- WILLIAM P. ROGERS, Chairman
- NEIL A. ARMSTRONG, Vice Chairman
- BRIGADIER GENERAL CHARLES YEAGER
- DR. SALLY RIDE
- DR. ARTHUR WALKER
- RICHARD FEYNMAN
- DR. EUGENE COVERT
- ROBERT HOTZ
- DAVID C. ACHESON
- MAJOR GENERAL DONALD KUTYNA
- JONATHAN THOMPSON, National Aeronautics and Space Administration
- AL KEEL, Executive Director, Presidential Commission
- WILLIAM G. GRAHAM, Administrator, National Aeronautics and Space Administration
- PHILLIP CULBERTSON, National Aeronautics and Space Administration
CHAIRMAN ROGERS: If I may, I would like to call the meeting to order, please.
The first order of business is to welcome our new member, Chuck Yeager, who was not with us at our previous meetings because he was breaking another record, and I just wanted to say  how happy we are that he is here, and how pleased we are that he is a member of the Commission, and we would like to give him a hand.
CHAIRMAN ROGERS: The second thing, Chuck tells me that he has to, because of previous commitments, he has to leave tonight and is going to be gone until when?
GENERAL YEAGER: When is the Commission ending?
GENERAL YEAGER: The 7th of March.
CHAIRMAN ROGERS: Anyway, we will look forward to your safe return and the opportunity to get together with you when you come back, and take part in the most crucial aspects of this investigation.
By way of preliminary comment, let me say that I have not had a chance to meet with all the members of
the Commission since the weekend developments. I talked to some of you on the phone, but we will have the opportunity to talk a little further in executive session about some of those developments and why we felt it was desirable to have this meeting, and why we felt it was desirable to have a public meeting.
And in that connection, I want to say that the public meeting was something I think that most of us felt we had to have, and I talked to Dr. Graham, who strongly supported that position. Otherwise I would have polled everybody on the Commission before we made the decision to hold a public meeting. But in view of the time pressures and in view of the fact that that is what we wanted, I felt it was quite appropriate to go ahead with this meeting.
So what we have asked for was the production of all the documents and records that relate to the matters that involve the seals, and we realize that it is not possible on such short notice to produce all of the documents, but I am sure that NASA has attempted to give us the key documents now, and Dr. Graham has agreed that he would give the Commission not only the documents that we have available, which will be supplemented by later documents, but also that he has here today and he will provide any further witnesses that you would like to discuss the matters that we are here to discuss.
I think it goes without saying that the article in the New York Times and other articles have created an unpleasant, unfortunate situation. There is no point in dwelling on the past. The important thing is to be sure that the Commission has all the appropriate documents and all the appropriate information. It may well be that we have all learned a lesson from this, that as much as possible we would hope that NASA and NASA's officials will volunteer any information in a frank and forthright manner. We don't want to be in a position that we have to ask for everything in advance.
This is not an adversarial procedure. This Commission is not in any way adversarial, and we hope that in the future, as much as it is humanly possible, when you think information has been developed that we should know about, that you will volunteer to give us that information.
And with that short statement, I would like to call on Dr. Graham to proceed and present whatever he would like to present on behalf of NASA.
And I might also say while he is taking the podium that he has cooperated fully with us, and we have
no reason to think that we will not get full cooperation from NASA.
DR. GRAHAM: Thank you, Mr. Chairman and Commission members.
As I said in the remarks opening NASA's presentation to the Commission last Thursday, that while NASA continues to analyze the system design and the data, you can be certain that NASA will provide you with full cooperation. That is NASA's policy and my personal position as well, and that continues to be NASA's policy, and will remain that way throughout the course of this investigation.
To help that process, I have put out the following internal memorandum today that I want you to be aware of. This is to the Associate Administrator for Space Flight, Jesse Moore, who is also the head of our Internal Design Review and Data Analysis Task Force, who has the overall responsibility within NASA and to me for the conduct of our work related to the Challenger. And it says all NASA testimony should be reviewed on a word-by-word basis by a knowledgeable NASA technical review team, and this refers to testimony which has already been presented to the Commission. Should any error, partial or incomplete statement or potentially misleading statement be found, an amendment to the
testimony should be filed in order to clarify the issue of concern.
And so I want you to know that in addition to trying to give you as timely and complete a volume of information as we can during our testimony, we realize that it is possible for NASA to occasionally misspeak or to delete something inadvertently, and should that occur, we will in any case be going back over the testimony and looking at it and checking it. As soon as we find something that appears to be-to warrant an amendment to the testimony or a clarification or an addition to the testimony, we will provide that to you.
CHAIRMAN ROGERS: We are going to have a little atmospheric problem here, and so I don't want to interrupt you.
Let's see if we can get it a little cooler.
DR. GRAHAM: Mr. Chairman, NASA hereby formally submits to you all of the reports, memoranda, briefing charts and other material that we have been able to locate to date concerning issues associated with the integrity of the SRB segment seals and other things related to that part of the solid rocket performance, and assembly and operation.
And I would now transfer to you, the Commission, the
material. We will continue to search for such material. As we find it, on an incremental basis we will transmit it to you through our channels of liaison and make sure that it is called to your attention.
From this point forward, I intend to turn the conduct of the NASA presentation over to Mr. Moore. But before I do, I thought I would be willing to entertain any questions you have.
CHAIRMAN ROGERS: When did you first hear of the possibility of the story by the New York Times?
DR. GRAHAM: Mr. Chairman, I first heard of that at approximately 1:40 p.m. yesterday- Saturday.
CHAIRMAN ROGERS: And what did you do at that time?
DR. GRAHAM: At that time I called you to make you aware of the general subject that was being addressed and the possibility of a story from the New York Times, and that certain documents  appeared to be in their hands, and I also informed others within the administration that this material apparently had come into the possession of the New York Times and had the possibility of the story going forward.
CHAIRMAN ROGERS: Have you since determined whether any previous work had been done by NASA in
connection with the preparation of the story or preparing a reply to the story?
DR. GRAHAM: I believe there was an awareness, at least earlier that same day within NASA, of the story, because it was brought to me by NASA employees. There was some thought given as to how to respond to it, but no response was transmitted outside NASA at that time because it seemed appropriate that the Commission be aware of the subject before a public response was put forward.
CHAIRMAN ROGERS: So that my question is not misunderstood, I want to make it clear that obviously you can't report to the Commission every time that some newspaper is going to write a story. We wouldn't expect that. On the other hand, there are certain types of investigations which you may be aware of that seem to have particular significance, and in such event, we would hope that you would, and members of NASA would immediately let us know about it so that it didn't appear that we were taken by surprise.
Do you agree with that?
DR. GRAHAM: Very much so, Mr. Chairman. I am in complete agreement with that policy, and I have transmitted that policy to the NASA staff both before last Saturday and since last Saturday.
CHAIRMAN ROGERS: Furthermore, I want to make it clear, speaking for myself, that we don't want to react to every newspaper story because it is inevitable there will be a lot of them, and a lot of them will be unfair and unfriendly.
I guess what concerns me a little bit about it, and I hope we don't have any further discussion publicly about it, is that this seemed to go right to the heart of the matter, and it seemed to be related to the plume that was started and shown to the public, and it occurred to us that there must have been a good deal of thought in NASA about how serious a story it would be if it appeared, and therefore I would have thought that there would have been an eagerness to present it to the Commission on Thursday, and particularly on Friday, in the private session.
But with no further ado, go ahead.
DR. GRAHAM: Yes, sir. I share your view of that, and I think that further discussion addressing that issue will be given to you today.
DR. WALKER: Is any of this material specifically classified?
DR. GRAHAM: Let me ask the people who compiled it all.
Is any of this package, have you identified
any material that is classified related to this subject that isn't in the package?
MR. MOORE: No.
CHAIRMAN ROGERS: In that connection, it would be helpful to be sure that any time we are given classified information, that it is made clear to us that it is classified because otherwise we will treat it as if it is not.
MR. ACHESON: Could I ask a question?
 In the Washington Post story on Sunday, a number of theories of the accident were expounded and illustrated in that story, and whether or not any of these are probable, I assume one or more pay have associated internal correspondence, and I would like to suggest that that be submitted to this Commission in advance of any similar publicity occurrence as that of last Sunday.
DR. GRAHAM: I have also asked that NASA staff pull together all of the information that may exist in our files related to any failure modes of the SRBs and make sure that is available first to me, but very quickly then transmitted to the Commission. That subject can be enlarged even further to the extent of the tank and the orbiter itself and the ground support equipment, and if you wish, we will try to do that.
I think that we will need to realize that there will be a large volume of engineering information, concerns and issues and so on, that it may take a little bit of time to pull that together in any complete way, and there probably will be a substantial volume of information as there has to be in any complex program such as this, a constant ebb and flow of engineering design checks, information, background and so on, such as this, and I strongly agree with the Chairman that this is a particularly pertinent one and very much to the issue now.
We will continue to pull that information together across the entire system and continue to provide it to the Commission. And with your concurrence, I would like to do that in the order, SRB first, expendable tanks second, and the orbiter third, and then ground support equipment and related matters fourth, subject only to particular issues that seem to arise that might put us off the track.
We will certainly do that, and you will have that within the day.
In fact, this information is information we need to collect internally in the course of our own analyses and review, and so this operation does not constitute a major interference. In fact, it is complementary with what we are doing, and we would certainly do it in any case, and we are pleased to provide it to you.
CHAIRMAN ROGERS: Very well.
DR. GRAHAM: Thank you very much.
MR. MOORE: Mr. Chairman and members of the Commission, the data that you have before you here is data that we immediately started collecting sometime last week in preparation for the briefing of the Commission on this coming Thursday at the Kennedy Space Center. It was our intention to review that data with you at that time, as well as status reports on the data on all other areas.
Let me say up front that we are looking at all areas of the 51-L incident. We are looking at the tank, the SRB and the orbiter and so forth, and anything that we judge sensitive on those  areas we will try to clearly make it available to the Commission prior to any data that we would want to present, and so forth. We will honor Dr. Graham's request to provide that, to the best of our knowledge.
One of the things we would also like to state for the Commission is that much discussion as you have doubtless heard over the weekend about O-rings has appeared in the paper. I would like to say that O-ring erosion, which we are going to address today, is only one of several areas that we are looking at for possible scenarios, anomalous scenarios. There have been some
concerns on the O-rings. We are going to try to relate that to you today. We will provide you with any additional information that we have in our hands to support that, plus any other things.
We are looking at a lot of additional areas in addition to the O-rings. As I say, there is a lot of additional data on flight readiness reviews. We could probably stack several feet of documents on you in terms of this Commission. What we have tried to do is to excerpt some of those documents, the most relevant pieces of information here today, and as the Commission has additional questions or needs additional information, we would be glad to do our best to provide that.
I would like to do two things here, if I might. I would like to first quickly review for you the agenda that we prepared.
MR. MOORE: I trust everybody in the back can see this as well.
I am following Dr. Graham's introductory remarks. I'm planning to just give you kind of an overview of setting the stage of this whole activity, and I particularly wanted you and the Commission members to meet the people, some of the people that are involved
in the Shuttle projects, and in particular, the solid rocket booster project, not only here in my office in Washington but also at the Marshall Space Flight Center, and also several members of Morton-Thiokol who are here as well, that handle the solid rocket booster project, and we would again welcome any questions that you or the members of the Commission may have on the booster activities as we go forward.
Mike Weeks is a deputy in my office at NASA headquarters. He is the Deputy Associate Administrator with emphasis on the word "technical." Mike has been in the program for some time, since about 1979, and is very familiar with the elements of the Shuttle program.
Let me introduce Mike Weeks right here.
Then Mike will also provide for the Commission documentation that we have at NASA headquarters and some concerns that we have had over a period of time on the solid rocket motor, and in particular, on the O-rings.
Then we have also asked Larry Mulloy-and Larry, would you stand up, please? He is right here-who is the Manager of the solid rocket booster project at the Marshall Space Flight Center, to go through some technical areas with you today to give you some historical data on the solid rocket booster and some of
the performances that we have seen out of the SRB in the course of the Shuttle program.
And finally, I will have a few closing remarks, and one item that I will want to discuss here with you this afternoon, Mr. Chairman and other members, is our participation at tomorrow's session. If you can give us some insight into that, I would appreciate it.
 Let me also say before I turn this over to Mike, let me introduce some of the other people that are here.
I would like to introduce Mr. Bill Hamby, Mr. William H. Hamby. He is the Deputy Director of STS Program Integration in my office at NASA headquarters.
I would like to introduce Mr. David Winterhalter. David is the Director of Shuttle Propulsion in my office in Washington.
And I would like to introduce Irving Davids. He is with the Shuttle Propulsion division.
I would like to introduce Paul Wetzel, who is the Chief of the Solid Rocket Booster Programs at NASA headquarters.
And I would also like to introduce Paul Herr. He is in the Shuttle Propulsion Division at NASA headquarters.
And finally, with NASA, I would like to
introduce Russell Bardos, who is the Manager of Productivity Operations Support, also at NASA headquarters.
These are, in effect, a large percentage of my staff that are working in this particular area. And so I thought if you or other members of the Commission would like to ask them questions directly, we would certainly be happy to try to answer any questions the Commission has.
In addition, I have invited Dr. William Lucas, Director of Marshall Space Flight Center here today, who has responsibility for all propulsion elements on the Shuttle program.
I have introduced Larry Mulloy previously.
I would like to introduce Larry Wear now of the Marshall Space Flight Center. Larry is involved in the solid rocket motor project at Marshall. And I would like to introduce John McCarty, who is Deputy Director of Structures in the Propulsion Lab at the Marshall Space Flight Center.
Now, we have four people here from Morton-Thiokol Corporation in Utah, and I would like to introduce Allen McDonald, who is the Director of the Solid Rocket Motor Project at Thiokol; and I would like to introduce Mark Salita, who is a scientist in the Gas
Dynamics Section of Morton-Thiokol; and I would also like to introduce Donald Ketner, who is the Supervisor of the Gas Dynamics Section at Morton-Thiokol; and representing the Washington office here of Morton-Thiokol is Frank Ross.
Now, that completes the number of people that I brought here today, and with your permission, Mr. Commissioner, we will proceed with the presentation of the information that we have brought.
And I would now like to introduce Mike Weeks.
MR. WEEKS: I put this briefing together, gentlemen and members, to address first the New York Times article, and there are six documents that obviously were provided to that news media, and first I want to go through those and bring you up to speed on that. [Ref. 2/10-1]
(Viewgraph.) [Ref. 2/10-2]
MR. WEEKS: And then I will go to this chronology of things that have happened on the O-ring problem since we first ran into it. And the first time we really addressed that was way back in 1980, and I will show you that and bring you up to date.
(Viewgraph.) [Ref. 2/10-3]
MR. WEEKS: As was spoken to, and it is in your document there, the first one is the Cook memorandum, and that is a memorandum that was written on the 23rd of July, and it was prepared by the financial analysts over in the Financial Department, and the person is a financial type person and not too knowledgeable of the whole program situation. [Ref. 2/10-4]
I am going along now at page 6. I am right here (indicating) at page 6, and I guess I would suggest to you that that is a less clinical analysis of
this whole situation because the young chap came aboard about the first of July and was just picking up things in a hallway, and wrote this to his immediate superior.
CHAIRMAN ROGERS: Is he here today?
MR. WEEKS: No, he is not.
MR. MOORE: We could bring him, Mr. Chairman.
CHAIRMAN ROGERS: We didn't expect him. I was just asking. He is still employed by NASA?
MR. WEEKS: Yes, he is.
DR. COVERT: This stuff you call putty, that might be an unfortunate choice of terms. It is really an inhibitor, isn't it? The heat burning from that at the joint might fit together perfectly.
MR. WEEKS: Dr. Lucas ought to handle that.
DR. COVERT: It is zinc chromate, isn't it?
DR. LUCAS: It is a zinc chromate, but it is not in an inhibitor that goes on the end of the train. It is separate from that. I think Larry Mulloy will demonstrate that for you.
MR. WEEKS: Now, the next one, Mr. Chairman and Committee, is a memo dated the 17th of July by Irv Davids over here, who I guess we gave him his 35-year pin some time ago, and he is very senior and very careful, and this is No. 2 up there. [Ref. 2/10-5]
DR. COVERT: Is it true that he changed this stuff, as Cook said, from being a sealant that has asbestos in it to being a sealant without asbestos?
 MR. WEEKS: No, I believe we still have asbestos in the system, and we eventually have to get
rid of that, and that is one of our longer term plans. But we aren't concentrating on that today. We are concentrating on O-rings.
DR. COVERT: You are concentrating on-the material that was used in this particular set of boosters was the old material and made by the old manufacturer?
MR. WEEKS: No. This is the second generation because the original vendor, and I have forgotten his name, went out of business, and we had to go to a Randolph type of one.
DR. COVERT: How many firings have you had with the new material?
MR. MULLOY: It was introduced on STS-8.
DR. COVERT: So it is about 17.
GENERAL KUTYNA: Mike, let me ask you, we used this same type of material on the Titan.
Did you change manufacturers also on the Titan?
MR. MULLOY: I do not know.
MR. WEAR: The one on the Titan is an Inmont putty, and--
MR. WEEKS: So we do not fly the Inmont putty?
MR. WEAR: No.
DR. WALKER: Is the putty supposed to be the
primary or backup seal?
MR. MULLOY: The putty is a thermal barrier, not a sealer.
MR. WEEKS: The pressure goes through the putty and gets down through the exterior of the case, and therefore that pressure of the 1000 psi in the chamber motor does go down to the 0-ring.
CHAIRMAN ROGERS: Just so you don't go too fast, let's focus up for a moment on the Cook Memorandum.
As I understand it, you are saying that he was just hired and was in a department where he really didn't have much knowledge of what was going on?
MR. WEEKS: I would believe that you should discount this to a fairly great extent because as you will see in the next memorandum of Mr. Irv Davids, who has been with our program for at least a decade, and is 30 years with the Agency, it is a very careful and thoughtful response to his memo. His memo was created because we had a failure in April of 1985 in which it is the first time in all of the program that we had the secondary seal have any difficulty, and the only time, whereas the other erosions were all in the primary seal, the primary being the one that first sees the pressure, and the secondary being the one that is backing it up,
if you will.
