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Columbia Accident Investigation Board Press Briefing
Tuesday, May 6, 2003

1:00 p.m.
Hilton Hotel
3000 NASA Road 1
Houston, Texas

LT. COL. WOODYARD: Good afternoon. Welcome to the Columbia Accident Investigation Board Press Briefing. As always, we'll begin the press briefing with opening remarks from our chairman, Admiral Hal Gehman.

ADM. GEHMAN: We're going to change the system a little bit here. I'm going to speak last. So I'll go right down the aisle here and ask for a brief introductory statement from my colleagues on my all-Air-Force panel here today, including Secretary Widnall.

General Deal.

GEN. DEAL: Thank you for the opportunity. I'm going to give you a very quick update because the main event, of course, will be Admiral Gehman when he talks to you.

Our panel. General Barry's in town. He's got a management focus this week and working on pulling the entire board story together. Admiral Turcotte was at Kennedy last week and will be joining us again this week.

Our three subgroups. Our first one is Maintenance and Sustainment. Everything they've been looking at, we've briefed you before. But a very heightened focus now on contracts. Multiple items from the Space Flight Operations Contract at Kennedy to the external tank contract operations at the Michoud assembly facility. They're also getting a lot more fidelity to the matrix ability, looking at past reports, what was recommended and also what has continued throughout NASA.

Our Management and Human Factors Group did a trip to Huntington Beach last week, examining not just the engineering organization there, the so-called brain drain, but also talking with the engineers that work the Crater program, that predictive tool for estimating the impact damage to the orbiter.

This week the team's also going to be bringing in two internationally-recognized experts to talk organizational issues with us. Dr. Karlene Roberts from UC Berkeley will be here to discuss high reliability organizations and managing high-risk technology; and joining us also will be Dr. Howard McCurdy of American University, who's the author of four books on space policy. Then next week we have Dr. Carl Weick from the University of Michigan to continue discussion on HROs.

Our Materials and Structures Group, particularly Larry Butkus and Lieutenant Commander Johnny Wolf, have been looking at the external tank and its testing both at Marshall Space Flight Facility, that I'll be showing you some slides on very shortly, and also Michoud, and also been working with Group 3 on the foam gun test parameters that Dr. Widnall will probably talk more about.

Then another lingering focus for us is still quality assurance. It remains a key area of examination. Yesterday, for example, we held a half-day session dealing with safety and mission assurance at Kennedy Space Center. As you have reported yourselves, inspections are down across the entire shuttle program by the quality assurance aspect, though most of those have been shifted to the contractor; but we've got extensive interviews and documentation that will reflect a likely need to update and fine-tune the steps that are examined and also the methods of examination. Simply said, some things that work great for an airline industry that has thousands of flights per week may not be right for a research-and-development manned space flight system with 113 fights under its belt.

So I'll show you a few slides before I get off the stage. Tom, could you bring up the next slide, please.

One of our favorite topics, of course, is the famous bipod ramp; and you see that there with the minus Y and plus Y.

Next. We've finished, as you know, 120, the cousin tank. I've already out-briefed that to you. Next week we'll have the ET94 sister tank brief for you.

Next. These are the pictures of what is under test now, up at Marshall Space Flight Center in Huntsville. These are some panels that they've built with bipod ramps in order to try to induce the cryopumping that we've talked about, and they're going to be doing that inside that 12-foot vacuum chamber at Marshall.

Next. We're going to re-address and correct the record the best that we know now with the known ET bipod ramp losses. We are now counting six, with an addition of one of STS 52 there, with the enhanced photography that we have. You can see when they all occurred. We talked about 7, 32, 50, 112; and then what we discussed in detail this morning was 107.

Next. Just a snippet for you. If you look at 50 and 52, they were separated by two flights in a four-month time period; and then 112 and 107 separated by one flight in a three-month time period. Those are things that Group 2 is looking at the Flight Readiness Review to see how the disposition of those foam events was handled.

Next. Just as a summary slide to you. 13 shuttle launches. We've got photo verification of the bipod condition on 74 of those. We don't have it on 39, due to a number of factors. It could have been a night launch and we had absolutely zero photo confirmation, or it could have been the orientation, such as happened on 107. By the time they were able to take pictures of the external tank floating away, it had already rolled over and you couldn't even see the bipod area.

Next. So we have six known foam losses. You could statistically extrapolate -- you could never prove it -- but you can statistically extrapolate three unseen losses, based upon those that you have not seen. So you might conclude that you might expect some degree of bipod loss every 12 to 13 flights, and how this became an acceptable risk is one of the things that we're looking into.

So thank you very much.

GEN. HESS: I must hurry so I can cede the remainder of my time to the chairman.

It's good to be here. I'll try to describe for you today the process that we're all kind of going through as we get to end game and how these various lines of investigation between the groups are going to attach.

Steve Wallace is leading the portion of our investigation that's going to take a look at the disposition of foam events, primarily across the six missions that General Deal highlighted to you on that previous chart. In doing that, he's going to look at the Flight Readiness Review process as well as the PRCB process that took decisions by the program as to whether to fly succeeding missions and how they handled the foam particularly.

Dr. Sally Ride, as you know, is taking a look at various things like the Crater analysis as well as the E-mail thing that was going on with the STS 107. So she will connect the on-orbit management decisions of that particular mission as they relate to the work that Steve Wallace is conducting across the top almost operational/strategic level of the program.

For my part, I'm taking the same walk; but I'm going down the safety chain -- I'm saying program-level safety, not trips-and-falls kind of thing -- to take a look at overall program and policy as well as the risk management and risk integration on those various steps and to see how NASA used trend analysis from within the various data bases that track safety information to help predict and work risk management problems.

