CHAIRMAN ROGERS: This morning, the first item on the agenda is the Thiokol discussion, and I thought that in order to lay a foundation for the discussion, I might have Dr. Keel, who is our Executive Director, refer to comments that were made in our executive session, whenever it was - I've lost track of the date, I guess last week - by Mr. McDonald.
DR. KEEL: Yes.
CHAIRMAN ROGERS: I think this will give you a good starting point. We didn't ask the questions at that time. We thought we should have the principals here so we could ask them. So with your permission, we will do that, and you can summarize it, A1.
DR. KEEL: Yes. I will just, Mr. Chairman, at your direction just - we have selected excerpts from this, and let the record show that this is excerpts from the closed session of Monday,  February 10th, before the Commission. I will begin - this is after Mr. McDonald first rose and explained the fact that there was a discussion prior to launch expressing concern about the temperature at the seal and the performance of the O-rings at that temperature.
CHAIRMAN ROGERS: You really said "discussions," so there were more than one.
DR. KEEL: That is correct.
"Chairman Rogers: 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 the temperature data we had 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 seal joint, was about the highest temperature we had launched at,
and that was true."
And I'm skipping ahead now in the testimony:
"Chairman Rogers: 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 the time, at the 53 degrees.
"NASA asked us for a reassessment and some more data to show the temperature in itself could 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.
"That caucus lasted for I think a half hour before they were ready to go back on, and when they came back on they said they had reassessed all the data. They 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
"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 then now you've got some more data and you say it is inconclusive and 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 that they 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 okay 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."
CHAIRMAN ROGERS: Well, this meeting today is in the nature of an investigation and not really a hearing, so it is not necessary to swear anybody in.
When we have our regular formal meetings, we swear all our witnesses, but this really is for us to assess the facts and to see how they will be presented later on.
So, although it is going to be recorded, it is not going to be sworn testimony. That doesn't mean we don't want the truth, but it means that this is not formal, this is informal and in the nature of an investigation, and we want to have you feel free to have a discussion about the facts.
And what I have in mind particularly, and I think the rest of the Commission does, is to be sure that we know precisely what the facts were, who was involved, and as much as you can remember what was said, and if there were any documents relating to those discussions we would like to take a look at the documents.
And if there was any impounding of documents, critical documents, we would like to know that, when it happened, who has them if there are documents of that kind - all of the facts that relate to this very critical period in the launch.
MR. REINARTZ: Mr. Chairman, I'm Stan Reinartz from the Marshall Space Flight Center. I'm the project manager for our propulsion elements.
What we would propose, subject to your
concurrence, is that Mr. Mulloy, our SRB project manager from Marshall, give you the background that led up to the discussion that we had with Morton Thiokol, list the participants, including myself, in that telecon, and run through what we had, a very brief summary, and then we would provide Morton Thiokol the opportunity to then discuss on their side of the situation how they viewed it, if that is acceptable.
CHAIRMAN ROGERS: Sure.
MR. REINARTZ: All right, Sir, Larry Mulloy.
MR. MULLOY: Mr. Chairman and members of the Commission:
(Viewgraph.) [Ref. 2/14-1 1 of 4]
The decision to scrub the 51-L mission on January the 27th was made at approximately 1:00 p.m. by my recollection. Now, I had put approximate symbols in front of these times but I don't have the precise times.
But of course during the launch process, the project managers at Marshall and Dr. Lucas are on a communication net with personnel back at our Huntsville operations support center and also personnel that we have in the backup firing room here at Kennedy. We communicate with those people - they are technical specialists - relative to any problems or during the launch count any anomalies that come up, any potential launch commit criteria violations that come up during the course of the count.
And then subsequent to the launch or subsequent to a launch scrub, we stay on the net and communicate with those people relative to our ability to turn around within 24 or 48 hours on any concerns that might be related to that.
So what happened on the 27th, after the
decision to scrub, we polled our support personnel who were on the net, and that includes USBI, Booster Production Company, and Morton Thiokol personnel, regarding any constraints to a 24 hour recycle, in other words of going at 9:38 on the 28th of January.
This was about 30 minutes after the launch scrub. Some input did come back, and what they had looked at was all elements of the system. Our request then went into the system, which Morton Thiokol will discuss as to how they reacted to that request, any constraints for a 24-hour turn-around.
The input that I got back about 30 minutes after launch scrub on the net was that the concerns that had been worked were related to the recovery battery temperatures on the solid rocket boosters. We have a launch commit criteria red lined for those, and the fuel service module, hydrozene modules in the aft skirt that work the thrust vector control system on the solid rocket booster.
At that time, at about 1:30, there was no concern or no input back relative to any concerns for the solid rocket motor, considering the predicted temperatures.
The next event that I am aware of is about 5:15 that afternoon. In response to that request to
work, Al had - well, I will let him cover what he did, but he called our MSSE resident office, Cecil Houston, to inform him that Thiokol engineering did have some concerns regarding the function of the O-rings at the predicted temperatures.
CHAIRMAN ROGERS: Could I interrupt. Was there a discussion about the weather prior to the scrub?
MR. MULLOY: No, sir.
CHAIRMAN ROGERS: In other words, the first discussions you remember about the weather occurred at 5:15?
MR. MULLOY: Yes, sir. It was in the assessment of, do we have any problems with going at 9:38 on the 28th of January. And then it was pointed out that the temperatures were predicted to get below freezing, and there were a lot of aspects of that consideration for the work. Of course, there was water on the pad and potential bursting of pipes, ice on the external tank, et cetera.
MR. ALDRICH: Excuse me, Larry. To be consistent with the discussion we had yesterday, between the 1:00 p.m. meeting and the 5:15 p.m. meeting there was a mission management team that met, too, which Jess Moore and myself conducted in the launch control center, where we met with all of the projects and discussed whether we should pick up for launch the next day.
And at that meeting, we elected to pick up, and we were most concerned about the temps on the facility. But we asked the facility and the other elements to review the temperatures and call if we developed any complications downstream which would make that decision.
CHAIRMAN ROGERS: So at 2:00 o'clock -
MR. ALDRICH: So at 2:00 o'clock we called the level two and the level one of the projects, which fits between these two times.
CHAIRMAN ROGERS: Excuse me. I think I've changed my mind. If you don't mind, I think all the people from Thiokol that are going to talk today, let's swear them all in at one time, because if we don't and we have sworn the other witnesses it may in retrospect look a little odd.
So if you will all stand up and be sworn.
 (The following witnesses were sworn: Jerry Mason, Cal Wiggins, Joe Kilminster, Robert Lund, Don Ketner, Roger Boisjoly, Arnie Thompson, Al McDonald, and Boyd Brinton.)
MR. MULLOY: Sir, I will show on the chart the participants who are here.
CHAIRMAN ROGERS: When you are asked to comment, if you would identify yourself so the reporter will be able to record this.
MR. MULLOY: And following up on Arnie's comment -
CHAIRMAN ROGERS: Now, as much as possible, when you say we called the facility, if you remember who you called or who somebody called, let's use names, so if we trace what happened we have people instead of buildings.
MR. MULLOY: Yes, sir, will do.
Following up on Arnie's comment, what I just stated relative to our concerns, I stated in that mission management team meeting that we had worked those two concerns. And I cannot recall any discussion in that mission management team meeting relative to SRM temperatures.
MR. ALDRICH: I do not recall such discussion.
MR. MULLOY: Now, Al called the resident office. He will testify to that. Cecil Houston about ten minutes later then was able to get in contact with Jud Lovingood, who is here today - he's the Deputy Manager of the Shuttle Projects Office, of Mr. Reinartz - and relaying this concern that Al had pointed out to establish a telecon with Reinartz, myself, George Hardy at the Marshall Space Flight Center, and engineering and program people who were at the Thiokol Wasatch division
That telecon did occur. I did not participate in that telecon. They were unable to get in touch with me at that time, but that telecon occurred between Lovingood, Reinartz, and Thiokol personnel, and other personnel at Marshall Space Flight Center. And the result of that was to listen to the concerns as expressed here just in oral transmission. They had no data at that time.
The result of that was to set up a telecon where we could get all of the data transmitted to all of the parties and have more personnel participating in that.
CHAIRMAN ROGERS: And we will be able to be told by somebody what the comments were at that time?
MR. MULLOY: Yes, sir. At the 8:15?
CHAIRMAN ROGERS: Yes.
MR. MULLOY: Yes, sir, and I'm going into that.
DR. WHEELON: Is it your practice to record these telecons on magnetic tape?
MR. MULLOY: No, sir.
DR. WHEELON: There is no record of that -
MR. MULLOY: To my knowledge, this telecon was not recorded.
DR. WHEELON: Are others, and this not? Or is it your practice not to do so?
MR. MULLOY: It is our practice not to do so.?
DR. COVERT: Do you write up notes?
MR. MULLOY: Yes, sir.
DR. COVERT: Does everybody write up notes? Or if you don't know -
MR. MULLOY: I don't know, sir, that everybody writes up notes. I am aware that I wrote up notes in this case. [Ref. 2/14-1 2 of 4]
 DR. WHEELON: May we have copies of those notes?
MR. MULLOY: Yes, sir.
DR. COVERT: We might want to collect these different notes and see if they all attended the same meeting.
MR. MULLOY: I don't think, when you see the number of participants - there were some 30 participants - I cannot say that everyone had notes.
DR. COVERT: I understand. Press on, Larry.
CHAIRMAN ROGERS: Well, we should, if there are notes, we should have them, because there may be a difference of opinion on what was said, and it would be helpful to us to have them all. And if there are some that exist and we don't have them, that would be a mistake. We should get them all.
MR. MULLOY: Yes, sir. We will collect those.
That telecon was a little late starting. It was intended to be set up at 8:15. The 30 minute delay was due to the transmission of the engineering material from Wasatch in Utah to the Kennedy Space Center and to the Marshall Space Flight Center. That did arrive, though, in Huntsville and here at Marshall, and the telecon was begun at 8:45.
And Thiokol will then present to you today the data that they presented to us in that telecon. I will not do that. The bottom line of that, though, initially was that Thiokol engineering, Bob Lund, who is the Vice President and Director of Engineering, who is here today, recommended that 51-L not be launched if the O-ring temperatures predicted at launch time would be lower than any previous launch, and that was 53 degrees. Yes, sir.
MR. WALKER: May I ask a question. I wish you would distinguish between the predicted bulk temperatures and the O-ring temperatures. In fact, as I understand it, you really don't have any official O-ring temperature prediction in your models, and it seems that the assumption has been that the O-ring temperature is the same as the bulk temperature, which we know is not the case.
MR. MULLOY: You will see, sir, in the Thiokol
presentation today that that is not the case. This was a specific calculation of what the O-ring temperature was on the day of the January 1985 launch. It is not the bulk temperature of the propellant, nor is it the ambient temperature of the air.
It was Thiokol's calculation of what the lowest temperature an O-ring had seen in previous flights, and the engineering recommendation was that we should not move outside of that experience base.
I asked Joe Kilminster, who is the program manager for the booster program at Thiokol, what his recommendation was, because he is the gentleman that I get my recommendations from in the program office. He stated that, based on that engineering recommendation, that he could not recommend launch.
At that point I restated, as I have testified to, the rationale that was essentially documented in the 1982 critical items list, that stated that the rationale had been that we were flying with a simplex joint seal. And you will see in the Thiokol presentation that the context of their presentation is that the primary ring, with the reduced temperatures and reduced resiliency, may not function as a primary seal and we would be relying on secondary.
And without getting into their rationale and  getting ahead, the point, the bottom line, is that we were continuing - the assessment was, my assessment at that time was, that we would have an effective simplex seal, based upon the engineering data that Thiokol had presented, and that none of those engineering data seemed to change that basic rationale.
Stan Reinartz then asked George Hardy, the Deputy Director of Science and Engineering at Marshall, what his opinion was. George stated that he agreed that the engineering data did not seem to change this basic rationale, but also stated on the telecon that he certainly would not recommend launching if Thiokol did not.