DR. RIDE: Which flight was that?
MR. WEEKS: That was 51-B.
GENERAL KUTYNA: Mike, you did not have charring of the secondary seal on 51
MR. WEAR: No.
MR. WEEKS: It was 51-D.
DR. RIDE: Did you see a problem with the primary seal on 51-C?
 MR. WEAR: We had some erosion on the primary seal in the K joint on 51-C. I will cover all of this later.
DR. COVERT: Did you have the same gel thickness on 51-B, C and so on?
MR. WEEKS: I believe all of these are the thinner steel casings. We started and had the first early flights with the thicker steel casings, but I believe all of the recent flights are thinner casings, and I guess they do get mixed, General.
GENERAL KUTYNA: They do get mixed. We try to use them whenever we can.
MR. HOTZ: Mr. Weeks, could you tell us whether there are any errors of fact in this memo, and if so, would you point them out?
MR. WEEKS: Which one?
MR. HOTZ: The first memo, the Cook memo.
MR. WEEKS: Could you help me out on that, Herb?
MR. MOORE: We can get Mr. Cook here if you
would like, Mr. Chairman.
CHAIRMAN ROGERS: Yes, we would like that, but let's just go ahead.
MR. MOORE: We will get an answer to that.
CHAIRMAN ROGERS: Just so we understand. I think Mr. Hotz and I asked the same questions. All right. This says: You have asked us or me to investigate reported problems, and then he says, discussions with program engineers show that these are potentially major problems affecting both flight safety and progress cost.
My question is, is what he set forth there accurate, and didn't he talk to the engineers and deduce this information? Isn't this information he got from the engineers?
MR. WEEKS: I think that his statement in here where he says that it might be catastrophic I think is overstated.
CHAIRMAN ROGERS: Well, that may be.
MR. MOORE: I think the best thing for us to do, Mr. Chairman, is to think about getting Mr. Cook here, and then we can ask Mr. Cook to sit down and try to answer your questions on this thing.
CHAIRMAN ROGERS: Yes, but we want to ask questions as we go along--
MR. HOTZ: We would also like your opinion of whether this is accurate or not. We can get a witness--
CHAIRMAN ROGERS: This is a case where you are saying, in effect, that you didn't have much confidence in this fellow because he was in the wrong department and had been there just a short time, and so we are asking is the material that he reported on accurate?
MR. WEEKS: If I may, I would like to pore over every word and come back to you.
CHAIRMAN ROGERS: Well, is it substantially accurate?
MR. WEEKS: I think it is substantially accurate.
DR. COVERT: I think the other thing, Mike, when you go through it, try to go through it from the point of view of a rather naive sort of guy who hears the words and doesn't necessarily understand all of the nuances but gets an overall picture of things. It has been my experience that sometimes people have amazing insight. Part of the problem is to understand the nuances. Thank you.
MR. WEEKS: Now, if we could go on to Irv Davids' memo, which is on page No. 9, and he is discussing there the two cases, the nozzle-to-case, which is at the back end of the booster, and the case-to-case, which there are three of those joints
along the length of it, and the one up from the bottom is the suspicious one in the movies of 51L.
CHAIRMAN ROGERS: Now, it looks to me as if this document preceded the Cook document, is that correct?
MR. WEEKS: It did, yes.
CHAIRMAN ROGERS: So this was not in response to what Mr. Cook wrote.
MR. WEEKS: That's right. This memo was written under the following circumstances. We have the secondary erosion on the flight of the 29th of April, and we asked Mr. Davids and Mr. Hamby to go to Marshall to review it because we were concerned about this being the first case of any erosion on the secondary seal. And that was a fairly small number of .032 inch in that particular case on the secondary seal on the nozzle-to-case joint.
CHAIRMAN ROGERS: Let us take this a glance at a time.
MR. MOORE: Mike, you might point out that Mr. Davids is here.
MR. WEEKS: Yes, he is here.
DR. COVERT: When you say heat affected, was it discolored?
MR. DAVIDS: Yes.
I would like to just mention that when we went down there, the secondary seal failure that we experienced, or erosion, was at the nozzle-to-case interface and not just the case-to-case.
THE CLERK: I'm sorry, Mr. David, you will have to speak up, please.
CHAIRMAN ROGERS: Excuse me. Would you want to swear the witness in, please?
And this is what we do for all witnesses. This is nothing personal.
THE CLERK: Do you swear the testimony you will give this Commission will be the truth, the whole truth, and nothing but the truth, so help you God?
MR. DAVIDS: I do.
CHAIRMAN ROGERS: This gentleman is a court stenographer, and he has to record what you are saying. So if you could speak a little louder, please.
MR. DAVIDS: I just wanted you to understand that the secondary seal that Mike was alluding to, with the type of erosion that we had was at the case-to-the-nozzle interface and not the case-to-case. That is significant to what we are talking about.
However, when we got that problem due to the
fact that it was a secondary seal, we thought we had better go down to Marshall and go through the entire area of seals to see what we were doing and what kind of problem we were having, and that is what initiated our visit to the Marshall Space Flight Center. And you will note from the memorandum that we did point out that there was certain-that we did experience some O-ring erosion of the primary O-ring on the case-to-case seals, and the nozzle-to-case seals. And what I wanted to do was obtain all the data that was available so we had a pretty good history of what kind of failure or erosion we were getting on the seals and make sure that all of this data was brought up to top management so that we all were well aware of what the problem was that existed, and we would try to get some pressure to accelerate trying to think about what we could do about clearing up this potential problem that we had, and that was the real intent of why we went down to Marshall.
 CHAIRMAN ROGERS: What is the pleasure of the Commission? Would you like to ask Mr. Davids some questions about this memorandum now, or would you want to come back and ask him questions later?
MR. ACHESON: I would like to ask one.
This memorandum refers in the B heading on page 2 to unseating of the secondary O-ring during joint rotation.
Is there a measurement of joint rotation made during flight?
MR. DAVIDS: There is no measurement taken, but Mr. Mulloy in his presentation is going to cover that area very specifically. We actually have a joint to show you what the joint rotation is all about, but we have no measurable measurement at all of that.
MR. WEEKS: Not in flight, but as he will show you it has been measured on the ground a couple of times in full scale motors.
DR. COVERT: The suit blow-bye, is that case to case, or case to nozzle?
MR. DAVIDS: That was two cases by the primary seals. If you look at my memo, you will find that the first part of it is just nozzle to case, and the second part of it is case to case. So I specifically separate the two.
DR. WALKER: Do you have a thermal model of what temperatures different parts of the assemblies see, and do you have any measurements of temperature of the various parts such as during firing, etc.?
MR. DAVIDS: I assume we have that.
MR. MULLOY: We do have a thermal model that shows some gradients of temperature, including the motor through the propellant through the
insulation, through the liner, into the case.
DR. WALKER: Could we have a copy of that?
MR. MULLOY: We can show you some results, yes, sir.
DR. WALKER: You have measurements, too?
MR. MULLOY: No, we do not have any direct temperature measurements.
MR. WEEKS: I am sorry, but I thought we measured some on the static firing out at Morton-Thiokol's factory. We have had many static tests. The static test is a single motor that is fired on the ground horizontally, and I thought we measured a number of temperatures during those early development cases.
Didn't we measure the temperature on the outside?
Well, we will dig into that.
MR. MOORE: Mr. Walker, we will provide you the data on thermal models as well as actual measurements that have been made.
GENERAL KUTYNA: Mike, this letter by Mr. Davids says the prime suspect is the type of putty used, and he notes that you changed manufacturers after STS-10, yet there was erosion way back in 1980, well before this change in putty on STS-10.
So how do you tie the erosion to the change in manufacturer of the putty if you had that problem before?
MR. DAVIDS: I think Larry will clarify this. If you look at all of the O-ring erosion that we have seen, you find you can actually follow a path through the putty that goes to the spot where  the O-ring erosion occurs. And so it is obvious that you are getting some blow-by through that putty to the point where the erosion occurs, and so you see a clear trace between the erosion and the putty itself.
Now, your question about why we didn't have it on STS-10, I guess my answer would be that we don't have erosion on every flight. There are times when we don't have it and times we did have it.
GENERAL KUTYNA: No, I misstated my question or you misunderstood.
You had erosion prior to changing this putty. Therefore, you had these blow holes or whatever you call them, through the old putty, which you claim was good putty, and now you are saying that after STS-10 you changed putty and therefore you had a problem.
Did you have it beforehand? Is that not true?
MR. DAVIDS: I guess that is true.
MR. WEEKS: You are reading where putty is the
prime cause of the erosion, General?
GENERAL KUTYNA: Yes. And I am asking, you had this problem as early as 1980, well before this time, well before the time you changed manufacturers.
DR. COVERT: When you say you received these things, I assume that when it comes back after it is hauled out of the ocean, and this comes from disassembly and refurbishment--
MR. DAVIDS: That is correct.
DR. COVERT: - and you take it apart very carefully to make sure that you don't interfere with anything of the visual data?
MR. DAVIDS: That is correct.
MR. WEEKS: In fact, that is, of course, one of the neat things about the Shuttle is this is the first time in history we have been bringing these things back. The Titan, of course, the only thing we can look at there on erosion is the firings they have had on the ground.
CHAIRMAN ROGERS: Do you happen to know whether there is any connection between these two memoranda, or did they just happen to be about the same time?
MR. DAVIDS: I didn't know anything about the Cook memorandum. I had never seen the Cook memorandum.
MR. WEEKS: The only connection is that in the New York Times article I elected to put them in the order of their occurrence in the article as just a way of formatting this. [Ref. 2/10-6]
Number one, as you will see in there, it shows up in the article on the second page in your handout up at the top where Mr. Cook, down about the middle of the second page is Roman number II which is Irv Davids' memo, and number III is the budget briefing that is spoken to on August 21 and then September 10 shows one of mine, which is the Propulsion Division of Mr. Winterhalter's internal preparation, preparing to come to Jess Moore, which is the next one.
The way we organize every month in the office is that we get the financial data, and then each division, the Propulsion Division, the Orbiter Division, etc., prepare their charts in their own house, and then it is brought to Jess Moore, and then after that we carry it to the Administrator, which is the final thing around the 17th, 18th of the month. And so we go through this ritual every month of how we do this thing. [Ref. 2/10-7]
CHAIRMAN ROGERS: Let me go back just one moment to the Cook memorandum. You will notice at the end of that he ties safety to budgetary considerations.
He said I would think that any NASA budget submitted this year for fiscal year 1987 and beyond should certainly be based on a reliable judgment as to the cause of the SRB seal problem and a corresponding decision as to budgetary action needed to provide for its solution.
Do you know whether any such action was taken or consideration was given to his memorandum on that point?
MR. WEEKS: I can state authoritatively that no action-I think this is true of Mr. Moore as well, because I didn't see this memorandum until yesterday.
CHAIRMAN ROGERS: Do you know whether anybody else took it seriously then?
MR. WEEKS: We certainly were alert, as you will see as we go through this whole chronology, you will see that we were alert to a problem, but we had not identified a precise amount of money that we thought would be required to fix it.
CHAIRMAN ROGERS: In other words, as I understand it, your memorandum was, as far as you knew, unrelated to anything in the Cook memorandum, so you were just considering the facts that you were dealing with here based upon what had happened in previous flights, and you were making a study of that, and you
were reporting on it, and you end up with I recommend that we arrange for MSFC to provide an overall briefing to you on the O-rings, including failure history, current status, and options for correcting the problems.
Now, I assume that was done, wasn't it?
MR. WEEKS: Yes. That is, as you will see, in the next set of charts that that occurred on the 19th of August.
CHAIRMAN ROGERS: Now as far as we know from this book, was any follow-up given to the Cook memorandum?
MR. MOORE: Sir, may I comment on the Cook memorandum?
Mr. Cook is in our budget office at NASA headquarters. He is in the Comptroller's office, and that is where you see the BRC. That is a code.
CHAIRMAN ROGERS: I understood that.
MR. MOORE: Now, he wrote this internally to one of the people in the budget office. Mike Mann works in the budget office, and Mike Mann is one of our people who looks after the overall Shuttle budget. To my knowledge, no one in my office, at least in the technical program area here, saw this memo from Mr. Cook.
CHAIRMAN ROGERS: Is Mr. Mann here today?
MR. MOORE: Mr. Mann is in the budget office.
He is not here today. We would be happy to bring him, too.
CHAIRMAN ROGERS: But as of now, we don't know if he did anything about this? He just treated it as another memorandum?
MR. MOORE: We do not. We are all seeing this for the first time.
I guess we saw it in the newspaper, just like you and other members of the Commission.
VICE CHAIRMAN ARMSTRONG: Am I correct in assuming that what you describe, that in the normal chain of authority, neither Mr. Cook nor Mr. Mann would have anything to do with deciding the technical aspects?
MR. MOORE: Mr. Armstrong, you are exactly right. They are budget analysts, and we at this time of the year are putting together our budget briefing for the Administrator for fiscal  1987, and I am sure the Code B people, our people that you see listed here, are sitting back and looking at areas that they ought to be sensitive to when we come before the Administrator with our budget.
CHAIRMAN ROGERS: Let me say I fully understand that, but we want to be sure that we face the facts. The fact is you have a memorandum, and Cook says certain things he thinks should be done.
All I want to do is find out what was done. If
it wasn't done, tell us why and we will understand and the record will be clear. That's all.
MR. MOORE: We will have to bring in Mr. Mann and Mr. Cook I think to make sure of that, or we can provide you a written statement.
CHAIRMAN ROGERS: No, we would like to have them.
MR. MOORE: Mr. Winterhalter, do you want to talk about this?
MR. WINTERHALTER: Yes. The very next document, document No. 3, will show that in our budget briefing we referred to the O-ring as a budget threat. We did not specifically add any money to the budget for that but understood that we were studying the situation, that depending if some redesign and some improvement was decided upon, then we would have to have some extra money to cover that outside what we had originally budgeted.
CHAIRMAN ROGERS: Are we going to find out through these papers that you as a matter of jargon, you spoke about budget threat and safety together and related them somehow together?
MR. WINTERHALTER: Not in anything that I have learned.
CHAIRMAN ROGERS: You just spoke about budget
MR. WINTERHALTER: We didn't look at that as a safety problem.
MR. MOORE: We identify a budget threat as something that the results of tests or the results of flight may require us to go back and make some changes in it, and so therefore, for the fiscal '87 budget which we were putting together, we identified this area as an area of threat based upon the tests that we had planned on the segments which you will hear about later on in this briefing, and that was the context of the budget threat.
CHAIRMAN ROGERS: Just so we understand it, because this is something that the press will clearly dwell on, I gather you mean when you say budget threat, that if you change conditions to approve whatever it was that you were talking about, that would increase your budget, and therefore it would be a threat to the budget.
Now, doesn't that necessarily relate to the safety of the personnel involved, and that leads to budget considerations?
MR. CULBERTSON: Dr. Graham asked me to sit in a while in his absence.
Let me define what budget threat means within the Agency: anything that could affect current
projections on the budget is referred to as a budget threat. We ask each of the programs when they submit the budget to do it as realistically as they can but also tell us where that budget may be in error, what kinds of things it can cause. It can range from DOD deciding not to fly a mission on the Shuttle and therefore change our income. It can come from any kind of action, including the results of tests which haven't yet been made, and it can certainly be based upon  somebody's concern that there may be a safety item that could affect our planning and could therefore affect our budget.
The word "threat" is an unfortunate word, but it is what we use, and it is a potential item that may change the budget.
CHAIRMAN ROGERS: So we are likely to find as we study these documents that from time to time when there seems to be a failure of equipment or something that should be improved, that it may be referred to as a budget threat, and therefore nothing should be done about it?
MR. CULBERTSON: No, not that nothing should be done about it.
CHAIRMAN ROGERS: Well, let me correct that.
By the use of the term and relating it to, as
you did in this case, or as Cook did in his memo where he makes it very clear that that is what he is thinking about, it may appear that from time to time that things were not done in the field of safety because that would present a budget threat. I mean, it just seems to me it is clear, and I understand it, but it seems to me it is clear, it is clear from this memo, the first one you have here.
MR. FEYNMAN: Suppose there is an item which may or may not turn out to be a safety threat, and there is some kind of difficulty, and it may be solved very easily. On the other hand, it may require a large amount of reconstruction of equipment which is quite expensive, and it is not yet known whether it is an important problem either for safety or for anything else, and it is nevertheless potentially a problem, and a problem that the budget has to appreciate may arise. It doesn't mean that they have decided that they are not going to make this change. As a matter of fact, the very fact that they are aware that the budget is going to be threatened represents a statement of the possibility that they will have to repair this for safety purposes, and there may not be an obvious relationship between safety and the budget.
CHAIRMAN ROGERS: Well, as I say-and I don't think there is any point of having a further discussion on it, but I think we can see that the way
these documents are written would suggest that, and I think that that is something that you would want to think about before we come to a public session because it says so. It says-well, the last paragraph, I don't have to read it. It says there are certain safety problems. My engineers tell me there are safety problems. You have asked me to make a check, and then he says we have got to consider the budget action needed to provide for the solution.
So I think there is no point of saying that you haven't thought about it. I mean, as Dr. Feynman says, it may very well, the documents would reflect that you did give full consideration and you decided that it didn't have to be fixed. I understand that.
But the phrase "budget threat" is very unfortunate.
MR. CULBERTSON: We do not use it as an indication that budget limitations threaten the possibility of taking corrective action. I don't know that it is every really used in that way in NASA, but you certainly can read that connotation into it.
MR. WEEKS: I want to make two points in this regard. In the manned programs, as I know them, through their history, the people making those decisions first look at if it is safety and it is mandatory, we find a way
in the budget to get it done.
 Now, in our budget that Mr. Moore carries across to the Administrator, we have two ways of taking care of things like this. We have changes in upgrading that we can absorb some of these and we also have a reserve account. In NASA it is called a PA. It is program activity to be allowed for. And so there are ways.
And when we have over the six years I have been here in the program, when we find a genuine safety issue, and we do quite often, we find the money, and have in the six years I have been there, are able to some how, in some way change other things to fit and get the safety not compromised. I cannot think of a case that we have ever said that we will not fix a safety item because of money. Sometimes it has been rather excruciating.