Now, all these lines of investigation should intersect here as we get to the end of our report and start doing our analysis level of what all that means in terms of how NASA manages these on-orbit decisions that they make.

Thank you.

DR. WIDNALL: My group, Group 3, has been following up engineering and technical analysis, behavior of the shuttle during flight, as well as the analysis of debris.

Just to mention what some of the group members are doing. Roger Tetrault has been down at Kennedy; and he's, of course, focusing on debris. He's also sitting in the back of the room. He's been focusing on the chemical analysis of debris to tell us what is it really telling us. He mentioned that the last scheduled truckload of debris was unloaded at Kennedy Space Center this morning. Clearly, the amount of debris that's been collected on the shuttle is really unprecedented.

Jim Hallock is working on constructing various scenarios, analyzing them in detail. He's also looking at the behavior of sensors, trying to look at the ones that failed as well as the ones that are giving us good data. He's our man to watch over the closeout of the various fault tree analyses that are being done.

Scott Hubbard is working on the foam tests. He's actually in town, but he all last week was down at Southwest Research Institute. He said that the foam impact tests began last Thursday. The original tests, I think, are more to test out the test setup, shooting small pieces of foam at an instrumented main landing gear door; and then they'll move up towards changing angles and moving up to larger pieces of foam and getting data on tile damage due to foam impact. Obviously there's a lot of focus on the testing of the leading-edge RCC. The test setup should be ready around the end of May. It's a fairly complicated test fixture, and he anticipates that the testing on the RCC or configuration will begin in early June.

As for myself, I'm sort of monitoring and participating in the aerothermal analysis of the various phases of the flight. So that's what's going on.

ADM. GEHMAN: Thank you very much.

Now, for my part, I'm going to walk you through what the board calls a working hypothesis or a working scenario. As we had previously announced, the board felt that we now know enough and we understand enough that it's time that we change the board's official policy, which was we don't believe in scenarios of the day or the most popular scenario, that everything was on the table, to the point now where we believe that we should focus our efforts; and that's what the purpose of developing a working hypothesis is.

We still have our antennas out, our senses sharpened for any indication whatsoever that we may have it wrong or we may have overlooked something; but by building a working hypothesis, as I will show you in my last couple of viewgraphs here, it really enables us to focus the testing. It enables us to much more narrowly direct the analysis. It really produces a very synergistic effect on a lot of different disciplines so that they now all point to the same direction.

So I'll go through what we believe we know and what we don't know. A lot of stuff is not in this working hypothesis. This is just a broad sketch or a broad scenario that encompasses a scenario which is wide enough and broad enough to capture most all of the data that we've developed.

So if I could have the first viewgraph, please.

First of all, this scenario is called a working scenario. The reason we say it's a working scenario is that we reserve the right to change any part of it at anytime without notice because we have to have something to go on to conclude this investigation but at the same time I don't want to suggest that the board has voted on every one of these statements and that we're willing to say that this is the end of it. It certainly isn't.

I would also like to acknowledge that this was done in conjunction with the whole investigation team. It's labeled as a Columbia Accident Investigation Board working scenario, but it represents the work of the entire team and I really want to thank the NASA part of this team for their hard work on this. The reason why we wanted to be sure that we had a complete understanding with everybody in this investigation is because I didn't think it would be helpful if there were other people out there proposing various versions of this. So we believe that this is an agreed position by most of the people that work on this.

The two members of the board who are most responsible for the work on this are Dr. Jim Hallock, who is unfortunately under the weather today, and Roger Tetrault and their group. On the NASA part, Randy Stone and Fran Benz and Jim Kennedy are the leaders of that group.

All right. Starting through here now. Based on the six items, six lines that you see indicated there, based on the analysis that we've done in every discipline, we have reached some agreement on what happened in both the ascent, on-orbit, and entry phase.

Next viewgraph, please. I'll just go through this in chronologic order and tell you a little bit about how we came to this conclusion. Obviously at seconds after launch -- 81.7 seconds, to be exact -- we have ample evidence that several pieces of debris came off of the left bipod ramp, one of which struck the orbiter. You'll notice that someplace in the vicinity between Panels 5 and 9. Later on in this presentation I will talk about other evidence that suggests different panel numbers, but we've just got to let the evidence speak for itself. You'll notice that there's nothing in this statement which makes any kind of a declaration about whether or not any damage was done.

Next. We have just samples of some of the evidence that led us to this conclusion. Here we have a still from some of the video loop that you saw earlier this morning of some of the foam coming off.

Next. We have been able to track the path of the foam, using the two cameras that saw this; and we're fairly certain we know the vicinity that the foam came from and we know the vicinity under the wing that the foam struck.

Next. We've got this trajectory analysis down, even though it continues to move around a little bit a couple of inches left and right, but we're down to the area -- this analysis narrows down the foam strike from what I said before, from 5 to 9, to in the vicinity of Panels 7 and 8, based on this analysis. There is a little tiny clipping on the corner of Panel 9 and there's a little tiny clipping on the edge of Panel 6, but the most likely area is in the area of Panels 7 and 8 and we think that this has been analyzed by so many different people that we're fairly content to say that we're in the ballpark. That's ascent.

Next. On orbit. We've not been able to turn up any evidence whatsoever that leads us to the conclusion that there's any way that we can detect on orbit any damage to the orbiter. There's no photography. There's no telemetry. There are no instruments like inertial navigation systems or sensitive accelerometers, all of which have been checked, that indicate that the orbiter was struck or in any way did not perform perfectly while on orbit.

On the other hand, surveillance of the orbiter's flight path -- just routine surveillance, nobody was tracking the orbiter -- but just because the orbiter is something in space and we track everything that moves in space, there was an observation that on Flight Day 2 that there was an object in company with the orbiter. As the testimony this morning indicated, if you heard that, there was an observation of the orbiter at a certain time. The next observation took place a couple of hours later and there was an object there that wasn't there before. That object was tracked for about 2 1/2 days. We know approximately the size, weight, and mass of this object; and we are attempting to match up what it might be.

