Columbia Accident Investigation Board Public Hearing Wednesday, May 6, 2003 9:00 a.m. - 12:00 noon Hilton Houston Clear Lake 3000 NASA Road One Houston, Texas BOARD MEMBERS PRESENT: Admiral Hal Gehman Brigadier Gen. Duane Deal Major General John Barry Major General Ken Hess Dr. Sheila Widnall Mr. Roger Tetrault Mr. G. Scott Hubbard Mr. Steven Wallace WITNESSES TESTIFYING: Dr. Gregory Byrne Mr. Doug White Mr. Steven L. Rickman Dr. Brian M. Kent Dr. Dave Whittle Mr. Paul S. Hill ADM. GEHMAN: Good morning, everybody. This public hearing of the Columbia Accident Investigation Board is in session. We have three panels of two people each to hear this morning. The purpose of today's hearing is to put into the record and let the board hear an update of the very latest data that we have on data from the orbiter, information from the debris, and information concerning the testing of the Flight Day 2 object which was observed orbiting with the shuttle. This will bring the board completely up to date with the latest information we have from all of the analysis that's been going on. The first of our panels today, we're delighted to have two people who have been working on this project since Day 1 and are very knowledgeable in exactly what went on onboard the orbiter. We are grateful, gentlemen. Doug White is the director for operations requirements in the orbiter element of USA; and Dr. Gregory Byrne is the assistant manager, Human Exploration Science, at JSC. What I would like to do, first of all, gentlemen, is read you a statement that you will attest that you are telling us the truth. Then I would ask you to introduce yourselves, say a few words about you, and then if you have an opening presentation, we will let you have the floor and we'll listen to your presentation. So before we begin, let me ask you both that you affirm that the information you're going to provide the board today is accurate and complete, to the best of your current knowledge and belief. MR. WHITE: I do. DR. BYRNE: Yes. ADM. GEHMAN: All right. If you would introduce yourselves, please, and then we will start the presentation. GREG BYRNE and DOUG WHITE testified as follows: MR. WHITE: I'm Doug White. I'm director of operations requirements for United Space Alliance. My responsibilities include turn-around requirements, problem-solving for during the turn-around, and in-flight; and I'll be presenting a summary of the MADS data today. DR. BYRNE: I'm Greg Byrne. My normal job at JSC is manager of the Earth Science and Image Analysis Laboratory. For the 107 investigation, I'm the lead of a much larger image analysis team which includes imagery experts from across the country; and I'll be presenting today some ascent video and film. ADM. GEHMAN: Thank you very much. You can proceed. MR. WHITE: Greg, why don't you go first. DR. BYRNE: Okay. I understand, Doug, that you have a long briefing. So I'm going to be short and just answer questions as they come. Can I have the first slide, please. First of all, by way of introduction to the team, the image analysis team consists of both NASA organizations and non-NASA. As I mentioned, imagery experts from around the country. The NASA organizations include Johnson Space Center, Kennedy, Marshall, and Langley; and then outside of NASA we have independent assessments from folks at National Imagery and Mapping Agency, NIMA, and Lockheed Martin at three locations across the country. So let me start with an overview of the imagery we have to work with. You've seen these views already. They have been released to the public. We have two primary cameras that we're able to work with to analyze the debris event on ascent, the debris that struck the wing. Two cameras. E212 and ET208. I do have some short movie clips of these. By way of introduction and background for these two views, E212, the imagery that we had to work with was original. We took the original negatives from the camera and had it digitally scanned at the highest resolution. So we had the best-quality digital imagery to work with from that camera, and that camera gave us the best view of the bipod ramp area which was the source of the debris. It also gave us the best view of the debris itself for size measurement. The drawback to that view was that we had literally no view of the impact area from that particular view. The other camera view is a video camera. It's called ET208. We also had it digitally scanned from the original tape. The advantage of that particular tape is that we do see the impact area directly; but it being video, it's inherently less resolution than the film. But it does give us a full view of the debris all the way to the impact area. Next slide, please. Also, by way of background, here's a layout of the KSC area. It shows the relationship to the launch pad, which is that circle right there, with the two cameras which are south of the launch pad. Then that red line, that is the orbiter trajectory going uphill. Now, the event happened at about 81 seconds. It would put it right around there by that Bubble 5. So these are the lines of sight to those respective cameras. E212 was the closer one. It was about 7 miles away. ET208, further south, was about 26 miles away. So the cameras were distant from the orbiter but are essentially telescopes with cameras mounted to them and they track automatically and so we get a good view. Next slide. Let's go ahead and go to the movie. Eric, if you would key up that movie for me, please. What we're going to show here is that ET212 view. It has both the visible frames and what we call a difference mode of frames. We'll show those side by side in movie format and then track the debris on down. So on the right is the normal view, and on the right is a difference view. Just looking at the normal view first, the debris exits from the bipod area and strikes the under side again. Again, we don't see the actual strike, but we do see the debris cloud. A close strike. It passes entirely underneath the wing. We don't see any evidence of debris or a debris cloud coming over the top of the wing. So that's an indication to us that the strike was entirely on the under side of the wing, below what we call the stagnation point on the leading edge. The difference view highlights changes from one frame to the next; and so it's useful for highlighting the debris because, of course, the debris wasn't in the frames previous to the event itself. So it does highlight the debris, and again you can see it tracking on down. Unfortunately, what it does is also exaggerate the size of the debris. So you can't use it for size measurements, but it does give you a better view of the debris itself and then the post-impact cloud coming on down. The cloud appears to be pulverized foam or perhaps tile. We can't tell if it's tile or not, but upon closer inspection -- and I'll talk about this later if I have time -- we do see actual chunks of debris. You can see them as they pass through this region here, the SRB. There are actual chunks of debris in that view, as well. Next slide, please. ADM. GEHMAN: Greg, let me interrupt here with a question. I think this is a good point. Are there launch commit criteria for the number of cameras that should be working? Are cameras a launch commit criteria? DR. BYRNE: I don't believe they are, but I'm not the person to ask. MR. WHITE: No, they're not. ADM. GEHMAN: So whether you've got one working, two working, or four working just depends on whether you're having a good day or not a good day. DR. BYRNE: Okay. This next view is another movie view. It shows the actual trajectory. We map the trajectory to try to understand the character of the debris as it comes on down; and what we'll see in this movie is that it appears that the major piece of debris acts as a parent, so to speak, that it spawns smaller pieces along the trajectory. So it's possibly shedding smaller pieces and we can see them pass under and then the major parent piece is the one that strikes the wing. So let's go to that movie, please. Another conclusion was that we saw no evidence of more than one strike other than the major parent piece. Okay. Here again, we'll see the event begin around the bipod ramp area; and maybe we can go slowly frame by frame, if that's possible. Yellow is the major parent piece. It originates here. Frame by frame. The piece is spawning off. Little pieces in blue and then other smaller pieces in red keep on coming down. You see the other red and the blue pieces pass underneath and then the parent piece striking and then here are individual post-strike debris chunks that we're able to track and measure sizes. We're still working on that. Okay. Let's go to the next slide, please. The other camera view, the ET208 video, again, as I mentioned, we see it all the way from the bipod ramp to the impact area right there on the leading edge. Again frame by frame, we can map it on down; and let's play this movie very quickly. I was asked to bring the best quality copies of these, and that's not possible on a setup like this to view it in best quality. For that we would need our laboratory facility or something similar to it. We might not have any luck with this one. It worked back at the facility. Okay. Why don't we go on? I apologize for that. Back to the E212 view. Once again, we can map frame-by-frame the trajectory of the debris coming on down, just as we can map frame-by-frame in the other view, and we can take those two camera views together. Go to the next slide, please. With those two camera views, we can define line-of-sight vectors for every point along the trajectory or every place where we see the debris in those frames and we can then use a two-camera solution to derive a three-dimensional trajectory of that debris as from source to impact. That's very important for us to be able to determine the point of impact and three-dimensional velocities. Next slide, please. Concerning the debris source, we have a couple of lines of evidence that tell us that, yes, indeed, it was the bipod ramp or the immediate area next to the bipod ramp that was the source of the debris. I mentioned the three-dimensional trajectory mapping that we do. Here this red line is one of those trajectories that we've mapped onto the CAD model of the external tank. So we take the imagery