GENERAL KUTYNA: Mr. Chairman, along your line of reasoning, I would ask Phil, might there be some unfortunate choice of words here that ties safety to schedule threat also?
MR. CULBERTSON: Well, it could be used that way.
GENERAL KUTYNA: Are there some you are aware of in your research of the documents, because those
could be misinterpreted.
MR. CULBERTSON: The way we use schedule threats as to the schedules is the same way we use budget threat for the budget, and nothing further is inferred. The budget people worry about threats to budget; schedule people worry about threats to schedule. The program worries about the overall quality of it.
CHAIRMAN ROGERS: Because we are going to have a public session and this is going to be discussed for a long time to come, in the Cook memorandum he says, he has talked to progress engineers, and in discussion with progress engineers, shows it to be a potentially major problem affecting both flight safety and program cost. And last, he says it should be noted that Code M management, what is that?
MR. WEEKS: Code M-Jesse Moore is the head of Code M; the Associate Administrator for Space Flight is called Code M.
CHAIRMAN ROGERS: He says it should be pointed out that Code M management is viewing the situation with the utmost seriousness. From a budgetary standpoint, I would think that any NASA budget submitted this year for FY 1987 and beyond should certainly be based on a reliable judgment as to the cause of the seal problem and a corresponding decision as to budgetary
action needed to provide for its solution.
Now, that memorandum either had not received much attention, on the one hand, which is understandable, assuming that there wasn't much confidence in Mr. Cook or based upon his experience, or it was followed up, and some decisions were made on it, and I guess that is what I think we have to keep in mind.
MR. MOORE: Mr. Chairman, let me just add one quick point to that, if I might. In the case of a situation that Mr. Cook describes, we have been following up, and we have been following up this O-ring concern for some time. In fact, you will see a program laid out that we have had under way leading up to some tests that are scheduled for the month of February.
So he is right in that particular aspect, and he is also right in the sense that it did represent in his common knowledge a budget threat, that we may come over and ask for a substantial amount of money in the budget request.
CHAIRMAN ROGERS: I think that is the answer to my questions.
 MR. MOORE: You will see, Mr. Chairman, the program that we have laid out has been under way for some time in this whole question about O-rings.
MR. WEEKS: Now, I think that we could-
DR. WALKER: Excuse me. When you have a situation where a system doesn't perform as you predicted, do you have some mechanism where you look at that and decide what the implications might be for safety or schedule, or whether something can be slipped? Do you have some procedures that you go through?
MR. MOORE: Mr. Walker, we have two major paths that we undertake. One is we have got a program path which people in my office work with the corresponding center people, and the center people work with the corresponding contractor people to go and address that problem from a standpoint of how do we resolve it. And then independent of that, using some of the same people, however, we have a whole flight readiness review process to determine if this particular problem is enough of a concern that we should not fly. That is done in parallel, and actions come out both in our flight preparation process that we described the other day, as well as in our program process where we go through that analysis. And I hope as we go through this today you will see some of that come out.
But we have those two major paths that are followed up.
DR. WALKER: It might be useful to be sure that that documentation is available and in place in
case you might need it.
MR. MOORE: You will see, Mr. Walker, the program side of this whole question of concern about O-rings today. We have laid that out in very great technical detail today, and we will tell you the actions that the program has taken in terms of trying to get a handle on this problem and so forth. So you will see that as part of the data that is presented to you today.
CHAIRMAN ROGERS: Well, I have been urging members of the Commission not to interrupt, and I have been the worst offender.
So please go ahead.
MR. WEEKS: I rather think that Roman II, Mr. Irv Davids, will be in better context, because his memo was followed up by this August 19th which Mr. Mulloy is going to speak to in great detail. And I think that will be a better context to put that whole memo in.
And then the next one is this briefing number three, which is the budget briefing material on August 21st, which was, as Mr. Moore said, around the August time frame is when we are putting together the budget for the following February 3rd, 4th, whenever it is submitted to the Congress.
And so this was a budget recommendation briefing that was going to the budget administrator on the 21st. It was made up on the 16th, as you can see there on the front page, and as it actually happened, this particular briefing because of the press of time did not get to the administrator in that particular case. A number of other briefings on the orbiter did get to him.
And so this is just a budget threat item that we in general tell the administrator about so that he isn't blindsided that we haven't told him of some threat that he may have to help us get money moved around in the agency to hold a tough problem together. Usually Jess Moore can handle it within his own resources, but
quite often he cannot and the administrator has to jump into the situation.
Then on number four, which is September the 10th, which is Mr. Winterhalter's preparation for this monthly meeting I spoke to you about, this is just a checklist of the erosion of the particular case on 51-I; that he is telling Mr. Moore at our monthly meetings about what the problems may be.
And then December 10th is the monthly status report. You will see there that number two on that one, which is now-and now I'm on page 15, and there is the case to case, nozzle, O-ring charring or erosion. When you see "charring" you will see Mr. Mulloy's pitch. Erosion-if you will use those interchangeably. [Ref. 2/10-8]
We are a little sloppy. We all know charring and erosion are fundamentally different, but sometimes we get lax with the imprecise language.
DR. RIDE: Can I ask you a question? Back on number three-and I guess I am back on the budget threats. You've got this SRM O-ring charring listed as a potential budget threat. What sort of threat to the budget was it being considered as?
In other words, were people thinking of it as a threat because they needed lots more O-rings, or were they thinking of it as a threat because there was a
potential redesign of the solid rocket? In other words, how serious a safety consideration was this and what kind of budget implications did it have?
I mean, when people were briefing this were they saying we may have a solid rocket design or redesign, or were they saying we need more O-rings?
MR. WEEKS: We had seen some of the alternates of the type of design that it might require, and some of them were quite livable in Mr. Moore's budget and some would have been very difficult to handle.
CHAIRMAN ROGERS: What about this one?
MR. WEEKS: Well, you see, as Mr. Moore stated we really haven't figured out what this failure is, at least not to my knowledge, and so haven't come down in any way on what - -
MR. MOORE: Excuse me.
CHAIRMAN ROGERS: You're not answering the question.
MR. MOORE: Let me try and answer the question from a budget threat point of view. What we had under way, we did not have a safety of flight concern in our program area that said we should not fly the shuttle at this point in time.
We did look at this thing as being a long term, because we had a different design on the filament wound case, that because we were seeing some erosion, that we might have to change that design and it would be better off to change that design in the long term.
So a program was put in place to look at the results of the filament wound case activity and some other tests to decide if we wanted to continue to fly with the erosion concern we had or whether or not we wanted to go back and redesign.
And that was the context of the budget threat and there was a question of how much money was in that thing. We didn't have a feel for particular money in there. We just said, we may have to go back and get good tests out of this filament wound case, and we may have to go back and redesign.
 So these were some of the things that we were talking about in Irv David's memo and what they were going to put into the filament wound case program, that we wanted to see how that particular thing operated.
DR. RIDE: I guess what I'm concerned about is, you're saying you might want a potential redesign because you were concerned at some level about erosion of the seals, and if there's any concern if the O-rings go you've lost the solids, and if you've lost the solids you've lost the flight.
So that seems like a fairly serious consideration.
MR. MOORE: It was a serious consideration, and in the analysis that will be presented by Larry
Mulloy and the Marshall people here this afternoon it was given a very serious look and everybody in the program felt that we did not have a safety of flight concern and that we should stop flying the program.
We also changed out after each particular flight. The O-rings went back for complete refurbishment on the entire case. And we also knew that at the same time there were some questions about the O-ring erosion, and we were using some of the data that we were planning to get from the filament wound cases and some of the other lab tests at the Marshall Space Flight Center in order to decide what the size of that particular issue was.
CHAIRMAN ROGERS: Do you know whether there are any documents relating to the arguments pro and con on that subject or any reportings of what was being said about it?
MR. MOORE: There are certainly a lot of documents on that, Mr. Chairman. There are a lot of documents leading up to the flight and there were a lot of people involved in being sent telecoms certifying that they were ready to fly. We have all of the documents from everyone in the program certifying the shuttle.
CHAIRMAN ROGERS: I'm really less interested
in that than whether there were two schools of thought, whether some people were saying we should stop and others thought it was such a serious safety consideration that we should stop and correct it, no matter what the budgetary considerations are, and other people say, no, it costs too much, or we're not worried about the safety aspect, or it has some safety features but were not very aware of them? Do we have that kind of a discussion? Because just these charts don't really help us too much.
MR. MOORE: To my knowledge-and anybody else in the room can address the question that you asked. To my knowledge, there was no concern on the part of anybody here who said we should stop flying because of the budget threat potential and so on.
CHAIRMAN ROGERS: Was there anybody who said we ought to stop for a little while and slow down and take the following corrective steps before we fly?
MR. MOORE: No, sir.
VICE CHAIRMAN ARMSTRONG: As I look down this list, it looks-and you can correct me, but at these seven bullets here, this is really the only one that is of a technical nature. Am I correct?
MR. MOORE: Which one?
VICE CHAIRMAN ARMSTRONG: Well, it has
"turn-around improvements" and "dual source" and "flight sets."
 MR. WEEKS: No. The top one, Mr. Chairman, is a technical question. And you understand the reason this is here is because it is in the New York Times article.
VICE CHAIRMAN ARMSTRONG: I understand.
MR. WEEKS: And we underlined it because it is the germane point. But truly, the top one is a technical question in getting the filament wound case comments.
VICE CHAIRMAN ARMSTRONG: The filament wound case is a technical consideration, but it's not a safety of flight consideration in this context because it is a potential improvement.
MR. WEEKS: Well, but it has to meet the full strength requirements or it indeed is just as safety in flight as any other item.
VICE CHAIRMAN ARMSTRONG: But what I'm trying to understand here, this charring item on the chart is on there, and that says that there was a concern of some sort and Mr. Moore is telling us that it wasn't a safety of flight concern. And what I'm trying to understand is, what might have made it a safety in flight concern.
What is the difference? What is the dividing
line that put it on this, and what is the dividing line that would put it into a safety of flight consideration?
MR. MOORE: I will ask Dave Winterhalter here, who is head of that division, to tell you of his perceptions on this fine line of the safety of flight concern, and also the concern we had about the O-ring.
MR. WINTERHALTER: Firstly, if I thought at the time that that was a real safety of flight issue that it wouldn't have been a budget threat. It wouldn't have appeared on this list. It would have appeared as a mandatory change, a make-work change, that we would say we don't do any more flying, we don't do any more testing, until we make some changes.
What we were talking about in this instance was we had seen some erosion on the O-rings. We had taken some action to take a look at some changes in designs, et cetera. However, we hadn't completed that evaluation to the point where we had scoped it moneywise to say, okay, it's going to take maybe $5, $10 million worth of extra testing and improvement in order to bring that on later in the program.
But we listed it as a budget threat, something that maybe would use up some of our APA, whatever reserve we had in the program. Now, obviously if we had a
whole list of things there that would also have the same effect on the budget. If they were an overrun, they weren't determined to be a budget threat.
DR. RIDE: What amount of erosion would have given you a problem to call it a safety in flight issue?
MR. WINTERHALTER: Well, we had test results on this and, even with the erosion on the secondary ring, which was the only instance we saw, we had a safety factor sizewise of over two to one in our tests.
DR. RIDE: What does that mean in terms of the amount of time?
MR. MULLOY: That is probably best explained with some charts that I have in my briefing.
MR. WEEKS: Sally, I don't think that you should get the idea that we weren't deeply concerned about that first instance of the secondary O-ring having erosion.
VICE CHAIRMAN ARMSTRONG: I find myself not really understanding the feeling of the people that were involved in this.
CHAIRMAN ROGERS: What is it that shows how you resolved your concerns?
 MR. WEEKS: Well, I think that if we could proceed and get past the New York Times thing and get into the genuine chronology, I think that would come
through a lot better.
GENERAL KUTYNA: Before you do, Mr. Chairman, I would like to call your attention to page 17. And when we look at the Cook memo you have a statement that the failure of the seal would certainly be catastrophic, and it was stated that that was overstated.
And if you look at page 17, here's another group saying the same thing. It says: "Failure mode and causes," and then about the fourth of fifth box down, "failure effects summary."
MR. WEEKS: Now, this is the document that is the December 1982, and that is when it was signed by myself, on the 28th of March in 1983. The critical items list were changed from a one redundant to a criticality one period, which means the redundance was to some degree compromised.
GENERAL KUTYNA: My problem is the New York Times kind of problem. Here it said that Cook says it's going to be catastrophic and here is another guy says loss of mission, vehicle, and crew. Somehow we've got to be able to explain in the open session tomorrow why this is different from what you said.
MR. WALKER: What action was taken as a result of this analysis?
MR. WEEKS: As you will see over the time
period, you will see in Mr. Mulloy's testing many, many things that were done as regards this O-ring seal deflection which he speaks to here as a problem.
MR. WALKER: Some changes were made?
MR. WEEKS: Changes were made and tests were done to identify how much erosion was liveable, how much deflection really occurs as a result of this CIL back three years ago.
Now, this critical items list, as you can see there at the bottom, here we were, after we had had eight static test firings, we had five flights. We had 180, 54 field and 126 factory joints that were tested with no evidence of leakage.
We also had the Titan III program, which is a single seal instead of a dual seal, and they had about a thousand joints that, to the best of our knowledge, had not had a problem.
MR. WALKER: It looks like the Titan seals have different characteristics.
MR. WEEKS: Well, in one of the critical things, it is not redundant. In one of the critical things, the dual is better.
DR. COVERT: Maybe it's a different pressure.
MR. WEEKS: I can't authoritatively speak to the comparative difference in the two joints. I haven't seen any
numbers on that. We know what our deflections were.
DR. LUCAS: I think you said we changed something there. Are you speaking of the filament would case? I don't believe a change was made on the steel case flight, was it?
MR. WEEKS: I stand corrected.
CHAIRMAN ROGERS: Could I make one comment? We're not talking about the New York Times article now. The New York Times article called the whole thing to the public's attention. Now we're talking about the documents that you produced, and let's forget the New York Times.
We're not analyzing the New York Times; we're analyzing your documents. As far as I'm concerned, that is what we're talking about, and that is what we will be talking about tomorrow.
 I mean, we're not here to decide whether the New York Times writes good stories or not. We're here because of the critical nature of the subject matter.
We're here to consider what NASA did in view of its own internal documents.
MR. WEEKS: If I could I think go to page 2, which is page 18 that shows the test program that was done, in which the O-ring withstood 1600 psi, which is the actual operating pressure. The test program
withstood-and this is back now three years ago-that the O-ring can withstand four pressurization cycles before any damage to the rings can occur or did occur.
We had over 540 joints exposed to the pressurization levels at the mean operating pressure, which is essentially 1,000 psi, with no leakage past the primary O-ring.
DR. COVERT: With the liner and the insulation in? What was the configuration in the tests?
MR. WEEKS: In the liquid pressurization system, I'm quite sure that that is oil out of the factory in Utah, and there is no insulation.
DR. COVERT: So there's no insulation at all?
MR. WEEKS: None. This was a liquid test.
DR. COVERT: So it is just the steel shell?
MR. WEEKS: And the O-rings, et cetera.
DR. COVERT: Essentially an isothermal test?
MR. WEEKS: Yes. I'm sure it's at room temperature.
And so this is a document that is our--
DR. COVERT: Is this thing lying on its side or vertical?
MR. WEEKS: I think they're tested vertically.
A critical items list is, if it is deemed to
be category one, and you will see that this was changing from category 1-R, which is redundant, to category 1, which meant the redundancy was not full. As you can see here, full redundancy exists-this is in the middle of the first paragraph: "Full redundancy exists at the moment of initial pressurization."
And that is of course a very critical time, because the pressure in the motor is coming up in about 600 milliseconds to the 900 psi. And this joint rotation-and the reason that this particular CIL was written was it was found that that joint does rotate, and in Mr. Mulloy's pitch you will see a detailed picture of the amount of rotation which lifts off the secondary seal to about 42 to 60 thousandths of an inch.
DR. COVERT: Is this natural frequency?
MR. WEEKS: I can't answer that. Can anybody answer that?
DR. COVERT: I would appreciate that information, because that's going to relate to the importance of the 600 milliseconds.
MR. WEEKS: We will get that for you.
DR. COVERT: Thank you.
CHAIRMAN ROGERS: Could I suggest that you make the answers to the Commissioner who asked the
MR. MOORE: Yes,
 MR. WEEKS: And so, a critical item one which has to be signed off at the associate administrator level is a safety of flight of the crew or the airplane or both, and therefore it is changing from 1-R to 1 or signing off a critical items list, Roman I.
DR. RIDE: So in late 1982 this was identified as a criticality one problem and signed off based upon tests and past performance and all that sort of thing. And then you had subsequent problems with the O-rings, or at least subsequent charring on the O-ring.
MR. WEEKS: Correct.
DR. RIDE: Did you go back and revisit the CIL?
MR. WEEKS: Well, I think that you will see each step that we went through as we found each of the flights, Sally, that got different amounts of erosion. We were in effect re-reviewing this document as to whether it was liveable or not.
MR. MOORE: Let me add, Larry Mulloy, you might comment on that, because each program element in the shuttle is required to go back after an anomaly and carry it out through the entire project.
MR. MULLOY: None of the data really changed.
It changed the basis for the acceptance of it as a criticality one item, but all of the data that we received in terms of the joint rotation and the reason we were getting the erosion-so yes, we did look at that, and we felt the margins we were seeing-and I will explain some of this- during the time that it takes to fill the gap between the primary and the O-ring, that it is an acceptable situation. And I have no data today to change that.
CHAIRMAN ROGERS: Not even today?
MR. MULLOY: No, sir.
(Viewgraph.) [Ref. 2/10-10]
MR. WEEKS: Now, if I could go on to the Titan experience. And here is the history as we best understand it on the Titan, that it is a design similar. But, whoever asked the question whether it was identical or not--
CHAIRMAN ROGERS: Could I go back to your last answer? Are you suggesting that you have come to the conclusion that these things did not cause the accident?
MR. MULLOY: Sir, I'm not aware of anything that has caused the accident yet.
CHAIRMAN ROGERS: Well, I asked you if you would have a concern today, based upon what happened, and you said no.
MR. MULLOY: Sir, I said I have no data that changes the basis for that being a criticality one item. The thing that changed it from a criticality one redundant to a criticality one is still valid today.