We have eliminated many, many things and we have a couple of parts of the orbiter that are remaining on the table and this viewgraph indicates that. A part of the a T-seal or a part of a RCC panel does pass the radar test as well as the mass-to-area ratio tests, and they are candidates for what this object might be. It does not prove that that's what this object was. It just says that those objects pass the test, whereas another 20 or 24 objects fail the test, and the testing guess on. We're not done with this yet, but we have some candidates which meet the tests and obviously since we have just discussed that the orbiter was struck in the area of T-seals and RCC panels, it becomes a possibility that we lost part of an RCC panel or part of a T-seal which came off on orbit.

Next. These are the pieces that we're talking about. This is what a full T-seal looks like from the inside. One of the reasons why we build this working scenario is because now it focuses on the debris. Obviously, if we end up with all the T-seals down at KSC, then it can't be a T-seal. So this is a very nice focusing thing.

Next. So that's what we're willing to say about on orbit. Now for the entry. The de-orbit burn was conducted properly. We found no anomalies. Everything worked as it should. The orbiter performed as it should, and the profile seemed to be nominal to us. Nevertheless, on the morning of 1 February at the time that the Columbia entered the atmosphere, we believe that she entered with a preexisting damage of some sort in the leading edge system and that damage was in the area of the RCC panels which we previously have mentioned.

The most likely area of damage is in the area of either RCC Panel 8 or 9 and the T-seal between them. This is based upon many, many measurements that are outlined in our scenario here, particularly the temperature sensors which rise very early and the strain gauges which indicate unusual strain very, very early in the re-entry.

Furthermore, forensic evidence of the debris further suggests to us that the pieces of RCC No. 8 and 9 and the surrounding pieces which we have recovered do show some patterns which suggest to us that the entry of heat started in the area of RCC No. 8 or 9 or one of the T-seals. We've listed some of the issues here. Extreme heating, the deposit of metal, the fact that some of the RCC material which we've recovered has been flame-eroded to a knife-edge sharp corner on it indicates that there was a heat flux past the RCC.

Next, please. We've drawn this out for you here just to show what we're talking about. We put a little blob around here to indicate that I'm not sure that we know exactly where it is. We haven't figured it out to the inch yet, but we're getting pretty close. It's RCC Panel No. 8 or 9 or the T-seal in between and we've brought along a model here, too, so you can see as we describe how the heat gets in there. Sometimes a model helps. What we're suggesting is that the heat entry started right around in there -- and this is just a blowup of it -- someplace around RCC Nos. 8 or 9.

Next. This graph here shows the deposit of slag on the RCC panels. This leads us to believe that because the slag deposits are extraordinarily heavy in the area of 8 and 9, and just plain heavy in kind of 7 and 10, that this is the area that was predominantly affected by the highest temperatures for the longest period of time and that metal from the internal parts of the leading edge was melted -- probably more melted. It may even have been vaporized to the point where it was actually flame-sprayed in some of these cases. A lot of it is just melted. It's slag. It's melted metal of several different types. This again is another piece of evidence which leads us to focus on RCCs Nos. 8 and 9.

Next. This is a view of Panel No. 9 on the left, Panel No. 8 on the right, as if you were standing inside the wing, looking forward. In other words, the flanges, you might say, are even with the screen and the apex is away from you. In other words, we're looking into the RCC panels. Of course, the T-seal goes in between 8 and 9. So this flange here and this flange here would be about 1 1/8 inches apart from each other, with a T-seal in between. These are the pieces which are eroded to knife-edge thin, with a sharp edge, which indicates that -- and what we don't have any color on here, we don't have. We don't have that piece of debris. It's gone and we can't find it.

So this is leading us to believe that perhaps on the lower side right here that heat got in here someplace either from the RCC itself, the T-seal, or this RCC, and as it blew by these edges here, it sharpened them to knife-edge sharpness. We have pictures of all that. Pictures don't show up very well, so we didn't bring them. But we have the debris and we have pictures of that.

Next. As far as the slag is concerned, this is a piece of the RCC, a typical piece, and what we wanted to show here is the composition of the slag. What we're suggesting is that it's not just aluminum. We have metallic particles from all of the parts, Inconel, stainless steel. Everything that's in there, we have some deposits from chemical analysis. So that indicates to us that the entire leading edge structure was impacted by heat long enough for it to work its way through, take all the pieces apart, vaporize them and melt them, and then spray them around. And that has a certain connotation of time as well as temperature because each of these things melts at a different temperature. So it tells quite an interesting story.

Next. Okay. Entry interface, of course, was 44 minutes after whatever hour you want to use. Eastern Standard is what we use here. GMT is what we got briefed on this morning. But at 44 minutes and seconds after the hour was interface. Then we now go through this time line of indicating when the temperature and strain sensors started to tell us that something happened in the leading edge, and it all kind of leads us to this same conclusion.

At Time 49:00 or about five minutes later, we have the first temperature sensors starting to rise. This is even before the time of peak heating, as we indicated before, and so we feel that it's safe for to us develop a scenario in which that Time 49 is when heat started to enter into the cavity.

By Time 52, three minutes later, temperature readings inside the wing indicate that the leading edge of the spar was breached. It took about three minutes for the heat to get inside the spar. Now, this is significant because we are hoping that with thermal analysis we will be able to determine what kind of a hole, how big a hole it would take for heat to eat its way through the leading edge of the spar. So this is significant.