and then we employ CAD models and overlay the imagery on the CAD model and that gives us a graphical representation of orbiter that we can overlay the trajectory onto for visualization and, as you can see, there's the bipod ramp on the left side of the tank. This trajectory maps it to right adjacent to and on top of. That's an indicator that, yes, it was the bipod ramp. In the next view, take the imagery itself. Next slide, please. And we do some enhancement. As I mentioned, the E212 view gives us a view of the bipod ramp but not a very good one; but if we do a technique of frame averaging in which you overlay multiple frames and do some enhancements and bring out detail, you can see in this before-and-after view -- before being on the left where we've averaged 22 frames immediately before the shedding event and then some 21 frames immediately after the shedding event -- if you look at the differences before and after, and there's the bipod ramp. It's a slightly different shade of color, slightly lighter color than the tank so you can see it. And after, it's very subtle but there is a definite change to that area. It's whiter, as if to expose the white substrate underneath. Next slide, please. We have measured the debris size, again from the E212. We took a frame-by-frame measurement of the debris. Here's one frame on the left and another on the right, just to give you an example of how the apparent size of the debris changes frame-by-frame. Obviously it's tumbling. What it is, it's tumbling and so it is changing its orientation relative to the camera line of sight. So in every frame it has a different appearance but if you take this frame-by-frame measurement and lay them all out, you can deduce from the multiple frames an estimate of the size and our estimate is given there, 24 by 15, in the length and the width. Now, we weren't able to determine that third dimension, which was depth; but we were able to determine that that depth is a much smaller dimension than the other two. It's plate-like, a length and a width and a much smaller third dimension, plate-like, and that we could not determine from the imagery alone. Next slide, please. 3-D trajectory analysis. As I mentioned, we're able to map to the wing to determine impact locations; and we had several analyses. Again, my team consists of many different organizations, in many cases working independently and so getting different results; but when you take them all collectively, we are able to determine that the impact location was in the range of Panels 6 through 8. Now, when I say impact location, we have to keep in mind this is a big piece of debris and that it's likely to strike multiple panels; but the center line of the trajectory, at least in this model -- and this is just one example of the several that were generated. Here's the center line of the trajectory, and the center line intersects the wing at that location right there. So in this model, X would mark the spot of the center of the impact; but, of course, it's a big piece of debris and then there's uncertainty in that trajectory on top of that. So that would then spread out our area of impact location across these three panels and then the other trajectories are also showing some dispersion, as well. So we can't exclude the possibility that Panels 5 and 9 were at least partially impacted. So that's our range, 6 through 8, plus or minus one, and more likely outboard than inboard. Next slide, please. We did measure the velocity, but we weren't able to pinpoint it. The total velocity, we got actually three components of velocity; and when you add them all up, the total velocity was in this range measured from the imagery, 610 to 840. Now, that's a wide range and I'm disappointed our team was not able to pinpoint it any better than that, but we're fundamentally limited by simply a few data points to work with. When you're working with so few data points, especially in four dimensions, X, Y, Z, and time, you can get a wide range of answers; and that's why we have this wide range. But I am confident that the total velocity, the true velocity is within that range. But it takes more than just imagery alone to nail down the impact velocity and so we've needed to apply some physics to the problem. So we're turning our results, our trajectory data over to the folks who are working the fluid dynamics and applying some air-flow dynamics to the problem to get a better estimate of the velocity. Of course, all of this is going to feed into the impact testing; and everything we've been doing up to this point has been driven by the need to feed the impact testing. So our schedule has been pushed to meet that schedule. Next slide, please. In regards to what can we see on the bottom side of the wing, ET208 gives us a direct view of the under side of the wing and, again, these frame averages before and after. On the left is before the event, before the strike to the left side of the wing or rather the left wing. Then on the right is the "after" view. Same averages. In the "after" view, when you do the differencing, we simply don't see any difference before and after. So that's an indication that tells us that we simply can't see any damage. Of course, the orbiter perspective is not the best in this view and our resolution is not very good and we estimate the resolution would be about 2 square feet. What that means is in order for us to see damage, we would need at least a 2-square-foot area of difference to see it. ADM. GEHMAN: Which is on the order of three or four tiles square, I guess. DR. BYRNE: Something like that. ADM. GEHMAN: 2 tiles by 2 tiles something. DR. BYRNE: Of course, that's presuming that the damage would be in the form of tile removal to have a high contrast between the dark normal tile on the top versus the white substrate underneath. So that would assume a high contrast in the damage. MR. WALLACE: What might you expect to be able to see as far as damage to the lower surface of the RCC and the T-seals? DR. BYRNE: We wouldn't expect to see any damage to the leading edge. Again, I mentioned -- MR. WALLACE: I mean, is there a degree of damage that you're confident you could have seen? DR. BYRNE: Yes. About a 2-square-foot. MR. WALLACE: Even in the RCC? Or talking about just the acreage? DR. BYRNE: Just in the acreage. I wouldn't expect to see any damage in the leading edge because contrast is all-important and a hole in the leading edge would be presumably a dark hole against a dark background. In a view like this with the resolution that we have, we simply wouldn't see it even if it were a gaping hole, I think. ADM. GEHMAN: I don't have any argument with that conclusion; but what about the sharp edge, leading edge of the RCC there? I'm thinking about a notch or something missing, even though I agree when you've got the dark RCC against a dark hole against a dark background, you can't see anything. But what about the leading edge there? Is that enough definition there to indicate some -- I mean, you've got that nice leading edge against that nice white background. DR. BYRNE: If there were a large enough gap, I think we might be able to see it. If there were an entire panel missing or two panels adjacent to each other missing, it's possible that we could see it because it would show up against the white background of the fuselage. So that's conceivable; but, of course, we didn't see anything like that. Next slide, please. The last slide, I mentioned the debris post impact. The wing is up in here, and the debris after the impact is sweeping on by. This is an area of work that we're still pursuing to characterize better the size of these chunks post impact and primarily to see, well, two things. Is there any hardware in there? Can we say it's tile or can we say it's a T-seal or something of that nature? That's a very difficult task, of course, but also to characterize it to compare it with what we see in the impact testing. My team is also involved with the impact testing, doing the photogrammetry in those tests to see does it make sense. That's all I have. MR. HUBBARD: Thanks, Greg, for that description. I've got maybe four or five questions here, a number of which are intended to just illuminate things that have been in the realm of rumor and give you a chance to talk about this and perhaps put it to bed if it's not factual. The first one has to do with a statement that I have heard several people make that there was another camera, a third camera. Some people have called it Camera 204. So can you talk a little bit about that? DR. BYRNE: I can, yes. There was another camera that saw the debris. If we can pull up that map. The second slide, I think. Camera 204 was well south of the other cameras. I don't have a mileage exactly, but well south. MR. HUBBARD: So much further down. DR. BYRNE: Much further south. It did see the left side of the orbiter with basically the same perspective as 208, but much further away. So a worse view in that regard, worse resolution. Now, early on in the analysis, of course, our analysis team, even during the mission, screening all of the imagery from all the cameras, we saw that debris in 204; but early on in the analysis, it was discarded as unuseful for analysis simply because it was so much poorer in resolution. The debris looked like a fuzzy blob. At that time, as I have mentioned, it was disregarded. Since then, especially in regards to the velocity calculation where we were strapped with having so few data points to work with and in that sense any data point is a good data point perhaps, one of the team members -- it was the folks from Marshall -- went back to the imagery to try to get more data points and they did access that 204 camera and determined that possibly two frames, two data points from E204 were useful for their trajectory analysis and subsequent velocity calculations. So they did fold that into their calculation, and we discussed that with them last week. Their result is brand-new as of last week. The bottom line is we don't know if it adds value or not. Marshall did their analysis with 204 and then redid it without 204 and got the same result. So although the error associated was much larger and they did determine that the error was much larger, it didn't seem to hurt the analysis but didn't