Posted: Tuesday, March 4, 2003
TETRAULT: You brought up the nuclear issue and, obviously, I come out of that side of the field. I've seen a number of articles which have asked why are there so many nuclear guys on this in the group, and not only in the board, but underneath, doing this at some of the levels.
My own personal opinion there is that nuclear history has a history, and because of that history, they have had to adopt certain attitudes and qualities over years, and, particularly, a questioning attitude about--prove to me that it's right rather than I assume that it's wrong. And I think to some degree, Sean O'Keefe saw the nuclear Navy as having some of those attributes that he probably wanted on this board to look at those kinds of things. And I know in certain areas that I've looked at, I'm a little bit suspect of that questioning attitude that should be there that I'm not seeing. And it's not in all areas obviously, but in certain select areas.
GEHMAN: Steve Wallace replied exactly the way I would reply. In my calls on the oversight committees last week, I assured them that all of these issues about management and culture and history and oversight and lessons learned from previous studies and Challenger, we're going to get to that. But you've got to remember that at this point in the Challenger investigation, they knew what went wrong. And so, the review of who did what to whom and who did his job well and who didn't do his job well was relatively, fairly focused.
I'm really not interested in casting about NASA to look for everybody who--without any particular focus or without any particular reason for just casting about and casting some big chill over NASA that we're searching for everybody who parked in the wrong parking place when they came to work this morning. So it has to follow either a deduced fault or an actual direct fault that we find, that we will then do a complete review of all the aspects of the history and culture of NASA, getting into all those issues. But it has to follow in logical order.
Now, we're going to review through these management boards and committees and all those kinds of things in nice-do process, but you've got to remember we're not following any particular fault here because we don't know what happened. So with that caveat, yes, we're going to go after all those things.
QUESTION: I think, for you, Mr. Tetrault, two things about what you were telling us. I've never understood the telemetry of wheel well temperature rise rates in the context of an actual burn-through in the wheel well. I've never understood how the plasma, if it was in the wheel well, you wouldn't see more radical telemetry. Have you got a better sense of that or can you tell me how something like that could happen that you wouldn't see more telemetry?
And the other thing is, when you're telling us about the aluminum and the coating on right and left, does any of that tell you anything about the attitude of the vehicle, you know, in that last 25 seconds or, I guess, 27 seconds before the final loss of signal? Do you have any sense--I mean, I'm guessing what you're telling me is you're seeing--this thing could have been going side ways or whatever--and you're seeing the kind of natural flow you would have before it broke up.
TETRAULT: I'm not sure I'm going to answer your question very specifically, but with regard to the attitude and the telemetry, let me say this. I'm having difficulty with some of the off-nominal timings, as I mentioned to you. And one of the reasons I'm doing that, where I'm having trouble is, it's very simple and it's very simple physics.
There was a temperature A, brakeline hydraulic fluid temperature A that went up very early in the event. It was either the second or the third one that went off-nominal. Temperature B, which sits about two inches away from it, did not rise until about a minute and a half later. Whereas, temperature C, which is, you know, probably six feet away, and temperature D, which is four feet away, are all rising off-nominal. That doesn't make a lot of physical sense to me.
What we found as we look at these temperatures is that, it appears to be a straight line up and at some point NASA has called it off-nominal. And it may be some variability in where that call is on where it is off-nominal. And so, what I'm trying to tell you is that if you're trying to put together a time line, I think you can be fairly certain when it went offline. But when it says it's off-nominal, I think you're going to have to take that with a little bit of grain of salt and eventually you may find us redoing that time line and shifting some of these sequences around to some degree. Hopefully that answered your sensor question.
The one with regard to attitude, if you look at the sensors themselves in telemetry, it is interesting to note that all of them were going up off-nominal, but then they went up in a very, very sharp fashion as soon as it rolled into the left wing-down attitude. I won't say anything more, but it's interesting to note that that occurred that way.