At that time Joe Kilminster requested a five minute off-net caucus, and that caucus lasted approximately 30 minutes.
DR. COVERT: Larry, I'm confused, and could I go back about four meatballs here. What is a simplex joint seal?
MR. MULLOY: No redundancy.
DR. COVERT: That's a single O-ring?
MR. MULLOY: Yes, sir.
DR. COVERT: Is this common notation, or is it named after Charlie Simplex or something?
MR. MULLOY: Perhaps it is an unfortunate
phrase. I guess I consider "simplex" singular and "duplex" dual, and I was using it in that context.
MR. WALKER: So you're talking about the secondary seal.
MR. MULLOY: Yes.
MR. WALKER: In other words, if the first one didn't work the second one would?
MR. MULLOY: Yes, that is correct. And the engineering rationale you will see for accepting the situation was counting on the secondary seal, and that will be developed. Yes, sir.
MR. SUTTER: Is this in line with - I thought the philosophy was at least dual redundancy on there being critical.
MR. MULLOY: Yes, sir, that - -
MR. SUTTER: Where is the rationale that says a single ring is okay and anything single is okay?
MR. MULLOY: The design goal is certainly to have redundancy in critical systems, and in late 1982 it was recognized that this joint design did not provide that redundancy and the criticality on the critical items list, the criticality for this joint was changed from criticality 1-R, which is redundant, to a criticality 1.
And there are numerous systems on the shuttle system that are criticality one. They are not redundant. They are indeed criticality one.
This was changed into that criticality, recognized, and the rationale for the acceptance of that
condition based on analysis and comparison to a similar joint design which flies with a single O-ring, namely the Titan, which at that time had had some 70 successful launches.
So since December of 1982, we have been operating the system with the recognition that under worst case conditions, worst case tolerance buildups, and certain other conditions, that you could indeed not have redundancy in the joint. And what I am stating here is that my  conclusion, based upon engineering data presented, was that that situation here was not any different.
MR. HOTZ: But doesn't the Titan use a different joint?
MR. MULLOY: It is a similar joint, sir. It's a tang and clevis with a single O-ring that they don't leak check. The primary - -
MR. HOTZ: But isn't it reversed, that the tang and the clevis go the opposite way?
MR. MULLOY: Yes, sir, I believe it is, yes, sir. It is the tang is down - or, excuse me, the tang is up in flight direction and the clevis is down.
MR. HOTZ: So you're not basing it on exactly the same type of a joint.
MR. MULLOY: No, sir; similar.
MR. WALKER: There's also a quasi-seal of the insulation, and that may be a very critical difference.
MR. MULLOY: There is an interference fit in the insulation, which is not related to the physical joint design. But it is related to the insulation layup.
CHAIRMAN ROGERS: Larry, in criticality one problems in the past, do you remember any other examples where there was such a late decision on a criticality one and whether there were disagreements among the participants?
MR. MULLOY: No, sir, I do not. We are researching those records now for the total shuttle system, and I'm certainly doing that for the SRM. I am not aware since December of 1982. I took over the project in November of 1982.
I do not remember any changes from a criticality 1-R to a criticality 1 in the solid rocket booster. What we're looking at now is what are all of the criticality ones and getting a listing of those for the solid rocket booster. The total system is doing that, I believe, are you not, Arnie?
MR. ALDRICH: Yes, sir, Mr. Chairman. We are preparing a summary for you on the critical items and the nature of some of them and the total set, and that
will be available and we can discuss it later today if you wish.
MR. SUTTER: Well, I think that that discussion shouldn't be discussed today, because I think it is a discussion that should take all day some time. This is not exactly the subject we're discussing now, but I would like to some time have a discussion on the design criteria, and is redundancy an objective or a requirement and how do you go from 1 to 1-R, how do you decide these things, and how do you say that at one place you've got redundancy and then you don't? I think that is a whole day's discussion.
CHAIRMAN ROGERS: I agree. Dr. Keel, would you make a note, and we will schedule one as soon as we can. I think you're absolutely right.
DR. RIDE: Larry, in your discussion relative to the CIL or your decision relative to the CIL, does that mean that you were assuming what the effects of temperature were on a secondary seal?
MR. MULLOY: No, I don't believe that was considered at that time. I believe the total rationale for retention on the CIL from 1-R to 1 is attached there, and all of the considerations are there, and I do not believe temperature is included in that consideration.
DR. RIDE: I guess I meant, when you were making this decision at the meeting were you assuming that the effects of the cold weather - -
DR. MULLOY: Yes.
 DR. RIDE: that you were assessing were going to affect the secondary seal and not the primary seal?
MR. MULLOY: Yes, and that will come out, I think, in Thiokol's - -
MR. REINARTZ: Wait a minute. Excuse me. Repeat your question, Sally, if you would, please, for Larry.
DR. RIDE: Okay. I guess I was just looking at the CIL, and it says that - it looks to me like it says that the primary O-ring is I heard now a single point failure, because you can't count on the secondary O-ring. Is that a fair assessment of the CIL?
MR. MULLOY: That is correct.
DR. RIDE: And then I guess my question was, in your discussion the day before launch and the evaluation of the effects of the cold temperatures on the O-ring, if you were going to base your decision on the CIL it seems that you would have to assume that the cold temperature affected the secondary O-ring, but not the primary O-ring, since the primary O-ring is the criticality one.
MR. MULLOY: Let me restate. I did not base
my decision on the CIL. The CIL states that we have a simplex - the rationale for a simplex seal. We do not have a redundant seal. My assessment at the time that I made this comment right here, that it did not seem to change that basic rationale, was related to the engineering data that Thiokol will show, that shows that even with the effects of the cold temperature that we expected to have a simplex seal under the worst case conditions, the basic rationale being simplex and not redundancy, a single functioning O-ring.
DR. RIDE: A simplex seal where the one O-ring was the primary O-ring?
MR. MULLOY: No. The rationale, you will see, says we were counting on the secondary O-ring to be the sealing O-ring under worst case conditions and the worst case analysis that is presented here.
DR. RIDE: But doesn't the CIL say you can't count on the secondary O-ring?
MR. MULLOY: Yes, and you have to see the engineering development for the rationale that states that if the cold effect on the primary O-ring - and I'm getting into Thiokol's engineering data, but basically, and I guess I should say what my understanding was, the effect of the cold on the O-ring is it reduces the diameter of the O-ring. It also reduces the resiliency of the
The primary seal under the leak check pressure is seated in the wrong direction. Therefore, there is a time required before the primary O-ring can become effective. The consideration was that if the primary O-ring under the worst case conditions, which was not predicted, incidentally, as you see the engineering data - it was predicted that the primary O-ring would have sufficient compression and sufficient resiliency to extrude into the gap and serve as a functioning seal.
But we went a step further and said, suppose under worst case conditions the cold effect caused the primary O-ring to be totally ineffective. If the primary O-ring is ineffective, the secondary O-ring, which is in a position to seal, will be pressure actuated in the time before the joint rotates.
DR. FEYNMAN: Excuse me. I'm getting very confused, and I would prefer a more logical description and order. I think your original plan was to explain the order of things quickly and then we could go back and listen to all of the arguments in the order in which they were presented. This way things are being pulled out of order and it is hard to follow. Is that okay?
 CHAIRMAN ROGERS: Yes, but if anybody else has questions they should ask them.
DR. FEYNMAN: Yes, but we have the opportunity for some orderliness - -
CHAIRMAN ROGERS: We haven't followed the procedure of not interrupting so far, so let's go ahead.
CHAIRMAN ROGERS: If anybody has a question he wants to ask, he should ask it.
MR. REINARTZ: Mr. Chairman, let me do one thing. When we considered the question of the joint and the simplex, that that was the conclusion of a worst case possibility. What we were looking at from the data presented was that there was an increased probability that you may not have a primary seal.
But we did not accept the fact that the basic starting condition was assume that you had no primary seal to start with. There was an increased probability of not sealing with the primary, and if that did occur then we had a simplex with a secondary seal, and that was the final point that Larry was making there.
So there was some increased probability, but it was not a foregone conclusion, that the primary seal would not operate, and I think that will come out today.
CHAIRMAN ROGERS: It's a little difficult to compare what you just said with what the document says, though.
Let's go ahead.
MR. MULLOY: Yes, sir. This is the list of the total participants, the total number of participants in the telecon. At Morton Thiokol in Utah were these. We brought the principal technical disciplines. We did not bring all of these people here today, Mr. Chairman, and of course they are available.
But in Florida there was myself, Stan Reinartz, Cecil Houston, and Jack Buchanan. Did he get in? Okay, Jack Buchanan is here also. He's the manager of the launch support services here, and Al McDonald; at Marshall, the following individuals with the disciplines that they represent indicated. There are some 30 people then involved in that 8:45 telecon.
The next chart, please.
(Viewgraph.) [Ref. 2/14-1 3 of 4]
Moving on, then. That telecon lasted, then, after Thiokol requested their caucus and it took about 30 minutes, at that point Mr. Kilminster came back on the net on the telecon and read the rationale for recommending launch. And that was rapid-faxed to me here at Kennedy about 36 minutes later, and I will show you what that says.
I guess it is an assumption on my part, Joe, that you were reading from that. It sounded the same.
MR. KILMINSTER: I was reading from some other
GENERAL KUTYNA: During that 30 minute off-the-net conference, were there telephone calls between the centers and Thiokol to discuss this thing?
MR. MULLOY: No, sir. We were off the net and we were not carrying on any discussion on this. Those of us who were here at Kennedy were discussing among ourselves and relooking at some of the engineering data, and I'm sure that perhaps George Hardy can testify to the fact of what they were doing back there. I don't know.
 We did not carry on any continuing dialogue during that 30 minute period.
What Joe Kilminster then essentially stated at the end of that telecon and what he subsequently faxed down 35 minutes later, which I then had, was:
"Calculations show that the SRM-25 O-rings will be 25 degrees-20 degrees colder than SRM15" - which was that one that was at 53 degrees.
MR. WALKER: 33 degrees, in other words, was the predicted temperature?
MR. MULLOY: I believe, yes, sir.
DR. COVERT: What's the difference between 25 and 15?
MR. MULLOY: That should be 25 degrees? That's an error? Well, this is the chart that I worked from.
MR. KILMINSTER: That is the way it read, but it should have said 25.
DR. COVERT: What's the difference between 25 and 15? Is that just a serial, or sequence?
MR. MULLOY: Yes, these are the SRM numbers. It's ten SRM builds later. It happens to be the difference between January and January.
DR. COVERT: Okay, fine. Thank you. Press on.
DR. MULLOY: "Temperature data is not conclusive on predicting primary O-ring blow-by. The engineering assessment is that colder O-rings will have increased effective durometer. They will be harder. The harder O-rings will take longer to seat, that more gas may pass the primary O-ring before the primary seal seats as it translates from its upstream position to its downstream position, that the demonstrated sealing threshold, however, is three times greater in terms of erosion than we've experienced on SAM-15."
And I will let Thiokol engineering explain more about the analysis that goes into that.
"If the primary seal does not seat, the secondary seal will seat. Pressure will get to the secondary seal before the metal parts rotate. The O-ring pressure leak check places the secondary seal in outboard position, which minimizes sealing time, and MTI recommends 51-L launch proceed on 28 January 1986 and
that SAM-25" - which are the motors that were on 51-L - "will not be significantly different from SAM-15."
And with that, sir, I will turn this over to Thiokol, who will discuss their deliberations during this period of time. Mr. Jerry Mason is the Vice President and General Manager of the Wasatch Division of Thiokol.
I might mention, Mr. Chairman, we also have from Thiokol here today Mr. Ed Garrison, who is the President of the Aerospace Group in Chicago, Mr. Mason's supervisor.