seem to help it either. So that's the story on 204. MR. HUBBARD: Okay. Very good. Thank you. So what you presented today, Camera 212 and Camera 208, represents still the best available evidence for all the calculations you've done. DR. BYRNE: Correct. MR. HUBBARD: The second thing has to do with the number of objects. A lot of speculation about the spawning, how many pieces came off and so forth. Can you just expand a little bit on how many objects you have clear evidence that exist and resolve that dispute a little bit? DR. BYRNE: Right. Early on, that was a big question, how many particles are we talking about, how many impacts were there. To this day, I don't think we've had total team consensus on that, simply because at the top of the trajectory -- first of all, on 208 we only see one piece of debris throughout, in that video view from far away. It's in 212 where you can see more than one piece, but how many there are is still indeterminate. There's almost a shell-game juggling act going on at the top, and trying to pick out which piece is which and when is very difficult to do; but we had determined early on that we think we saw three pieces, three distinct pieces. Now, whether they originated as three pieces from the bipod -- in other words, came off in three pieces originally -- or whether they were spawned, that we have never been able to determine because literally now you see them, now you don't. It's that sort of game going on at the top. Even frame by frame, when you see a piece of debris, the next frame it's gone. So either it's a very thin piece that when it turns edge on, you simply don't have the resolution to see it, or whether it goes behind another piece, we don't know. So it's very difficult to determine, but at one point we thought we saw at least three distinct piece. MR. HUBBARD: Okay. And the best evidence that's available shows only a single strike. DR. BYRNE: Only a single strike and that being of the major piece and all these others. MR. HUBBARD: Now, you did mention tumbling; but you didn't talk about the rate. I've seen numbers and viewed these videos, of course, several times. The sense from one group was it was tumbling at about an 18-hertz rate, 18 cycles per second. Is that still the case? DR. BYRNE: Well, that was the measurement that was done. Our partners at NIMA did a very innovative calculation to try to discern the tumbling rate. What they did was look at the different color channels in the film -- the red, green, blue, RGB -- and the foam, being a shade of orange, would stand out better in the red-green channel. So they looked at the different channels and plotted frame-by-frame the intensity of those three color channels and looked at the variation in the intensity; and just in that rough calculation, that variation in intensity came out to be 18 hertz. Now, we all recognize -- and NIMA did, too -- that that's very crude because we have so few data points to work with that to try to do a frequency determination from so few would give you an enormous error bar. But that was the only handle that we had, the only analytical handle that we had at all to try to determine rotation rate of that piece of debris. I do not have confidence that the rotation rate was 18 hertz, but that's all we have. MR. HUBBARD: So the conclusion there is -- would you say it is clearly tumbling but the rate is -- we've only got one data point? DR. BYRNE: It is clearly tumbling and in our analyses we worked with the still frames to get the exact measurements, but you have to work with the motion as well to get a big-picture view of what's going on. In that motion, when you put the debris in motion, you can clearly seen with your mind's eye -- your mind's eye can integrate between frames and you can determine at that time it is tumbling; but to take it the next step and say what the tumble rate is, in an analytical process, that's difficult. MR. HUBBARD: The before-and-after picture you showed of the bipod ramp area where it's dark, light, dark, light -- and I think if you were able to flicker those, it might be even more obvious. DR. BYRNE: Yes. In fact, I should have brought the movie form of that where they're overlaid before and after and you can form that and it shows it clearly. MR. HUBBARD: Do you have an estimate for how large that bipod ramp area is? DR. BYRNE: That's something we've been working on. That also is very difficult because when you apply a software routine to do the differencing, the software is detecting the change in the image before and after. Well, when there's so much noise in the imagery, which there is here at that scale, then literally the entire image after looks different because of the noise. So what we've done to date is do a manual estimate of that area of change, and our area was consistent with the size of debris. I believe we were getting somewhere in the order of 30 inches by 15 or 16 inches of the size of change. Again, consistent with the ramp itself, consistent with what we measured. ADM. GEHMAN: Scott, how you doing down there? MR. HUBBARD: Ready to yield the floor, sir. I'm probably dangerous because I have a little knowledge about this area. ADM. GEHMAN: I'm watching the clock. Mr. Tetrault. MR. TETRAULT: Greg, last week I think we were using a velocity of approximately 640 feet per second; and I noticed today that 640 is in the lower element of the range that you threw out there. Would you describe what's been going on that appears to have revised your calculations a little bit? DR. BYRNE: Yes. As I mentioned, that was one of our disappointments, that we weren't able to nail it down better. The first four or five analyses that were done by the various team members came up with a range of total velocities between 610 and 700, and the average of all of those were 640. So that's what we put forward originally. Last week our friends at Marshall came in with a new, different analysis. They used a fundamentally different technique than some of the others. They came up with a much higher velocity that was in that higher number, 840. Well, we had a peer review, so to speak, of that and with all team members last week -- and this is brand-new, last week -- and the Marshall analysis passed the peer review, so to speak. We couldn't say, "You're wrong." In fact, I can't point to any one analysis and say it's the best. I can't point to any one analysis and say it's wrong -- because, again, so few data points that we're working with in four dimensions. You can fit almost any curve to those data points and get a reasonable answer. MR. TETRAULT: Does a higher velocity suggest a smaller piece? DR. BYRNE: Now, that's straying a little bit away from our area of imagery alone; but in the transport analysis, the next step that we're feeding our trajectory data over to, in order to meet the transport analysis model, that is true. The smaller mass would require a higher velocity. ADM. GEHMAN: Okay. General Hess, you have a question? GEN. HESS: I just have a couple here. Real quick. In your earlier comments, you kind of qualified the bipod ramp as being the source, by saying we have a couple of lines of evidence that indicate. Do you have any lines that indicate that it's not the bipod ramp? DR. BYRNE: No. GEN. HESS: Looking at the video, I know that most of your effort almost entirely was focused at the debris, the debris strike. Have we analyzed the video beyond 81 seconds to see if the debris is -- DR. BYRNE: Oh, yes. What I've shown here is a tiny fraction of the whole analyses that we've been doing; and, yes, we have looked thoroughly at from pre-launch all the way through SRB sep and beyond. We have looked for any and all indications of events before and after, debris coming off after the 81-second event and so forth. The answer is, no, we don't see any debris other than some normal stuff that we see all the time, SRB slag near the sep. GEN. HESS: Has your work with all this post-video analysis given you any ideas about what the current state of the art in terms of what the cameras are and what they should be that would have helped you do this better? DR. BYRNE: The return-to-flight effort is a big one and a lot of that is focused on enhancements, upgrades of the imaging capability of the orbiter. That's one area that's being closely looked at, what can we do in terms of launch cameras to better our capability to analyze. That's still in work. High-definition TV might be one way that we need to go. The film cameras are good. You really can't do better than film, but we're strapped fundamentally with the problem that here we are on the coast and the orbiter is moving away from the coast very quickly. So we're going up and away from our camera assets and so just losing sight of it very quickly. ADM. GEHMAN: I'm going to have to interject myself here so we can get on. We'll reserve the opportunity to ask more questions later, but let me ask two quick ones. This level of photo analysis takes a considerable amount of time. It's taken a couple of months now. Would I be incorrect in saying that this level of photo analysis, for example, these 20- and 30-time enhancements and things like that, would not be available during the 14 or 16 days of the mission? DR. BYRNE: No. They were, actually. That before-and-after view of the under side of the wing, for example, was something that we had done during the mission and, again, to see if there were any damage. It's interesting that much of what I am presenting here, we have concluded after three months and thousands of manhours across the country, much of what I'm presenting is similar, if not exact, to what we had reported a week after launch, during the mission. ADM. GEHMAN: That's important. Thank you. And the last one is you did not discuss what you can determine about the angle of impact with respect, for example, to the plane of the wing or however else you want to measure it. Very briefly, can you say something about the angle? DR. BYRNE: Yes. The three-dimensional trajectories that we measured were three-dimensional, X, Y, and Z. So from those trajectory analyses we were able to measure a range of impact angles. Almost all of it was in the X. However, we did measure a slight Z component, upward and into the wing, of approximately zero to 3 degrees; and in the Y component