!!! From what I recall, these are closed very soon after ET sep to make sure that the Orbiter is in a good "come back home" config underneath. I wouldn't want to risk that for photography purposes past the ET photos. There have to be other ways... Roger -- Roger Balettie former Flight Dynamics Officer Space Shuttle Mission Control http://www.balettie.com/ |
#10
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![]() "Roger Balettie" wrote in Ouch... I totally disagree. I would rather come up with some *other* solution than not closing these potential "plasma entry points" ASAP!!!! From what I recall, these are closed very soon after ET sep to make sure that the Orbiter is in a good "come back home" config underneath. I wouldn't want to risk that for photography purposes past the ET photos. There have to be other ways... Could be. Good point on the hazards of keeping them open, but don't forget that now we're not stuck with the trash-bag-on-a-line desperation EVA access for manual close. So we have MUCH more ability to manually close them in case of trouble. |
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