CHAIRMAN ROGERS: Mr. Mason, might I suggest in your discussion with us today that, please disclose anything that you know about that may turn up. If you have documents that we don't know about that would be embarrassing to you, tell us about them now.
We don't want to have to pry information out of you. You know what's there. Tell us the whole story, if you will.
[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.2/14-1 1 of 4] [Chronological events recalled by Larry Mulloy- January 27-28, 1986] [Ref.2/14-1 2 of 4] [Chronological events recalled by Larry Mulloy- January 27-28, 1986]
 [Ref.2/14-1 3 of 4] [Chronological events recalled by Larry Mulloy- January 27-28, 1986] [Ref.2/14-1 4 of 4] [Chronological events recalled by Larry Mulloy- January 27-28, 1986]
 [Ref.2/14-2 1 of 7] [Larry Mulloy's handwritten note regarding 51-L assessment of cold o-rings].
 [Ref.2/14-2 2 of 7] [a written testimony/deposition, presumably from Larry Mulloy] [Ref.2/14-2 3 of 7] [a written testimony/deposition, presumably from Larry Mulloy]- continued.
 [Ref.2/14-2 4 of 7] [a written testimony/deposition, presumably from Larry Mulloy] - continued. [Ref.2/14-2 5 of 7] [a written testimony/deposition, presumably from Larry Mulloy] - continued.
 [Ref.2/14-2 6 of 7] [a written testimony/deposition, presumably from
Larry Mulloy] - continued. [Ref.2/14-2 7 of 7] [a written testimony/deposition,
presumably from Larry Mulloy] - continued.
MR. MASON: We will do that. First off, what we had in mind was that I would give you the kind of overview that Larry has, except to give you more specifics of what occurred at the Wasatch Division in Utah. And then after that, our Vice President of Engineering will go through the specific technical charts that were reviewed that evening, and then Mr. Kilminster is prepared to provide the additional rationale that led us to the final conclusions.
But one thing I would like to explain. Larry's introduction was a little bit in error. I am actually the senior vice president of the Wasatch operations, and I need to explain that. We have three divisions there, the space division, strategic, and the tactical division. And of course, the space division is dedicated to the shuttle program, and we have a general manager for each division.
Mr. Wiggins, who is with us today, is the general manager of the space division, and reporting to him is Mr. Kilminster, who is the program manager over manufacturing and quality operations. And then Mr. McDonald reports to Mr. Kilminster as the program
manager on space and the solid rocket motor itself.
On the other side, also reporting to me, is the vice president of engineering, Mr. Lund. So I hope that clarifies the relationship a little bit.
The chronology is essentially as Larry had identified there.
MR. SUTTER: Can I ask one question now? Between Kilminster and Lund, who makes the "technical" or engineering decisions?
MR. MASON: Lund makes the technical recommendation to Mr. Kilminster.
MR. SUTTER: He can act on it as he sees fit?
MR. MASON: The final decision comes from the program manager to the general manager, and if necessary to me. The engineering, since it is a separate function, does provide a bit of an oversight on the program manager's functions. In other words, he doesn't report to him on a hard line; he reports to him in an advisory role, if you will.
The sequence was essentially as Larry had identified it. We were notified both from Marshall and Kennedy that the temperatures were going to be quite low the next morning for the launch if it were to occur at 9:38.
As a result of that, our engineering people
looked at all of the aspects of the motor, particularly at the propellant mean bulk temperature, which is normally something we are concerned about, and that was not of any concern in this case, and identified that the only area of concern was the seal.
And they wanted to get together more data that existed in various places to take a further look at the seal, which they did. They started gathering that information, and the preliminary telecon occurred and arranged for the subsequent formal telecon.
In the formal telecon then, we reviewed the technical data, which Mr. Lund will cover with you, and the sequence was that we were gathering this data and attempting to reach our firm recommendation at the same time. So we were in a position that we got the charts together and  were trying to make the final chart on our recommendations, and at that point had not had any, I would say, complete discussions.
There were differing opinions within the group, and the only opinion that survived everyone was to launch at 53 degree O-ring temperature or higher.
CHAIRMAN ROGERS: What was the nature of the discussions? I mean, you say there were a lot of different views. What were they, some of them?
MR. MASON: Well, they centered around the
effect of the cold on the ability of the O-rings to respond, and it was primarily the primary O-ring because, as has been mentioned, when you pressurize, when you run the leak test, you put the primary O-ring on the wrong side of the roof, whereas the secondary goes onto the side that you want it on.
So the question was, will the cold change the response time enough to keep that primary from sealing? And we did not have hard data that would give us that answer.
DR. RIDE: What was the lowest temperature that your data went down to?
MR. MASON: We had - the only meaningful, I guess the only conclusive data was the flight data, which was the 53 degrees. In other words, we had information on the hardness of the O-ring and various other things like that, which Bob will cover with you in the chart. But we did not have anything that said specifically how long does it take for the O-ring to move across.
Now, the reason, of course, that is the primary issue is that it needs to seal before you get a high enough pressure in the case to open that gap, or the so-called joint rotation. So it needed to seal in the 160 milliseconds.
GENERAL KUTYNA: If I may, sir, this has been a problem since about 1980 off and on, and it was looked at as a criticality one failure mode for a few years and it has been continuing. It seems strange that you had to gather the data on the environments of this thing at this very moment; that if I had a problem like this in an airplane, I would have been working that environment data from the year 1980 or 1981, and not 1985 or 1986.
Why was the environment not considered and why hadn't you gone through an exhaustive review of the environmental effects on the failures prior to this time?
MR. MASON: Well, some of the data that we were gathering is data that was currently being created at that time as a result of the effort we were making to improve the reliability. For example, there is a blow-by test in there. That one had been run with argon and we were going to run it with freon, and we were getting the latest, very latest information we had, because we were giving consideration to that.
DR. RIDE: Let me ask Don's question in maybe a slightly different way. You had at some point to sign up for the SRB's working at 31 degrees ambient temperature, because that is the launch commit criteria on the entire system.
What data did you use to certify the boosters to work at 31 degrees before you allowed that to be taken into account?
MR. MASON: Well, let's see. I think the way it is set up is, we signed up to work - to have it work with the propellant mean bulk temperature from the 40 to 90 degrees. I believe that is the performance requirement.
MR. WALKER: Why was there no separate requirement on the O-rings? That is the issue.
 DR. RIDE: I mean, surely that requirement was imposed on you by NASA. NASA must have said: Your solid rocket booster has to work at 31 degrees; do the analysis of all the parts to determine that it does.
MR. MASON: Well, I have to say what my current understanding of the requirements is, which is that it has to perform, the propellant, at mean bulk temperature from 40 to 99, and that says it has to withstand temperatures of 31 to 99. And the attention has all been focused on getting the performance when the propellant mean bulk temperature was 40 to 99.
DR. WHEELON: A question. It is normal to establish specifications on a unit and then to complete a qualification program for a unit, prior to flight. Did you have a
temperature specification on the O-ring or the joint assembly, either one? And can you describe what your qualification program of testing to verify that that specification was being met?
And if you personally don't know the answer to that question, I would like that question then to revolve to whoever in your organization picks it up. But I think we need a clean, crisp, clear answer to the question.
MR. MASON: Okay. I think it would be better that I not - I think I know the answer, but I have not enough confidence to try it.
DR. WHEELON: Who are you going to lateral that football to?
CHAIRMAN ROGERS: Who can answer that?
MR. MASON: Joe, can you answer that?
MR. KILMINSTER: I believe, as Jerry mentioned, the major focus of emphasis was on the 40 to 90 degree requirement for the mean bulk temperature. When it comes to the seal, we have a procurement spec for that material, a Mil R specification, that calls out that material being capable over the temperature range of minus 30 to 500 Fahrenheit. And it was on that basis that we qualified the use of that material as far as the seal is concerned.
GENERAL KUTYNA: Capable of what?
MR. WALKER: Isn't that specification for a captured O-ring inside of a groove with a flat mating surface, not this kind of configuration?
MR. KILMINSTER: I don't believe the specification specifies what type of construction or what kind of design. It is a material capability.
MR. WALKER: Could we have that information? That information must be in Parker's specifications.
MR. KILMINSTER: It's in the Mil R specification.
DR. WHEELON: What did you do to assure your material was meeting that specification? What was the qualification program?
MR. KILMINSTER: Early in the program, it was determined that we would not have a program, a development program, and a test program that would qualify over that full temperature range.
DR. WHEELON: What range were you going to qualify over?
MR. KILMINSTER: Again, the emphasis was based on the solid propellant bulk temperature, and that qualification was done by analysis. We did not conduct a test.
DR. WHEELON: Let's set aside the question of
bulk temperature on the propellant. The question is what specification did you have on the joint and the O-ring, and how did you test to verify that in fact you were meeting that specification, or did you not have a specification and not test?
MR. KILMINSTER: The specification we have is a Mil R specification.
DR. WHEELON: Which is a generic spec to cover a whole range of military equipment, right?
MR. KILMINSTER: In this case, it is this specific material.
DR. WHEELON: Okay. So it is minus 30 to plus 500, is that correct?
MR. KILMINSTER: That's correct.
DR. WHEELON: And how did you shade that requirement and how did you test to make sure that you had met that shaded requirement?
MR. KILMINSTER: We did not test specifically to identify that requirement or test against that requirement.
DR. WHEELON: Don't you find that a little surprising?
DR. KILMINSTER: There are many areas, as I mentioned, based upon the original intention that we would not conduct full-scale firings, full-scale tests, using
a full range of temperatures.
DR. WHEELON: Did you use any subset of that full range of temperatures in your tests?
MR. KILMINSTER: Yes, we did.
DR. WHEELON: What range was that?
MR. KILMINSTER: That will be discussed when Bob discusses his charts. I believe we had a static firing as low as 47 Fahrenheit.
DR. WHEELON: Ambient?
MR. KILMINSTER: No, that was the predicted O-ring temperature, using ambient calculations lower than that.
CHAIRMAN ROGERS: Could I make a suggestion about procedure? Let's not worry about - if there is a question that is asked and somebody can answer it, have them answer it. I mean, you can still continue your presentation that you have organized, but you are all here now and it's reasonably informal.
So when Bud asks a question like that and somebody can answer it, just have them stand up and answer it.
DR. WHEELON: So you think went down to 47 degrees, in terms of a spec for ground testing of the seal?
MR. KILMINSTER: Yes.
DR. WHEELON: But no lower than that?
MR. MASON: That was the seal temperature.
DR. WHEELON: I understand, not the ambient. But you qualified the seal at 47 degrees Fahrenheit?
MR. KILMINSTER: We verified it in a static test at 47 degrees.
DR. WHEELON: A static ground test?
MR. KILMINSTER: Yes, sir.
DR. RIDE: And you did no tests on the joint below 47 degrees?
MR. KILMINSTER: That is correct.
 GENERAL KUTYNA: Bob Crippen, I thought somebody said yesterday, maybe it was you, that the shuttle was cleared to fly with a shuttle temperature of 31 degrees or thereabouts.
VICE CHAIRMAN ARMSTRONG: Arnie said that.
GENERAL KUTYNA: Now, how do you correlate the fact that the shuttle is cleared to fly at 31 degrees and yet you have only tested down to 47 degrees, and by analysis only to 40 degrees? How do you explain that?
MR. KILMINSTER: The only explanation I have is that we felt that we had a margin because of the material being capable down to minus 30 as identified in the specifications.
DR. WHEELON: Capable of what?
MR. KILMINSTER: Capable of functioning.
MR. WALKER: I really think we need to understand exactly what that specification implies in terms of the use of O-rings in various kinds of configurations. We would really like to have that information as soon as possible on exactly what that specification implies.
DR. WHEELON: Or better yet, can you give us the specification from which you were working?
MR. BOISJOLY: The specification in question is Mil R 83248A.
DR. WHEELON: A further question. Did you do any further testing of the O-rings or the O-ring material on your own, independent of the motor?
