CAIB News Conference NASA JSC 25 Feb 2003 – Part 2
STAFF: Do you have a question?
QUESTION: How much of the left wing have you actually recovered? And what does that tell you, what you have recovered from the left wing?
GEHMAN: I believe that the number of debris that we have recovered is 8,110 pieces total, of which 5,297 have been identified. That’s total.
Once again, as I mentioned last week, probably weight is more significant than numbers because some of them are little chips. We are over 10 percent of the weight of the vehicle.
And if you were to look at the floor and look at the left wing, it’s not impressive. What I mean is, not a lot of the area is covered. So a small part of the left wing has been recovered. A small fraction of the left wing has been recovered.
QUESTION: Is it enough to tell you anything?
GEHMAN: Not yet. Not yet. But debris still comes in. And as you can see from this tile, we’ll learn something from this tile. And we’ll learn something from the next one too.
QUESTION: What do you know about the object, the mysterious object that was seen trailing the shuttle some 24 hours after it came into orbit? And also, what information do you get on this and other matters from DOD assets, please?
GEHMAN: I’ll let General Deal with that.
DEAL: Well, it’s important to note that it wasn’t seen 24 hours later. It was seen on a delog, an extensive delog of the tapes after the mishap. So . . .
QUESTION: What does delog mean?
DEAL: That’s where you go back and you look at all the tapes of all the observations throughout the shuttle’s 200-some odd, 50-some odd revolutions around the Earth. There were nearly 3,200 observations.
Now an observation does not mean you are tracking it very closely. That means that, okay, you know the shuttle is coming overhead. You get a radar track on it. And then it passes. So that’s an observation.
What happened after the mishap is the people in the Space Command went back and they started doing what is called a delog. That’s where you look at every single observation as fine tooth as you possibly can. And I can tell you, it’s been the most laborious examination that’s ever taken place in the history of Space Command, looking at every single one of those observations.
And then on the–I believe it was the 6th of February is when they had enough analysis to say, “Okay, something is there.” And then further analysis, which has gone further now, is it appears to be a piece about .3 meters by .4 meters of undetermined composition. As a matter of fact, the Air Force Research Lab at Wright Patterson Air Force Base is going to be working with NASA to do some tests, based on radar reflectivity, of what type of material it could be.
So that test is not underway yet. But that’s on the books to take place.
So they followed this piece. And it was characteristic of something accompanying the shuttle. And then it started to separate from the shuttle. It started–it was initially semi-stable, in a slow rotation.
Then as the shuttle went away, it had no propellant and it didn’t stay with the shuttle, making its maneuvers. And it did a characteristic re-entry of something of that size.
And on the 20th, it re-entered over the South Pacific. So that’s what we know right now. More tests are ongoing to determine what it was. It does not have the characteristics of being anything dense.
It has the characteristics of being some type of lightweight piece of that size that I told you. So again, that was not seen by anyone on the second day. It was seen afterwards, as they went back and did the delog?
QUESTION: Anything else coming from other DOD assets?
DEAL: DOD has provided information that has helped on the timeline that NASA has reconstructed. And they have been helping in numbers of ways, from providing additional analysis to having National Guard troops on the ground looking for debris.
I mean, I could go into a long list of different things DOD has provided. But as far as the timeline itself, they have provided whatever data that they have to NASA. And they have used it in building their timeline.
QUESTION: General Deal, you referred to a series of interviews that you have now begun. I’m wondering whether the order in which you are doing those interviews, the areas in which you’re examining, is that essentially arbitrary, based on the availability of people? Or does it reflect the strength of your interest in one area of inquiry, such as aging aircraft?
DEAL: Initially, we’re starting out, as we mentioned, wide. And we’re starting to go deeper. We’re starting at higher levels, with those that are easily available targets right here. I hesitate to use the word target–but interviewees.
And we’ll work with them. And they are all giving us names of people. And we’re building our interview list based upon that.
And it’s also something we’re sharing with the rest of the groups because we also have some common things that we need to ask of certain people so that, as we’re asking one individual, they may have another member of their group in our interview at the same time.
We are starting to drill down, if that answers your question. It’s going to take us to get a little bit smarter, and that’s what we’re doing on the road this week, with some of the systems themselves, so that we can then pull in some people and say, “We have been through this maintenance data. This is our conclusion.” Can you comment on that?
QUESTION: You said that the debris was starting to tell you some interesting stories. I wonder if you can elaborate on that.
And has any of it shown evidence of any impact by space debris at this point?