there was a small outboard Y. The range was about 2 to 10 degrees. ADM. GEHMAN: All right. Good. Thank you very much. Mr. White. MR. WHITE: If you could pull up the presentation. I'm going to talk about the MADS data. That's the Modular Auxiliary Data System. This is a separate data system from the operational instrumentation system that we were able to see realtime. This data is only recorded on board, and we were very lucky to find the recorder intact and the tape in very good shape and able to pull that data off. Go ahead to the second slide. ADM. GEHMAN: Doug, I think it's useful for the people who have been following this that this is the recorder that the board has been referring to as the OEX recorder. MR. WHITE: That's correct. ADM. GEHMAN: We're going to properly name it here. MR. WHITE: Well, the MADS system is the name of the entire system, which is the avionics, the electronics to condition and report the signals and the sensors and the wires connected to them. The recorder itself was an early model of the recorder, which was called the OEX recorder, the Orbiter Experiments Recorder. In the subsequent vehicle, we just called it the MADS recorder; but the version that was on 102 was called the OEX recorder. On 102, it had the most sensors of any of the vehicles for the MADS system because it was the first vehicle built. Through the years, some of those sensors have broken and fallen off line and during the recent major modification a lot of the sensors were removed or the wires were cut and just left in place, but there were 622 measurements on board, located throughout the vehicle. Most of those are pressure, temperature, and strain measurements; and I've broken down into three large categories there. You can see the left wing, about 259 -- we had more of our measurements there than anywhere else -- right wing, about 220; and then other places altogether, 143. The avionics to condition all of these signals, all of these wires run to the mid-body, about Bay 8 of the mid-body, and then they're recorded actually on the OEX recorder, which is in the crew module. As I said before, none of this data is available to us realtime during the flight. Next slide, please. First thing I'm going to talk about here is failures of this data. What we see mostly in this data is all of these sensors beginning to fail and going off line, with a wildly variable signature where they oscillate between off-scale high and off-scale low. To us that indicates that the wire bundles that contained these measurements in the left wing were being burnt through and being destroyed. Most of that happens between about 480 seconds to 600 seconds from entry interface; and for those of you working in GMT, that would be 13:52:09 to 13:54:09 in GMT time. ADM. GEHMAN: Entry interface being? MR. WHITE: Entry interface is when you first start to encounter a little bit of the atmosphere. That would be 13:44:09. So I broke that down between temperature, pressure, and strain gauges in the left wing, the right wing, and then other measurements we were interested in. You can see the numbers there. What this chart tells us is that we saw, surprisingly, some failure signatures over in the right wing. There were a number of right wing pressure sensors that went off line, about 30 of them, and that is because they have commonality with left wing measurements, they share a common piece of avionics in the avionics boxes that condition the signals, and as things were being shorted or destroyed in the left wing, that affected measurements in the right wing. So we've been able to tie those events together. The other thing you notice from this chart is that there were two measurements only that did not eventually fail in the left wing, and those hung in all the way through the loss of vehicle. Those two measurements are strain gauges which are on the wing surface or on the spar actually that runs in front of the wheel well. That's the 1040 spar. If you look at the wire routing for those particular measurements, those two measurements peel off from the main bundle in front of the wheel well and stay there as opposed to running farther back into the wing. That tells us that the damage that was going on was farther back in the wing and that the wire bundles were being burned farther back in the wing rather than up near the front of the wheel well, because those two measurements did hang in there. There were 241 measurements that are what we call snapshot measurements. By design, they only take data for a few seconds at a time and then they go off line and the recorder goes and looks at something else. So you only see these little snapshots, bits of data, and it's very hard to determine whether those are failing or not. We suspect that they failed the same way that the other measurements in the left wing did, but we just don't have the data that will show us that. MR. WALLACE: Can you discuss the time sequence -- maybe you'll get to this later -- with respect to the first off-nominal indications in the telemetered data? MR. WHITE: Yes. I'm going to talk about that and, depending on how much time we have, I have another version of this which, last time I was here, I talked about the operational instrumentation data in sort of a graphical sequence, marching through the time line. I have one of those available if we have time to get that done today, but I thought I'd start off with showing you the data and showing you where it looked off nominal and we'll talk about the sequencing, too. Next chart, please. Just real quickly all I wanted to talk about in this chart here was we said we saw these measurements oscillate wildly between off-scale high and off-scale low and can we explain that from an instrumentation system point of view that these were, indeed, failure signatures of these measurements and not really data that it was trying to tell us. We have done that. We've had our instrumentation system experts go and look at how the system could fail and if you shorted this wire to that wire, could you get the signature that you observed in the data. The answer is, yes, you can pick from what we saw in the data just any combination of shorting or variable resistance between wires to get the observed data. The other thing we see is that sometimes after this oscillation, off-scale high, off-scale low, that it looks like a measurement returns to a normal state or something that reads real data. This has to do with bias, the way the measurement was set up and its residual voltage in the system; and it should not be interpreted as real data. So after you see the data do one of these wild swings, you shouldn't believe anything that you see afterwards. Next chart, please. Let's go one more. We'll concentrate on the leading edge of the left wing which is, as Greg told you, where we narrowed down the strike to the Panel 5 through 9 region. We did have some measurements in the left wing, near Panel 9 and 10. We had two temperature measurements, one in the clevis area where the RCC attaches between Panel 9 and 10. That's on the outside of the spar but inside of the RCC. We had another temperature measurement on the back side of the spar, so inside the wing. There's a third temperature measurement in that area, which is on the skin just behind Panel 10; and there is also a strain gauge measurement in that area which tells us the relative strain in that spar. Those are all the ones that you can see highlighted right in this area here. I've also highlighted the wire run that feeds measurements along the wing leading edge. There's a group here and a group out there and some here and some back in here. Each of those measurement numbers and each of those times is the time when those went off line. So you can see the ones in the leading edge went off line almost all together. The only one that stayed around for a while was this one temperature measurement here on the back side of the spar. That hung around for 522 seconds after entry interface, but the rest of them failed early and we'll talk about those sensors right there at Panel 9 and what they showed us. Again, that tells us that something was coming through the left wing and destroying that set of leading edge bundles first before it got to some of the other sensors in the wing. Next chart. This is just a wiring diagram of the back of the wing. If you start over here -- these are from photos from the last major mod of Columbia. This is looking on the side of the wheel well. Here are some major bundles here that run down the side of the wheel well, but the bundles for the leading edge of the wing go off this way and you can see there's several different bundles here run across the wing. This is the back side of Panel 9 and 10 region, which is down here; and I've got some more pictures of this here later, showing some of the measurements. This particular one is a pressure measurement and a temperature measurement. They go through the wing here, and then they run on down the back side of the wing. Next chart, please. This is just a close-up of the bundles along the side of the wheel well inside the left wing, and we've just numbered them arbitrarily. We started at the front side, but they change their routing and switch over each other. So the order that you see here happens to be 1, 4, 3, and then this is the wing spar and you can see the wires going down the leading edge of the wing there. Next chart, please. This particular chart is in the Panel 8-9 region, and I highlighted the split there. This is the back side of the wing, looking forward. These are wire bundles running down the wing spar. We, again, arbitrarily labeled these A, B, C, D, E, and you can see measurements there and which bundle they were in, Bundle A, C, or D, and when they failed. Just lining these up in time order, it appears to us that the damage was maybe higher or at least the wing spar began to fail higher up before it worked its way through. There's one measurement here at the bottom, the one that lasted the longest. We're not quite sure because it's very difficult to tell from the photos whether it's routed in Bundle D or Bundle E. That's this temperature measurement here which is under this red piece of tape. This is the temperature measurement I mentioned that's on the back side of the