MR. KILMINSTER: Not that I can recall.
DR. WHEELON: So you were just working to the specification of the material as provided in the Mil Spec?
MR. KILMINSTER: I'm talking in the original qualification program. We subsequently have done testing.
DR. WHEELON: How subsequently? The last couple of days?
MR. KILMINSTER: No. Over the last probably year, year and a half.
DR. WHEELON: And what did those tests over the last year tell you?
MR. KILMINSTER: There is one test that is included in Bob's presentation that goes down to 30 degrees and identifies no blow-by at that point in a sub-scale joint configuration.
DR. WHEELON: Is this a scale test?
MR. KILMINSTER: It is a scale model.
MR. MASON: It's a full scale O-ring and full scale joint. It's just short, a small diameter.
DR. WHEELON: How many such tests did you run?
MR. KILMINSTER: I can't recall.
DR. WHEELON: Can you get us that data? I don't mean to tax your memory.
MR. KILMINSTER: Roger, do you recall the number of tests that were run at the cold temperatures?
MR. BOISJOLY: No, I don't.
MR. THOMPSON: Arnie Thompson here. There were two tests run at 30 degrees and two tests run at room temperature with the blow-by device, using argon as a tracer gas. The results were that we could see no blow-by with the apparatus.
We recognized that we needed to have a better sensitivity, so we went to freon 14, which shows better
on the mass spectrometer. And those tests are proceeding and we have some data from that.
 DR. WHEELON: In view of that apparently satisfactory validation, why were you concerned on the day before launch? It seems to me these tests should have set you at ease, and yet you were uneasy. Why?
MR. BOISJOLY: It should be emphasized that that test simulates the gap on a subscale basis, but does not simulate the dynamics of the joint and O-ring. It is not a joint. It is a gap, a physical fixed gap. And it was intended to measure if blow-by could occur past an O-ring at a very low temperature - not the temperature, but at a very low pressure, at the beginning of the ignition transient.
That test was specifically set up after the SRM-15 blow-by, which occurred a year ago last January, because at that presentation we made a point of saying that there is a small, miniscule portion of air that will go past any seal, any O-ring seal, in its attempt to do its initial sealing at low pressures. And then rapidly, as the pressure increases, the seal is functioning better and better at higher pressures, and that was the purpose of that test. That is the climate in which that test was developed.
GENERAL KUTYNA: But yesterday we were shown that that joint does in fact compress. The gap moves, opens, closes.
MR. BOISJOLY: That's correct.
GENERAL KUTYNA: at the light of the SRB's. and possibly even before that, when the SSME's are lit and you have the twang effect.
And what you're saying is you did not take that into consideration during this test?
MR. BOISJOLY: On that particular test, that is correct.
GENERAL KUTYNA: It's a totally static joint with no compression?
MR. BOISJOLY: Yes.
DR. COVERT: I would like to ask a procedural question, please. Is that spec you gave us and that number, is that the one that was in force at the time the decision was made, or is that the one that is in force now? Or what's the deal?
MR. BOISJOLY: That is the mil spec that controls the flight-on? O-ring material.
DR. COVERT: What is the date of the spec?
MR. BOISJOLY: I don't think I have that information.
DR. COVERT: I think that would be helpful to know.
DR. WHEELON: Did these tests figure in your
decision to proceed, or were they not a part of your thinking when you re-made the decision to proceed?
MR. BOISJOLY: To proceed with flying?
DR. WHEELON: With flying?
And I'm trying to say, there apparently was a caucus out in Utah at which you were asked to consider your decision not to go and in effect you wound up going. Were these test results a part of that reconsideration?
MR. BOISJOLY: Yes, sir.
DR. WHEELON: What role did they play?
MR. MASON: Well, sir, if I could, maybe I could pull that, the next steps together, and explain what things were involved in the reconsideration. We got to the point where we had faxed these copies of these charts, and at that time our best conclusion was to stay within our experience base.
 We had not been able to determine whether it was rational to extrapolate, and so at that point we recommended the 53 degree or higher temperature, because that was our experience base.
DR. KEEL: Mr. Chairman, could we have it clarified for the record exactly what "that point" means in the time sequence?
MR. MASON: That point was at the time when we faxed the charts to start the formal group telecon.
DR. KEEL: And in addition, can we have those charts? Do you have them with you today? MR. MASON: Yes, sir. Mr. Lund is going to review those charts for you.
CHAIRMAN ROGERS: When you say "formal telecon" and "informal," how do you distinguish?
MR. MASON: Well, it really was whether you have the whole group on or there is an individual telecon. Earlier there had been a telecon that Larry mentioned with Mr. Lovingood, in which there was just talk between Marshall and Morton Thiokol. And then there had been the call from Kennedy to us saying it was going to be cold, and so I call that the informal telecon. It was just communicating generally.
And then it culminated in what I call the formal telecon, at which we had everyone on the net - Marshall, Kennedy, and ourself.
MR. LOVINGOOD: To clarify that, Kennedy was on, Jerry, during the 4:45 telecon, but we didn't have all the people in that 4:45 meeting that we had in the later meeting.
CHAIRMAN ROGERS: Let's discard the idea of "formal" and just call it telephone conversation, and who was talking and what was said.
MR. MASON: I think now I probably ought to
address it as the final telecon in which we had everyone that Larry had listed to on the line. And it was interrupted by our caucus, and some people would call that two meetings or two telecons in one, but in my mind it was a continuing one, just interrupted by the caucus.
Now, we reviewed the charts in there and drew our conclusion that we ought to fly at 53 degrees or warmer. And at that point we received a number of comments on the net. The ones that I looked upon as being of consequence were that we were reminded that there really wasn't good correlation or valid correlation between temperature and blow-by, and that was pointed out because we had two cases of blow-by and one had been at 75 degrees and one had been at 50 degrees, and we had a lot of cases at varying temperatures where there had been no blow-by, and so we had very limited basis for saying that blow-by correlated with temperature.
MR. WALKER: Now you're talking about seal temperatures?
MR. MASON: We're talking about seal temperatures, right.
DR. RIDE: Where was the lowest temperature that you had no blow-by?
MR. MASON: Well, in the static test motors it was 47, I believe was the lowest, but
it's on Bob's charts. We have cases where we had blow-by listed and we have - what we did was pick the coldest static test and the flight test. And of course, the static test didn't have any blowby.
The static tests are slightly different and Bob will explain those. We tended to not put a of weight on those.
 GENERAL KUTYNA: But the worst blow-by you had was at the lowest temperature, which was 51 C. did that not give you a strong correlation?
MR. MASON: That was the exact discussion that we had, was whether the fact that that one was somewhat worse than the one at 75 degrees, was that a correlation with temperature or was the fact that they blew by at both the 75 and 50 indicating that it was relatively independent of temperature.
DR. COVERT: Did you have any data on the stacking or the clearances on the 75 degree one as compared to the other?
MR. MASON: Yes, we did.
DR. COVERT: And were those clearances different significantly?
MR. MASON: They were relatively nominal, and we have that on the chart also.
MR. WAITE: Is last year's experience what led
to this increased level of testing? In other words, the decision to go back and test?
MR. MASON: Well, you might say cranked up the gain in August when we had summarized everything and concluded that we needed to get a more aggressive effort on improving things.
MR. WAITE: So it was your experience on this one occasion that led to this need for more testing?
MR. MASON: I would say it was collective experience, sitting down and looking at it totally.
In any event, with the one comment about the lack of hard evidence that there was really a correlation, although instinctively we felt that the cold would make it somewhat worse. The other point that was made was that the concern about the primary having to move and it being colder, it might move slower. We said, don't overlook the fact that the secondary is in position and therefore it doesn't have to move, so the time element is not as of great a consequence on the secondary as it is on the primary.
So with those two comments and others, but those were the ones that we considered of consequence, we decided that we ought to have a caucus and assess whether it would be reasonable to extrapolate below our experience.
DR. COVERT: How much more rigid is the grease at 30 degrees than it is at 50 degrees? MR. MASON: I can't give you a number. The grease is somewhat stiffer, but it is just a film on the outside of the O-ring.
DR. COVERT: At least in principle it is.
MR. MASON: Yes. And we made that observation, that both the grease and the O-ring would be stiffer. Now, we had durometer readings on the O-rings and we had the general knowledge that the grease gets somewhat stiffer.
DR. FEYNMAN: Could I interrupt, because there's some physical thing that I don't understand quite clearly, and that is why the need to move the O-ring makes it so much less likely to seal than if it is in the right place.
MR. MASON: Because if it doesn't move fast enough and the joint opens up before it is seated, then it won't seat.
DR. FEYNMAN: Why?
MR. MASON: Because it doesn't have enough compression of the O-ring to hold the gas that forces down into the crack.
MR. WALKER: In other words, it has to be deformed initially before the gap opens up?
MR. MASON: It has to initially so that when the gas hits it it will flow down into the crack and if you lose too much of that compression then it will flow by instead of pushing it in.
So that was our exact concern, that that very small distance that it had to move, if it didn't move that within the 160 milliseconds before the gap opened.
DR. FEYNMAN: That theory of how it works would account for the very much larger fraction of nozzle joints which failed compared to field joints, in which the nozzle joints have to move about seven times as far as a field joint, and that is consistent with your view.
MR. MASON: Exactly.
So we then had our caucus, in which we revisited all of the things we had talked about before. And we recognized two primary things that are covered in Mr. Kilminster's chart, and that was that the worst experience we had had in erosion was 38 thousandths, and we know from tests that the O-ring would seal with over 120 thousandths of erosion.
So our first thought was that if we had more erosion on the primary because it took longer, it would still seal, even if it were eroded three times as much. So we said we still had a reasonable expectation that
the primary would seal, but we didn't have absolute data that said how long it would take to move.
So we then said, what happens if it doesn't? And we took the second point, which was that the secondary was in position and did not have to move. So we felt that the primary probably would seal, but if it didn't the secondary would because it was already in position.
DR. FEYNMAN: During this discussion, nobody noticed the possibility, I presume, that even though the secondary is in position, if the thing opens up and the resiliency of the material is zero because it is too cold, it won't close, it won't fill into the seal? Was that considered or not?
MR. MASON: That was considered, and the key issue became that what had to happen is either the primary or the secondary had to seal in the 160 milliseconds, before resiliency came into play, because in both cases if it seated before it opened up then it would extrude down into the joint.
But as you pointed out, if it started to open, then the resiliency question came into play.
GENERAL KUTYNA: But that's 160 milliseconds after lightoff of the solids. How about the resiliency effects in the seven seconds that the SSME's are
compressing and bending this particular joint? Is there not an opening and closing of the gap during that time, that could have compressed the seals?
MR. MASON: Well, I can't answer that with certainty. I believe that those effects are relatively nominal on that joint, because the stiffener rings take out the bulk of that load on that joint.
DR. RIDE: Has that analysis been done?
MR. MASON: They have been looking at that effect again since the incident, and I can't tell you what the outcome is right now.
DR. RIDE: Where is that done? Is that done at Thiokol?
MR. MASON: Both. We're doing it both at Thiokol and at Marshall. We cross-check each other.
But I know there were some rough numbers done that said that that is quite stiff and it is not likely to be, but it needed to be done in great detail.
 DR. RIDE: But it hadn't been done before 51-L?
MR. MASON: Yes, the analysis, the load analysis in the joint had been done. I can't tell you whether we had looked at whether it had any effect on the O-ring. I can't answer that question.
DR. FEYNMAN: I've got the timing problem
mixed up with the 160 and 600 milliseconds and so on. Let me understand. Supposing the secondary seal is in place at some time and the primary seal has failed or something, and so the secondary seal is supposed to be pushed in by compression.
Now, it opens? Or is that not the way it works?
MR. MASON: Now it opens.
DR. FEYNMAN: How does it stay against the metal?