CHAIRMAN ROGERS: I don't think that anybody who would hear that could understand it. Could you explain it so that the public would understand it?
MR. MULLOY: Yes, sir. If I could get to my charts, I will explain what happens during this rotation and why we think that it is a criticality one but the design is safe, given the criticality one design, and redundant.
DR. COVERT: Mr. Chairman, might I suggest that some of these things might be resolved by data? And I would hope that sooner or later we're going to get some numbers on these things, so we can get a feel for what they are. And I would suggest that some of these judgments might be withheld until we have some numbers.
 CHAIRMAN ROGERS: Yes, I think what I was suggesting is we want to be careful that NASA doesn't suggest by his answer that nothing has changed. That would be a devastating comment. I think the answer to that is, we're not sure yet, that is what we're studying.
MR. MOORE: Yes, sir, I think that's exactly right.
MR. CULBERTSON: The thing that hasn't changed, Mr. Chairman, is that this is still a
criticality one item. It is not a redundant system. That is what that piece of paper says. It placed it in a non-redundant category, causing it to get a lot more attention than would have been the case if it is a redundant item, and it remains that way.
DR. FEYNMAN: If I understand what "criticality one" means, it means it is important for safety of the flight. Is there a higher category than that?
MR. WEEKS: No.
DR. FEYNMAN: So that a failure of criticality one doesn't mean it was safe.
MR. WEEKS: It means if there is a failure of a criticality one item you can live through it.
DR. FEYNMAN: It doesn't mean there can't be any failures, of course. I heard someone suggest that something was criticality one and you would fly with it. So we still have to discuss later, I presume, the evidence that this criticality one was sufficiently unlikely or something that we could fly with it.
MR. WEEKS: I'm going to suggest, Mr. Chairman, that I finish these two or three charts on Titan. And then what I think would be more meaningful is that the chronology is there in your documents, and I think that if we went to the technical briefing of Mr. Mulloy immediately after that, we will get to the
heart of this matter much quicker and most everybody in this room will be happy.
CHAIRMAN ROGERS: I think that's a good idea. Proceed.
MR. WEEKS: Okay. So just to tidy up the Titan thing. Now, General Kutyna may stand me corrected. The 26 ground test, which is the only place you will see any of the charring-and there was very little. And think we looked up something, and the worst one that existed was 10 thousandths on the single O-ring on the Titan, and there are 20 of the five-segment. That was the earliest version.
There were four of the seven-segment, which never went into production, but was just a development in the laboratory, and then two five and a half segments, which was a way of getting a little additional performance. And I believe every one of them flying now is the five and a half segment device.
And there is not any leakage, but there was this 10 thousandths. And there have been 77 flight tests, in which we have used 154 motors, and over 800 joint experiences.
MR. WALKER: Are you arguing the Titan experience applies directly to the shuttle experience?
MR. WEEKS: I am inferring that in that CIL
that was signed three years ago, that was a germane thing that gave us some degree of confidence that we could proceed to sign up on it.
MR. ACHESON: Question: Would there be stresses set up by differences in design between the Titan and the shuttle flight assembly which would produce different types of rotation and different values for rotation?
 MR. WEEKS: It certainly would, I'm almost certain, even though I do not know of their rotation numbers.
MR. ACHESON: Could those be simulated on the ground in any effective way?
MR. WEEKS: They certainly on those 26 tests-and I don't know whether maybe General Kutyna can tell us, but I'm sure they instrumented these and you can measure it on the ground. That's your best thing to do.
MR. ACHESON: My question, though, is whether the differences in the stresses in rotation between the two systems could be measured on the ground?
MR. WEEKS: I believe they could.
GENERAL KUTYNA: Let me address this. In talking to the space division, if they were on the stand right now they might say that their joint was stiffer
than the NASA joint and therefore the rotation was not as great as the NASA joint, and so the joints should not be compared as essentially the same.
MR. WEEKS: I wouldn't quarrel with that. But when I signed that document, of course, I did not know the details of the Titan joint.
(Viewgraph.) [Ref. 2/10-11]
This is the detail of the single joint of the Titan, and it shows here, this is the inside. The centerline of the motor is here, and this shows the single one fitting down in, when 850 psi comes down and it pushes up against that O-ring.
But it is similar, of course. This detail is very similar to what you will see in Mr. Mulloy's pitch, similar, but I accept General Kutyna's point that the amount of rotation could be slightly different.
GENERAL KUTYNA: Mike, let me point out what the differences would be. They say it's a beefier joint, it's longer, it may be heavier, and actually there is a crosshatch section or actually a compression and they have to sit for a while before they can get the pins in, to the extent that almost all of the putty is squeezing out of it. So there is very little putty within those two surfaces.
So it is a compression joint, versus the kind of joint that you will see on the shuttle, which is an open one.
MR. WEEKS: Well, General Kutyna, I sure wouldn't expect the stiffness coefficients of this insulation to be the same overall.
GENERAL KUTYNA: No, not very much.
MR. WALKER: Is that insulation ceramic?
MR. WEEKS: I assume that insulation is rubber.
MR. McDONALD: I'm pretty sure it is NBRO. I don't know. I didn't put it in.
MR. WEEKS: Now, this chronology, which is in your second frame, let me tell you what it is. But I think that if we went to Mr. Mulloy, which has extensive detailed numbers of calculations and so forth, I think we will be better off in this chronology, and then let us decide to come back to that.
CHAIRMAN ROGERS: All right, let's go to Mr. Mulloy. And do you want to swear him in.
[Please note that some of the titles to the references listed below do not appear in the original text. Titles are included to identify and clarify the linked references- Chris Gamble, html editor]
 [Ref. 2/10-1 1 of 3] ["The Shuttle Inquiry: Flight Safety 'Comprised'; NASA had warning of a disaster risk posed by booster". THE NEW YORK TIMES, FEBRUARY 9, 1984.]
 [Ref. 2/10-1 2 of 3] ["The Shuttle Inquiry: Flight Safety 'Comprised'; NASA had warning of a disaster risk posed by booster". THE NEW YORK TIMES, FEBRUARY 9, 1984.- Continued.]
 [Ref. 2/10-1 3 of 3] ["The Shuttle Inquiry: Flight Safety 'Comprised'; NASA had warning of a disaster risk posed by booster". THE NEW YORK TIMES, FEBRUARY 9, 1984.- continued.] [Ref. 2/10-2] [NEW YORK TIMES REREFENCES.]
 [Ref. 2/10-1 1 of 2, 2 of 2] STS - SOLID ROCKET MOTOR O-RING CHRONOLOGY.
 [Ref. 2/10-4 1, 2, 3 of 4] MEMORANDUM: PROBLEM WITH SRB SEALS. [From: BRC/Richard Cook; To: BRC/Michael Mann Subject: Problem with SRB seals; Date: 7/23/85].
 [Ref. 2/10-4 4 of 4] [Marshall Space Flight Center; SRB- SRM FIELD CONNECTIONS. April 1978].
 [Ref. 2/10-5 1 + 2 of 2] NASA MEMO ON SEAL EROSION PROBLEMS [From: Irv Davids; To: Associate Administrator for Space Flight; Subject: Case to case and nozzle to case "O" ring seal erosion problems].
 [Ref. 2/10-6 1 + 2 of 2] SOLID ROCKET BOOSTER.
 [Ref. 2/10-7] PROPULSION DIVISION SOLID ROCKET BOOSTER.
 [Ref. 2/10-8 1 of 2] PROPULSION DIVISION MONTHLY STATUS REPORT, DECEMBER 10, 1985.
 [Ref. 2/10-8 2 of 2] SOLID ROCKET BOOSTER ISSUES.
 [Ref. 2/10-9 1 of 3] SRB CRITICAL ITEM LIST. [Date: December 17, 1982; Failure mode & cause: Leakage at case assembly joints due to redundant O-ring seal failures or primary seal and leak check port O-ring failure].
 [Ref. 2/10-9 2 of 3] SRB CRITICAL ITEM LIST. [Date: December 17, 1982; Failure mode & cause: Leakage at case assembly joints due to redundant O-ring seal failures or primary seal and leak check port O-ring failure] - continued.
 [Ref. 2/10-9 3 of 3] [SPACE TRANSPORTATION SYSTEM - LEVEL I - CHANGE REQUEST; Title: SRB Critical Items List (CIL) Requirements.]
 [Ref. 2/10-10] SRB MAJOR TITAN III EXPERIENCE.
 [Ref. 2/10-11] [Detail of the single joint of the Titan].
MR. MULLOY: Mr. Chairman and members of the Commission:
What I will give you today is an overview of the SRM case joints, some of the experience that we have had with those case joints, the erosion that has been experienced in the O-rings in those joints, and how we have addressed those as we have progressed through the program.
The CIL or critical items list document that has been under discussion as generated in December of 1982, we generated shortly after I took over the SRB program, where we had a recognition from the structural static testing that we had done at Marshall and some hydro-proof testing, where we actually measured the rotation of the joint, that we did determine that we did not have redundant seals, which was the initial design intent.
Now, Mr. Chairman, as you have asked if we can explain this in some terms that are understandable, I hope to be able to do that. The simple fact of the matter is that, due to this joint rotation, which I will explain, one of the seals is not effective, in that it is essentially lifted off its sealing surface.
And the rationale for the retention of that is the analysis and
the testing that I will go through, as being we would like for it not to be a criticality one, we would like for it to be a criticality three. What is done in the process is to look, is there any practical way to make something a criticality three that isn't, and can you make it a criticality two; and if you can't make it a criticality two, which is simply loss of mission and no loss of life, then you make it redundant. And if you can't make it redundant, is it a reasonable risk to continue with the single failure of the system leading to a catastrophic failure?
MR. WALKER: Can I ask a question?
MR. MULLOY: Yes, sir.
MR. WALKER. Does that mean it's a single point failure, category one?
MR. MULLOY: Loss of mission and life.
MR. WALKER: It doesn't necessarily mean it has been a negative connotation?
MR. MULLOY: That is correct. It simply means you have a single point failure with no backup and the failure of that single system is catastrophic.
(Viewgraph.) [Ref. 2/10-12]
To orient you as to all of the joints that we have in the motor, what I have here is a profile of the motor. The two joints that I will be concentrating on because they are primary areas of interest to NASA and to this Commission are the Nozzle-to-Case Joint, where at the aft end of the motor case the nozzle is assembled into the motor case. This is the aft dome of the motor, and then the nozzle noses in. That is, it is bolted in with
a bolt circle, and it goes around that aft segment.
The other joint-this is a factory-made joint. That joint is made at Thiokol.
The other segment joints that we show here are made at Kennedy Space Center, because we ship the motors as an aft segment with its fixed nozzle attached, we install the nozzle extension at KSC, and then have a center segment, a center forward segment, and then a forward segment.
Those joints are-these individual casting segments contain a joint also. That joint in between there is the same type of joint as the field joint. In fact, when we recycle the hardware what is a factory joint on one flight may become a field joint on another flight.
This joint we have never had any problem with, because we had the layer of insulation over that joint, because that joint is made prior to laying the rubber in the motor and casting the insulation.
The configuration of this nozzle to case joint is considerably different, as you can see by this diagram, than what we call the field joint, where we have this clevis. And we brought a section that is a little easier to see exactly what you're dealing with here. This is a section cut from a motor.
This portion here is called the clevis, and this is the direction that it is assembled. The clevis is pointed up and the assembly is made. The tang end of the motor segment is aft. It is lowered into the clevis for the assembly.
There are two O-rings and two O-ring grooves that are in the clevis, and then there are pins of one inch diameter, high strength steel pins. There are 177 of these pins that go around the circumference, that secure the joint in place.
Then in between where the insulation is, in this area right here, is where the zinc chromate asbestos-filled putty goes, in here, as you can see in the diagram. These two O-rings in this case joint are 280 thousandths, .280 inches, in diameter. They are of Viton material, which is a Dupont fluorocarbon material.
We have a specification for the minimum squeeze, the squeeze being the compression on the O-ring when this is joined together. That minimum compression is 20 thousandths of an inch or 7.54 percent compression on that. That is a calculated squeeze. You can't measure it, and what we have done is measure the dimension of the clevis, the dimensions of the tang, and then we have assumed a minimum diameter O-ring, because
there is a tolerance on it, of 280 thousandths minus 3 plus 5 thousandths.
So we assume the minimum diameter. We assume the maximum stretch on the O-ring, because there is also a tolerance on the stretch. And then we assume a certain, about eight percent compression set, because under that load the O-ring is sitting there for months in that configuration. And so when it is energized and the joint spreads, there is some compression set. So we don't count on that.
And we require a minimum squeeze on that O-ring. The purpose of having that minimum compression in that O-ring is such that when the motor is pressurized this putty in here will not take 1,000 psi. I don't know, we haven't found a putty that would sustain 1,000 psi.
So the gas has to go through the putty. The putty is there as a thermal barrier. What has been happening to us is, you might get a very small hole through the putty. So during that ignition transient when you're coming up to pressure, you essentially have a jet, a hot gas jet here.
 At the same time, due to the pressurization loads, the joint is much stiffer than the rest of the case, and so this part of the case tends to expand more
than the joint. Also, you're putting tension loads into the joint due to the pressure in the motor, and it's pulling on these pins, which tends to rotate the joint.
So when we speak of joint rotation in this presentation, what I'm talking about is during the pressurization cycle this inner clevis tends to spread in this direction, which tends to reduce the squeeze on the primary and secondary O-ring.
DR. FEYNMAN: I'm sorry to interrupt, but I think when you were explaining the origin of the tension that you pushed your hands the wrong way, which way the material bends.
MR. MULLOY: I'm sorry. Inside out.
GENERAL KUTYNA: Could I ask, how did you determine the number of pins you put in there? Are more pins better?
MR. MULLOY: Well, primarily it's based upon the pitch, the design standards for the pitch between holes in the structure. And we have 177 of those pins in there. There are three of them that are aligning pins, so there's really 180 of them, and they're divided at 2 1/2 inches with 1-inch pins, and that's about as close as you want to go.
GENERAL KUTYNA: This is not meant to fit one against another. The Titan has 237.
MR. MULLOY: What size?
GENERAL KUTYNA: I don't know. They might be
DR. LUCAS: Larry, mention the clips. Do you want to mention the space there?
MR. MULLOY: Yes, we have-and this was introduced early in the design phase of the program. There is a 32 or 36 thousandth inch shim. And Mike did mention that there had been some changes made, and one of these was after some of the early testing. The concern was for getting a good squeeze on the O-rings.
At each pin we put one of these shims in here, the intent being to increase the squeeze on these two O-rings here. It's driven in with a leather mallet.
DR. FEYNMAN: That is in the 51-L?
MR. MULLOY: Yes, that has been in all the flights. That was incorporated early in the test program.
Now, there are other joints on the motor that I won't talk about today. One of them is the igniter joint. This is where the igniter assembly goes into the forward dome. We did have a little minor problem with that that concerned us.
We look very carefully at this hardware when we get it back. As someone mentioned earlier, this is the first for bringing back solid rocket boosters and
reusing them, and it also provides a wealth of information and it provides some learning that we never had the opportunity to experience before.
But we did see a little minor erosion in this igniter. We tracked that to a problem where this is not an O-ring, it is a gask-O, what is called a gask-O seal. It's a metal seal that has a little rubber bonded to it, and we were finding that the manufacturers were putting an overfill condition in there and we weren't getting a good seal.
And we subsequently fixed that.
CHAIRMAN ROGERS: When did you discover that?
 MR. MULLOY: That was DM-7, I believe, or DM-6. That was the fall of 1984. That was one that said, hey, we're seeing something here that we could go by the secondary part of that gask-O seal, and we still had a tertiary seal there, a third seal, and there's a donut seal around the bolts for any kind of a gas leak. So we cut down on the overfill.
There's another joint here we won't be talking about today, except in this context as I get further along. This is the filament wound case field joint. The filament wound case has steel rings, just like we have on the steel motors that we're flying out of Kennedy.
But it has another clevis at the other end of it where a 1.6 inch carbon-phenolic material- or, excuse me, graphite epoxy material-phenolic's in the nozzle, but graphite epoxy material that is bonded into another or pinned into another clevis. And what we have there is a much greater joint eccentricity, so the rotation problem on this one is greater than it is on the steel case.
Here you will see something I will talk about later. We put what we call a capture feature, which is a little tang machined in here to keep this joint from rotating. That also can be applicable to a steel case.
MR. WALKER: I notice that where the O-rings are in the sample there's a gap between the pieces of metal. Is that how it is actually?
MR. MULLOY: Between the tang and the clevis, yes. And I will show you what the dimensions are. We are dealing with a 146-inch diameter motor case here, which is designed to be used 20 times. And they're not perfectly round after you have brought them back three of four times, and so there is a tolerance built in there to assure assembly.
MR. WALKER: Ordinarily with these O-rings there would be compression in the metal, between the metal groove and the clamp or contact.
MR. MULLOY: You try not to have metal to metal.
MR. WALKER: Have you analyzed this difference?
MR. MULLOY: Yes, sir. We have done that in a lot of our testing. What it means is you have a cavity, and in this erosion situation, obviously, if you can get an interference fit and have and an interference fit on the insulation and eliminate the putty, it will be very hard to get any kind of flow down to the O-ring.
The inference of what you're saying is there is a volume here which takes in between the putty and the O-ring, and then this gap here which takes time to fill, which allows flow to impinge on the O-ring before it can be sealed.
The O-ring extrudes. This O-ring does not seat by compression. It seats by extruding into the gap, or seals by extruding into the gap.
DR. RIDE: If you were not going to reuse the SRB segments, would you have designed that to have metal to metal behind the O-ring?
MR. MULLOY: I still think you have to design it so you can put it together, and that requires a tolerance. And I think we have about the minimum tolerance that you can, even for single use. And I'm just saying that that gets exacerbated by continued
We use a rounding procedure at KSC by using a two-point pickup, a three-point pickup, or a four-point pickup, and let the motor hang until it meets its mating part. And the direct answer  is I think, even for a single use the tolerance should not be introduced you would have to count on it being able to be put together for a segmented motor.
Now, on the bottom down here is typical when you talk about O-ring erosion, and I wish I had time to bring an eroded O-ring with me. Possibly we can get one for you. This is a cross-section of that 280 thousandths.