Next. So what we are hypothesizing is that -- and we've drawn it in Panel 8 but we don't have any proof that it's Panel 8 -- it could be Panel 8 or 9 -- that there was a breach on the lower end of either Panel 8 or Panel 9 or the T-seal in between and that heat got into the area behind the leading edge system for about three minutes and then started to eat its way through the spar.

Next. Once hot gas has got into the spar, it immediately began to attack the spar structure, which is all aluminum, of which we have not found so much as a shred, and it began attacking the wire bundles that were in there. The wire bundles go to hundreds and hundreds of sensors. We know at what time those sensors went off line, whether the sensors rose because of heat or whether it failed because its wire was cut, so that we can paint a fairly complete picture, a fairly confident story, because we have hundreds of sensors that are agreeing here. So we're pretty confident about what happened.

We hypothesize, as you may recall from two viewgraphs ago, that the leading edge of the spar, the spar front bulkhead was penetrated at about Time 52, 52:00. The first wire fails at 52:16. The first sensor fails at 52:16 -- 16 seconds later. Then over the next four minutes, over 164 other sensors fail because their wires were cut, most of which failed almost immediately but some of which hung on for a while.

Next. So our scenario then is that at Time 52 we breach the spar.

Next. And we got into the interior of the wing. This is the spar breach right here and heat now has filled this entire cavity in here. Many of the wire bundles run along this bulkhead right here, and some of them run along both this bulkhead and also a bulkhead which runs right here which we'll show you a picture of in a second. Once the heat got in here, it started cutting wires here and cutting wires right along here. And what we're talking about is, of course, right in here on the model, is what we're talking about there.

Now, we showed that the heat -- there is a vent hole. There are vents in here, and we don't know if the flame was able to breach this bulkhead and get in here or whether or not it just went in through the vent hole. We're not ready to make a positive statement about that, but there's no question that then heat got into the wheel well, because we have a lot of sensors that tell us this. Of course, it vents out. There are large vents in here. You see that square right there? That's that square right there. Once the heat gets in here, it can go all the way through the wing.

Next. So at 52:16 we have heat in here. This is the outboard wall of the wheel well. This is forward. This is top. This is bottom. This is out. This is left, out on the wing. So on this diagram here, we would be looking at this bulkhead right there. There are the wire bundles that we're talking about, some of the wire bundles. They begin to burn.

Next. About this time, because of all this heat inside the wing, the wing begins to deform and a whole lot of things happen which we can't prove but we believe that probably, because the wing began to deform, tiles started popping off and losing their adhesive bonds because they aren't bonded to a flat surface anymore and the debris-shedding events occur, the first of which is about a minute and a half after the wing is breached. The first observed one. Now, there may have been debris-shedding events for a long time before that and we just didn't know about it, but this is a minute and a half later now from 52:16 to :46. We see the first piece of debris come off. But by now damage is extensive inside the wing. Hundreds of sensor have had their wires cut. Communication blackouts are occurring because of probably disruption of -- the hot gas flow around the orbiter.

Again, at Time 52:06, which is back up just a little bit, is the first significant increase in drag. The aerodynamic control surfaces begin to work against that aerodynamic drag. The vehicle has no problem at this point maintaining the proper attitude, the proper angle of attack, and a proper roll angle; but it is beginning to work at it.

At Time 54:20, there is a fairly significant aerodynamic change as the vehicle begins to work considerably harder. There are debris-shedding events during this period of time, but we can't relate them directly. By two minutes later, at 56:16, the wheel well temperatures, temperatures along the wheel itself begin to rise, and so now we know that the heat is into the wheel well itself.

Next. 58:09, there is another aerodynamic change in the aerodynamic surfaces, accompanied by more debris-shedding events. By 58:56, all of the tire pressures and temperature measurements in the left main landing gear wheel well are lost, due to damage in there, mostly to cutting of wires and sensors.

At 59:29 there was a major aerodynamic event which causes the shuttle to bring its nose down. It wants to roll left which, when you're at a 70-degree roll angle, that means down. This causes all four of the RCS jets on the starboard side to fire to try to counteract that. Of course, the loss of signal occurred at 59:32. The MADS recorder continued for another 30 seconds or 40 seconds; but as we indicated before, there was nothing particularly significant in that additional 40 seconds.

So that is the scenario that we've agreed on as to how this orbiter failed; and as I indicated in my preliminary comments, the real value of this is that it tells us what to do now and where to go next.

If I could have the next viewgraph, please. We have now listed -- and it's in the little handout that we've given you. We've listed the areas that we're going to focus on, the areas of analysis and the areas that are in work by both us and NASA that we want to put some more steam into so that we can get some of these things answered. We've listed them. I won't read them all, but they are the foam impact testing that's very important to us. We have to continue the very, very hard work on the aerothermal analyses to correlate some of these events that we have really good data on but yet we can't quite fully understand everything that's happening, like how long does it take to burn through Kapton wiring, how long does it take to create a knife edge in a piece of RCC that's a third of an inch thick, how long does it take to burn through aluminum skin, and those kinds of things. So we have really good data on this, and so we need to work real hard at fully understanding this.

As was mentioned this morning, there are several skin temperature anomalies where some of the skin temperatures up on the fuselage actually get cooler than normal and return to hotter than normal. That is pretty easily explained by a change in the flux, the flow around the orbiter to where a hot spot which is normally located at one place moves; and that is probably accounted for by a change in the geometry of the wing. We have a lot more analysis to do before we're able to say anything specifically about that.

And then continued forensic testing on the debris. We have all this wonderful debris down there. We are doing several things with it, including building a 3-D model with the debris with have. A lot more chemical analysis, metallurgical testing of the debris, and including more dissecting of foam and a better understanding of the cryopumping issues.

So that is in viewgraph form, which we have also typed up in a printed form, and all of these will be posted on our website and we are now ready to answer questions.