QUESTION: As you step back, sort of just to sum up some of these earlier questions and look at the evidence you've accumulated so far, in your opinion, does it seem to be moving you more toward a breach in the leading edge or a breach in the wheel well?
TETRAULT: I think those are both equally alive. Everybody has their own theory. I'm sure each of you has your own theory. Everybody on the board has their own theory. I'm going to be patient and not express my theory at this time.
QUESTION: I wondered if you could bring us up to speed on the foam story; what you're looking at now; if you're any closer to where the foam debris struck the underside of the left wing, whether it was one or more pieces?
TETRAULT: I really don't have a lot more to report other than what you've already heard. I do know that earlier this week that NASA is trying to develop a variety of experiments where they can look at cryopumping and some of those kinds of things in small scale experiments when they can look at how well does this adhere and what is the likelihood that something would come off and so on and so forth.
We reviewed that test plan--that's group three--reviewed that test plan earlier this week and gave them permission to go ahead and run that test plan. They also wanted, as part of that test plan, the authority to chop into a bipod--starting with the right bipod on external tank number 120, which is very lightweight but has the same configuration that you would find on the 93 that was on the OV-102. We have not given them permission to do that and cut into it until they come back to us and tell us the results that they get on the initial test plan.
TURCOTTE: And to walk that backward, there is another tank there, ET-92, I believe it is. It's a sister tank. 94, I'm sorry.
We're looking backwards at the processes; when that was put together, what were some of the process flows that went into that where some of the propellant was changed. At a certain process point some of the epoxies were changed. We're looking at all of those to figure out, in many ways, if it did separate, how much did separate, and why did it separate, what lot number of the paint was used, and what lot number, et cetera, et cetera. So it's just much more than just looking at the photos. We're trying to what-if; if there were some failure modes present, how much would come off and when?
QUESTION: This is kind of an accounting question, so I don't know which one of you wants to tackle it. But could you clarify the most recent significant debris finds in the last week or so, what have been the most significant pieces? And also, can you just re-clarify your western-most find, what it was and where it was, again?
GEHMAN: The western-most find is still a fraction of a piece of tile. It's not a whole tile. It was found in the area of Littlefield, Texas, which is well west of Fort Worth, as you know. We don't have a picture of that piece of tile. It's only a fraction of a tile. It's just now being inducted into the system. And I think Mr. Tetrault has already gone over his favorite pieces several times. Certainly the landing gear, the wheels are very significant, but we're not--you're never sure what the most--you know, when the golden nugget is going to show up. So it's hard to say what's significant.
TETRAULT: A lot of times it's a very overlooked piece initially.
QUESTION: I guess I was just trying to get a timetable. I'm sorry. Were those found within the last week, is what I was trying to get at?
TETRAULT: Not necessarily. The stuff that we're beginning to find or are continuing to find is mostly fairly small things. My understanding is what's happening in the field is most of the big stuff has been found. And we are finding lots of screws and bolts and tile and tile pieces and those kinds of things which continue to come in. But we're not finding many of the really large things. Just hearsay, if you will, about what they're finding in the field.
QUESTION: I'm still interested in this aluminum spray. I'm wondering whether this flow that you mentioned that was 90 degrees to the flow of the air, was that flowing from the left wheel well toward the right inside of the craft? And is it conceivable that could have been some aluminum in there?
TETRAULT: No, it actually appears to be opposite of that. It appears to go from the inboard left wheel well frame toward the left wing tip.
QUESTION: Can you say anything about what the mechanism might be to get that spraying across...
TETRAULT: None whatsoever at this point.
GEHMAN: I don't think it's molten aluminum. Yes, it's not aluminum, it's a discoloration which seems to indicate the heat flow and it seems to flow from the left forward inboard side of the wheel well toward the fuselage.
TETRAULT: I'm going to agree with the admiral, because that's the side that the tiles are on.
TURCOTTE: That's correct.