And looking back here at the nozzle-to-nozzle case joint, I would point out another difference in the design of the nozzle-to-joint versus the case-to-case joint. The primary O-ring in the nozzle-to-case joint is what we call a bore seal, just like the case-to-case joint. But the secondary O-ring is a face sealer, whereas on the case joint they're not.
Now, the kind of erosion that we have been seeing, which our tests demonstrate is a margin of two or three less than what we can sustain and still seal the O-ring into the gap, is this type of thing here from the jet impingement.
Now, this is the exposed side of the O-ring
looking into the gas flow, here or here, and then it erodes away. And the time that it takes to do that is about 300 or 400 milliseconds of that jet flow. Then the O-ring extrudes into the groove and the pressure equalizes and the flow stops, and I will tell you some more about that.
DR. COVERT: Is that always on the same part of the periphery?
MR. MULLOY: Generally yes, but I will show you some diagrams where we have had some rather severe erosion, where it doesn't tend to follow that. But generally it is right there where the gas jet is impinging right in this area.
DR. COVERT: I didn't ask my question correctly. There are also some fittings on this where the solid rocket motor attaches, and if I call that zero phase angle, because I don't know anything else to call it, then these erosion points are always in the same clockwise position?
MR. MULLOY: No. I will show you that. It has been one that we have been looking for: What is the common denominator? What causes some O-rings to erode and others not to, and is there a common denominator in anything, materials, process, putty, gap, reuse, particular joint, temperature?
DR. COVERT: How about temperature gradient?
MR. MULLOY: I can't answer that.
MR. WALKER: What about the azimuthal extension of erosion? Is that always about the same?
MR. MULLOY: No, it is not, and I will show you a couple of examples. It generally, for a 32 mil erosion, the aspect ratio is usually about 100 to one, if they have 32 mils of erosion over a three-inch area.
(Viewgraph.) [Ref. 2/10-13]
Let me show you in some more detail now on the joints, the dimensions and so forth. This is our case-to-case joint. As I pointed out, we have 280 thousandths O-ring, plus 5 thousandths and minus 3 thousandths, with a design gap in there which is 10 thousandths, and the groove is .305 to .310 on the bore seals and the pin is one inch diameter.
As I said, there are 180 of them, although three of them are alignment pins and they don't have a retention pin in them. And then we have gap dimension criteria that the segment has to meet on inspection before we use that motor.
Now, what we have come up with, we're beginning to get what we call matched pairs. We're getting pairs where the clevis has spread to the point where we have to use the high side of a case that has a wide tang on it in order to meet these requirements.
But we're very sensitive to that, and dimensional inspections are very thorough to assure that when we assemble as case-to-case joint we have a minimum of a 7.5 O-ring compression.
DR. COVERT: The drawing leaves the impression here that the inner side of the outer clevis is metal to metal.
MR. MULLOY: No, it is not. As I showed you in there, there is a shim in there. That is a graphics error.
GENERAL KUTYNA: You said the temperature had little effect?
MR. MULLOY: I didn't say that. I said I can't get a correlation between O-ring erosion, blow-by an O-ring, and temperature.
GENERAL KUTYNA: 51-C was a pretty cool launch. That was January of last year.
MR. MULLOY: It was cold before then, but it was not that much colder than other launches.
GENERAL KUTYNA: So it didn't approximate this particular one?
MR. MULLOY: Unfortunately, that is one you look at and say, aha, is it related to a temperature gradient and the cold. The temperature of the O-ring on 51-C I believe was 53 degrees. Is that right, A1?
MR. McDONALD: Yes.
MR. MULLOY: We have fired motors at 48 degrees. 51-C was one of the worst case-to-case joint erosions.
GENERAL KUTYNA: And what was the temperature on 51-L?
MR. MULLOY: The temperature of the O-ring is calculated to be about 25 degrees.
GENERAL KUTYNA: Much, much colder?
MR. MULLOY: Yes. I think the coldest was 48 degrees on a static firing motor, if I recall.
DR. RIDE: Do you have a thermal model that you calculate that upon, based upon the ambient temperatures?
MR. MULLOY: Yes, it is based upon ambient and the temperature cycle. We have modeled the propellant and we have modelled the liner and the insulation and the steel case, and then, given a beginning environment, we can take a 24-hour period and calculate the mean bulk temperature and the temperature of the structure and get a temperature gradient.
VICE CHAIRMAN ARMSTRONG: Was the proximity of the external tank included in that model?
MR. MULLOY: Yes, it is. The effect is primarily through like a heat short in a strut, rather than a
convective action. The temperature of that tank seldom gets below freezing on the surface itself. On very cold days you might get some ice formation on the tank, but that is not a normal condition.
Normally the temperature of the tank is above freezing.
DR. RIDE: Are you running this temperature model at Marshall pre-launch?
MR. MULLOY: Yes, we're running it at Marshall.
DR. RIDE: And you must have various temperatures that you check?
MR. MULLOY: During the count? No, we have not been doing that. You mean like 24 hours during the count? We do predict the temperature on the day of launch, but the thermal model is not, to my knowledge, is not run during the 24 hours to launch.
 The launch commit criteria is that the vehicle can be launched in a 31 degree ambient environment, with a five degree sky. That is the LCC.
There is a TMX that explains how you apply that model. We have been looking at that and searching our certification and qualification on the motor. There are two thermal requirements: that the motor operates at 40 degree PMBT, propellant mean bulk temperature, the
average of all of the particles in the propellant; and that it will operate in a 31 degree ambient environment, looking at a five degree sky.
DR. COVERT: Do you address how long?
MR. MULLOY: That is a TMX. I cannot answer your question. We are researching that now: How is that to be applied per the TMX? Rationally, in the absence of that, we have been discussing this since-I guess my opinion would be to start out with a 60 degree motor and you set it in a 31 degree environment until the propellant mean bulk temperature is 40 degrees, and that is the design environment. That is one rational approach to it.
DR. COVERT: What is the griddle-ductile transition temperature on the Viton motor?
MR. MULLOY: Since I've heard about two or three numbers in the last two days, I hesitate to quote one. Tests are being run, and the reason is tests are being run-and as you know, depending upon how you run a test, you will get different results, and there is a range of that right now.
The literature says one thing. There are some tests that are floating into the system that I think are wrong. So I just don't care to quote a number on what that is right now.
DR. COVERT: But you're using a band?
MR. MULLOY: Yes, sir. I will tell you that the Mil Spec that Viton material is procured to requires that it operate at minus 30 to 500 degrees F.
DR. FEYNMAN: I don't really understand how this seal works, and let me explain what my question is. It says that you have .280, you might even have .277.
MR. MULLOY: That is correct.
DR. FEYNMAN: Now, it is round and sometimes it could be under compression for a while.
MR. MULLOY: We want it in compression all the time.
DR. FEYNMAN: So then we have a condition where, if you open it, it doesn't go back to round, it stays oval. And that is about ten percent.
MR. MULLOY: We use eight, sir.
DR. FEYNMAN: Now, use .28 and use 10.
MR. MULLOY: That's fine.
DR. FEYNMAN: That's easy to do. You have 10 percent of .280, and now it's only .252 wide now. It's compressed.
MR. MULLOY: I'm sorry, I misquoted. The compression set in the O-ring is 8 mils and not 8 percent. I apologize. There is 8 mils allowed in a compression set in calculating the minimum O-ring at the
time it has to operate.
DR. FEYNMAN: I will go back and check, because I thought I saw a test which had ten percent, but I may be incorrect. Therefore that could solve my arithmetic problem. If the percentage change was that great, this would just fit, it would just touch. So I must be wrong.
 But there is one more question that I wanted to make. When you have 900 or 700 pounds per square inch on the left and virtually nothing on the other side, how much do I have to have touching in order for this to work?
If it's only touching at a thousandth of an inch I would expect that it would go through. So can you tell me anything about how much excess I have to end up with so I will be able to hold?
MR. MULLOY: I hope I'm correct in this, but at 800 psi you don't have to have any of it in compression, because at 800 psi the O-ring has extruded into this gap and it seals by extruding into the gap and not by compression.
MR. LUCAS: Larry, would this be a good time to explain the pressure check between those O-rings?
MR. MULLOY: Yes, I think it is a very good time. I'm going to talk about it later.
We have a leak check port that is installed in
the tang between the two pressures to the O-ring seals. In the pressure check we run, we take the pressure up to 200 psi and hold that for five minutes with an open source. And what we want to do is assure that we have seated the secondary O-ring in a position to extrude into the gap.
It unfortunately drives this O-ring in the wrong direction, and the reason we use 200 psi is because the putty that is in this joint out here, that I showed you on the previous diagram, we have found will mask a leaking primary O-ring at up to about 100, 150-well, 100 psi. At 150 psi it always blows through the putty. So the leak check is done by going to 200 psi with an open source, holding that for five minutes, and then doing a 50 psi leak check for ten minutes, with one psi pressure drop allowable during that ten minutes.
GENERAL KUTYNA: On 51-L, for a matter of interest, the leak check on this one there was no pressure drop on this particular joint.
CHAIRMAN ROGERS: Could I just break in for a minute here to talk about our schedule? It's obvious you have a lot more information to present here, and we talked at lunch-some of us had lunch together-about repetitious testimony and we're going to have to do pretty much the same thing tomorrow, so I think there is something to be said for coming to a conclusion pretty soon and then starting again tomorrow.
We will have the whole day tomorrow. And I think if we continue much longer today that we will all be tired. I think that it would be helpful, at least for planning purposes, if you could tell us what you think you would like to present today to finish up and then we will have the whole day to present anything else tomorrow.
I think it would be a little repetitious if we go over it all twice, and I'm sure you feel the same way about it. Is there anything that you would like to tell us now that we should know about that it would not be wise to disclose in public at this time? We want to try to be sure that we don't do anything or say anything which injures or impairs your investigation, but, on the
other hand, we want to disclose as much as we can in the public session.
Is there anything that we should not disclose tomorrow, as far as you know?
MR. MOORE: Certainly the O-ring is an area we're spending a lot of time investigating.
CHAIRMAN ROGERS: And everybody who is here today will be available tomorrow?
MR. MOORE: Everyone will be available tomorrow as well and, Bill, I don't know. Do have anything else you want to add?
 DR. LUCAS: I would suggest, if I might, that out of Larry's presentation you might want to skip over to the actions that we began taking in about June of 1985, because that goes across this correspondence that was referred to.
CHAIRMAN ROGERS: I think that would be very helpful. As much as you can when you come to charts and things of this kind, if you can explain it to begin with and then say this is reflected in the chart or whatever it is, because for a lot of people it is very difficult to understand what it is that you've done.
So if you could give the explanation as you go along and say what this means and that when we were told about this particular problem that we did the following
things, and then we had a meeting and at that time it was decided that we would do so and so, and these are the reasons why we decided that.
MR. MOORE: I don't know what your thoughts are specifically on tomorrow, but I thought we would go back this afternoon and try to put a textual story together to give you some context, and then probably ask Larry to go through some of this stuff that he is doing here tomorrow.
CHAIRMAN ROGERS: I think that is good. Well, let's go ahead and you do whatever you think.
MR. MOORE: Larry, let me ask that you go through the actions that have been taken, the chronology of the Marshall actions that have been taken, and kind of a summary and conclusions and recommendations as part of yours. And then if you would like to stop at that point in time, we can, and then we can discuss what you think we ought to see tomorrow.
CHAIRMAN ROGERS: Well, it would be helpful to summarize what you think will be presented, but you can do it in more detail. As I say, the details we can wait and do tomorrow. But if you can summarize what it is you plan to present, then when we leave today I will have Mark explain that NASA provided the material we asked for, there was a full discussion of the matters
contained in the documents, and we will continue to discuss that information in a public session tomorrow. Then we will start all over again and do it.
But you can make it a little bit briefer tomorrow. What we would really like to acknowledge-and I think we're getting a lot of very useful information in the chronology of things that concerns you-how you dealt with those concerns, who made the judgments about what went on. And I think if you can do that it will alleviate a lot of the problems that have developed.
DR. RIDE: Is there any internal correspondence on potential concern over the operation of the O-ring or the joint? Because I think that is probably the next thing. Since we've dealt with erosion, that's going to be the next question.
MR. MOORE: I will ask Larry. Do you know of any documentation at Marshall on O-ring operation at low temperatures? And I will ask McDonald at Thiokol if they know of any documentation on O-rings.
MR. MULLOY: There are documents that are test results that are even now in progress of some tests that have been done previously to understand the resiliency of O-rings at various temperatures.
DR. LUCAS: I believe also, Larry, that
there was a discussion in close proximity to the launch between you and other people and Thiokol.
MR. MULLOY: Yes. Now that is not correspondence. What we did have on the evening of the 27th that came out in your first hearing- Dr. Lovingood mentioned that-when we stood down on the 27th it was known that the temperatures were predicted to be below freezing during the night and into the morning on the 28th.
As a matter of routine, those of us working the launch asked our technical people and our contractors what concerns we might have for low temperatures, and that was immediately after the stand-down. The only concerns that were presented to me were for the recovery battery temperatures. The recovery batteries are located in the forward skirt, the forward end of the solid rocket boosters.
And there was some concern expressed for the adequacy of the GN to gaseous nitrogen that went into the aft skirt of the boosters. That was analyzed and it was concluded we did not have a problem at the recovery batteries, that we would be above the red line limit on the recovery batteries at launch time, given the temperatures, and we did not have any problem with that amount of GN to the gaseous nitrogen purge going into the aft skirt, the primary concern there being because the temperature of the fuel service module contained
hydrozene fuel that provided the power steering for the solid rocket booster.
At about 7:00 on the evening of the 27th I received a phone call from Stan Reinartz, who is my immediate supervisory, Stanley Reinartz, who is the manager of Shuttle Projects Office at the Marshall Space Flight Center, who works directly for Dr. Lucas, and he had been informed by our resident manager that Thiokol had looked at the conditions for the solid rocket motors and wanted to discuss the situation as they saw it for launch and what they were looking.
And Stan Reinartz and I went out to our resident office and we had a telecon. That telecon involved Reinartz, myself and a Thiokol representative and A1 McDonald at KSC-Kennedy Space Center-a number of people at Marshall Space Flight Center, including the deputy director of engineering, Dr. Lovingood, who is Stan Reinartz deputy, and John McCarty, who is our deputy chief of propulsion, and probably eight or nine other people and probably a dozen or so people at Thiokol.
Thiokol presented to us the fact that the lowest temperature that we had flown an O-ring or a case joint was 53 degrees and they wanted to point out that we would be outside of that experience base.
CHAIRMAN ROGERS: Who did that for Thiokol?
MR. MULLOY: That was the Director of Engineering for Thiokol, a gentleman named Bob Lund.
CHAIRMAN ROGERS: Were you there at the meeting?
MR. McDONALD: Yes, I was there.
MR. MULLOY: Also present at Utah was General Manager and Vice President of the Wasatch Division and manager of the space division at Wasatch-they have three divisions there; space division, tactical division and strategic division-all of the related propulsion people and the project manager, who is Mr. Joe Kilminster.
After hearing the discussion, we all concluded that there was no problem with the predicted temperatures for the SRM and I received a document from the solid rocket motor project manager  at Thiokol to that effect that there was no adverse consequence expected due to the temperatures on the night of the 27th.
DR. RIDE: I guess maybe what I'm asking is we read in the New York Times about NASA internal memos where people within NASA were suggesting problems with erosion before, and I guess I am wondering whether similar memos exist relating to problems of launching with the 0-rings at low temperatures.
MR. MULLOY: I'm not aware of any such documents at Marshall. That is not to say that there aren't any, and we will go research the files to see if there are any.
CHAIRMAN ROGERS: Can we then make it clear that we have requested such documents, if there are any, and that you will provide them?
MR. MOORE: Yes, sir.
CHAIRMAN ROGERS: Secondly, there was a report not about Thiokol but about I think Rockwell, that shortly before the launch, 20 minutes or something to that effect before the launch, someone from Rockwell called and expressed concern about the icing conditions. Do you have any recollection of that call and who made it?
MR. MOORE: As you asked Mr. Aldrich the other day, we had no direct contact with anyone from Rockwell who made that phone call. What we did have was, we did have-Mr. Aldrich held a meeting at about 8:00 in the morning of the launch-and recognize the launch was at 11:38-with a group of technical people who sat down and talked about the ice conditions down on the launch pad. And, as he reported the other day, Rockwell did express some concern initially at that point about some ice that may be coming off the launch platform and
impacting the tiles on the orbiter-and that is the only tie that we have been able to find out that Rockwell may have had a concern.
CHAIRMAN ROGERS: Will someone from Rockwell be there tomorrow?
MR. MOORE: We will see if we can get someone from Rockwell there tomorrow. They are out on the West Coast. I will go back to the office and see if we can get somebody in from Rockwell tonight.
CHAIRMAN ROGERS: Well, I'm not sure it's essential, but I think it is important that we have an answer to that. If Rockwell was the one that raised the concern, then we want somebody from Rockwell to say I raised the concern, we talked it over, and my concern was satisfied and we said go ahead. As long as we still have that concern on the part of Rockwell, if you testify or someone testifies from NASA that there was the meeting and everybody was reasonably satisfied, then someone from Rockwell comes along and says that's not so, we told you not to go ahead and you went ahead anyway, that is the kind of thing we want to try to deal with at these meetings.
DR. FEYNMAN: I just want to go back to something that I would need to know in order to help me to determine what caused the accident rather than these
other problems. When you were giving the thermal data, I've seen some thermal data which may be the same as you are talking about about the O-ring response to the compression set at different temperatures.
But the obvious question is how fast did it return, and I didn't see any data that told me it was millisecond, a second goes by; how much do temperatures vary. I mean, that is typically what a temperature does, is it changes an apparent viscosity, and I would like to get some idea if  the low temperature could have made it so that when things separated temporarily that the joints moved, that it did not do the usual thing and close the gap so quickly so as to let the gas go through.
This seems to me an interesting question and I would like to know as much information as you have on that.
MR. MULLOY: All right, sir, we will collect those test data.