GEHMAN: It has not been reported to me that we have any evidence of space debris. But it’s way too early.
The tiles that we have are pretty beat up. And it’s not until we get enough of them to put them together in some kind of order that we’re able to develop a picture of what happened.
So it’s a bit too early. But my comments were meant to encourage the continued pickup of debris because they are beginning to talk to us now. Some things are beginning to emerge. But no answers are beginning to emerge.
You must understand that you get a piece of tile here and a piece of tile here, it might not be tiles. It might be metal. And then, pretty soon, we’ll be able to connect the dots. But not yet.
QUESTION: I guess this is going to wind up being Mr. Hubbard’s question.
Could you discuss what you know, where you’re at in the whole concept of the Columbia’s left wing being rougher than the other wing? And the boundary layer transition, laminar flow, turbulent flow–all of that, as it fits into your investigation?
HUBBARD: I’ll start and we’ll follow up. The aerodynamic analysis has just begun. And very fortunate that we’ve added to the board Sheila Widnall. Aerodynamic analysis is a specialty of hers. And she has taken this on as something she wants to look at personally.
As I mentioned in my opening remarks, there have been some calculations about something called “center of pressure.” This has to do with whether or not the wing was responding in the manner in which you would expect. There is a whole series of discussions and calculations about this.
About eight different timelines and data entries were looked at. And they don’t quite agree with each other. And this is not surprising at all because we’re dealing with a regime of flow and turbulence here, which is very complex.
So I think on this one again, stay tuned. And we definitely, I think based on some of the comments by Professor Cornell, need to look at things like the roughness. Was Columbia any different than the other orbiters? What happened to it during the major orbital maintenance it went through?
And this, I think, will be an emerging story.
Ken?
HESS: Scott has pretty much echoed a good strategy for us to follow here. We think when we start looking at the operational period of the shuttle past the launch, we’ll want to do some comparisons against other Columbia re-entries. And key to it is to take a look at when the shuttle actually went through its major maintenance overhauls to see if there are actually any changes in its entry performance coming back through there.
And we’ll probably, at some time, have an opportunity to talk with the astronaut that had indicated that he felt that there was more roughness in Columbia. And we haven’t done that yet. But it’s coming.
GEHMAN: I might add that a review of many post-flight reports, many shuttle commanders report that each shuttle flies uniquely differently. The light ones, they say, are quite discernible from the heavy ones.
And several pilots, several commanders have reported this left wing roughness on Columbia. And others have said they never noticed it.
So we’re going to get to that part of it, too.
QUESTION: I wanted to know what the crew might have known during that last 32 seconds. Would they have gotten some master alarms in the cockpit so they would have been aware that the hydraulic system had failed, for instance?
And what kind of G forces would they have been feeling normally at that time? And might they have–the people who were in the mid-deck, would they have felt anything?
GEHMAN: The G forces, I’m told, as you may be aware, we have all flown simulator missions, including the re-entry. The G forces, I’m told by our astronaut instructors, who have multiple missions, are relatively light. Compared to ascent, the descent is not a vigorous ride.
The data that we have on such things as control surface operations, attitude of the craft, all appear to be operating normally. As far as we can tell, the computer was still flying the orbiter. And the yaw jets and elevons were acting to keep the orbiter in its proper attitude up until loss of signal, including the 32 seconds.
Therefore, we have no reason to believe that there were any unusual G forces involved. There is no sign that the pilot or aircraft commander took control. There is no sign of anything like that.
And of course, there is no–as of this time–there is no more voice communication in the 32 seconds. So the best we can tell is that, at loss of signal, the craft was operating properly. When I say operating properly, with the exception of these anomalies that have been reported.
But the craft attitude was right. It was on course. It was in its proper entry for a normal landing at Kennedy. And beyond that, I wouldn’t want to speculate on what the crew may have been able to see or sense.
Ken or anybody else want to follow up on that?
HESS: No, sir. I think that the G forces are going to be very, very early in the onset measured intense at this point.
QUESTION: If they had a floating pen, it would have fallen?
HESS: Perhaps. Yeah. I mean, if they have gotten to the G-onset piece there, it would be.
GEHMAN: I don’t think it would have fallen. It would have floated down.
HESS: Floated down. But it would have come down.
HUBBARD: If you put it down, it would have stayed there.
STAFF: We’re going to take two more questions and then move to the other centers. And we will come back and do follow up here after that.
QUESTION: A follow up for Doctor or General Hubbard there, please? On this data–and we’re getting a lot of the data being dribbled out–when do we expect that this last 32 seconds, you’ll have a report on what it is you have found, when you are satisfied you can’t find any more?