GEHMAN: Now, what does that mean? Stay tuned.
QUESTION: Can you give us any progress report on the two or three or four different analyses going on with regard to trying to locate the breach, the thermal analysis, the aerodynamic analysis and whatnot?
GEHMAN: I can tell you that the studies that we mentioned last week, which were kind of thumbnail studies, are now getting to be a little bit more sophisticated. Some of the things that we thought they would show us are now being challenged by experts. But we are still trying to do what we call a back-fit. And Mr. Tetrault--Roger mentioned this two or three times.
We're trying to find a scenario which fits the temperature readings, and we are inducing holes, and we are inducing heat flow into the vehicle at various places, and we are more sophisticatedly modeling how the heat flows in through...
GEHMAN: ... getting more sophisticated and we're doing more of it.
Same with the aerodynamic analysis that Dr. Widnall is working on. We're trying to get smarter about that. The only thing I can tell you about the aerodynamic analysis is that, even at the time of the final two seconds in the extra 32 seconds after the loss of signal, the vehicle's attitude and position was correct. We do believe that the vehicle was fighting forces more strongly than we had--the fight was getting a little more vigorous at that point. And we also believe that the beginning of some of control measures that the vehicle was taking to maintain its attitude started earlier than we previously thought.
So you know, we're down now to a little bit more refined, and so it looks like the vehicle was fighting aerodynamic flow forces a little earlier than--I'm talking seconds now, I mean, not minutes, you know--a minute or two earlier than we previously thought. Little, tiny deflections that we hadn't actually noticed before. But I can't tell you anything more about localizing it or anything else.
QUESTION: For Mr. Tetrault. On the debris issues, we were told last week that the cassette that was shown last week was recovered near Palestine, and press reports I've seen on the other crew module structure and contents being found further east. Was the debris spread from the crew module indicating that this cassette was unusually up stream or were crew module materials spread out among a much wider area?
TETRAULT: All the crew module debris is kept in a separate location that's in the same hangar, and I haven't spent a huge amount of time there because I've been concentrating on the left wing. I don't know exactly at this point where any piece of debris has landed. We have asked for that information; we have not received it.
For us to analyze and go backwards and try to say, "Where did the heat come from?" we have to subtract out all of the reentry heat, if you will, and in order to do that what we need to do is find out where the debris landed, then try to get a ballistic coefficient for that and back it into the sky and say it left the aircraft here. And that's part of the all the analysis we have to do yet. So my realistic answer to your question is, I don't know.
GEHMAN: And I'm the spokesman on crew issues and because of the sensitivities to the families and things like that, we are conducting that examination pretty circumspectly. And anything that we learn--if we learn anything that's unique or special from the crew debris, the crew module, the cabin or anything like that, we take it over the curtain and put it out on the floor. And so far nothing remarkable has come out of it.
The cassette was located kind of in the primary debris field. I mean, it was, you know, it was kind of in the same area where lots of stuff was found, so nothing remarkable about where it was found.
QUESTION: Has one side of the vehicle--have we found more of one side of the vehicle, and do we know a percentage of which side we found, a 60-40 percentage? And the tiles that we haven't identified, are we going to be able to identify what part of the vehicle those are from? And how is that process going to happen?
TURCOTTE: I just left there yesterday. I'll jump into this one. I spent about five, six hours yesterday and the day before. It's pretty evenly split. And not all of what we have is there.
For example, we don't have the hydrogene tanks and some of the other vessels that are in. They are in a separate location. So not all of what we have is there. But as a broad brush scope, most of what you see, it's kind of a scatter-gram. If you were to take a shotgun, it would be a good analogy to that. Again, not a lot of what you see there is also stored on the left-hand side there, and those are still for further processing. So as those come out and they're identified, it could begin to come to take shape a little better, but right now it's pretty much of a general scatter-gram.