CHAIRMAN ROGERS: On that, might I suggest that you deal directly with Dr. Feynman and give him that information. Then he will give that information to the rest of us. He can perform a very useful function because of his background and knowledge of analyzing that. After he's done that, then he will brief the Commission on his knowledge.
MR. MOORE: Yes, sir. I have made notes where specific members of your Commission have requested data, and I plan to supply that directly to them.
DR. FEYNMAN: I have another request, if I can ask directly, and that is that the leak test point where you are putting pressure in at 200 psi and so forth that you are talking about, is it an escape route that is a principal possible for any gas which goes past the primary seal, and the secondary seal is no longer redundant for another reason; even if it was successfully maintaining the seal, if the gas were to be able to escape through that port because it was closed effectively, would you have also a danger?
Therefore, I would like to get information eventually, and I know you've got so many things to do, but eventually I will be asking about the technique for closing the leak port to be assured that it doesn't itself leak.
MR. MULLOY: Yes, sir. That is one of the trails.
MR. MOORE: Dr. Feynman, our task force which has been set up is trying to get all of the close-out photos and we will make all of that data available to the Commission, hopefully when they come to Florida.
MR. ACHESON: How many leak ports are there in a joint?
MR. MULLOY: One per joint, and on the case joint it is located-one of them is on what is called the minus-,, the side away from the orbiter, and on the other booster it is on the plus-,, and they are all lined up on the case-to-case joints.
DR. FEYNMAN: On the right side booster which side is it on?
MR. MULLOY: On the right side it's on the minus-, away from the orbiter, and the reason they are are clocked that way is we can interchange from left to right the boosters.
DR. LUCAS: But it is in proximity to where the news media photographed, that the leak port is on the same place where the flame was seen.
MR. ACHESON: That is why I asked the question. I can't visualize whether the axis of the port is in the direction toward the tank or the orbiter, or where it is.
MR. MULLOY: The direction of the port is in a direction away from the bottom side of the orbiter on the right-hand booster.
DR. LUCAS: At about a 45-degree angle up?
MR. MULLOY: Yes, sir. And there's one in each joint.
DR. RIDE: So it is in the same area as the
plume was seen?
 MR. MULLOY: The same quadrant, I would say, the same 90-degree segment. I can't get any closer than that.
DR. COVERT: About the same distance from the nozzle-up?
MR. MULLOY: I cannot tell.
MR. ACHESON: I don't want to anticipate how it works, but at the Thursday meeting one of the data we asked for was data relating to what conditions bring about cracking of the propellant material in the motor and if one were to pursue, for example, the hypothesis of not a joint failure but a burn-through on the side, I would assume one would be interested in cracking.
MR. MULLOY: Yes, sir.
MR. ACHESON: So at some point we would like to see that, I don't know whether when we go to the Cape or at some time later, and I just wanted to remind you that that is a request outstanding.
MR. MULLOY: That is one of the trails that the team is following also. The propellant temperature on 51-L was about 56 degrees.
CHAIRMAN ROGERS: My thought is if it is agreeable to the other members of the Commission that we have this public session tomorrow and we will go as long
as we can. We want to be able to obviously answer all of these questions, but then we take a day off and go to the Cape Wednesday night and be there Thursday and Friday.
MR. MOORE: Yes, sir. Our task force is preparing for the Committee to come.
MR. MULLOY: Mr. Chairman, Al McDonald from Morton-Thiokol wanted to make a point.
MR. McDONALD: I wanted to say a point about the meeting. That meeting was called by Thiokol and I got a telephone call to set up a meeting at the Cape, and the meeting was set up at the Cape and we tied Marshall in and Thiokol back in Utah about the concerns of the lower temperatures. The meeting was set up to send material on the fax so that people could review data and concerns and the basis for that concern.
That data was transmitted to Kennedy and also to Marshall from our office at Thiokol. Our Vice President of engineering, I asked him to give that briefing. He did that. The recommendation at that time from the data that was sent out from Thiokol was not to launch below 53 degrees Fahrenheit because that was our lowest acceptable experience base and did demonstrate some blow-by from a year ago and also we had some data that indicated the poor
resiliency of response of the Viton seal to low temperatures, so that was the first transmittal of information saying you should be aware of that, and where the data was discussed.
GENERAL KUTYNA: You said not to launch below 53, and what was the actual temperature?
MR. MULLOY: The actual temperature predicted at that time, based upon Thiokol's calculations, was 29 degrees.
CHAIRMAN ROGERS: Could you stand up again and say that a little louder so we could hear it? I'm not sure we all understood what you said.
MR. McDONALD: What I said was when the concern of the predicted cold temperatures at the Cape were transmitted to our plant our engineers were asked to examine that and see if there was any concern about launching the SRM or any concern with any component. The people who were working the O-ring seal problem were concerned. They called me at the Cape and said we looked at these predicted temperatures. It looks like the O-rings are going to be very cold.
 We have run some tests in the past few months that shows the resiliency of the O-ring is very sluggish at low temperatures. It's very hard. And we would like to review that information. And I said yes, I will set
up a meeting to review that information. We need to review the information and recommend whether we want to launch or what temperature we're willing to launch.
I called Mr. Mulloy at Merritt Island at the Quality Inn and didn't reach him. We had the wrong number or something. And I called Mr. Cecil Houston, who is a resident office manager of Marshall at Kennedy and told him the concern, and he said fine, I will get everyone on the network. I have a four-wire system right off my office in the conference room and we will get all the proper parties involved.
You tell your plant to be available at 8:15 and we will transmit the charts and the data that you have both to Kennedy and to Marshall and I will contact Marshall and have the appropriate people there. He set that meeting up. I went to Kennedy. There was a group of people at Marshall and a group of people at Thiokol.
The material was a little bit late getting there. We waited for about a half hour and then finally the material was transmitted from Thiokol, and in that material was the data that we had on our erosion history and the fact that a year ago we did see some blow-by of the primary seals of the case joint. That was the lowest temperature we calculated the O-rings to be in the flight vehicle. That caused us some concern.
We also had run some resiliency tests on the
O-ring where essentially they were squeezed in between the plates and we removed it very rapidly and the pressurization motor would not respond. We were concerned about what impact that might have in low temperatures and as a result of that our recommendation at the time was to not launch below 53 degrees, because we didn't know how much farther below that we could go and be in the acceptable range.
VICE CHAIRMAN ARMSTRONG: Was that ambient?
MR. McDONALD: That was the temperature of the O-ring. To calculate the temperature in the O-ring containing area based upon what the ambient conditions would be. And, of course, the steel does cool off fairly rapidly. But the liner is somewhat of an insulator so we could tolerate some temperature difference there for a while. But the O-ring finally gets to that temperature. That is what we calculated the temperature of the O-ring at launch a year ago because the local ambient temperature is actually higher than that.
But, if you recall, there were several days of very cold weather on that previous launch a year ago, and we calculated from that history what we thought the O-ring temperatures might be.
DR. COVERT: That was on 51C?
MR. McDONALD: That is correct.
DR. COVERT: What was that temperature?
MR. McDONALD: We calculated it to be about 53 degrees Fahrenheit in the O-ring area. GENERAL KUTYNA: And on this launch it was 29 degrees?
MR. MULLOY: No. That was the single dimension analysis that Thiokol had run during the discussion we had on the 27th. Since then we have run a multi-node thermal model and I believe it is 25 degrees. Bill, do you recall?
 CHAIRMAN ROGERS: Before we come to that, I'm not sure I understand. Am I hearing you say that you recommended against launch and you never changed your mind?
MR. McDONALD: No, I did not say that. We did change our mind afterwards.
CHAIRMAN ROGERS: What brought you to that decision?
MR. McDONALD: Well, the data that was reviewed, NASA concluded that the temperature data we had presented was inconclusive and indeed a lot of the data was inconclusive because the next worst blow-by we had ever seen in a primary seal in a case-to-case field joint was about the highest temperature we had launched at, and that was true-the next worst blow by.
DR. RIDE: Which one was that?
MR. McDONALD: I can't remember exactly. I have it in my notes.
MR. MULLOY: I have it here.
MR. McDONALD: That was true. We did not calculate the effects of all that from the data that we had, but we did have some data that indicated that the timing function of the O-ring seal was going in the wrong direction, in the direction of badness. The O-ring was getting harder. The grease in there was getting more viscous. The time to seat the O-ring took longer and it would be more difficult to extrude it because of the hardened O-ring.
We didn't know exactly where the right temperatures were that would make it so it could not seal, but it was in the wrong direction. And the temperatures that were being reported for the 51-L were so much away from our experience base that we didn't feel comfortable operating that far away.
MR. MULLOY: I don't remember which one it is. We could get it. But one of these it was 75 degrees.
MR. McDONALD: That is 22-A. If you will look at the double asterisk, we saw a certain amount of soot in the primary O-ring even though we didn't see any
erosion. Apparently some gas got past the primary O-ring between the two O-ring seals.
CHAIRMAN ROGERS: Could I say that on this-well, go ahead.
DR. FEYNMAN: It's just a matter of understanding and I want to be clear that I understand that you said you launched at a temperature "that was below 50 degrees Fahrenheit". This was presumably a temperature in the neighborhood of the O-ring?
MR. McDONALD: Yes.
DR. FEYNMAN: At the same time some estimate was being made as to what the temperature in the neighborhood of the O-rings would be as a consequence of the weather at that site at the time of the launch?
MR. McDONALD: Right.
DR. FEYNMAN: The first figure was 50 degrees. What was the second figure?
MR. McDONALD: The 53 degrees was what the O-ring was from a year ago that had the problem.
DR. FEYNMAN: I don't want that.
MR. McDONALD: We calculated, on the projected temperature that was given to us from the Cape, between 26 and 29 degrees Fahrenheit would be the O-ring temperature.
DR. FEYNMAN: In other words, to make it absolutely transparent to me, you are saying that you said, at least at that time, that you didn't want to launch if the O-rings were below 50  degrees and, secondly, you made an estimate, in view of the history of the weather, that the temperature of the O-rings might be as low as 26 or 30 degrees?
MR. McDONALD: That is correct.
DR. FEYNMAN: Therefore, below 50 degrees.
MR. McDONALD: Well below.
DR. FEYNMAN: I just want to be sure. I got the 53 mixed up.
MR. McDONALD: I'm sorry if I mixed you up.
DR. FEYNMAN: So as far as 51-L is concerned, 50 degrees was your first statement, and I'm going to find out what the change in their mind was in a minute. But there were two numbers that didn't match-the 50 that you said you shouldn't fly and the distinctly below 50 they did fly. I just wanted to be sure that I understood.
CHAIRMAN ROGERS: I still don't understand your explanation. Did you change your mind?
MR. McDONALD: Yes. The assessment of the data was that the data was not totally conclusive, that the temperature could affect everything relative to the seal. But there was data that indicated that there were
things going in the wrong direction and this was far from our experience base.
The conclusion being that Thiokol was directed to reassess all the data because the recommendation was not considered acceptable at that time of the 53 degrees. NASA asked us for a reassessment and some more data to show that the temperature in itself can cause this to be a more serious concern than we had said it would be. At that time Thiokol in Utah said that they would like to go off-line and caucus for about five minutes and reassess what data they had there or any other additional data.
And that caucus lasted for, I think, a half hour before they were ready to go back on. When they came back on they said they had reassessed all the data and had come to the conclusion that the temperature influence, based on the data they had available to them, was inconclusive and therefore they recommended a launch.
CHAIRMAN ROGERS: When you say inconclusive, what does that mean?
MR. McDONALD: Well, the fact is - -
CHAIRMAN ROGERS: You told them the day before not to do it and now you've got some more data and you say its inconclusive and so you changed your mind?
MR. McDONALD: I was not back at Wasatch when that discussion was being held. I was at Kennedy and I do not know what other data they were looking at other than the charts that I had in front of me and others had in front of them at both KSC and Marshall. I do not know. I do know they came back on and said they had reassessed it and concluded that it was OK to launch, and at that point in time Thiokol was requested to put that in writing.
CHAIRMAN ROGERS: Well, I think in view of the very serious nature of this and the fact that it will be scrutinized for years that we should have precisely what the data was before we present it.
MR. McDONALD: I have that in my notes, sir.
CHAIRMAN ROGERS: Well, you are just conveying information that pertains to a decision somebody else made.
MR. McDONALD: I have the Fax's that were distributed at both of those meetings in my book that were transmitted, all of the charts from the original meeting and the one afterwards.
CHAIRMAN ROGERS: Who made the decision from Thiokol?
 MR. McDONALD: I do not know who made the final decision. I do know that the fax was signed by Mr. Joe Kilminster, my boss, the vice president.
DR. WALKER: So there's no evidence that the evidence was looked at in this caucus that persuaded Thiokol that your first view was incorrect, that perhaps the first view wasn't based upon solid evidence?
MR. McDONALD: I cannot say specifically about that because I was not there to see it, and I think you need to get people that were at that meeting to discuss that.
CHAIRMAN ROGERS: I'm sure you can see the logic of what you're saying. You recommended against a flight on one night and then you have meetings with NASA people and they seem anxious to go ahead, or at least they were asking questions about it, and they gave you
some data and you checked back with your home office and you got word back from home office to go ahead because the evidence is inconclusive.
DR. COVERT: I believe, if I'm correct, he said that there was first evidence of the low temperature in 51-C, where there was soot but no erosion. And this was a cold launch. This was a 50-degree launch. And you went back to the plant and talked to them and subsequently they were looking around for other cases, if I understand what you said, and they found another case where there was soot, and this was A, which took place in 75-degree temperature.
So at this point the thing suddenly becomes less clear. Do I remember that correctly?
MR. McDONALD: That is correct.
DR. COVERT: So that the additional data, then, was the discovery of 61-A in leafing through the files, where they launched on a warm day and then they decided they didn't know.
DR. RIDE: They also said that they had the data on rebounding or whatever it was of the O-rings.
DR. COVERT: I just wanted to bring up what the other data seemed to be.
DR. FEYNMAN: It would seem to a rational person there might be some other reason why there was a
blow-by at high temperature and that is there was a likelihood at low temperature that you could cause difficulty because of the slowness of response and, therefore, there must have been some technical discussion out there in the plant. And I wasn't quite clear.
You said you had some things with you about the rates of flow. Is that material available to us or could it be made available to us? I don't want to get involved with that as a specialist, but the consequences would be that just because the decision looks like it was technically sound, so I would like to know what kind of logic and so forth was gone into. Is it possible for me to have that?
CHAIRMAN ROGERS: Oh, sure.
DR. FEYNMAN: I would like as much detail on the logic or the apparent logic as was there at that time from that plant; is that OK?
CHAIRMAN ROGERS: Absolutely. And could I suggest that you give Dr. Feynman whatever he wants, but I would express the caution that it's hearsay as far as you're concerned. We really want to get the people before the Commission who made the decisions and ask them why did they appear to change their minds and ask them specifically. Unfortunately, you are just
DR. FEYNMAN: He said something about having something.
CHAIRMAN ROGERS: He does have some data there from the people who made the decision, I guess.
MR. McDONALD: I have some of that, but I also have the material that was reviewed at the meeting by all three parties, because I was party to that.
CHAIRMAN ROGERS: Which meeting now are we talking about?
MR. McDONALD: This was the first meeting scheduled to review why we had any concerns about low temperature, and I have that as a matter of record.
CHAIRMAN ROGERS: Let's be sure that we make it clear if it's one meeting, two meetings, who was there, when was it held, because otherwise it gets all blurred in the minds of the listener, and I gather you had several meetings on this subject-two meetings, three meetings.
MR. McDONALD: Well, there were probably three meetings, yes.
CHAIRMAN ROGERS: Well, make that clear or have your people make that clear.
GENERAL KUTYNA: In your opinion what is the greatest indication of the problem-the amount of erosion or the fact that you have some soot, i.e.,
something that has a lot of erosion like this? Is that more of a problem, than something that has a little soot and no erosion?
MR. McDONALD: I think soot was more of a problem than the erosion. That shows that you had violated the primary seal in some way to get gas between the two seals. The erosion itself, as long as you don't violate the seal it still has the integrity and is not a problem.
GENERAL KUTYNA: So on the coldest day of launch you had erosion and soot and on the hot day of launch you had very little erosion but you had soot?
MR. McDONALD: You had no erosion, but you had soot.
CHAIRMAN ROGERS: Okay.
MR. MOORE: Larry, why don't you go to the last couple of charts there on the program and then let's kind of summarize.
CHAIRMAN ROGERS: Why don't we take a short break?
(A brief recess was taken.)
CHAIRMAN ROGERS: If we could get started again, I will take just a moment, if I may, to introduce to the members of the Commission who don't already know him A1 Keel, who is going to be our Executive Director. He comes with the highest qualifications. He was a
student of Dr. Covert's, but, in addition, he has other minor qualifications, such as he is now and has been for three years-well, you go ahead, A1. You were over in OMB, the Office of Management and Budget.
MR. KEEL: As certainly most of the NASA people around the room have seen my bearded face and even seen it when it had less gray in it, I have been associate director of OMB for international affairs and national security, which deals with everything in the budget except Medicare, Medicaid, and NASA.
For about the last three years, and I've gone through four budgets and before that I was Assistant Secretary of the Air Force for Research, Development and Acquisition, and about the last honest work I did for a living was one minor part of doing some space shuttle aerodynamics about ten or 12 years ago.
 But I'm delighted to be on board, Mr. Chairman.
CHAIRMAN ROGERS: I was hoping you weren't a doctor.
MR. KEEL: My educational credentials are bachelor of aerospace from the University of Virginia and then a doctorate at the University of Virginia, and
then I did some post-doctorate work at UC-Berkeley, which I've hidden from our Administration -(laughter.) - on high altitude aerodynamics.
CHAIRMAN ROGERS: We are very fortunate to have Al with us. He had made some plans to do other things, but because the White House wanted him to work with us and because he realized how important it was, they talked to him about coming with us. So we are very pleased. It looks like we picked exactly the right man, and he will now proceed to develop a staff as soon as he can.
We wanted to continue to get people with the highest qualifications for our staff because we feel it's very important.
Okay. Dr. Mulloy?
MR. MULLOY: Mr. Chairman, you heard Mr. Moore's suggestion that I go to the last three charts I had here that we laid out and have been doing.