MR. MASON: Because the pressure is high enough. You see, it's now got 800, 900 psi, so now the pressure overrides the lack of resiliency.
DR. COVERT: Have you calculated how far this thing opens during this twanging motion because of the - it is a two-part system and it is a pin-connected thing, with a clamp there and the rest of it acts like it's free, in effect.
MR. MASON: We've calculated how fast it opens and how much due to pressurization, and I believe that the data will show that that is the primary driver, that that overrides any impact from the loads.
DR. COVERT: From the bending.
MR. MASON: But that I can't say has been verified yet.
DR. COVERT: But I agree with you that the pressurization deformation may be large compared to the
bending deformation. But if we are at a marginal situation, it seems to me you can't throw away the small part, because that might be the thing that tips it across the edge.
Is that a reasonable way to look at it?
MR. MASON: I think we have to look at every small potential contributor, yes.
MR. HARDY: Mr. Chairman, I might make one comment to Sally's question earlier about calculating the effect of the transverse loads on the joint. We did in the early part of the program run static structural tests, and I talked about the dynamics of the joint, but we did run static structural tests where the test article with a flight representation of the joint under pressure, under a number of pressure cycles I think it was said yesterday. I don't know how many, but a large number of pressure cycles, where we did put in the transverse load and the maximum design transverse loads on the case, both at the aft joint and at the forward joint while we were pressure cycling.
GENERAL KUTYNA: But did you do it prior to pressure cycling? Because that's when it happens.
MR. HARDY: We did it in the precise sequence of the pressurization: the twang load, the pressurization, and then the flight dynamics.
GENERAL KUTYNA: And how much opening or closing of that gap did you get?
MR. HARDY: Well, we measured the opening and closing. We measured it for the to effect, that is both the pressure effect and -
GENERAL KUTYNA: But now the pressure happens afterwards. How much did you get?
 MR. HARDY: I can't recall that. I don't remember that. I don't remember the precise effect of the pre-ignition load on the joint.
GENERAL KUTYNA: But would that be a factor if we have in fact a seal that has lost its resiliency, that you would be concerned about how much that gap opened and closed and squished that seal prior to the pressurization?
MR. HARDY: Depending upon the effect and how much that load might open the gap, it could be a factor. And we are after that answer right now.
MR. SUTTER: On these tests, was it just on one set of O-rings, or did you change your gaps and the dimensions of the O-rings? Did you run a variation?
MR. HARDY: I can't remember how many sets of O-rings were involved. I do remember that repeated pressure cycles were done on the same O-ring, but I can't remember exactly how many sets of O-rings were
CHAIRMAN ROGERS: You took part in all of these conversations yourself?
MR. MASON: I took part in the final conversation from the beginning, the whole telecon, from when we faxed the charts down until we drew the final conclusion. I was there.
CHAIRMAN ROGERS: Mr. McDonald testified, at least I thought he did, that the recommendation was not to launch, Thiokol's recommendation was not to launch. Who - at one point. Who was involved in that discussion leading up to the decision not to launch?
MR. MASON: All of us that were in the meeting, we were gathered and we were reviewing the data and attempting to reach our recommendation simultaneously.
CHAIRMAN ROGERS: Now, could you give us, without being too precise, the nature of the arguments against launch? Tell us what was being said. There must have been a consensus against launch if that is what you conveyed to NASA.
MR. MASON: Well, at that point we were trying to meet the deadline of getting the data together and getting the recommendation in, and so the engineering people were generating that and put together the
CHAIRMAN ROGERS: What were they saying, though?
MR. MASON: They were saying, we're going to be outside of our data base to go colder than 53 degrees, and we're concerned about whether the O-ring will move fast enough to seat and seal before the joint opens up. And that was the thrust of the issue, is not knowing exactly how long it would take for the O-ring to move into position.
DR. COVERT: Jerry, if the O-ring has been eroded a little bit or ablated or charred or whatever the damn thing does, it is now oval rather than round, and the action - is this going to tend to rotate vertically? Is that the stable motion, or does it tend to, say, slide in, skinny in the vertical direction as opposed to rotating like this?
MR. MASON: I don't know. Perhaps. There is probably some theory there, and Roger is probably the best one to answer that. I'm not sure we know exactly.
MR. BOISJOLY: That was one of my major concerns, and I addressed that as a timing function to seal. And I believed and I still believe and I believed that night that there isn't anybody on the face of this earth that can tell you exactly the mechanism that happened in that joint.
And even before the fact, you don't understand if it's going to rotate and walk up and delay or either slide because of its stiffness and delay. But the timing function that I spoke of that night had to do with the fact that I was afraid that that timing function could throw us in from an ignition transient at the start to somewhere after that start time, and that is what my major concern was about.
DR. COVERT: I think Roger and I are thinking along the same line. If it rolls in, then it is not a problem because you have the full exposure. But if it slides in and it is not skinny, it may in fact continue to blow by.
MR. BOISJOLY: But my concern even went beyond that point, because as it is performing this function at the beginning of the transient cycle, it still is being attacked by hot gas.
DR. COVERT: Precisely.
MR. BOISJOLY: And it is eroding at the same time it is trying to seal, and it is a race between, will it erode more than the time allowed to have it seal.
And that was my major concern, because SRM-15 showed erosion and hot gas blow-by at a low temperature, and that was the major issue on the table at that time.
DR. COVERT: Thank you very much.
CHAIRMAN ROGERS: Did you change your mind?
MR. BOISJOLY: No, sir, never.
MR. SUTTER: Can I ask a question, Mr. Chairman?
In these conversations, this discussion about this simplex seal right there, was that discussed with you?
MR. MASON: Well, on the telecon Mr. Mulloy did go through his rationale and talked about the simplex seal.
MR. SUTTER: Did Thiokol agree with the fact that you could work with the simplex seal? Did that influence your decision? What if there was no statement that the criteria said the simplex seal is okay? Would you have still made the decision you did?
MR. MASON: I'm not sure I understand that question.
MR. SUTTER: Well, I guess my question is, were you designing the same criteria that NASA was designing, and who established the criteria, and what were your ground rules for design?
MR. MASON: Well, let's see. If we get back to that fundamental design criteria, I really can't answer that. I'm not sure whether Joe or Bob can.
I know what we were endeavoring to do was to be confident that it was safe to fly, and we weren't
going back to that kind of a fundamental issue.
MR. WAITE: I have the same question in regards to the initial conversation about the single seal versus the two seals. You didn't really address the simplex seal until the latest conversation.
MR. MASON: Our thought has always been that it is essential to have a seal in that first 100 and - well, 160, 180, 200 milliseconds, before the joint opens up. If we get a seal at that point, then it doesn't really make any difference whether it's the primary or secondary. Once it is sealed, then it is reliable.
 And so from a practical standpoint, we have been addressing getting the high confidence of getting that seal at ignition, and in that sense - -
MR. SUTTER: But you're saying that when that seal - when one seals, then there's no assumption that any other failure might wipe out that seal?
MR. MASON: Well, everything we have known and everything demonstrated that once you had that seal, that there wasn't another cause that we could identify that would cause it to fail, because once it's sealed there is no more gas flow and then it is simply a benign environment.
DR. COVERT: But if it seals on the secondary flow before the joint enlarges or rotates, whatever you
call it, and now it is a benign environment because there is no gas flow, and if the primary seal is not yet seated and now you get joint rotation and you feel the pressure, is what you said before, the pressure is sufficient to deform the secondary seal so that the primary will never be called into play again, is that right?
MR. MASON: That is correct. And there is - on that point, there is a unanimous position. There isn't any difference in that, that once it is pressurized it will handle the joint rotation. The issue is whether it gets pressurized rapidly enough.
VICE CHAIRMAN ARMSTRONG: I am unclear as to why you considered 53 degrees was the limit of your experience base, rather than the 47 that you had had in the static test.
MR. MASON: Okay, I will explain that. In the static test, we static test it in a horizontal position, and in the process of mating the segments the putty is exposed differently. It flows differently than it does in the vertical mode.
You don't have to touch it in the vertical mode, but in the horizontal mode we have to go inside the motor and tamp the putty to get it in the right position. So our feeling was that that probably made -
well, it made a putty job that could be classed as better than the flight condition, and so it may have masked something.
And so we were hesitant to use it absolutely as evidence that it was okay.
MR. WALKER: Why didn't you ask for inspection of the putty seals in the flight, or didn't you think that was important, the vertical mating?
MR. MASON: Well, we had finally reached the conclusion that you can have - you can trap air in the mating operation. You can cause an air void when you leak test, when it blows back into the putty, and you can't be sure. You can go look and if it hasn't erupted through the putty you may have a path that is there but it hasn't exposed itself.
So even if you inspect it, you have the possibility of that path. So we felt that inspection wouldn't eliminate that possibility, and so we had to have a design approach that would tolerate that. That was our thought.
MR. WALKER: Can you respond to the question as to why the shuttle SRB design is different than the Titan design in terms of these seals? Were both of these designs done by your company?
MR. MASON: No, no. United Technologies.
MR. WALKER: That is probably the answer.
 MR. MASON: And I think maybe there are some difference in burning surface requirements. I'm not sure. But anyway, I know the Titan was considered at the time the joint design was done, but I think there were reasons.
But the point I would like to get to, however, is that we had the caucus and had these discussions, and it was clear that we were not going to reach a unanimous position there, and so we were then faced with the issue: Shall we stay with 53 degrees or is it reasonable to extrapolate?
And we had the reasons that I've already identified that made us feel that it was reasonable to extrapolate. So our final conclusion was reached by me having a review with the vice president of engineering, the program manager Lund, Kilminster, and the general manager Wiggins, and my own opinion.
We collectively agreed that it was reasonable to extrapolate, with the rationale that was listed on Kilminster's chart that said that we had a substantial margin, that we could erode more in the primary by a factor of three than what we had seen before; and that even if that didn't happen, that didn't seal, we had the secondary in a position where it did not have to move in
order to seat, and therefore it would seal.
And that was the basis for our conclusion. And we have brought with us today the people that had objections. In fact, Roger, as you just noted, is one who says he didn't change his mind. But it was one of those where it becomes the responsibility of management to make we think a rational decision, and that is what we did.
MR. WALKER: How many people in the meeting were considered seal experts? That is, their primary interest or their knowledge would qualify them as particularly knowledgeable on seals?
MR. MASON: Well, to varying degrees I guess there's a half a dozen people there. Bob, you would be best to respond to that.
MR. LUND: It is a matter of degree. It's a judgment factor. Certainly Roger Boisjoly is a seal expert, and Arnie Thompson.
MR. WALKER: Did you seal experts agree, or is it kind of a confusing issue?
MR. LUND: There was much data, and I will present that data to you in a little bit, that is both ways. Some say it's okay, some say it's not. So each engineer that was there reached his own conclusion from the data that was presented, and so there is a diversity
MR. MASON: Mr. Chairman, I did make one point while you were gone that was consistent with your earlier request, and that is that when we came down here we did review - and first, I made the point that we did not have a unanimous opinion, and because of the fact - we had a unanimous opinion among the key people reporting to me, but because of that we did identify and talk to the people who had concerns, and we brought the people that had concerns, so that if you wanted to you could talk to them, or if they wanted to they would have an opportunity to speak.
CHAIRMAN ROGERS: Very good. Thank you.
MR. MASON: Now, that is as far as I was intending to proceed. I thought Mr. Lund could go through the charts that we looked at that night.
CHAIRMAN ROGERS: Any other questions?
 MR. WAITE: I have one more. I still haven't got the sequence of events in terms of this single versus dual seal concept. Did the dual seal discussion come up after you had been contacted or after your caucus, or before the caucus?
MR. MASON: Well, I think that it became a thought, a primary thought, after we had said that we ought to fly to 53 and we had that ensuing
conversation. And it was pointed out at that point that the secondary seal was in position. And we had been focused so much on the primary seal that we said: Wait a minute, let's take a look at that, because we really hadn't - -
MR. WAITE: Who pointed it out?