spar. Next chart, please. This is just a graphical way to look at all of those wire bundles failing. We pulled out the ones from the leading edge which we showed in purple; and you can see how quickly those failed, starting here about 480 seconds after entry interface. You can see how quickly those failed relative to the other bundles that I showed you, the larger bundles that ran down the side of the wheel well, Bundles 1, 4, and 3. Also you notice that Bundle 3 had the two measurements that never did fail, had 117 measurements in that and only 115 failed. That's because two of those peeled out of that bundle very early in front of the wheel well. I also tried to indicate, just for timing, some of the other major events in the time line that we're familiar with that we were able to get from the realtime flight data. So you can compare when these events were happening relative to those other events. For example, the first orbiter debris event is way down here. Next chart, please. We'll talk about some ascent data that we got from those Panel 9 temperatures. This again is just a graphic to show you where things are located. This is a skin temperature measurement which is on the skin behind Panel 10. We had two temperature measurements, one in front of the wing and one behind the wing, and then we had one strain gauge measurement right here. Then in a side view you can see the one that's in the clevis there of the RCC and then the one that's on the panel behind. Next chart. Again, just to get you oriented physically, looking at the back side of the wing, this is the strain gauge here about the center of Panel 9. There's the temperature gauge on the spar. This is the feed-through for the temperature gauge that goes inside the RCC but outside of the spar, and then there's that lower skin temperature measurement that I was talking to that passes through the skin right there. Next chart, please. So this data compares the temperature rise for the Measurement 9895 -- that's the one on the back side of the spar -- to data from other flights. The RCC cavity is vented. So as you go uphill, the air comes out of the cavity. So you normally see a cooling kind of a trend, which is why all these measurements drop down a couple of bits. Then as you go through ascent, you get ascent heating and the measurement tends to warm up a little bit. What we see here on STS 107, which is the black line, is it drops down a few more bits than the other ones do and it rises back up a few more bits than the other ones seemed to do. Now, this in itself is not conclusive that we actually had a hole in the wing at this point and that we did have abnormal heating on this spar, but it's just something a little bit different than what we have seen. We've looked at some more data than what I presented on this chart. We have found some flights where we were able to see the dip maybe as big as this one was, but we still haven't found any that rose back up quite as much as what we saw here. GEN. BARRY: Can you argue that this is definitive evidence that there is a breach? MR. WHITE: No, I cannot argue that it's definitive evidence; but if I were to put this in a big scenario that says there was a breach at this time, then this certainly would be supporting evidence for that. But I would not hang my hat on this evidence alone. This is not strong enough to say that there definitely had to have been a breach, but it's not inconsistent with the fact that there might have been a breach at this time. Next chart, please. This is just comparing in numbers what I just said, the other flights, how many bits down it went and how many bits back up. For 107 here, we did indicate that it's a little bit different than other flights. Next chart, please. Let's go talk about the entry data. Again, we'll talk about the leading edge area here on Panel 9. This is an under side view. There's also pressure measurements -- MR. WALLACE: Doug, can you sort of equate bits to degrees? MR. WHITE: I believe, on that measurement, one bit is about 5 degrees, I believe. On the order of 5 or 6 degrees. So there were some pressure measurements we'll look at back here and other measurements along the side wall and the lower skin, as well. Again, that's the inside of the RCC, showing the two temperature measurements we had there. Next chart. This is that lower skin measurement that's just behind Panel 10, and we compared it to other measurements on this flight. You can see that one gets a little hotter and then the next chart will show you that this area right in here is anomalous heating. This is a little hotter than that measurement ever got on other flights during the entry, and this little bump right in this area here also appears to be a little outside of our experience base. Next chart, please. Here's that same measurement in the black, plotted against that same measurement for other flights. You can see this area here that I talked about is a deviation from the heating we've had before. This measurement normally comes up and flattens off. So we saw a little bit higher. Then all of this stuff here you see, that's the failure signature. That's where the measurement goes unreliable, where we believe the measurement itself or the wires to the measurement were being burned through; and then any of the data out here you can't believe, even this little bit out here at the very end. You also see this little bump here which is a little bit different than we've seen before. Next chart, please. This is just some graphics showing you some of the temperature measurements along the side wall. Next chart, please. Some more toward the aft. Next chart. We'll talk about this data. Here's some of that data, plotted for side wall temperatures; and you see some off-nominal heating in these two particular measurements. These are on the side wall fuselage. You can see this measurement rising here, and this one rising here is off-nominal heating. This is not something that you would have seen from other flights. Next chart, please. Again, these are measurements on the OMS pod. We saw a curious effect on the OMS pod. We saw lower heating for a portion of the flight and then we saw higher heating. So that tells us the vortex that comes along and normally would heat the OMS pod was moving around. It was off of the OMS pod early, when it normally would have been there, and then it was more intense on the OMS pod later. So this black line here, these measurements are actually below where they would have been for this period of time in other flights; and then where all these arrows are about here, all of these measurements start going high again and getting higher heating than they would have been in other flights. Next chart, please. Getting back to the wing leading edge at Panel 9, the approximate area where we believe the impact was. Next chart. Again, just the back side view to help you remember. This is the strain gauge, temperature gauge inside, temperature gauge outside, and then the lower skin temperature. Next chart. So I put all of those on the same graph, and this is the graph that says the first events we saw happening were in this area. These are earlier than the wheel well measurements that I talked about last time. The first thing we see is this strain gauge measurement go up and off, and this is the off-scale failure again. But about 290 seconds is when we see the start of the off-nominal rise. Here you see the two temperature measurements in the blue and the purple. They began rising earlier than we've ever seen before; and again, they all failed about the same time right here in this region. This one other strain gauge measurement that I showed you was one of the snapshot measurements. So you only have a little bit of data in here and here. You can argue that this might have been off nominal, but we just don't really have enough data to say. Definitely this part here and then down before it failed was off nominal, and this is an indication that because of temperature and heating in this area that the strain and the load was shifting and that there was something happening to the leading edge of the wing in this region, the Panel 9 region. Again, as I said, this is the earliest indication, about 290 seconds after entry interface -- this is the first indication of something going wrong that we saw in the vehicle data. This measurement, again, I already showed you a couple of times. This is the skin temperature measurement, again showing deviation. There's this little hump here and then higher heating before it goes off scale, as well. ADM. GEHMAN: In front of me, I have the advantage of having the Rev 15 of the time line; and what you classify as start of peak heating occurs at Time 50:53, is what arbitrarily is called start of peak heating, which works out to entry interface plus 400 seconds. So you are seeing temperature rises and some strain prior to peak heating? MR. WHITE: That's correct. ADM. GEHMAN: So what's happening is that as the vehicle heats up, so are these leading edge. MR. WHITE: Right, these leading edge. Inside the RCC, where we wouldn't be expect it to be heating up, before peak heating -- I mean, peak heating, like you said, is kind of arbitrary. ADM. GEHMAN: It's still hot. MR. WHITE: It's still hot. We have heating all the way from the beginning of entry interface. So what we're seeing is that heating manifesting itself inside the RCC cavity where we would not expect it to manifest itself. So again, this is a good indication that at this point we did have some sort of breach in the RCC. Any more questions here? We'll move on and talk about the pressure data a little bit. Next chart. I'm not going to go through each one of these sensors, but you can see they're all arrayed in more or less the same Y location away from the fuselage. This is the lower surface. We also have a lot of pressure measurements on the upper surface that I won't talk about. This band right here, the forward 8, we see some interesting measurements here; and I'll go through that. Next chart. These are on ascent. So we're back to ascent now and looking at the pressure on ascent to see if we can determine anything going on on ascent from these pressure measurements. What we see is all the measurements decaying, as you would expect. As you go uphill, the