And can you comment specifically on the report of the four RCS jets firing? Was that in the first five seconds? And also, the reports of RCS leak alarms in the last seconds?
GEHMAN: Let me address the question of the report. And then I’ll let Scott talk about individual jets firing and things like that.
Since we don’t know where we’re going, I can’t tell you where we are. At this time in the Challenger investigation, 20-some days into the Challenger investigation, they already knew what did it. And they were busy going around finding out whether or not NASA people had done all the things they were supposed to do to prevent it.
So this is a different scenario. We don’t know what happened here.
Since we don’t know what happened, we are obliged to do a full court press on every one of these avenues–safety, flight crew performance, materiel, aerodynamics, thermodynamics, imagery reconstruction, debris reconstruction–because we don’t know where the golden nugget is going to be. So I can’t tell you when we will submit a report or anything like that, except to say that the board has talked about that, in general terms, and that we probably would follow the FAA model in which if we find a specific fault or flaw or cause, we will advise NASA of that so they can get started fixing it, at the same time, advising NASA that that’s not the end of the story, where there’s a lot more to go.
There may be multiple causes. And then, whether there is one or more direct causes, there are certainly going to be many, many contributing causes–safety, quality assurance, contractor performance, you know, et cetera, boards and committees, oversight, interdepartmental communications. I mean, I’m just making all this up, you understand?
So it’s pretty hard to–it’s hard for us to say how this is going to come out at the end. I wouldn’t want to get into any kind of a speculation on that, except to say that, in order that we can make sure that NASA gets started on fixing things, when we have a preliminary finding, we’ll say that. Of course, NASA will know it at the same time and they will already be halfway down the road.
But at least for the Congress and the president, in order to make the return to flight decision, they will know our views.
As far as which jet was firing when, Scott, do you want to take that?
HUBBARD: Sure. Let’s see, let’s deal with the first five seconds . . .
QUESTION: The four yaw jets, were they firing . . .
HUBBARD: Yes. The first two came on earlier. And then in the reconstructed five seconds, we see evidence of the third and the fourth RCS jets firing to maintain the attitude of the orbiter.
Now your second question, you will have to repeat for me.
QUESTION: Were RCS leaks detected–leak alarms detected in the last two seconds?
HUBBARD: No, there is no evidence of that of which I am aware.
STAFF: Okay.
QUESTION: Okay. I’d like you to clarify a little bit for me the last few seconds of data regarding the APU. You said that the fluid is at zero. And I’m wondering if that’s pressure, temperature, quantity, what we’re talking about?
You indicated that, at some time, all three APUs failed. Then at another point, I think you said the APUs were running. So I need a little clarification on that.
And then finally, have you looked at whether–at the point at which the orbiter broke up, whether that was going at a sufficient speed to actually vaporize a fair amount of the debris, such that you will never find it?
HUBBARD: I can comment on the first one.
(UNKNOWN): Go ahead. First, we’ll take care of APUs and reservoir levels.
HUBBARD: Right. The APUs were all running throughout the 32 seconds. They were running in the last two seconds, the auxiliary power units.
The telemetry shows that the hydraulic fluids were now at zero pressure; that is to say no pressure in the line. And the reservoirs that measure the hydraulic fluid had come down to zero percent. So it looks like the hydraulic fluid was dumped somewhere.
So the thought here is that even though the power was still there and things were turning, that there had been some failure in that period of time that affected the hydraulic lines and therefore, the fluids and the reservoirs.
GEHMAN: As far as the weather, the weather at re-entry is being looked at very, very carefully by a number of people, including independent agencies, not including NASA, because we are using the weather in our trajectory prediction of where the debris is. Our analysis of the videos and pictures of the return is getting more sophisticated.
And as you may be aware, we have asked a sheriff in Nevada to go look in a certain spot. That’s because we are now down to actually tracking piece by piece.
Now don’t get me wrong. We’re not tracking thousands. But we’ve got a couple of pieces that we have been able to track. In order to do that, we have to be aware of the upper air patterns.
And it turns out that, in general, in the south central and southwest part of the United States, on that day, it was a particularly calm and benign environment. Jet stream was relatively low. Upper altitude winds were relatively low.
But yes, we are studying the weather.
QUESTION: Was the heat of re-entry sufficient to vaporize some large portion . . .?
GEHMAN: Absolutely.
STAFF: Thank you. We’re going to take some questions from Kennedy Space Center now. If the reporters could identify themselves and give their affiliation, it would help.