MR. MASON: Mr. McDonald. He said, don't overlook that. His comments were that the cold is in the direction of badness, but that - and that is the concern with the primary. The secondary, however, is in a better position. Don't overlook that.
And we said, well - -
DR. COVERT: Could I ask you one more.
MR. MASON: Well, I guess we ought to have Al say just exactly what he said.
MR. McDONALD: I commented that lower temperature is in the direction of badness for both O-rings because it slows down the timing function, but that the effect was much worse for the primary O-ring compared to the secondary O-ring because the leak check port puts the primary O-ring on the wrong side of the groove, while the secondary O-ring is in the right direction, and that this condition should be evaluated in making the final decision for recommending the lowest acceptable launch temperature.
Based on the data presented in chart 2-1, I considered this very important because, depending upon how much delay one has with getting a good, reliable primary seal affects the capability for the secondary O-ring to seal.
MR. CRIPPEN: Excuse me. And we made that in light of even though we had a CIL saying the secondary might not be there during separation?
MR. McDONALD: Well, the charts that were presented that night, one of the charts, and I had presented that chart earlier in August in a meeting at NASA headquarters, and it was presented that night and we looked at that and it showed the - -
DR. KEEL: Do we have that chart, so all the Commissioners can see it?
MR. McDONALD: Yes, in Mr. Lund's presentation.
DR. KEEL: Can you pull it up now if you're going to talk about it, though? Can you put chart 3 up and let Mr. McDonald make his point.
(Viewgraph.) [Ref. 2/14-3]
MR. MASON: Do you want to do it right now?
DR. KEEL: Yes, it is up there.
MR. McDONALD: That was one of the charts, and what I was looking at was that we could conclude that this lower temperature doesn't affect the timing functions,
which I said I really feel it does - so that we really don't change the time for the primary seal to really seal, what is being eroded, up to the 170 milliseconds. That is, we haven't changed this launch from any other.
 However, if the colder temperature takes longer to not only move the seal, but also to extrude it in the gap because it's harder, then that might throw us into those longer times where, as you can see, it reduces the probability of the reliable secondary seal.
That was my concern, and if you go through it far enough it says that we had already stated that we have a high probability of no secondary seal because of the rotation problem, and I said that is a very important consideration.
MR. MASON: Let me address then the CIL question, because the basis for - -
DR. COVERT: What's a "CIL"?
MR. MASON: Critical Items List.
The reason that that was changed from the 1-R to 1 was this very rationale here, which said that after early on, after the 170 or 330 milliseconds, you didn't have a redundant seal, and so it was changed because it was not redundant all the time.
But it didn't really remove the redundancy at ignition.
CHAIRMAN ROGERS: Could I put the case and oversimplify it just a bit, because this is a good opportunity to be argumentative, if you will, on why you changed your mind. First, it was criticality item one, so that meant that if it was a failure, the mission was a catastrophe, and there had been discussion about that, a lot of it.
Then you made a decision, you and Thiokol made a decision, to recommend against launch for this very reason, that you were concerned. And then Mr. McDonald, in describing what happened, said that Thiokol had notified NASA that they should in effect not launch or conditions were not appropriate for launch, however you want to say it.
And then there was a phone call and he said, the conclusion being that Thiokol was directed to reassess all the data because the recommendation was not considered acceptable, in that - he was a little unclear about what he said, but anyway the recommendation was not considered acceptable.
And then you were supposed to have a five minute phone call caucus, which lasted 30 minutes, and you changed your mind.
Now that, you know, it is hard to explain it to an average outsider. You would think that that was
one of the most critical things you can imagine in this program, and it had been so considered by NASA for a long time, and you obviously knew it.
What caused you to change your mind? Try to explain it. The impression is that you were directed to do it, that there was so much pressure to get this launch off that you were directed to do it, and you did it.
Now, if that is not the case, try to explain it in language that the public will understand: Why you changed your mind and how you did it so quickly?
MR. MASON: Well, I think I would start by saying that when we picked the 53 degree temperature it was clearly the most conservative approach, and it was done because we had only gotten to a position in time to get to the telecon discussion. We had not established it as an unequivocal position, but rather one that was conservative, that stayed within our experience base.
That was what we were thinking at that time.
When we had the telecon, then the other factors that I mentioned came out, and I would not characterize that NASA said, directed us to reassess. What NASA said was: Here is our feeling  and our rationale, and we wonder whether you feel strongly that that 53 degrees is as low as it is rational to fly.
And I think we all recognized that it certainly was good at 50 degrees and 45, and so the question wasn't one of do you go below 53 degrees.
It was a question of how much below 53 can you go.
DR. RIDE: What data did you have to make that extrapolation? Did you have any data at all?
MR. MASON: Well, we had the effect of the temperature on the durometer of the O-ring. We had the one blow-by test that showed that it didn't blow by at 30 degrees. And other things that don't come to my mind that are in Mr. Lund's charts.
We had the higher margin of erosion. I mean, we had the ability to tolerate considerably more erosion than we had ever had and still seal.
But the reason for the debate was the fact that we didn't have hard evidence of how quickly that O-ring would move. And it became a matter of judgment rather than a matter of data, and that is the reason we couldn't reach a unanimous opinion.
CHAIRMAN ROGERS: What was the split? How many people were against it, even at the last moment?
MR. MASON: We didn't poll everyone.
CHAIRMAN ROGERS: Well, roughly.
MR. MASON: Well, I really couldn't guess. There
were so many people - people were shuffling their positions within their own minds during the conversation.
CHAIRMAN ROGERS: But I mean, was there a substantial number or just one or two?
MR. MASON: There were I would say probably half a dozen, five or six in engineering, that at that point would have said it is not as conservative to go to that temperature and we don't know. The issue was we don't know for sure that it will work.
DR. RIDE: Roughly how many in engineering said they felt it was okay?
MR. MASON: Bob, do you want to guess?
MR. LUND: Just from an informal poll, I would guess there were five or six, the same way.
CHAIRMAN ROGERS: So it's about evenly divided among the engineers?
MR. LUND: That's a very estimated number.
MR. MASON: Remember, of course, it's a lot easier to say just stay conservative.
MR. CRIPPEN: Mr. Chairman, if I may make an observation. Since the earliest days of the manned space flight program that I've been associated with and Mr. Armstrong has been associated with, our basic philosophy is: Prove to me we're ready to fly. And somehow it seems in this particular instance we have
switched around to: Prove to me we are not able to fly.
I think that was a serious mistake on NASA's part, if that was the case.
DR. WHEELON: May I make an observation while this chart is up, Mr. Chairman. You notice that it says from 330 milliseconds to 600 milliseconds there is a high probability of no secondary seal capability. I just point out that at 445 milliseconds was when the black smoke was starting to come out. I presume they are correlated. That's no big deal, but just before the chart gets away from us.
 CHAIRMAN ROGERS: Just one more question. In the final telecon, did you or anybody from Thiokol let NASA know that the engineers were reasonably evenly split on whether to launch or not launch?
MR. MASON: No, we did not. We did - it was on the telecon when it was asked individually of the three gentlemen down there, Mr. Lund, Wiggins, and Kilminster, whether they agreed to fly. But there was no discussion about the overall vote or poll.
Now, it was clear, I believe, that it was not unanimous because of the lengthy discussion and the caucus and so forth. But we did not say in detail
CHAIRMAN ROGERS: In other words, I'm not speaking about a poll now, an exact count. But I wondered whether you told NASA, we've got a pretty good split here among our engineers and you should know that, and we've decided to recommend it, but we have got some engineers that are pretty well split.
I mean, did you say something like that?
MR. MASON: No, sir, I did not. But during the telecon I think most of the people know most of the people by voice, and the pros and cons as discussed by the telecon I think would have conveyed the general statement.
CHAIRMAN ROGERS: So those engineers that opposed it were on the telecon, too?
MR. MASON: Oh, yes.
CHAIRMAN ROGERS: And they expressed their opinion at that time?
MR. MASON: Yes.
DR. WHEELON: To NASA or to you?
MR. MASON: To the group on the telecon.
DR. WHEELON: So NASA heard their reservations on the telecon?
MR. MASON: Yes, sir, I believe so.
MR. SUTTER: Can I ask a question. Why wasn't Houston in on that phone call? Aren't they responsible for the design of the machine?
DR. COVERT: Marshall is.
MR. REINARTZ: Mr. Chairman, I might answer that directly. The item that was being considered was an SRB item, a level three item, and that was treated as a level three item, as are many items by all of the elements, either orbiter, SRB, or ET. And we considered that, and depending upon the outcome of that telecon, an unfavorable recommendation by Thiokol to not launch or by the level three group, we would have then gone to JSC and said: Here is the situation as we see it and why we would not recommend launch at this time. In the conditions.
We treated it as a level three matter. It did not violate any of our - it did not require any waivers for our hardware and did not violate any launch commit criteria that we were made aware of by Thiokol. And on that basis, we did not bring in the level two organization into that discussion.
MR. SUTTER: Do you mean the decision to not have a redundant seal situation was not a waiver?
MR. REINARTZ: No, sir, it was not a decision to not have a redundant seal, as we indicated that the worst case condition that you could get into would be a single seal, which is the same situation as is now in the critical items list, that you could have a single
seal, and that would be a worst case situation that you would get into.
We indicated during the discussion there may be some increased probability of erosion on the primary, but it was not concluded that you would have as a foregone conclusion - -
MR. SUTTER: You don't understand my question. At one point in time, somebody laid down the design criteria that this would be a redundant seal. Somewhere along the line it got changed, and all I would like to know is who made that decision, and then would he go along with this decision.
MR. ALDRICH: Could I speak for Houston and for the level two organization, which is responsible for the integration of this total shuttle system? The critical items list is prepared and managed by the level two across all the projects, and they contribute to it, either with compliance through the two and three tolerance requirements that were described, I think yesterday or earlier last week.
And that process is formal, and the document that Sally has here in front of her is a document which in fact existed as 1-R early in the program for this case. It was changed in 1983, and it was reviewed and signed off at all levels of NASA, not only the level
three project, but also in Houston by the level two project management and in Washington by the level one management, as the final concurrence in that.
So the situation of agreeing to accept this joint as a single seal during the timing period described here when only one of the seals came into play was reviewed and accepted for the program at all levels formally and understood.
This meeting that we're discussing here, however, where that was discussed as it pertains to the cold or the performance of the seal on the actual flight day of 51-L, is a meeting that was held only at level three, as Stan just discussed. And not only the synopsis of the points considered in that meeting, but the fact that the meeting was held, was not known to myself or to the level one organization, Jesse Moore, above it until subsequent to the event of the launch day.
MR. CRIPPEN: Sir, if I might point out, I guess maybe it's a matter of interpretation of the CIL. I don't think the CIL was written to say it's okay to fly with one seal. I thought the CIL was written to say that it is okay to accept that after the thing separates the secondary may not be sealed.
DR. KEEL: Mr. Chairman, I think that is just
the point I was going to make. If you look, there is some ambiguity here or the danger of ambiguity. The criticality items list says specifically that the primary seal, the primary seal, not a single seal, is considered criticality one, which means that therefore the primary seal presumably has to be viewed as working and cannot fail.
DR. FEYNMAN: Could I ask a question? Could you tell me, sir, the names of your four best seal experts, in order of their ability?
MR. MASON: I would ask Mr. Lund to respond to that. Bob, did you hear the question?
MR. LUND: Yes. Roger Boisjoly I think is number one, with Arnie Thompson - I'm not sure who the best is. It's one and two.
DR. FEYNMAN: Approximately - what was that?
MR. LUND: Roger Boisjoly and Arnie Thompson, and Jack Kapp, K-a-p-p.
DR. FEYNMAN: And some other guy. And if you don't have any further, that'll be all right.
MR. LUND: Jerry Burns.