LT. COL. WOODYARD: Okay. We'll begin right here in Houston. We'll start on the end.

A REPORTER: ABC News. Admiral Gehman. I'm a little bit off topic; but because I get one question, I have to go with this. The missions operation director last week released their report on what they thought they could have done, if anything. It was very limited in scope. We had chatted briefly about what the board thought its involvement would be in those kind of scenarios. Given that report, are you looking at readdressing this issue down the road?

ADM. GEHMAN: I have to say that the board is not finished with that level of inquiry, and I really don't know how the board is going to express itself on what could have been done. Anything I said would be getting out in front of the board, because we have not spoken on that.

I don't have any comment on the study that NASA did. I mean, it was good that they did this and it would have had to be done anyway, but I don't really have any comment on it because we put things like that in kind of the second tier of priorities. Whether or not we address ourselves to that or not, I'm just going to duck that question because it hasn't come up yet.

A REPORTER: Orlando Sentinel. For Admiral Gehman also. The foam impact tests at Southwest Research. If the results of those show that it's unlikely that damage could have been done on the scale that you would need for it to have been done to make the scenario work, what does that do to not only the scenario but the entire sort of investigation? I mean, do you go back to Square 1? Where does that leave you?

ADM. GEHMAN: We are very careful in our work to not have a scenario-dependent investigation unless we can prove it. We are very careful to make sure that our scenario and our working hypothesis cannot be contradicted by a confirmed fact, but we're very careful to make sure that we don't have a scenario-dependent investigation. If we find areas of safety or risk assessment or budgets or oversight or quality control that we think need to be improved in order to make the shuttle safer to fly, our report will be rich and complete in that we cover all these subjects and not be dependent upon whether or not the foam broke the RCC or not.

If we find, for example, that we feel that the fault originated in the leading edge system in some way and then we start to look at such things as whether or not the aging of the leading edge system has been properly measured, we can make a recommendation that would make the shuttle safer to fly because NASA would understand the characteristics of the aging process better and it wouldn't be dependent on what broke -- keeping in mind that, as I have said before, we may hit the RCC, for example, a good hard shot and the RCC does fine and the bolts break or the linkages break or something like that. So we're being very careful not to have a scenario-dependent investigation, particularly since at this time we can't prove beyond a reasonable doubt what initiated this thing.

A REPORTER: Associated Press. Can you describe or characterize the level of agreement with members of the board on this particular scenario or, alternatively, could you quantify your level of certainty so far as your conclusions here?

ADM. GEHMAN: We have been working on developing this scenario for about ten days and in that ten days we have attempted to build the scenario general enough and generic enough that we have embraced everybody's opinion and anytime that we had a fairly large or fairly strong view one way or another, we either have accommodated that or we left it out. In other words, there's all kinds of data and work going on in this investigation that's not included in this scenario. So I would say we have a very, very high degree of agreement that this working scenario is something that everybody can live with. Remember my caveat at the beginning. The reason we call it a working hypothesis is because we reserve the right to change any part of it at any time without any notice. So with that caveat, it's hard not to agree with it.

A REPORTER: USA Today. Just for the record, Admiral, it seems to me, in looking through this, that you do not ascribe a root cause -- that's probably the wrong language, a cause -- do you not draw any link --

ADM. GEHMAN: Direct cause.

A REPORTER: Yes, direct cause. You do not find any link between the events on launch and what happened. Am I right in thinking that; and, if I am right, when did you expect to have a direct cause?

ADM. GEHMAN: You are correct. We're careful not to say that the foam knocked a hole in the leading edge of the orbiter, because we can't prove it. Now, that's not to say we don't believe that's what happened, but we were careful here to base our working scenario on agreed facts. And right now we aren't willing to make that kind of a statement.

It's too early to characterize how the board will form the words that describe the direct cause. I mean, whether we say "most likely," "we are sure," "probably," "maybe," "could have been," "would have been" -- I mean, I don't know how strongly the board will characterize the cause chain here. I would say that the board is certainly leaning in the direction or the board is certainly suspicious that the foam had something to do with this, but we were very careful in here to not make a statement that we couldn't live with.

A REPORTER: CBS News. Maybe Dr. Widnall can answer this. I don't know. But the two things that survive the radar cross-section and ballistics analysis -- to date, anyway -- are the T-seal or large piece of a RCC fragment. I mean, the sizes of these things are pretty different in terms of the resulting hole you would have in the leading edge. I was just wondering how the date or the timing of sensor failures -- would it be easier to believe it if you had a big hole, like a 120-square-inch piece of RCC, or this 1.8-inch gap or whatever it is. I don't understand. I mean, it would seem intuitively to a non-expert it would be pretty easy to pick which one of those would explain the data.

DR. WIDNALL: Well, my understanding is that NASA is, in fact, doing specific analysis for those different shapes, sort of two-dimensional analysis for the slit and then -- I think my understanding is that the hole sizes they have been using to date are quite a bit smaller than the RCC panel that was suggested in the Wright Patterson radar tests. So I think more analysis is clearly required.

ADM. GEHMAN: I'd expand on that by saying that this is one of the key areas that we're going to continue to focus on and the way I like to describe it is that the breach that was there at the time of entry has to be big enough to cause the heat scenario that we saw but it also has to be small enough that permitted the orbiter to get all the way to Texas. So keeping in mind that we've got some bounds in there and we've got a very, very rich time line, I believe that we've got a good chance of achieving the analysis it's going to take to be more specific about this; but we're talking about weeks of work here. It's just plain hard work.

A REPORTER: NBC. Admiral, looking at the issue of the direct cause versus the contributory causes to -- possibly connecting the foam impact with the breach, can you discuss for us the various contributory causes to the unobserved weakening perhaps of structure that could have combined with an impact to lead to a breach? What sorts of options have you been looking at and what kind of interesting things have you found?