pressure gets less and less; but there's one measurement here which is behind the Panel 9-10 region. We see this bump at about 84 seconds or so, then coming back down, and then another spike farther out. Now, to us that's an indication -- we don't worry so much about the particular value that it went up to but the fact that it took two jumps is an indication to us that something hit that sensor, either clogged the port or moved it or did something to the sensor to cause it to have those two spikes. Also there's another sensor. There are two types of pressure sensors. One's called a statham sensor, which is mounted on the surface of the skin and has essentially a very short tube that goes through the tile to sense the pressure. Excuse me. I said those backwards. That's the Kulite. Then the statham sensor is mounted inside the vehicle, away from the point where the tube goes through, and has a rather long tube running inside the vehicle and then poking through the skin. So the statham sensor, which happens to be right next to this, we don't see this kind of a spike on, because the actual sensor and wiring and everything was inside and protected; but if you had something hit in the tile where this Kulite sensor was mounted right on the skin, you could have done damage to it. So this data tells us that we did have some kind of a hit in this region, but it doesn't tell us anything more exact than that. GEN. BARRY: Two quick questions. We know the impact occurred at 81. So this is about 85, . MR. WHITE: Right. So this number is a little bit downstream from the leading edge of the wing. So there could have been something tumbling or coming back a few seconds later that affected this sensor. GEN. BARRY: When you say tumbling back, you mean like something could have gotten loose and then just rolled back? MR. WHITE: Right. It could have been debris. It could have been that the tile where the sensor is was damaged and then suffered some further damage, some bits of it came off or part of the sensor became de-bonded somehow or was affected. So there could have been a delayed reaction from the hit. GEN. BARRY: We know that sensor's not 100 percent reliable. Have we got any indications of any previous flights where we have these kinds -- MR. WHITE: No, we have never seen these kind of spikes before on pressure sensors. MR. HUBBARD: Just to be clear, again, you're not measuring here -- what you're saying is not a pressure change. You're saying it is something, it's an electrical signal as a result of -- MR. WHITE: Well, it's possible that that was -- especially the first one. The second one is a lot harder to explain as a real pressure change. It's possible there was some sort of real pressure change in this region here. Again, that would be a result of the instrument being affected and maybe the flow around that instrument being changed. So there was temporarily a higher local pressure around that measurement; but it also could be just an effect of the instrument being damaged, as well. ADM. GEHMAN: And you're confident that the time line differences between the camera time hacks and the MADS data recorder time, that you don't have a second and a half of -- MR. WHITE: No, these are pretty good times. So whatever it was here was a little bit delayed from the impact that Greg told you about. Next chart, please. This is another measurement which was again in this same region farther back from the leading edge where we believe the strike happened and you can see the pressure here -- this is compared to other flights of Columbia. You can see the pressure there just kind of decayed off a little bit faster. Again, that could have been from debris plugging the tube or something like that to cause it to have apparently lower pressure earlier than the rest of the flights, the earlier flights would have shown. Next chart. Finally, there are three measurements, again in this same band, that show a very odd behavior around 102 seconds here. Two of them go down, come back up; and one of them makes a jump up. This one we haven't been able to explain yet as any kind of hit or anything, thus appears to be some sort of glitch in the instrumentation system. Again, it's something we've never seen before and it's odd that all three measurements, which are not -- two of them are located together. This one and this one are close together. This other one's a little farther up. It's odd that they would all have the same behavior at the same time and then return to what appeared to be sort of a normal reading. Just kind of connect the line here. It looks like it came back to where it would have been. So we're not sure what to make of this yet. It's something else we're still looking at. Again, this is ascent data; and the scale along the bottom is seconds from liftoff. That's all I had, as far as showing you pictures of the data. If you wanted to go in and look at how these things relate in time, we can go into the time line charts. ADM. GEHMAN: Let's see if there are any questions before we do. MR. TETRAULT: Is it possible to go back to your Viewgraph No. 9? MR. WHITE: Sure. MR. TETRAULT: I have two questions. On the upper right and the lower right, there are two pressure sensors, if we get back there. MR. WHITE: Okay. MR. TETRAULT: See the pressure sensors in the upper right and the lower right? Those have wires which run back into the bundles, but those are also cut at Times 495 and 497, which to me would suggest that the breach had to be close enough to -- MR. WHITE: Talking about it might have been over here somewhere. Right. MR. TETRAULT: Right. You had mentioned that you thought the breach was in No. 9. MR. WHITE: Well, from Greg's data, it's anywhere from 5 through 9. To get a little off of this, our forensic evidence says that it was more likely in this region of Panel 8. So it's very possible that it was over here and got these wires. MR. TETRAULT: That's what I'm trying to get at is to catch that wire right here and this wire right down here, you would probably have to have some breach that would be in this area or further over to the right. Now, the other question that I have is this one here, this Temperature Sensor 9895. You indicated that there's a certain degree of ambiguity as to whether it comes down and goes out this run or goes back up. MR. WHITE: Right. It's hard to tell whether -- I don't know if you can see this or not. The wire runs down here. It's hard to tell whether it doubles back in this bundle here and it runs up this way or whether it just stays in this bundle and goes that way. MR. TETRAULT: It is, however, I've been told, that you have a specification requirement that does not allow you to make a pigtail like that on a wire run, so that it would be more likely that, in fact, this wire run goes down this route. MR. WHITE: That's correct. Yes, sir. MR. TETRAULT: I see that as important because this wire run comes back up and joins these wire runs at Panel No. 7; and because of the lateness of this sensor going off, it would tend to preclude the breach from being over here in 7 since it joins the other wire bundles. MR. WHITE: That's correct. MR. TETRAULT: Would that be a good assumption? MR. WHITE: That's a good assumption, yes, sir. MR. TETRAULT: Okay. Thank you. MR. WHITE: Did you want to get into the time line? ADM. GEHMAN: Yes. Please. I'm thinking we have about 20 more minutes. The two leading edge temperature sensors in the vicinity of RCC Panel No. 9, which are labeled 9910 and 9895, I think. I was looking through. You did not actually plot that temperature rise? MR. WHITE: Yeah, let's see. If we go back -- I'm sorry, go back to Chart 26. Sorry to back up. Let's see. Can you get Chart 26 of the previous presentation back? Those are plotted here. It's just difficult to see because of all this noise from the strain gauge. They're the two. The purple and the blue. Sensor 9910 is the blue, and 9895 is the purple. So you see the one from the blue begin to rise here. That's the one outside the spar, in the RCC cavity, and then followed behind by a rise maybe somewhere in here for the one inside the cavity, and then both of them get very hot very quickly and then begin to go off scale. As I said, in this particular graph, because I plotted everything together, it's masked in here by the failures of the strain gauge. Here's the first temperature rise and then the one outside the spar; and then here's the temperature rise, maybe somewhere in this range, of the one inside the spar. ADM. GEHMAN: I want to make sure I'm reading this right. In the case of the blue one, which is 9910, which is outside the leading spar, both the temperature rise and also the time scale is significant in that this almost certainly could not be a cut wire or burning insulation or a slow ground or -- MR. WHITE: No, sir, we believe the data is real data up until right here, somewhere in this area here; and then it becomes very difficult to tell when it starts to go vertical. ADM. GEHMAN: Now, in the other one, 9895, which is the lower one, that argument's a little bit harder to make because both the temperature rise is -- MR. WHITE: It's more subtle. ADM. GEHMAN: It's more subtle and it varied over a small period of time, but your conclusion is that that also is a legitimate temperature rise. MR. WHITE: Yes. Both of these we believe are real, to somewhere in this point here. We believe those are real indications that we had heat inside the wing at that point. Now, whether or not the breach was farther down and we just had convective heating coming down to that part or whether the breach was nearby -- and you heard some of the other arguments why it should be farther upstream, maybe in the Panel 8 region -- but we do believe that was real evidence of real heat inside the wing. ADM. GEHMAN: Now, for the temperature sensor outside the spar, the area between the spar and the cavity in there between the spar and the RCC, it's hot in there. MR. WHITE: Yes. ADM. GEHMAN: Because the RCC is not really an insulator. MR. WHITE: Right. The RCC, it re-radiates. We have a lot of insulation inside the RCC, in the front of the spar, to protect the spar and protect it from the re-radiation of the RCC; and that temperature sensor is buried down underneath that insulation. ADM. GEHMAN: My next point. 