 DR. FEYNMAN: Now, I would like to ask one further question. What is the opinion of Mr. Boisjoly about the seals, about the decision that was made? Were you in agreement with the result of this caucus that
said that it was okay to fly?
MR. BOISJOLY: No, I was not.
DR. FEYNMAN: Now, Mr. Thompson, were you in agreement, and so forth?
MR. THOMPSON: I was not in agreement.
DR. FEYNMAN: Mr. Kapp?
MR. LUND: He is not here.
DR. WHEELON: Does anyone know what his position was?
MR. LUND: Yes. I talked to him and he said - after the meeting, because there had been so much discussion - I asked him, I said, how did you really feel, Jack, and he said: I would have made that decision, given the information we had that evening.
CHAIRMAN ROGERS: Would or would not?
MR. LUND: Would have made the same decision.
DR. FEYNMAN: So it may be that he would be in agreement?
MR. LUND: Yes, he was in agreement. That is as close as I can put it.
DR. FEYNMAN: And the fourth man's name?
MR. LUND: Jerry Burns. I don't know.
DR. FEYNMAN: So of the four, we have one don't know, one maybe yes or very likely yes, and two who were first mentioned without doubt as being the seal
experts, they both said no. That is the information I wanted, that's all. Thank you.
MR. ACHESON: Could I ask a question. This Mil Spec A3248A that was referred to earlier is described as meeting the requirement that this material be capable, I think was the word, of between minus 30 and 500 degrees Fahrenheit. Capable of what wasn't clear to me.
Capable relating to the function as seals, or capable only in the sense that the raw material would not disintegrate or break up or something?
MR. KILMINSTER: I can't recall the specific working in the back of that specification.
MR. ACHESON: What I'm trying to find out is how much reliance was placed by MTI when it acquiesced to fly in this stack and that they were confident of the material in that respect.
MR. LUND: We didn't discuss that specification at all. We depended upon our data. I don't think we discussed the specification at all.
MR. WALKER: Is that a materials specification or an operations specification?
MR. LUND: It's a material specification for the Viton.
MR. WALKER: So it doesn't speak to the use,
configuration, or operation?
MR. BOISJOLY: Just in the form of an O-ring, but it does not speak to the form of how that O-ring - -
MR. WALKER: That wouldn't seem to be an appropriate specification for this particular question, would it? Wouldn't you need a functional specification to say that under a certain configuration the O-ring would operate? Wouldn't that be what you would want, rather than just a specification on the material?
DR. COVERT: Let the record show that Mr. Lund nodded yes.
 MR. LUND: Yes.
CHAIRMAN ROGERS: Mr. Aldrich, going back to your statement, neither you nor Mr. Moore knew about this telecon or the discussions that took place on that?
MR. ALDRICH: Yes, sir. I can comment that it is my understanding that Mr. Moore did not know of it, because I did not know of it, and I have only found out about this meeting since the incident.
CHAIRMAN ROGERS: And were there others like yourself, that we would have expected would have known about it that didn't know about it? Do you understand my question?
MR. ALDRICH: The two important people in terms of responsibility in the chain of command are Jess and myself. And I should comment that the following day we met early before the launch in the firing room, myself and Mr. Reinartz from Marshall and Mr. Moore and Mr. Lucas - Dr. Lucas from Marshall, all of us in the same area, physically adjacent as we are in this meeting.
And we discussed concerns and progress in the countdown continually during that time, and we also called for flight readiness - that is a specific goal of each project for myself and Jess - at minus 20 minutes in the countdown and at minus 9 minutes in the countdown.
And through that morning, because of the launch delay there was probably a five or six hour period when we were gathered there, with a break which I took to review the ice situation outside of the area. During that period of time, we did not discuss the concern with respect to the SRB and the temperatures, or particularly with respect to this joint or the seals.
CHAIRMAN ROGERS: And you did not know that there was a split among the engineers in Thiokol about whether the launch should occur?
MR. ALDRICH: I did not know that there was a
concern about the solid rocket booster joints, nor that there had been discussions relating to the possibility of concern.
CHAIRMAN ROGERS: And you think that is true about Mr. Moore, too?
MR. ALDRICH: Yes, sir, I would be certain of that.
DR. RIDE: Do you think that is appropriate?
MR. ALDRICH: Let's see. I would be more pleased if we would have had a full discussion. As you saw earlier, we had a series of meetings and a series of requests from each element of our program to review their concerns and put them forward.
CHAIRMAN ROGERS: How is the final decision made? Is it made between you and Mr. Moore, or is there a committee?
MR. ALDRICH: We have a process of a lot of formal documentation, and you have had some extensive questions about wanting to understand it, and it is a complex system. But the formal process of documentation specifies the criteria to conduct a launch, such as the 31 degrees for the system launch failure is one criteria.
And the management is not in an in-line role of allowing the launch to proceed. We have a launch
team in Houston with a flight director. We have a launch team here at Kennedy with an operations director, and they conduct the entire launch from prior to the countdown through the 43 hour countdown period and through the launch, based upon the rules, regulations, and data with respect to those rules that their people are looking at.
 Management monitors that process and gives concurrence at the points we have talked about: the flight readiness review, maybe a week to two weeks before, the L minus one day, one day before, and at these commitment periods I talked about.
But that is a concurrence that we know of no reason not to proceed, and if we were not there to manage it the structure of the documentation in the team is such that they could go through all of the orderly engineering checks and procedures and process to allow the launch to occur.
MR. SUTTER: But aren't they given instructions that, yes, they are supposed to clear the vehicle for launch, but within the approved documentation?
MR. ALDRICH: Yes, sir.
MR. SUTTER: Well, wasn't this outside of the approved documentation?
MR. ALDRICH: No, sir. There is no requirement in any level in our formal documentation that violates any of the criteria that had been reviewed over the years and documented and was in place.
VICE CHAIRMAN ARMSTRONG: This is one I was going to ask earlier, once we got past Thiokol. But we're in this discussion and I would like to bring it up now. It seems that if everything is falling within the mission rules, the launch rules, 31 degrees and so on, then for concerns that people have - and let's talk specifically, as an example, about that temperature, the bulk mean temperature or the seal temperature or other temperatures - your process depends on people at one or another of these commit meetings bringing their concerns to you, even though you are within the launch range rules, bringing their concerns in.
And then you make a decision at that point that, even though we are in the launch rules, because there are certain concerns, this type of thing, you depend upon these contacts, personal contacts, is that right, coming in to tell you about things that would prevent you from going?
MR. ALDRICH: Yes. In fact, at our 2:00 o'clock meeting, the afternoon meeting - that didn't appear on today's list, but did appear on yesterday's -
it was a level that had Jess Moore and myself also and our people there. We concluded that meeting, where there had been a discussion of concern about whether the facility would make it successfully through all of the parameters because of temperature, that if any concerns for temperature did occur, would we please be called and we would discuss them.
And it was highlighted with respect to the facility, but it was a general request to the team that was there, that represented each of these.
DR. WHEELON: Arnie, had you known of this divergence among the technical people at Morton Thiokol, would you have proceeded to launch?
MR. ALDRICH: I would have proceeded to review it in detail at the next higher level, which is my level, and I can't say what decision we would have made. But we would have pursued the same things that are being pursued here today and were pursued in the discussion that was held by the people on that night.
CHAIRMAN ROGERS: I think Mr. Armstrong's question goes to the heart of the matter. Let's talk a little more about it. I mean, if you just have a checklist and you say everybody is checked off, and then you have no assurance that the human factors are going to come into play, so that if there is real concern on
the part of people that you're not going to notify, it seems to me that that is - -
 VICE CHAIRMAN ARMSTRONG: Let me just characterize the question is a little different way. Your rule says that you should be above 31 degrees, and beyond that there is no detailed specification of past history. So one could assume that, within your mission rules at least, it could have sat there for two months at 31 degrees and everything could be at 31 degrees, seals and the mean bulk temperature.
MR. ALDRICH: No, there is a rule on the bulk temperature and that would have been violated.
VICE CHAIRMAN ARMSTRONG: I guess I am questioning whether you believed that the kind of approach, this approach of deviations being required to be reported to you and discussed at commit meetings, is satisfactory?
MR. ALDRICH: Well, I'm certain we will discuss downstream today and as we go forward the formality of our process, the types of meetings we had, and what might be more appropriate or more adequate now.
I believed up until this point that the process we were using was thorough and adequate. In fact, could I characterize the meeting? I might have
talked too long, but if I could characterize the meeting.
CHAIRMAN ROGERS: No, why don't you talk more.
MR. ALDRICH: This meeting came out of a day where we held, because the hatch handle had a problem and that delayed us, and during that delay this weather front progressed into the Florida area. The winds became too high to support a return to launch, and so we scrubbed.
There were no other problems known with the launch system or the flight system at that time. We had this meeting to decide if it was reasonable to proceed the next day, and the primary point of discussion was whether, if the winds had been high, to scrub on the 27th.
It was projected to be cold on the 28th, and so the focus of the meeting - the way we do that is we have a weatherman come in from the Kennedy weather station, that supports us in great detail, and he made a full presentation of the weather forecast, which we had at the prior meetings also, because that was the point of involvement.
All parties there in this meeting heard the weather forecast and heard the report that the night
before the temperatures had dipped to 22 to 24 degrees and the predicted range was 24 to 27, but perhaps as low as 22 to 24, that for the preceding, but it was going to be above freezing by launch because that was going to be at 11:00 or 11:30.
So that was a well-known fact of the condition we expected. Now, one year previously we had the STS-51-C launch, in January of the year before, and we came up on a very cold night with a similar set of discussions at that time, and we had management meetings.
And this is all, by the way, my recollection, and I'm not reading this from a formal review, but this is my recollection.
We had a meeting that day. The forecast was it would be very cold that night, and should we tank the external tank and should we proceed with the launch? And we said we don't know, let's meet again later in the evening and see how we are proceeding with the filling of the tank.
We met late in the evening, and the concern we expressed, that the cold might be difficult for us, was in fact true, because the facility was already experiencing ice and problems with their equipment. And at that time we elected not to go because it was clear
the facility needed a better procedure for protecting it from cold weather that was not in place. However, also at that time a year ago, we had no discussion about other elements of the launch and flight system being concerned or proceeding with that cold and proceeding on the launch day.
In other words, it was a similar situation. However, we did not proceed because of specific problems with the ground equipment. And I think in some of our minds, in my mind - and by the way, I was not in this job at that time. I was in a job where I was at the meeting, where I was involved directly with the orbiter at that time.
But I got a good impression out of that meeting that there was, beyond the facility, not a concern with launching at cold temperature in the range of 30 degrees, and my impression was we were proceeding to launch.
CHAIRMAN ROGERS: You're speaking about a year ago?
MR. ALDRICH: A year ago.
CHAIRMAN ROGERS: But did you go through them on that launch? Wasn't there a blow-by that launch in the O-rings a year ago?
MR. ALDRICH: There was an item that was worked
CHAIRMAN ROGERS: Now, why wouldn't that call everybody's attention that weather might have been related to that blow-by, and why a year later, when you had even colder conditions, wouldn't anybody in the loop have said, my God, even the Thiokol people are split on whether this will work or not.
MR. ALDRICH: Well, that had been reviewed in a series of meetings over the course of that year, and in fact there was more blow-by and more erosion. And I would have to yield to these people that worked this problem better than myself, that the correlation of that to cold was never made totally clear in the discussions that I am aware of or the documentation that I know about.
CHAIRMAN ROGERS: In other words, no one related the fact that that happened to be the coldest launch and that launch was the only one that had the blow-by?
MR. ALDRICH: I couldn't say no one related that. That was not raised as an issue at the level in the program that I'm speaking from.
CHAIRMAN ROGERS: Just going back for a moment to the procedure, just speaking personally now, I'm really surprised that you and Jess Moore were not made
- that you weren't given the knowledge that there was such a considerable question and even a split among the engineers at Thiokol.