(Slide.) [Ref. 2/10-14]
MR. MULLOY: To attempt to better understand the phenomena that you are seeing here with the occasional O-ring erosions, there has been a great deal going on up until August, but it was specific testing that was related to what had we observed on the last
flight and what was our tolerance to that, and has anything happened that changed our rationale that we had from the CIF?
And when we see a particular occurrence we have run analyses and special tests to determine what is the limiting mechanism. Are we still in a situation where we're assured that we still have a safe crit one system? So they were kind of, in that period of time it was more or less ad hoc testing from flight to flight.
And then, as Mike Weeks explained in his presentation, around April, as we began to see more of this and decided what we needed was a systematic effort to see what would be a longterm permanent solution to this, as opposed to living with a limited type thing, we developed and presented in that August 19th briefing a plan that we have essentially followed since that time. And it was to better understand the mechanism and our tolerance to that mechanism and what limiting mechanisms might be in effect to be sure that they were still the same.
I will just describe these. I don't have any diagrams of them. But a cold flow test is essentially just putting air through a joint to understand flow in the joint and in the crevices to see what type, given the input flow, what type of flow we're getting at the O-ring. And we did that on the nozzle because the
nozzle is subject to circumferential flow in the joint, as opposed to the case across the nozzle gimbals and thus gets pressure differential as the nozzle swivels. There is a delicate pressure from one side to the other which can be set up in that O-ring grove as a circumferential flow.
So we ran those tests to understand that, to support what Mark Salita has done in the modeling of this particular event. We decided that the case cold flow wouldn't tell us anything. We dropped those.
 The other key point, as I mentioned, is the rotation of that joint. We only have two measured data points on what that rotation really is, but one of them was on our structural test article, which was the first structural test that we did at the Marshall Space Flight Center, and the other was on a hydro pretest pressure test of a lightweight case, and we got two different results there.
So we're going to run some tests to better understand it.
CHAIRMAN ROGERS: Can you tell us what the chart means? Looking at it, the average person doesn't know what it says. It looks like a series of tests. Can you tell us, not necessarily today, what the tests show?
MR. MULLOY: Yes, sir, I can do that. I won't go any further with that one.
(Slide.) [Ref. 2/10-15]
MR. MULLOY: Then this chart just simply says that with that we have our last qualification motor, which is called QM-5,which was in the stages of assembly. It is a filament-wound case qualification motor and we wanted to take the opportunity for any improvements that we could make in this joint configuration to put more margin into this critical point system and to incorporate that into what is called QM-5. That motor is now assembled at Thiokol.
We had been planning to fire that on February 13. We have that on hold right now. But I will show you that out of all of this testing that was on that previous chart what the conclusion was as to a fix that didn't move us totally outside of the experience base that had taken us through 48 successful motor firings in flight and nine successful motor firings on the ground.
DR. COVERT: I gather that you are satisfied that the rotation isn't the source of the leaking, that this has moved out of the realm of a hypothesis into the realm of fact?
MR. MULLOY: The rotation is a major contributor to the source of leakage. I am satisfied
with that. I don't know that it is the sole cause.
DR. COVERT: I guess I haven't seen any data one way or the other.
MR. MULLOY: That the rotation is or is not?
DR. COVERT: Yes. Is there some data we can look at?
MR. MULLOY: Yes. The data is that the minimum squeeze on the O-ring is 20/1,OOOths of an inch.
DR. COVERT: How did you determine the separation distance when you pressurize this exceeds that 20/1,OOOths?
MR. MULLOY: By having a hole drilled into the clevis and a direct measurement of the rotation at that point, a direct measurement under pressure and load. It is measured.
DR. COVERT: How many measurements?
MR. MULLOY: I'm not sure exactly on the hydroproof. There were several of those measurements. The mean measurement on hydroproof turned out to be 42/1,OOOths rotation. The mean measurement on structural test article turned out to be 60/1,OOOths.
DR. COVERT: This is a deflection really and not a rotation?
MR. MULLOY: It's the measurement of the spreading of the clevis from the tang; that is correct.
DR. COVERT: And this is through the clevis and through the tang and to where the O-ring cavity is?
MR. MULLOY: That is correct, a direct measurement.
 DR. RIDE: Have you calculated any distortion that you might expect in the joint as a result of the loads put on the SRBs before liftoff when it's still held down?
MR. MULLOY: Yes, that is calculated. The joint-from ignition the joint is always under tension within 600 milliseconds. The pressure overrides the compressive loads immediately after the ignition when the joint goes into tension, and the tension, of course, varies because when the SSME is ignited it tends to put pressure on one side, more pressure on one side than the other. But that is calculated and the distribution of that is known.
DR. FEYNMAN: This is just a minor technical point and I shouldn't even interrupt you, but don't you hold the outside with some kind of a skirt or something and the nozzle doesn't get any torque on it with winding?
MR. MULLOY: The skirt is held. The skirt on the motor is held at four points and the nozzle is attached to the aft dome of the SRMs, as I showed in that previous picture. But with the twang, yes, there
is some response of the nozzle also.
MR. MOORE: Let me comment. That is one of the critical things that we're looking in terms of the post-flight analysis.
MR. HOTZ: I can't hear you.
MR. MOORE: Let me comment that we're trying to understand completely the loads at the time the SSME's came on the liftoff during the entire flight of 51-L is one of the primary tasks that our group is trying to work right now.
Johnson Space Center is working those loads as well as the other Centers to try and understand the effects of loads on this particular flight, and we should have some indication of the status of that when you come to Florida on Thursday. We're not sure we will have a complete loads analysis done, but we will certainly give you a status of where we are.
And the other thing we're looking at in addition to a loads analysis, as I said the other day, is a very detailed time line sequence of events of different kinds of forces on the flight as a function of time. So we will try to give you what we can on Thursday of what we have available.
DR. COVERT: I would like to ask one more question and that is this type of a test is vertical
and, therefore, I assume this forward part is down and not the nozzle.
MR. MULLOY: It depends upon which segment you are testing. The closure is on the aft end and then there's a hydroproof dome put on the center segment joints in order to put pressure into the segment.
DR. COVERT: Do I misunderstand then when you hydro test that you have the whole assembly in one big long-
MR. MULLOY: Oh, yes. The hydro test is an individual casting segment, which is two segments with a factory joint.
DR. COVERT: So you have never done any pressure testing or any load measurement of this thing when it's all put together as opposed to just these?
MR. MULLOY: Yes. The structural test article was intended to simulate that. The structural test article is an aft segment, an external tank attach segment and a forward segment and a forward dome. And that had loads and pressure on it.
DR. COVERT: Is that vertical?
MR. MULLOY: No, sir, horizontal.
DR. COVERT: And you put tension on that to simulate the thrust?
 MR. MULLOY: Yes, and we put 1,000 psi on it and then put the loads that, as Jesse mentioning,
the bendover loads, and we measure the joint deflection during all of those tests.
DR. COVERT: And you did that with the heavy gauge and the light casing?
MR. MULLOY: With the light case and the hydroproofing.
GENERAL KUTYNA: Mr. Mulloy, on the 17 July letter from Mr. Davids discussing the changes that might be incorporated in the test, there is a sentence that says, "I have reservations about incorporating the changes considering the significance of the QM-5 firing qualifying these cases for flight." Was that a schedule consideration?
MR. MULLOY: No. I haven't been able to go through all of the information that I have here, but that was a very correct reservation about some of the concepts that were being considered, and I think his reservation was that I hope none of these concepts get on the QM-5, and those concepts are not even programmed because they were not good ideas. I believe that is correct.
I want the QM-5 to represent what we have out at Vandenberg right now, which is the QM configuration and I will.
VICE CHAIRMAN ARMSTRONG: Just one further question. Would you tell us simply what was intended at
the hydro testing? It seems to me it's primarily a load kind of test and it wouldn't tell you much about leakage or those kinds of considerations.
MR. MULLOY: The main driver, as I understand it in researching records on that, the main driver was that the lightweight case just took about 26/1,OOOths of an inch off of the steel cases. The concern was that's going to increase joint rotation first because now you've got a wet membrane, the joint hasn't been changed and therefore you have more joint rotation. That was a driver.
And the other thing was just to run the ultimate load test to be sure that that case would take 140 percent of the maximum extended operating range.
VICE CHAIRMAN ARMSTRONG: So it is a loads deflection kind of measurement?
MR. MULLOY: Yes.
VICE CHAIRMAN ARMSTRONG: What is the configuration again of the test article for the hydro test?
MR. MULLOY: The configuration of the test article, it is mounted into the test fixture a segment, a segment that is shipped to Florida and assembled. And then it has a dome, a test dome that is put onto it, bolted and sealed, such as you would put pressure into
VICE CHAIRMAN ARMSTRONG: What's the other end?
MR. MULLOY: The other end is the test fixture. You just set the clevis down on the test fixture, seal it, and the closure end on the top is the forward dome of the motor.
VICE CHAIRMAN ARMSTRONG: So it is not considered necessary in this application to have case-to-case joint?
MR. MULLOY: That is correct. Or an alternate pressure test. We use the structural test article, the single test article, to get all the joints in, to put the combination of loads and pressures  on them to 140 percent of the limit load with extensive instrumentation, such as we could by test and analytical extrapolation qualify the basic structure.
And then each article goes through a hydroproof test before it is used and reused, which is 112 percent of the maximum expected pressure. And then we thin the walls down and we run 140 percent test on one article to measure the joint rotation and assure the pressure integrity of the thinned-out wall. We have been flying that since STS-8.
MR. WEEKS: Mr. Armstrong, the test he is speaking of has two sections in it and there is a case-to-case joint there, but it is a factory joint and
it is covered with propellant when it is shipped to the Cape for launch.
VICE CHAIRMAN ARMSTRONG: Is it the same configuration as the cross section that we passed around here?
MR. WEEKS: Yes, it is the same, but it is not critical because it is covered with propellant and there is no joint, and wouldn't have putty or any of that sort of thing so it is all cast in a double-sided flank. Each of those sections of the big steel material is about 12 feet long and your whole thing is about 24 feet long when you ship it, but there is a joint there, but it is a factory joint and then covered with propellant.
VICE CHAIRMAN ARMSTRONG: I need to understand the question information that you extract from such a test is applicable to a case-to-case joint where it is not a factory joint and there isn't a propellant across there?
MR. WEEKS: Well, it is a joint, but, you see, there is no putty and no thing for the pressure to enter and break the seal.
MR. MULLOY: Dr. Armstrong, when that test is run, they would not know whether that was a factory joint or a field joint because at the time the test is run there is no propellant and insulation in there.
VICE CHAIRMAN ARMSTRONG: That was the point I
MR. MOORE: It's tested and then taken out and then loaded and then shipped.
MR. MULLOY: Mr. Chairman, the question you asked, what is the bottom line of all of that, is that we concluded-we had planned to fire this QM-5 in December. I made the decision in September to hold that configuration until we could complete this testing to look at what would be the most feasible improvement that would go toward reducing the incidents of erosion and blow-by.
CHAIRMAN ROGERS: What was your conclusion?
(Slide.) [Ref. 2/10-16]
MR. MULLOY: The conclusion was that the best thing to do at this time-and we ran an assembly test to make sure we could do this, but the thing that constrains the size of the O-ring that you can put in a groove is that in putting it together that you don't shear the O-ring or do damage to the O-ring in putting it together.
We concluded through assembly tests that we could go up in the size of the O-ring in the case-to-case joint from .280 to .292, and we demonstrated that that could be accomplished. Now what that does, it increases the initial compression on the
O-ring and enhances the capability for it to maintain a compression such that when the motor pressure hits it that it can extrude into the gap and give us a good primary seal.
 Now if we have a good primary seal we now have a reliable, a good, reliable primary seal. The concern for having the liftoff situation where the secondary seal cannot be pressure actuated is reduced somewhat.
The other thing we did-and I can show you a picture here from all of that cold flow testing-is in the nozzle joint. This refers to a Turcon spacer, and Turcon is an unfilled Teflon. We found on this nozzle joint--
(Slide.) [Ref. 2/10-17]
MR. MULLOY: - that this groove had been made as wide as it is. Because this nozzle has to slide over this and there's an interference, almost an interference fit at this location. The design was made with a very wide groove there to allow that O-ring to move as you install the nozzle to assure that we didn't damage that O-ring.
We found that through assembly test that if we can put the nozzle on in the vertical instead of the horizontal, when you lay the motor case down in the horizontal it develops an ovality and now you're trying
to mate a round part to an oval part. We found that if we would install the nozzle in the vertical we could reduce the size of this gap.
Now the effect that that has, we thought we would have a leak check port between the two seals such that when we run that leak pressure test at 200 psi and then 50 psi for ten minutes to validate that we have a good seal that tends to move this O-ring in the wrong direction.
This is the motor pressure side over here, and so now when the motor pressure comes through this putty and impinges on this O-ring that's sitting over here and it's not sealed-it has just got compression on it-that O-ring has to travel from this side of the groove to this side of the groove and then extrude into this gap. That is when you are getting your erosion, while that hot gas jet is impinging on that O-ring.
So what we concluded was put this Turcon spacer in there such that when we run the leak check we don't move this O-ring all the way back over to the other side of the gap, which now should reduce the incidence of erosion that we're seeing on the nozzle joints.
DR. FEYNMAN: Why? The same gas comes.
MR. MULLOY: But the time of blow-by is not as long.
DR. FEYNMAN: There's blow-by either way?
MR. MULLOY: If you don't have initial compression there is, but if the O-ring has the 7.54 percent compression and it's over here, it is going to immediately extrude into the gap. If it is over here, it has got-1,000 psi has to move that O-ring to the other side during the time it leaks through because that compression is not adequate to hold 1,000 psi until the O-ring gets over here and extrudes in the gap.
So the bottom line of all that testing was these-putting a bigger O-ring in the joints and putting a spacer in this is the best solution of all of the testing that we did.
CHAIRMAN ROGERS: Is that what you did in 51-L, then?
MR. MULLOY: No, sir. 51-L is the same thing.
CHAIRMAN ROGERS: This is just a consideration for improvements in the future?
MR. MULLOY: That is what we had been doing for the last year, is running all of these tests that were on the bar graph to determine what kind of a fix might work to reduce the incidence of erosion.
CHAIRMAN ROGERS: This was for the future, though, and didn't affect 51-L?
MR. MULLOY: It did not affect 51-L.
CHAIRMAN ROGERS: These are studies you had been making to try to improve it?
MR. MULLOY: Yes, sir, and my point is we would never put a change on a flight vehicle before we qualified it.
DR. RIDE: This was just for the filament wound cases?
MR. MULLOY: No, I wanted to qualify it on the filament wound case, but the case-to-case joint other than the rotation is not any different-is not really any different than on the steel cases. The nozzle joint is identical.
DR. RIDE: So this really is something you are thinking of.
MR. MULLOY: What I wanted to do was qualify this on the QM-5. If I qualified it on QM-5, based upon the other testing that I have already done and the analysis that Mark has done, I would put the spacer in the nozzle joint, and I don't have to do anything. I don't have to get any metal parts or anything, and I can improve that O-ring situation. As far as the case joint, .292, if it would extrude into the gap on QM-5 where the joint isn't rotating, it would certainly extrude into the gap on steel, and I am
putting a .292 O-ring in the seal.
DR. WALKER: What is QM-5?
MR. MULLOY: That's the last qualification motor on the filament wound case program. The nozzle-to-case joint on QM-5 is identical to the steel casing.
MR. MOORE: Let's get to the last couple of charts.
MR. MULLOY: That's it.
MR. MOORE: I understand that.
CHAIRMAN ROGERS: We will have plenty of time to study the other things you have been doing to improve things, but I think the focus of attention is going to be what caused this accident.
MR. MOORE: Sir, what we tried to do with this briefing today was to bring you all the documentation that I have available in my office that deals with the question of O-rings because that is a highly suspicious
area. So we wanted to give the members of the Commission the data that we've got on the O-ring situation, and I think tomorrow that is something that you ought to talk about, I guess, after this briefing, what area do you think from the Commission's standpoint you would like to discuss tomorrow, and we will go back and work this thing.
Larry has got two more charts, and that's it.
(Viewgraph.) [Ref. 2/10-18]
MR. MULLOY: I think we can wind up with this one. This chart is the one right out of the August 19th briefing. This is general conclusions about what happens with O-ring erosion. That was good on August 19, and it is still good today.
DR. COVERT: Does it follow logically if you eliminate erosion or you eliminate soot?
MR. MULLOY: No, sir. As long as that O-ring has to move before it extrudes into the gap, you will have gas blow-by. If the gas burns grease in the process, you will get soot. If there is not much grease there, we have indications of blow-by where it has been clean.
 DR. COVERT: Mark, is it your view that there would be blow-by--
MR. SALITA: No intuitively I would say not. There are going to be many times
when you have enough pressure or enough O-ring squeeze that you will not have blow-by. We have already seen four instances of soot behind the O-ring, and we have fired 177 field joints so far, flight and test motors. Of the 171 we have looked at, we have only seen four cases of any evidence of soot behind the primary O-ring.
DR. COVERT: Well, if you could have blow-by without soot-
MR. SALITA: Well, what evidence do we have that we have any heat effect in the zone? We haven't seen any heat effect in the zone that I've seen.
MR. ACHESON: Could you explain why erosion in the nozzle joints is more severe due to eccentricity?
MR. MULLOY: Yes. I was explaining we assemble the nozzle in the horizontal. The nozzle is round. The case is laying in the chocks and tends to get oval, and so you are putting a round object into an ellipse, so there is eccentricity there.
(Viewgraph.) [Ref. 2/10-19]
MR. MULLOY: Now, the recommendations that were presented in August are these. This recognizes the concern that the lack of a good secondary seal in the field joint is most critical, and ways to reduce the joint rotation should be incorporated as soon as possible to reduce criticality.
Now, what we did in response to that-
(Viewgraph.) [Ref. 2/10-20]
MR. MULLOY: - is even before that recommendation was made in August, in July I had moved out to procure larger billets for the motor. The way these motor casings are made, ladisch, a proprietary process, rolls these things with no welding on them, so we just told them to build the billets with three inches less ID so that we would have extra material inside such that we could machine a capture feature just like we have on the filament wound casing.
MR. FEYNMAN: None of these things went into 51-L?