ADM. GEHMAN: The way the board is going to structure the report is we're going to attempt to state -- we're going to use three or four layers of causes. The first level is going to be at what we're calling a direct cause; and this would be, for example, if we were to come to the conclusion that the foam striking the leading edge put a hole in it. Then that would be either the direct cause or the physical cause or the mechanical cause of this accident.

At the second level, we're going to use the term "contributing factors." Not causes. Contributing factors. Those would be such things as a weakening of the leading edge. They might be things such as quality control at the shop floor or the construction processes in building the ramp in the first place or budget constraints or something like that.

Then at the third level, we're going to have what we're calling the root cause. This may not be the way the safety experts do this, but the root causes are the cultural kinds of things -- the age of the orbiter, the budgets, the manpower, the climate, the management systems that the program operates in. The climate. The background kinds of things. Attitudes.

Then at the fourth level, the board is free and is charged to make what we are calling any significant observations. This would be any observation that the board members make that may have nothing to do with the shuttle program. It may be something that we noticed when we were visiting at one of the plants or factories or centers and we just felt that NASA would benefit from us saying that this hasn't got anything to do with the loss of Columbia but we did notice something.

As far as giving you a list of possible contributing factors at this time, it would be fairly premature, but I certainly can say that things that we have under consideration are things like crew performance, whether they made a mistake or not. The payload would be a contributing factor. Maybe. Maybe not. What I'm saying is that they are contributing factors and we would say that they're non-causal. In other words, the payload, for example, we will have examined in great detail to see whether or not it was a contributing factor, and then in the report we will say whether or not it had anything to do with this or not. But it will be in the report.

Weather. Space weather. Micrometeorites. I mean, I do have any list with me, but I'm not going to get any more detailed than that. But I would suggest that we probably will end up with , 12, 15 factors that we will address in the report and we will then adjudicate whether or not we believe they had anything to do with this or not.

LT. COL. WOODYARD: Any other questions from Houston?

A REPORTER: New York Times. I just wanted to ask whether there's any significant difference between the working scenario you're laying out here today and the NASA briefing which you recently received, that lays out what they came up with as a working scenario. Where's the daylight here between these two versions?

ADM. GEHMAN: There is no daylight, and that is the purpose of us massaging this for the past ten days. We have been meeting at the working level, as well as the leadership level, to make sure that there is only one working scenario. That's what we did. That's what we've been doing for the last ten days. As of this afternoon, this is the working scenario. You know how it is. Every time we announce something, then we go find another piece of debris and it changes. But there is no daylight and we have worked hard to make sure that the whole organization is speaking with the same script at this time.

A REPORTER: Washington Post. Just sort of a variation on the earlier question. If the tests show that the foam strike doesn't turn out to be the cause of the breach, what would be the strongest backup theory as to what would happen; and are you determined to continue the investigation until you're able to say definitively what was the cause?

ADM. GEHMAN: No. I have to answer both questions in the negative. Even if the foam impact testing does not break any of the leading edge systems to the degree that it creates a plausible hole -- or let me take the other side. Even if the foam impact testing does break the RCC or does break the leading edge system, that doesn't prove that that's what happened. It just proves that it could have happened. It's just like radar cross-section testing of the Flight Day 2 events. If we conclude that it could have been a part of an RCC panel, that doesn't prove it was part of an RCC panel. It just proves it could have been. So the foam impact testing will demonstrate to us whether or not we have a plausible scenario or not, but it doesn't seem to me that it will prove anything one way or another. Therefore, the report doesn't hang on that -- at least in my mind, it doesn't.

A REPORTER: Houston Chronicle. I guess I'm backing up a little bit with my question. I just want to make sure that I sort of understand your thinking on why it's important, beyond just good investigative analysis, not to reach for the foam right now if it's not there. I guess I'm thinking in the context of how NASA would respond to change the way the orbiter is constructed or prepared for flight or actually the flights are executed.

ADM. GEHMAN: I don't understand your question about why don't we latch onto the foam.

A REPORTER: Yes. Why don't you latch onto it?

ADM. GEHMAN: You mean why don't we state that the foam caused a hole --

A REPORTER: No, I understand that. Beyond good investigative technique, why would it be bad for the space program to be premature in taking that position? I guess I'm trying to explain, to people who are lay, why you're not going there yet.

ADM. GEHMAN: Okay. Let me see if I can answer it this way. Anything that has to do with an event which the orbiter is not supposed to be subjected to, which includes being struck by debris, is being analyzed and examined very, very carefully by the board, up to and including taking a foam object about the size that came off and actually firing it at the leading edge. And we may come to the conclusion that no foam should strike the orbiter. And I think NASA knows that and, I mean, that will be a blinding display of the obvious.

We are going after every single aspect of the foam hitting the orbiter -- and every other anomaly that's happened on ascent -- with a lot of rigor. I don't believe that it's necessary for us to state at this time that the foam strike causing a fatal flaw in the orbiter is necessary to energize the investigation. As we said, our scenario is based on things we know. The one thing that we did in our scenario is we made sure that we have no facts that would contradict our scenario. So that's still a possibility, but I don't think it's necessary for us to move forward.

GEN. DEAL: If I can inject on that, sir, there is extensive, extensive work already going on that the board is closely monitoring at Marshall Space Center, not just the dissection of the tanks but also the redesign of the bipod ramp, for example, looking at the flange and the ramped area on the tank as well. Plus the most extensive work is in different types of NDE, non-destructive examination of the tank itself and the foam. So we're monitoring that very closely, and we have an entire foam team made up from members of the entire board that are going to and from Marshall and working with them on a daily basis.