9910 is actually buried inside the insulation. MR. WHITE: Yes, sir. It's down in the clevis where the panel would attach, and then there's lots of insulation over top of that. ADM. GEHMAN: Right. Okay. Thank you very much. Go ahead with your time line. MR. WHITE: Let's see if we can get the other presentation up. All right. This is similar to the time line I showed you the last time I was here for the operational instrumentation data and we've mixed in some of those time line points here. There's an awful lot of ones here. I'll maybe skip some, and there's some that I just left out of here even putting this together, just to try to make it more brief. This is not every single event we have on the time line and I'm not going to walk you through every single failure of every sensor here, but I'll try to look at this in a big picture. Next chart. Now, these are some of the sensors that I decided to plot. I did not plot all 622 of the MADS measurements, just some of the ones that are more interesting. We also plotted some of the OI measurements that you're familiar with here in the wheel well and some of the ones in the wing. Again, these are the sensors that we were just talking about here, and you'll see this area start to have things happen first. We also tried to keep a color-coding, trying to show what was on what bundles. The blue ones here on this blue bundle which is No. 3 which runs down the side of the wheel well and also splits off and runs along the front of the wing. Bundle No. 4 is this pinkish one. Bundle No. 1 is the yellow one, and you can match those up with the pictures I showed you earlier. As we walk through this, I'm going to keep score over here on how many sensors in a bundle had failed, but you won't necessarily see a dot for each one. So sometimes you'll see these numbers jump a lot and you won't necessarily see that many dots change color. Next chart. So this is now our new first event that we have at 13:48:39 or 270 seconds -- I believe I said 290 in the other one. Because the rise is so small, you can put a tolerance around the front of that. But that's the strain gauge measurement on the front spar there near the Panel 9-10 interface and we see that begin to rise off nominal. That's real data we believe that says something is happening to the strain in the wing leading edge spar at this time. Next chart, please. Again, we see that first rise we just talked about, 9910. That's the clevis. It begins its very subtle rise. Next chart, please. ADM. GEHMAN: And that's only 20 seconds now. MR. WHITE: Right. We've only gone now to 13:48:59. So not very far in the time. As we get closer in, you'll see lots of events starting happening within seconds of each other. The next thing we notice again from the MADS data which we did not have before is now we have an OMS pod temperature sensor which is now showing cooler. As I talked about when I showed you the data, some of those temperatures went down. That says the vortex has now been disturbed and is not hitting the OMS pod the way it normally does. So this temperature here showed a little blue, to indicate it's cooler than it normally would have been. ADM. GEHMAN: Even though you're not going to show every sensor of all 600 and whatever, you have more than one sensor that does that. MR. WHITE: Yes. We have several in the OMS pod, and I think I have some of them highlighted in here. ADM. GEHMAN: So it can be corroborated. MR. WHITE: Yes. It's not just one lone sensor doing this. We see cooling trends on a number of OMS pod sensors, we see them on the side wall temperature measurements here, and then we see off-nominal heating trends as well in this region. Let's see. Go on to the next one. All right. This is a comm dropout. We're still way out off the coast of California. Next chart. Another comm dropout. Next chart. This is another corroborating measurement. This is payload bay surface temperature again going cooler than it normally would have been at this point in the flight. Shows a little blue dot there. Next chart. Another comm dropout. Next chart. All right. Now we see the lower surface temperature. This is the one behind Panel 10 on the surface, and it's starting to rise. It says we've got some kind of heating that's now getting to the surface from probably through conduction through the skin of the vehicle. It's starting to heat that up right there. Again, all of these events are now earlier than anything we had seen in the operational instrumentation data before. Next chart. Comm dropout. Next chart. Another comm dropout. All right. Now, we're back to the spar temperature itself. This is the one in the inside. Now it's beginning its rise; and we're at 425 seconds past entry interface, or 13:51:14. ADM. GEHMAN: Once again, peak heating is arbitrarily defined as some number 40 seconds ago, if it turns out that 400 or 404 or something like that. MR. WHITE: Yes, sir. ADM. GEHMAN: So we are now at peak heating. MR. WHITE: Yes, sir, we are now at peak heating. All right. Now we see OMS pod temperatures where we're seeing cooler measurements here and here. We're seeing hotter measurements than we would expect, a little further back on the OMS pod. So right about here. All right. Next chart. Somewhere in between maybe a slide or so ago that I showed you and maybe a slide or so from now, we believe that the wing leading edge spar got breached. It's hard to tell from the data exactly where that might have been. In a few seconds, I'm going to start showing you a lot of sensors dropping off line. So we know that it had to have breached before the sensors drop off line. It's difficult to tell exactly when that wing leading edge spar was breached, though. This is at 52:05; and this is now where we're starting to notice something different in the aero. This is data that we had seen before, and it could correlate with a time that we started to make the hole bigger or had burned through the wing leading edge. Next chart. Another comm dropout. Next chart. Now, this is something different; and we can't really explain this yet. We've tried to get our thermal folks to explain it; they can't. We've tried to get our instrumentation folks to explain this instrumentation failure, and they can't. We did not see this data until we got the MADS data, but there is a temperature measurement up where the chin panel and the nose cap attach and one of those measurements began an off-nominal rise. If you look at the plot of the data, you'll see it going on a normal kind of slope and then it takes a jump, a higher heating rate, and then for some reason it cools back down and joins where it would have been at that time if it had just kept going and continues on its way. So we don't know what to make of that either physically -- it's hard to explain something heating up and then cooling down and getting back to exactly where it would have been if it had kept on its same rise rate -- but instrumentation-wise it's also difficult to explain it. It's different than the vent nozzle temperatures that we talked before from the OI data. There when you see a higher heating rate and they cool back down again, they're offset from their slope where they would have been. So that extra heat stayed there and they're a higher temperature but at the same rate. Here it actually comes back to the same temperature it would have been and then resumes. So it's kind of odd, and we don't know how to explain that. Next chart. All right. These are the first measurements that we start to see go off line. So at this point here, 5216, we know the wing spar has been breached and that we are burning wire bundles. So there's one back in the back of the wing here. This is a left wing upper surface pressure that goes off and a corresponding right wing upper-surface pressure that shares a common power supply in the MADS system. Both of those were affected. ADM. GEHMAN: Doug, can I ask you to go back one or two. I want to go back to the first aero event, I think, which is 5205, I think. First clear indication of off nominal. I happen to have your detailed line here. The QBAR and the pressures here are still extremely low. MR. WHITE: Extremely low. Yes, very low. ADM. GEHMAN: We're talking, according to this, 22 pounds per square foot or something like one tenth of a pound per square inch. MR. WHITE: Yes, sir. ADM. GEHMAN: So even though we've got some aero events, the aero pressure -- MR. WHITE: It's less than 1 percent of atmospheric pressure, yes. ADM. GEHMAN: It's practically nothing. MR. WHITE: Yes. That's correct. But yet we can see an effect in the way the vehicle's flying. ADM. GEHMAN: Also, in about another 11 seconds, we're going to project that the heat penetrated the spar. So even though we've got extraordinarily low pressures here -- in other words, we don't have anything like a jet, a high-velocity jet here. MR. WHITE: But the amount of air that's there is very, very hot. There is a lot of heat there. ADM. GEHMAN: A lot of heat. MR. WHITE: And the wing spar actually may have been penetrated at this point. In another few seconds, as you said, we'll start seeing sensors drop off line. So we know that the wing spar was breached somewhere before that. The timing of how soon it was breached versus how soon wires start to drop off line, we haven't nailed down yet. So it could have been breached right here at this time. ADM. GEHMAN: But this is almost exclusively a thermal event at this point. MR. WHITE: Yes, sir. ADM. GEHMAN: I mean, it becomes an aero event later. MR. WHITE: Yes. MR. TETRAULT: You have done some testing, heat-testing of Kapton wiring and how long it takes. MR. WHITE: Yes, we have. MR. TETRAULT: It's my understanding -- and I haven't seen any data -- it seemed, at 2,000 degrees, to take quite a lot a long time. MR. WHITE: Depending on where the bundle is or where the wire is and how big the bundle it's in, because you know it provides some heat sink and stuff, there's a lot of variables in there. They're still trying to devise some more testing to get a better feel for the kind of heat rates you can put into bundles, but it's not inconceivable that you could breach the spar and less than 30 seconds later you could start burning wires. ADM. GEHMAN: As we did. MR. WHITE: Yes, sir. GEN. BARRY: One quick question on the nose