MR. MULLOY: No. I was just responding to the recommendations of August, and we now will have the first of those parts delivered in 1986, in August of 1986, where we can reduce them, and respond to that recommendation to reduce joint rotation in the field joints.
(Viewgraph.) [Ref. 2/10-21]
MR. MULLOY: This recommendation was to go do that testing that we did in order to determine what the proper fix was and incorporate it in QM-5. It was recommended that we use the QM-5 or an alternate putty. It has nothing to do with a better putty. People who use asbestos are stopping making that material, and the
reason we went from Fuller-O'Brien to Randolph was because Fuller- O'Brien wasn't making it and Randolph might quit making it. So we discussed what to do with the filament wound case in that first flight out of Vandenberg. But again, a recommendation to do additional testing, which we have done, that was the program plan I showed you, and the conclusion at that time was that the analysis of the existing data indicates that it is safe to continue flying existing designs as long as joints are leak checked with a 200 psig stabilization pressure, and are free of contamination in the seal areas, and meet the squeeze requirements.
DR. RIDE: How do you determine the contaminations?
 MR. MULLOY: Well, that's a visual inspection. We go to great lengths to be sure that we keep the O-rings clean. The joints are initially greased and put into what we call the short stack. The aft assembly is put on the aft skirt and the motor and then moved over, and that is all degreased and inspected and then regreased, and great caution is taken to be sure that the surface is clean, and when we get the motors back we do a thorough inspection of that to assure that we haven't gotten any pitting due to the fact that they have been in the water. We take great care to be sure that we have got good seals. And then the O-rings are brought in to Wasatch, in Utah.
There the O-rings are inspected, cleaned, greased, and then they are sealed, and they are not taken out of the bag until the O-rings are delivered at the assembly point to assure that we don't pick up any contamination.
DR. RIDE: Have you ever found water in any of the soot?
MR. MULLOY: It has been reported to me, and that is being verified because we have not found any documentation yet that indicates it, but it is reported that on STS-9 that we had to roll back and destack STS-9 because of the 8A nozzle erosion. It is reported that when they pulled the pins on that joint, that water came out of the joint.
It is also reported when they broke a segment open one time, that water came out of a joint. That is being-KSC is tracking that, and we are looking for any documentation that indicates that. That was reported to me after the 51-L accident.
DR. WALKER: That would be water trapped between the two O-rings?
MR. MULLOY: No, it would be water in the-if I went back to my joint that I ran, the crevice was up.
CHAIRMAN ROGERS: Go ahead, but I really want
to get to a discussion of what we are going to do tomorrow.
What you are saying is we have conducted extensive tests of this type and that type, and have concluded as follows, and these are the recommendations, but anybody there is going to be interested in what are the things that happened that relate to 51-L. I mean, others are going to say that this is a filibuster.
Now, you have told us now, and we will have a chance to ask a lot of further questions, but if we appear to be ducking the issue, the issue is what happened prior to the launch of 51-L.
DR. COVERT: Sir, it seems to me when we first sat down and went through the first letter, one of the concerns was have you fellows done anything to react to this-I don't want to use the word "threat" because of the discussion today-but this problem that may come up in the joint, and the last few viewgraphs here have been the result, as I understand it, of what they have done in the last year to try to make the integrity of this joint be more satisfactory.
CHAIRMAN ROGERS: Yes, I think that is good. But I just think we ought to shorten it.
DR. COVERT: I misunderstood what you said.
CHAIRMAN ROGERS: I think that is fine, but if
you went through all of the things that Larry has gone through and then the last question is does any of this relate to 51-L, and the answer is no, everybody is going to say well why did you spend all of that time on it? I mean, he can say it and we can report it in our report and all of these things, but I think these last three charts were fine.
 GENERAL KUTYNA: The next to the last bullet says it is safe to fly if you pass the 200 pound test.
Did 51-L pass the 200 pound test?
MR. MULLOY: Yes. There were no anomalies reported to me yet. In fact, I understand the people that did the psi leak--
DR. RIDE: Do you have closeout photos on that?
MR. MULLOY: Yes, we have gotten closeout photos in my task force at the Cape, and we also have had a very preliminary report on the leak check-the supervising of the leak check process out at Kennedy Space Center, and the preliminary indication is there were absolutely no anomalies in the leak check on this particular flight.
GENERAL KUTYNA: But Jess, do you see my dilemma, that it is safe to fly if you pass this test, and you passed the test?
DR. COVERT: Maybe the test we have been pursuing is not the source of the accident.
DR. LUCAS: If it turns out that the O-ring is a problem, and we haven't determined that. VICE CHAIRMAN ARMSTRONG: I am concerned, Mr. Chairman, in looking ahead at the perspective of the audience and the people listening, that we will have demonstrated that there was a concern in this particular technical area, but it wasn't deemed dangerous to fly, it was deemed safe to fly, but it was also deemed that it ought to be fixed and be better, and work was going on, which makes an understandable story to me, but I am not sure that it will be understandable to everybody else.
Why was it safe? You know, they are always trying to simplify points to the things, of give me a black or white or yes or no answer, was it safe or not? And if it was, why were you fixing it? And that concerns me a little bit.
MR. MOORE: It concerns us as well, too.
MR. FEYNMAN: If you look at this from a naive point of view, which many people will, I am just emphasizing his point that it was-presented this way, it does look terrible because if you juxtapose the first sentence, the first item, with the next to the last item, you find two sentences-and I am just emphasizing your point to make it more dramatic-that
say-and I am giving the report-the lack of a good secondary seal in the field joint is most critical, and ways to reduce joint rotation should be incorporated as soon as possible. Analysis of the existing data indicates that it is safe to continue flying.
CHAIRMAN ROGERS: That is really what it is saying, but you are just making it more dramatic.
MR. HOTZ: You have got a real problem with that.
[Please note that some of the titles to the references listed below do not appear in the original text. Titles are included to identify and clarify the linked references- Chris Gamble, html editor]
 [Ref. 2/10-12] Space Shuttle SRM Joints.
 [Ref. 2/10-13] Space Shuttle SRM Segment Joint.
 [Ref. 2/10-14] Past History Comparison.
 [Ref. 2/10-15] QM-5 Options
 [Ref. 2/10-16] Concepts Implemented in QM-5. [Ref. 2/10-17] QM-5 Nozzle Joint.
 [Ref. 2/10-18] General Conclusions. [Ref. 2/10-19] Recommendations.
 [Ref. 2/10-20] Capture Direction.
 [Ref. 2/10-21] Concepts Implemented in QM-5.
 CHAIRMAN ROGERS: Well, thank you very much.
Let's talk a little bit about tomorrow. We will meet at 10:00 o'clock. We will say that we had material presented in some detail, and we want to go over pretty much the same information. You can summarize some of it because we heard it, and we want to deal with some of the questions that have been raised and that were publicly made, and we will try to relate our investigation tomorrow to those issues.
Now, we have to decide who we should ask to testify or to make statements, and I would think that Larry is fine, but now we have got to get down to answering the specific questions about what was done, and in 1985 you had these concerns, and it seems to me somebody should deal with it in chronological order and say yes, we had these problems; here's what we did: we
had a meeting, we wrote a report, here's what we said. We still had concerns. We did the following things. Here's how we did it, and just have a chronology in narrative form of what happened, because otherwise it looks as if-and I heard some of the people the other day felt it was too long or windy. Well, I don't think we have to worry about it as long as we tell a narrative story in which the conclusions that you reach-and I mean, conclusions in the sense that you say well, after those studies were made, and so forth, that we made the decisions, and here is why we made them. Somebody has to say that.
Now, everybody recognizes that you are going to make mistakes in judgment, but at least we have to show that it wasn't done in a careless fashion and that there were meetings and you thought about it and who was there and things of that kind.
Now, whether you can do that tomorrow or not, I don't know.
MR. MOORE: I would like to volunteer to start it off tomorrow and try to put some of this in context and so forth to try to give the flavor that you were just citing, Mr. Chairman, about the context of the actions that were taken.
CHAIRMAN ROGERS: Would you give us a list of
the people that you think you may want to call?
MR. MOORE: I think the only two people that we would like to have testify is probably myself and I think Larry Mulloy will talk tomorrow, and those are probably the two principal ones.
I think I would put a question mark on Mike, and I think Mike and I can sit down and talk tonight and decide that. I don't know if we need that precise answer immediately, but I think we will go back to NASA headquarters and begin working on that.
CHAIRMAN ROGERS: What documents can we provide and make available to the public?
MR. HOTZ: Is this whole thing going to be available?
MR. MOORE: No, sir. What my proposal would be, I made these documents specifically for the Commission. My proposal would be to go back and take a subset of this documentation, much smaller than that, and present it to you and the other members or the Commission as we will testify on it tomorrow, and we will go through on a slide by slide basis the charts as we did in our testimony to you on Thursday.
MR. HOTZ: Mr. Chairman, I wonder if the memos that are specifically referred to in the New York Times story will be presented as part of our public record.
MR. MOORE: Yes, sir. I would propose to do that in the morning, absolutely. I would propose to put those memos in the context is why I suggested, if it was acceptable to you, that I would plan to initiate this whole discussion to try to put those memos in context.
CHAIRMAN ROGERS: Are there any memos in here that haven't been made public?
MR. MOORE: No, sir.
CHAIRMAN ROGERS: I mean, if we say some documents were given to us but we can't make them public, that creates a whole new question.
MR. MOORE: No, sir. The thing we also can't control, Mr. Chairman, is there is none of this documentation that is, you know, of a classified nature and being held tightly. I mean, this is information in our files, and it is hard to tell where copies of the information are, and why we tried to present you and the
Commission with as comprehensive a set of documentation as we can, is so we don't get surprised in the future by somebody showing up with another document.
DR. RIDE: Are there any documents in here that were not made public in the New York Times?
MR. MOORE: Yes, there was a document in there by Russ Bardos who wrote a document to Mr. Winterhalter suggesting that the SRM system should continue to fly and we should not make any quick fixes to the SRM in preparation for the QM-5 flight testing.
CHAIRMAN ROGERS: Why don't we make all of these documents public?
MR. HOTZ: That's a good idea.
CHAIRMAN ROGERS: I mean, if - -
MR. HOTZ: It would be very salutary if we made a very complete record public, more than what the New York Times had. That would defuse a lot of this issue.
MR. MOORE: Could I suggest that the Commission consider releasing the document we provide you tomorrow which will have all of the memos and so forth? There will be the New York Times data plus additional data, and I would suggest to you, Mr. Chairman, that that be the document released to the public, although I personally don't have any problem if
you want to release this.
MR. HOTZ: No, just the relevant material.
MR. MOORE: Sir, we may appear a little disorganized here today, but we put this stuff together very quickly, and I would like to have a chance to go back together and organize it.
CHAIRMAN ROGERS: Well, why don't you do that, but why don't you proceed on the theory that all of this is going to be made public. If we don't do it tomorrow, it will be-I mean, it will be a mess for the press, and it is hard for us, and I am not being critical, but you do what you think you should do, and you say we are going to make all the documents available to the press, and if there are any classified documents, we won't, but as far as we can tell, these are not classified.
MR. MOORE: To my knowledge, in my office back there and my people that are working there that have
identified that, we do not have any additional data that is relevant to this subject that is not compiled in this document here.
VICE CHAIRMAN ARMSTRONG: Mr. Chairman, I think it would be helpful if at some early time they describe how the seal is intended to work. I think we sort of had to dig that out of them here. If you could describe how it is supposed to extrude and so on, and what a normal course that that seal would seek, the normal environment that it would seek, it would be helpful for everybody to understand.
CHAIRMAN ROGERS: We can also say, of course, tomorrow that we are going to meet on Thursday and Friday when we have an opportunity to see them first hand, but I think you are right, I think tomorrow if you could assume that you are talking to people who are not experts in it, because you have got the public there, and explain it to them.
 MR. MOORE: What about the Rockwell person also?
CHAIRMAN ROGERS: Well, I don't think, if nobody knows anything about it, I mean, have already testified to that here today.
MR. MOORE: I testified-Arnie Aldrich and I did not receive to my knowledge any comments or any calls from Rockwell management persons.
CHAIRMAN ROGERS: And no one is here from Rockwell today?
MR. MOORE: No, sir. No one is here from Rockwell.
CHAIRMAN ROGERS: Well, I think it might be a good idea for you to check and ask them so we are not surprised again.
MR. MOORE: I will do that. Someone is supposed to be doing that down in Florida, and I just haven't gotten a report back.
How long should we plan on going tomorrow, Mr. Chairman?
CHAIRMAN ROGERS: Well, I would guess it would go all day, maybe not. If we could get out earlier, I would rather do it, but I think you will find tremendous interest as we expected. I mean, we have been shown a list of newspapers and networks. I mean, we want to try to be-I tell you, I like the questions that were asked today, and I wouldn't hesitate to ask the same questions tomorrow because it shows that members of this Commission have a lot of background on this subject, and I don't think we should hesitate to ask these questions again, and I thought they were all good.
DR. COVERT: We might dig up some new ones overnight.
GENERAL KUTYNA: We spent all day on the seals. What if we were to ask you what other avenues
you are pursuing?
MR. MOORE: We would be able to talk about that. As a matter of fact, I would be able to tell you in general terms what other avenues we are putting, not fault trees but problem trees, if you want to call it, together in all areas. None of the systems in the Shuttle system have been exonerated at this point in time. My task force is just getting started, and I see it running for many months, and no system has been checked off as being completely exonerated from any cause of the 51-L incident, and that is one of the opening statements that I was going to make in the morning about the activities that we are going through.
CHAIRMAN ROGERS: And another thing you could say is that when we are down there we are going to meet with the head of the team so that we get a better idea of how they are proceeding and how we can cooperate and coordinate our activities.
MR. MOORE: Maybe I should give a brief status of what the task force that I have been charged with is doing down there.
Sir, do you think on Thursday and Friday's meeting, will you want to have it closed, or do you want to have it open?
CHAIRMAN ROGERS: Well, I think it has got to be closed. We are not going to have a meeting. We are
going to look at things, and we are going to have a lot of private discussion. So we are not having a meeting as such.
And let's decide whether we want a meeting on Friday or not. Let's just say we are going to be there and we have no meeting scheduled.
 MR. MOORE: We want to make sure that you see some of the hardware and see the SRBs and the stacking and those kinds of things.
CHAIRMAN ROGERS: So if Thursday if we decide to have a short meeting, sort of summarizing what we have seen or telling people what we have done, we can do that, but let's not preempt ourselves.
DR. COVERT: Is there a travel schedule prepared?
CHAIRMAN ROGERS: Do we have any schedule?
MR. THOMPSON: What I would like to do is sit down this evening with Al and try to put together between--
CHAIRMAN ROGERS: Are we all going to be leaving from Washington?
MR. THOMPSON: I am anticipating that.
CHAIRMAN ROGERS: I said when we had lunch that I will not prevent any question from being asked. At least I won't answer any question that relates to
anything more than 12 hours away.
DR. WALKER: When will we start on Thursday?
MR. THOMPSON: Well, we tentatively plan to start at 10:00 a.m. on Thursday.
MR. KEEL: The notion that John had was to have a plane leave early from National on Thursday morning so we wouldn't have to stay overnight.
We will stay overnight Thursday.
MR. THOMPSON: There are a couple of things I would like to talk to the Commission about.
CHAIRMAN ROGERS: Do you want to do it in executive session?
MR. THOMPSON: Yes.
MR. CULBERTSON: If I could say this, and I have not been involved in the investigation and all, and that is this, that there is a concern I always have. We have internal investigations about everything, but I can see it coming. NASA is by its nature an organization in
which we try to encourage everybody to express his point of view, and the meeting that we have on the kind of decisions that we have gone through here today, we go around, and if anybody has a dissenting point of view, we want it expressed.
When we get ready for a launch, as Jesse said, he polls 27 people or some such number, all the contractors and all the government people, are we ready, and in a lot of the kinds of things that we do there are no black and white answers on these issues. They are grey. And I don't know, if what I am going to say is going to influence what you are doing, but I would hope that the system that we use to draw out points of view is not impugned by the Commission judging the way we do things. It is an important process.
CHAIRMAN ROGERS: Well, if I understand your question, it breaks down into two parts. Anything that happened prior to the launch or immediately after is public property. It is all going to be in the public domain, no matter what you think.
MR. CULBERTSON: I'm not saying that. I think we ought to be forthright in giving all the data we have got, including every point of view, but don't expect not to find many points of view which would say don't do that or make a different decision because those were
all expressed, and as you go through this, you will find many, many times eight people said yes and one person said no, and that person may have been right, and you are going to have to evaluate all of those things.
CHAIRMAN ROGERS: That is true throughout government generally. Everybody knows that. Anybody that has lived in government in Washington knows all of those things come out, whether it is the President of the United States or anyone else. I mean, he has all kinds of people saying what they told him and so forth.
I think the more difficult problem is it is your investigation. We don't want to intrude on your investigation, and you should go ahead and try not to. At the conclusion of your investigation you will give us information and you will come to some conclusions, and we can then take that and not-we are not going to tackle everybody who has been involved in the investigation, but let me tell you-and I told some of the members of the Commission, I have two letters from Congress, one from the Senate, one from the House, saying they are going to not do anything while we are going through this process, but as soon as it is over with they are going to analyze the report we make, and they are going to have an overview of us. So at that time we will be in the same position you fellows are in now. We will
be spending three or four or five days up there and trying to say why we said what we said in the report.
And that is just the way it operates.
MR. CULBERTSON: Well, as I said, I don't know how what I said could influence what you are doing, but you must expect that you probably haven't seen the last of these memos where somebody says hey, don't do it. You will probably come across many.
We are searching our files to find those things.
CHAIRMAN ROGERS: Well, that's fine.
MR. McDONALD: Could I find out when you want the people from Thiokol?
CHAIRMAN ROGERS: It won't be tomorrow. Maybe you will have to say something tomorrow, but if you do, depending upon how it goes-but if you do, I will just say that we have asked you to have other witnesses with firsthand information a little later on.
DR. WALKER: Where are we meeting tomorrow?
MR. KEEL: In the State Department.
CHAIRMAN ROGERS: Okay, thank you very much.
(Whereupon, at 6:05 o'clock p.m., the Commission recessed, to reconvene at 10:00 o'clock a.m., Tuesday, February 11, 1986, in open session.)