ADM. GEHMAN: That's very pertinent and very relevant because it illustrates that everything that we think is related to this damage scenario is being investigated and reviewed and recommendations are being considered and whether or not we state that the foam caused this chain, I don't think, in any way lessens the urgency by which we're going after all these things.

LT. COL. WOODYARD: Okay. We'll go to the phone bridge.

A REPORTER: A question for Admiral Gehman. It would be very helpful to visualize this, if you wouldn't mind pointing out on the model of the wing right where Panels 8 and 9 and the T-seal are and showing where you're theorizing the strike was and the path of the hot air or plasma.


(Indicating) All right. This is the under side of the left wing. This is forward. This is outboard. This is aft obviously. This is RCC No. 9 right here. This is the wheel well with the landing gear obviously. This is RCC No. 9. This is RCC No. 8. This is the T-seal between 8 and 9. This goes 7, 8, 9, , like that. What we are indicating is that whether the breach is in 8 or 9, right in here, that once you get in here, you're free to move about. The heat can go through here and then work its way. As a matter of fact, these things come off.

Wait a minute. I misspoke. This is 8 right here -- 7, 8, 9. This is 8 that we were referring to and the idea is that -- these things come off, by the way, if I can do this without breaking this wonderful model. The idea is that once you get through here -- they're magnetic -- once you get through here, then you burn through the spar. Then once you burn through the spar, you're into here.

What we are hypothesizing is that the breach is on the under side here, on one of these under sides and then goes through the spar. That's what we were hypothesizing. Then once it gets new here, this is all open. You can go through here. These are just little struts, and the heat can go any way it wants to and then starts cutting wires. There are wires that run along here. There's a big wire bundle that runs along here on the top. In fact, you can see it. Here's the wire bundle that runs along here. Once the heat gets in here, it starts cutting wires. I hope that answers your question.

LT. COL. WOODYARD: Next question on the phone bridge.

A REPORTER: Los Angeles Times. Admiral Gehman, do you have a working scenario for why NASA had a half-dozen foam strikes that originated in the area of the bipod ramp and that all apparently violated its launch criteria and yet it continued not to regard that as a safety problem and do you have a working hypothesis for why during the mission dozens of engineers convened a meeting and concluded that the foam strike was serious enough to warrant photographs to be taken and that was never executed by management?

ADM. GEHMAN: General Hess and his group are looking at that very hard. I'll let him answer that.

GEN. HESS: I think the best way I can answer your question is to talk about it in terms of over time there were many changes made to the external processes of applying the foam to include the type of blowing agent that were used as well as looking at ways to stop the popcorning of foam off as it was hitting the orbiter. So I wouldn't characterize that NASA took no action to abate the foam strikes over time.

As we have looked at the Flight Readiness Review in preparing for the COFR for various flights, we found quite a bit of detail in terms of how they discussed the foam issues; and they have a piece of hazard analysis that they conducted that kind of led them to believe that there would be no safety-of-flight issue with regards to foam coming off of the orbiter. I'm not willing to characterize this as just kind of a normalization at this point but they were working the problem but over time they became, I think, very used to the fact that foam was coming off and they never had a disastrous outcome as a result of it. So that probably led them to believe that they could continue to try to work the foam problem in some way without any adverse effects to the shuttle.

Now, with regards to the engineers that were working and the E-mails that you're talking about and the requests for imagery, we are fairly certain that the damage assessment team that was working the problem of this particular mission was attempting to get DOD imagery because they needed to be able to characterize the level of damage to the wing in order to complete their analysis. There were other people inside the NASA organization who had requested an opportunity for the DOD imagery; and inside the NASA decision-making apparatus, the MMT and below, the two requirements kind of ran into one another. When they did, they canceled each other out because it was never realized by management that the request for imagery really was coming from the damage assessment team, because the communication was not totally clear there. They thought that the request was coming from kind of outside Johnson Space Center, like from Kennedy; and we're trying to nail down at the management level who was asking for the requirement and it was never made clear to them that the people who wanted the requirement were actually the damage assessment team altogether.

So as a consequence they said, well, we haven't asked for an image. That message got back to the damage assessment team as, no, we're not going to let you get an image; and that was really the wrong message to be sent. At the end of the day, what happened was that everybody went back and did the best they could with the information they had and never moved forward or pursued down to the root exactly who was asking for an image and why there was all this pressure that was down at the working level.

I'd also say that by the time they were briefing the mission management people, they did brief them in a very short fashion that there was no safety-of-flight issue and that even though that there could be pretty serious damage to the orbiter, it was the consensus of the working group that it was not a safety-of-flight problem. So all this served to be a pretty good deal of miscommunication about the problem altogether.

LT. COL. WOODYARD: Next question from our phone bridge.

A REPORTER: Newsday. For Admiral Gehman. If you can't say for sure that the foam did the damage, what are the implications for return to flight? I mean will fixing the bipod and doing better NDE on the RCC panels be sufficient?

ADM. GEHMAN: Those two things alone won't be sufficient, but we can make a fairly good case of what we think the return-to-flight criteria should be, with or without any positive knowledge or positive proof that the foam caused the accident, because we are going to make return-to-flight recommendations which are designed to enhance the safety of the orbiter in every way that we find that it needs to be enhanced. Just fixing the foam alone won't do it.

So I'm not in the least bit concerned that our inability to make a positive statement with proof that the foam knocked a hole in the leading edge of the orbiter in any way slows us up or in any way restricts what we need to do in order to come up with criteria for return to flight. Most of our work or most of our thought processes on return-to-flight issues have to do with the fact that the safety margins have been changed over the years, and we're going to try and restore those safety margins back at least to where we're comfortable with them.