QUESTION: Mr. Tetrault, you mentioned an interesting point, that it's important to recognize what you don't have as well as what you do have and the importance of that. Given that you have most of the frame of the landing gear door but not the door itself, does that support the notion that the door might have been damaged or even been dislodged fairly early in the dissent? And also, if so, might that have anything to do directly with the trauma that has now been recognized in the tires that have been there?
TETRAULT: At this point I would say it's just an interesting observation, and I wouldn't want to jump to any conclusions about what might have caused us not to find the landing gear door. I think at some point we'll be able to answer that question, but I think it's way premature at this point to speculate on it.
GEHMAN: Our job is to fit six or seven of these investigatory themes together into a pattern that fits. And if, for example, the thermodynamic investigation indicates that the loss of a tile would not have induced enough heat to show these kinds of things--that the heat had to be introduced directly into the wheel well, then the door becomes very interesting. So these things all have to fit together before we can answer any of those questions, and right now they don't fit together, not that we can see.
TETRAULT: But we do have some interesting tools. I mean, we know when various metals melt, so when we find deposits, we can get an idea of heat. We know that the core bond used on the aluminum skin begins to degrade at about 400 degrees. The RTV degrades at 500 degrees. All of these things we can put into a pattern as we look at this debris and try to figure out what was the cause, where was the heat coming from and how do we back into it.
QUESTION: Just listening to the general conversation here, it sounds like you people are dramatically farther along this week than you have been in the past. Would you characterize it that way? And does it mean anything for the speed with which you might reach a conclusion?
GEHMAN: I would characterize this week as a very good week because we have so many independent investigations going on, which are beginning to lead to little tidbits of information. The problem is that since we don't know where we're going, we don't know how far along the road we are.
I think Yogi Berra had a saying, something about: If you don't know where you're going, any road will do.
That's kind of where we are. We're investigating everything right now because we don't want to leave any stone unturned. But, yes, I would characterize this a very, very good week because of the travel and the investigations that you've heard reported by these officers, plus you multiply every one of these guys by six or seven and you realize how many things we've got going on at the same time.
QUESTION: Has the work in the last week on the photography--ground-base photography shown anything provocative beyond last week? And secondly, as you look for debris in the coming two weeks or so, in the world of black box-type retaining data or cameras retaining imagery, what are some top priorities there?
GEHMAN: The photo imagery continues, but there's nothing new since I reported last week.
What the photo imagery shows, debris shedding over California, which surprised me how early it showed debris shedding, tiny little pieces which probably never made it to the ground, or if they did we aren't likely to find. The larger pieces of debris that shed early, thanks to the NTSB and the FAA and the military, we've tracked several of them all the way to the ground. And those are the ones where we are asking the local sheriff to go out and look in this spot. We're pretty sure there's a piece of debris out there. Unfortunately, the weather's been bad. It's covered with snow and things like that. But we're not going to give up. We can't give up on that. So the answer to your question is, no. The analysis of the photography continues, but nothing remarkable to report there.
We continue to put a high emphasis on the recovery of anything that has data, anything that stores data. It turns out that there are literally dozens and dozens of pieces of equipment on the shuttle that store data of one part or another.
As we come across them, just like we did with the crew tape, after we finish and we're pretty sure that we've analyzed them and we've taken anything sensitive out of them, then we make it public as soon as we have it. And there are no black boxes on the shuttle.
TURCOTTE: Right. There are no black boxes in the flight data recorders. And, of course, with the telemetry they're actually in many respects way ahead of the civil aviation sector in that area.
But I would, as far as cameras, there are three cameras which photograph the external tank separation right in the umbilical, two moving cameras and one still. You may have seen on past missions extremely high resolution photographs of the external tanks separating, and, unfortunately, that requires the return to Earth of the film. So it'd be something we'd love to see, but I don't think we're optimistic.
GEHMAN: Thank might possibly show the famous left bipod ramp, so that's why we'd like to see that.
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