sensor. We've had failures before in MADS data sensors. MR. WHITE: Oh, yes. We have failures, yeah, maybe a couple per flight, where the sensor fails for one reason or another. GEN. BARRY: You can tell a difference between a failure and one that -- MR. WHITE: Yes, sir. The folks that are used to looking at the data at every flight can tell when it's failed and we put them on a list and depending on how much time we have in the turn-around -- because these measurements are all Crit 3, that means that we don't need them for anything in flight. It's good data to have and engineers like to see this data, but we don't rely on it for anything in flight. So if they have time to fix them during the turn-around, they'll fix them. Otherwise we'll just fly with a piece of paper that says this one's broken and we'll fix it when we can. GEN. BARRY: A point to be made. The ones you're showing in this briefing are ones that you determined -- MR. WHITE: Yes, sir. These were all working measurements. Right. I'm not showing you any that were determined to be bad here. Yes, sir. Let's see. Keep going a little farther. Okay. We talked about the clevis. We talked about the first sensors going off line. Next chart. DR. WIDNALL: Could I ask a question. Where is the wire that they share in common? You said they both went off line at the same time. You said they share a common something or other. MR. WHITE: Well, the power supply and the avionics for the MADS would be about here in the mid-body; but the wiring that they would share would be wiring that comes from here into the avionics box and this wiring here, this blue wiring that runs along the spar and then connects in through here to the mid-body and then over to the MADS avionics boxes. We believe what happened is, because of a short or a burn-through in this blue bundle here along the leading edge, that it pulled down the voltage to the power supply, which also dropped this off. DR. WIDNALL: Because otherwise it's sort of mysterious. MR. WHITE: Yes. We believe we can correlate the right wing ones with the left wing ones where they have failures. This particular point here, 5217, is the previous earliest measurement that we had seen. This is from the OI data. This is where we thought things were beginning to happen. Again, if the wing is breached somewhere in this area and we have hot gas entering the wing, there may be enough that gets around into the wheel well just a little bit to cause that temperature. You remember that was just a bit flip and it was very small; but it is possible, with heat coming in through the wing, that we are now seeing that sensor begin to respond. ADM. GEHMAN: Now, that is significant, what you just said. The temperature rises that we saw on those two spar temperature lines were measured in big numbers, hundreds perhaps. MR. WHITE: Yes, sir. And I indicated those by making these dots red which says that these were quite significantly out of what they should be at this time, greater than -- well, let's see, I guess in the color-coding here it would be greater than 30 degrees by this time. It gets significantly hotter. Here this is a very small temperature range. All right. Next. This is a strain in the spar, the 1040 spar that runs in front of the wheel well. Again, we believe we're seeing off-nominal measurements here because of the shifting loads within the wing as the heat begins to damage things; and this is one of the two measurements that never did drop off line. You notice here in my count I'm starting to show how many have failed in Bundle No. 3, which is the blue bundle here and down the side. Next chart. A couple more sensors drop off line. Again, these are all connected to this leading edge bundle here again, which is the one that you would expect to fail first, the ones I showed you in the back of the spar, and probably haven't gotten over to start burning any of these yet. Next chart, please. Okay. The measurements for the temperature here on the leading edge. The surface temperature behind Panel No. 10 on the lower surface and the one in the clevis are starting to look off nominal. It looks like they're being damaged at this point and that we can no longer trust the data. Next chart, please. This is the spar measurement itself and, again, the lower surface pressure measurement here showing, again, unreliable data, showing damage trend to the wire. Next chart. Another comm dropout. Next chart. You notice we're still at 52 minutes and only 27 seconds now. We haven't gone very far forward. ADM. GEHMAN: We're going to go second by second here. MR. WHITE: Pretty much. So if you want to jump a little faster. But you can also notice that my count is increasing here. I've got two failed in Bundle No. 1. I've got 20 failed in Bundle No. 3. ADM. GEHMAN: Well, just go ahead and just clip through them. You don't need to describe each wire that breaks because the next significant events -- MR. WHITE: Next chart. This is OMS pod temperatures. These are the supply water and waste water vacuum vent nozzle temperatures that we talked about before. Showing a little off-nominal heat rise. Again, we still haven't been able to explain how that correlates with anything that was happening back here in the wing. GEN. BARRY: A point to be made. Is this about the time we had our first telemetry reading on the previous operational sensor? MR. WHITE: Yes. That was actually a few seconds before, when we saw this one in the wheel well rise. GEN. BARRY: 52:17. So all this that you've shown is preceding. MR. WHITE: But is very close. Yes. This is only 52:32 now. Next chart. Okay. There's another measurement off line. Next chart. There's some brake temperatures. Again, we had seen these before. That's starting to rise. More heat in the wing. More heat in the wheel well. Next chart, please. Okay. Supply water dump nozzle. Next chart. Another comm dropout. Next chart. The attach clevis now went back to nominal. Next chart. This is the one on the temperature on the spar. Now it's starting to go off line; and we're still at 52 minutes, now 51 seconds. Next chart. More sensors off line. Next chart. Vacuum vent nozzle begins to rise. Next chart. Now that front spar temperature finally does go off line. So the size of the hole here must have increased enough to take out that sensor. Next chart. Some more skin temperatures going off line. Next chart. This is where we start to see roll moment happen. So now the damage into the wing has begun to be serious enough to affect the roll of the vehicle. Next chart, please. Some more sensors off line. Now we're only at 53 minutes. We've barely gone a minute, and you can see the wire failure counts are pretty high -- 9 of 11, 99 of 138, and 6 of 35. Next chart. This is an OI measurement that went off line. Next chart. Some more. These were ones from the OI that went off. ADM. GEHMAN: Now, these are the four elevon actuator temperatures that went off essentially at the same time. MR. WHITE: Yes, sir. ADM. GEHMAN: And this was then noted in mission control in conversations. MR. WHITE: Yes. These are the ones that alerted something. The MCC began to notice something that was wrong, that these four should not have failed all nearly at the same time. ADM. GEHMAN: So you might say this was the first indication people on the ground had any idea that anything was happening that was unusual. MR. WHITE: Yes, sir. That's correct. The temperature rises that we had in the wheel well were pretty subtle and were hard to pick up if you didn't know -- you know, it's only going back and looking at it that we know and pick this up. But these measurements failing here were picked up immediately and, as you said, were the first indication to the folks on the ground that they had a problem. ADM. GEHMAN: And depending on what displays were being displayed at MCC. So even though those wheel well temperatures are telemetered to the ground, they may not be actively looked at at every instant. MR. WHITE: Yeah. I can't answer that. I can't be sure what the MCC looks at routinely. ADM. GEHMAN: We do know, based on the video and audio recording, that the loss of these four elevon actuator line temperatures was noted and reported and this is when the conversation started. MR. WHITE: Yes, sir. And then this, position-wise, we're still not quite at the California coast yet. Next chart. OMS pod temperatures now start to rise. This is one that was cooler earlier. It's now starting to rise. You can see other parts of the OMS pod. This one is still cooler, and this one is very hot. So we've shifted the vortices around considerably. Next chart. More pressure measurements going off line. Strain measurements. Next chart. Some side wall fuselage temperatures rising now. Some of these had also been cooler and now are getting hotter. Next chart. Again, another side surface temperature behaving badly. Next chart. Comm dropout. Now some more strain measurements and elevon return line temperatures going off line. Next chart. Now my supply water dump nozzle, my vacuum vent nozzle returned to nominal. Next chart. Another hydraulic system elevator -- excuse me, elevon actuator return line temperature going off line. Next chart. Now, the strain. This is the other measurement that hung in there but, again, is showing an off-nominal reading in front of the wheel well on this spar. Again, it tells us that the load is being redistributed within the left wing. I can't tell you exactly what damage would have caused these measurements to behave the way they did, but there was damage and it was causing the load to redistribute. Next chart. This is now the first debris sighting. We're over California, and so this was the first debris event. Again, it could have been tile falling off the lower wing. We know we had a lot of heat in here that damaged all these sensors in here. It could be upper-wing skin. It could be upper-wing tile. It could be lower-wing tile. We see a number of tile that indicate that they fell off because they were melted off from the inside, not that they were damaged or melted off from the outside. ADM. GEHMAN: Of course, this is the first observed debris. MR. WHITE: First observed debris. There could have been debris earlier. Of course, we haven't found any tile out in California or any debris of any sort out in California