A REPORTER: Aviation Week. I have what you might call a fairly fundamental question on quality control for General Deal. Correct me if I'm wrong; but philosophically at least, the shift to the contractor, United Space Alliance, was to have freed up NASA personnel for more broader oversight. Now that you've looked at it for two to three months here, can you characterize whether this was actually occurring effectively?

GEN. DEAL: Well, you'd have to look in the bigger context. That's a great question, because there's been many, many changes as you go through looking at the history of it and how they have gone down in the number of GMIPs that were put out, Government Mandatory Inspections Points, and how they've actually added on some more since them. You'd have to go even deeper to look at the manning that they have there and what they are tasked to do. We're to the point now where we're ready to present some things to the board to reference that because they have moved toward some things that are in light of ISO 9000 and some other types of quality progressions where you're doing sampling versus doing a continual look at something that only flies once or twice a year. So we're looking very heavily at that as to whether that is the right answer for a program like this that's manned space flight.

Effective? If you look at the number of rejects that they have and their metrics that they have, it's pretty good. However, is it up at the level that it should be? That's what we're looking at. I'd be hesitant to give you an answer today on that because we still have more analysis to do and more metrics that we're receiving.

ADM. GEHMAN: But that will be a significant part of the board's report.

A REPORTER: New York Times. Admiral Gehman, if you don't conclusively connect the foam strike to the damage, do you raise a permanent doubt about whether the shuttle with fixed foam is, in fact, safe to fly in the future?

ADM. GEHMAN: I don't think so. It's the board's view that our review of this program is so much wider than that, and this is one area in which we differ from the Challenger investigation. Our review is considerably wider than foam striking the leading edge. It has to be, since we can't be absolutely sure that that's the direct cause. Therefore we believe that we have a good chance of coming up with recommendations that will, indeed, make the orbiter safe, the shuttle safe fly. I mean, that's our goal is to come up with a number of recommendations that cover a broad area of the program, not just foam striking the leading edge. That's why, for example, you heard these comments about quality assurance and committees and boards and organization.

General Hess, do you want to follow up on that?

GEN. HESS: I think it would be important to add at this point that the board is never going to make the shuttle program risk-free. It's always going to be risk-risk trade-offs; and at the end of the day whenever they decide to fly a mission, they're going to be accepting a high degree of risk in a lot of areas. So I think it would be a little bit naive of us to think that we were going to be, by our proceedings, able to give them a zero-risk program.

ADM. GEHMAN: That's absolutely right. I know that is an obscure and complex issue in the sense that we don't have any concrete, irrefutable proof that the foam striking the leading edge was the cause of this accident yet and then for me to say that it really doesn't make much difference to the board; but that's the truth. The truth is that we are looking at this program and these shuttles in a very, very broad way. We have to because we don't have a single-point failure like the O-rings. Therefore we're going to come up with a broad range of recommendations which, taken together, we believe, will make the program safer. The fact that we don't have a single causal event doesn't bother me in the least -- I don't know about my fellow board members. It may not be quite so easy to explain; but practice-wise and function-wise, it doesn't bother me in the least.

A REPORTER: Discovery Channel. Admiral Gehman, what would constitute the concrete, irrefutable proof that the foam strike did cause the breach?

ADM. GEHMAN: We've actually asked ourselves that a couple of times: What would it take to prove that the foam did it? Obviously if we had a picture, that would be nice. That's why this morning when we had the ascent experts here and the video reconstruction experts going over this with some detail, we brought this issue out and we dragged this issue out. That would be nice. If we found a piece of debris, if we found a piece of leading edge RCC with a lot of foam embedded in it, that might convince us of something. But the answer is I'm not sure what it would take to prove that the foam did it.

As we have said two or three times already today, even in the foam impact testing, if we do major damage to the leading edge system, that still doesn't prove it. That just proves it's plausible. So those are two things that pop into my mind. I don't know if there's any others, but we would love to find some evidence like that but it isn't out there, I don't think.

A REPORTER: NASA Watch. A very simple question. You brought up the issue of the fact that this is never going to be risk-free, but is the panel going to endorse any specific safety-of-risk number that NASA uses, encourage NASA to go back and revalidate that, or make any statement on the specific level of risk that is acceptable?

ADM. GEHMAN: The board is going to attempt to characterize the true risk in our own words. Now, whether or not we put a number on that, the board hasn't decided; but we are going to attempt to describe for our constituents -- the Congress and the administration and the astronauts and the people of the United States -- what the risk is in this enterprise.

As General Hess said, it's not zero. It's not anywhere near zero. I don't know that the board would be interested in putting a number on it. Maybe we would. We haven't got that far yet. And we certainly would not -- well, I better be careful what I say here because I don't know this to be a fact -- whether or not we pass judgment on any number that NASA uses remains to be seen. But we will attempt to characterize the risk in our own terms. If it differs from NASA's, so be it; but that will be one of our goals, to restate the risk in terms that there can be a good public policy debate on whether or not we should be doing this or not.

LT. COL. WOODYARD: One more here in Houston.

A REPORTER: Stern Magazine, Hamburg. I heard conflicting versions to which extent the crew was informed about the foam impact and the discussion that followed. Could you clarify this for me, exactly what exchange took place and when did it happen?

GEN. HESS: Yes. I can't remember exactly which flight day it was, but there was a scheduled press event with the crew. In the day prior, there was an E-mail sent up to them that said they had a foam strike on the orbiter on ascent; and then they also E-mailed up to them an impact file that showed the same images that we saw earlier today with the debris striking the shuttle. They were also advised by the NASA management that they didn't think that there was a safety-of-flight problem. So they were very much aware that the strike had occurred.

LT. COL. WOODYARD: Any other questions from Houston? If not, that will conclude today's press briefing. We thank you for coming; and again, as always, the board members will remain here to answer a few more questions. Thank you.

(Press conference concluded at 2:15 p.m.)

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