Didn't you know that at one point that evening they had recommended against launch and changed their mind?
MR. ALDRICH: I did not know that they had this series of telephone calls.
CHAIRMAN ROGERS: But did you know they had recommended against launch the night before?
MR. ALDRICH: No, sir.
MR. ACHESON: Who is the senior NASA official who knew of the split of opinion at MTI?
MR. REINARTZ: I was at Marshall. The discussion that we had, and as Jerry Mason indicated, that the evidence of the informal poll that was mentioned here today, was not provided as  a matter of course on the telecon that we had that evening. There was the initial discussion, as Jerry had indicated, Mr. Mason had indicated, that the initial recommendation and question as Mr. Mulloy went through a set of rationale and asked for comment. I then also asked Mr. Hardy, who was our senior technical representative that was on the line in Huntsville, to comment or add the technical position from Huntsville. And he stated that he had in essence
agreed with the rationale of Mr. Mulloy, but however he did not want MTI to be recommending or to indicate that they would not - excuse me, let me start again.
MR. ACHESON: I was asking for a name, the name first, and then the description.
MR. REINARTZ: All right. I was the individual. The Marshall projects, including the SRB, report to me, the Marshall projects, shuttle projects manager, and in that sense I was the senior program official that was on the line on the telecon.
And we had the discussion. We were not made aware, as was indicated - your other question was the poll. We were not made aware of that situation. We knew that the initial discussion had been the 53 degrees. We were certainly aware of that.
And after we went through and Mr. Hardy had said - and maybe it would be best to let him directly say, that he made a comment asking Thiokol for their further views, because he was surprised at their recommendation on the basis of the data they had with that for the 53 degrees.
And he asked them to - he said: Does that confirm that? He did not want to put them in the position of saying, hey, we are trying to force anybody to launch. He wanted the MTI opinion and their
technical opinion of that. He asked them if they had any additional data supporting their opinion.
It was at that time that Thiokol then went off the line to have their caucus.
And in regard, I might address the other one, Mr. Chairman, that, as I believe that Arnie said and as far as was made available to me at that time, that we were within the ground rules and had no violations of ground rules regarding any of the written requirements.
And as Mr. Armstrong said, in discussing any concerns that would prevent you from going, that after we had our discussion and then we came to our final conclusion, we did not have a concern that would prevent us from going at that time.
DR. RIDE: Why did you not at least bring up the meeting the concern, the original concern, and the discussions, and Level 2?
MR. REINARTZ: I guess, Sally, at that point it was because there was not any violation of the activities. There are a number of activities at all of the projects, both at Marshall and JSC. There are Level 3 considerations or items involving their hardware, and they are discussed, and the concerns are discussed and then resolved. And if they do not have an impact or waiver of the requirements, it is not a foregone thing that each one of those is then brought to Level 2, if they are successfully resolved within the framework of the criteria.
DR. RIDE: Did you at Marshall have any data or any models for simulations that you considered reliable to indicate that you could launch at 38 degrees, or 31 degrees?
MR. REINARTZ: George, I would have to ask you, on that question.
MR. HARDY: Let me just go back a little bit and cover the consideration of the discussions and my own position regarding the meeting.
 CHAIRMAN ROGERS: Hold on just a minute, before you tell us, because I think we have an idea what
the general argument is and the position is, what you knew about Thiokol and the engineers and their attitude, I mean, specifically now.
These things are tough, and we're not trying to make it tougher for you, but we might as well know. Were there two or three engineers in Thiokol who expressed a view that the launch shouldn't take place, and did you know that?
MR. HARDY: I did not know, specific, by name, at Thiokol, who was making firm recommendations as to launch or not launch.
CHAIRMAN ROGERS: But did you know there was a division?
MR. HARDY: I did not know the degree of division. I was well aware of the concerns that Mr. Boisjoly had and that he did express during the conversation, and the points that he brought out about the concern of the performance of the seal under cold temperatures.
I would say that, of all the people involved in the teleconference, my ability to detect levels of concern during the course of that discussion would be that he appeared to be the individual that expressed the greatest concern.
CHAIRMAN ROGERS: And you didn't convey that
to Mr. Aldrich and Mr. Moore?
MR. HARDY: No, sir. That would not be in my reporting channel to do that.
VICE CHAIRMAN ARMSTRONG: Mr. Chairman, I think I kind of understand all the details of this, but the gap that appears in my mind is the fact that we seem to have a situation where we are intended to have an operational vehicle that is going to fly on winter mornings for twenty years, and it should be able to handle conditions that are down around freezing, certainly if it is going to be operational in that category; and we have the mission rules, a launch rule that says it ought to be able to launch at 31 degrees or above; and yet we have seals that have constraints that are substantially away from what I would think would be a normal operating environment.
They have had to work very carefully to make sure that, in fact, this critical system was going to operate well within what I would think would be an operating envelope.
If I don't understand that right, I would like to have somebody tell me why that doesn't characterize the system.
DR. WALKER: In fact, there weren't any specific constraints on the O-ring temperature, specific
to the O-ring.
DR. RIDE: Well, that is one of the things I don't understand, because I guess I agree with Crip, that the NASA philosophy is it is supposed to be proved to me that it works under these conditions, and, as far as I can see, there is no data and no tests that indicate, that give you any confidence that the joint would be expected to operate at 31 degrees. I mean, maybe it does, but there is no data that proves that.
MR. SUTTER: Could I ask one more question, a quick one, I hope?
In this case, there was an input - don't fly, and then it was changed to do fly, and over all of the other launches. Has this happened before many times? And was it settled at Level 3, Level  2, or Level 1? Can you go back in history? Is this a normal occurrence or is this a very unusual occurrence?
MR. ALDRICH: I would try to answer that. It is hard to recreate history of a fifteen year program, and all of the critical things we have worked. But I would personally think that the process that these gentlemen talked about, polling all of the engineers and hearing all of the opinions and their positions, and finding there is disagreement, is probably something that has occurred often.
CHAIRMAN ROGERS: I think you ought to consider, though, on criticality one - I mean, I could see others, but Joe's question seems to be, in my mind, too directed toward criticality one. Everybody knows if there is a failure, all is lost. So it seems to me everybody would be alerted, and you had the experience the year before, and that was a cold day.
It's hard for me to understand why everybody didn't talk to everybody about it and say my God, there are some concerns, are we sure that we are going to be protecting, that the astronauts are going to be protected?
They just assumed, everyone assumed, the temperature of the O-rings would be the same as the ambient temperature, or would be at the time of launch?
MR. MASON: No.
We ran a calculation based upon the temperature forecast and the heat transfer to get the O-ring temperature. And, again, that is on one of Mr. Lund's charts. We didn't make an assumption. We ran a calculation what the temperatures would be.
GENERAL KUTYNA: And you had IR readings, is that not true, of some sort?
MR. ALDRICH: The IR readings that were discussed yesterday were taken at various points on the
external of the vehicle, and they were taken on the lower portion of the SRB. It would take a calculation to extrapolate that also, to get the O-ring temperature.
GENERAL KUTYNA: But what did that calculation reveal as far as the temperature?
It was down in the twenties, below?
MR. ALDRICH: I wish Horace Lamberth were here to give you exactly what he said yesterday. But the gist on the discussions of the readings that were taken with the IR was that there was a requirement to take them on the external tank, and that is taken with the understanding that we want to understand ice on the external tank for its impact to the launch system when we lift off. The readings on the SRB were taken by the team because they chose to, and there is neither a requirement to take them nor a specification for what range would be acceptable or not acceptable.
They were not reported to any point in the chain because there is not such a requirement.
DR. WALKER: That raises a question as to why there was not a requirement to get a temperature on the SRB near the position of the rings if Morton Thiokol thought that was a concern.
I mean, for example, why didn't the Morton Thiokol people ask for a temperature measurement there?
DR. KEEL: Mr. Chairman, if it will clarify the record according to my notes, Mr. Lamberth said yesterday that the IR readings indicated that the left solid rocket motor had temperatures  as low as 25 degrees, and the right-hand as low as 10 degrees, and with some lower temperature in the neck of the nozzle.
CHAIRMAN ROGERS: I suggest we take a recess for ten minutes.
DR. WHEELON: I can't let that go by. You said there was a requirement to take higher measurements. He said there weren't. What is the story?
DR. KEEL: No, I just said that there were measurements taken, and that is where he indicated the readings were.
MR. ALDRICH: He is reporting on the measurements that were taken as a matter of course, on the day before the launch. It was not a requirement, specifying SRB constraints. There was no requirement to measure that.
DR. WHEELON: But, in fact, measurements were made and they were 25 degrees.
MR. ALDRICH: Measurements were made. They are under investigation and test, because the measurements on the right SRB were lower than expected or can be explained, and that was part of the discussion
yesterday. They were 24 approximately on the left SRB, and they were in the seven to nine range on the right SRB. We think there is a magnitude of error between five to as much as, I guess, perhaps twelve degrees being worked by the team now.
CHAIRMAN ROGERS: Okay.
If we may, I would like to have a recess now.
[A brief recess was taken.]
CHAIRMAN ROGERS: The Commission will come to order.
We have just had a private meeting and decided to eliminate a couple of the items on the agenda, so that we can complete our work today. Mr. Keel will point that out.
We want to go ahead with this discussion, and when you finish your presentation, then we would like to have -
MR. MASON: I think I am finished, unless there are more questions.
Mr. Lund was next up.
CHAIRMAN ROGERS: And then we would like to have the two engineers that raised some questions about it.
This gentleman - what's your name?
MR. BOISJOLY: Boisjoly, Roger Boisjoly.
MR. THOMPSON: Thompson, Arnold Thompson.
CHAIRMAN ROGERS: One other thing that I would like to comment on, and I hope everybody is listening, is this.
I would like everybody to consider that the Commission has requested from each of you all of your private notes - not only your official notes and your official files, but any private notes you have in your own handwriting or any other notes you have, particularly as they relate to these conversations we have been talking about this morning.
MR. MASON: Would it be appropriate if we gather all of those notes - some of those would be in Utah and some in Huntsville - if we gathered those and delivered them on, like, Monday?
CHAIRMAN ROGERS: Yes.
I would like to have you work it out with Mr. Keel, the Executive Director. I mean, there may be some that we would want to get directly, I don't know. What we want to be sure about is, because of the nature of these documents, to be sure that we've got them first-hand, and then  anybody who wants to give us documents should feel free to give them to the Commission directly, if they would like to.
So, I will leave that up to Dr. Keel about how
those will be delivered.
The principal point is we want to be sure that they are protected and to save them, so that no claim can be made later on that they were destroyed, because of their importance.
Okay, Mr. Lund.
[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.2/14-3 1 of 13] Temperature concern on SRM Joints- 27 Jan 1986. [Ref.2/14-3 2 of 13] History of O-ring damage on SRM field joints
 [Ref.2/14-3 3 of 13] Primary concerns. [Ref.2/14-3 4 of 13] Field joint primary concerns SRM 25.
 [Ref.2/14-3 5 of 13] Primary concerns (continued). [Ref.2/14-3 6 of 13] Blowby history.
 [Ref.2/14-3 7 of 13] O-ring (viton) shore hardness versus temperature. [Ref.2/14-3 8 of 13] Secondary O-ring resiliency.
 [Ref.2/14-3 9 of 13] Blow-by tests (preliminary). [Ref.2/14-3 10 of 13] Field joint O-ring squeeze (primary seal).
 [Ref.2/14-3 11 of 13] History of O-ring temperatures. [Ref.2/14-3 12 of 13] Conclusions.
 [Ref.2/14-3 13 of
(Viewgraph.) [Ref. 2/14-4]
MR. LUND: My intent to the Commission is to review those charts that we reviewed in this Monday night telecon and to make it very clear I was not the presenter on any of the charts, except the conclusions charts. There were other engineering people at the Wasatch Division making the presentation on the individual charts that they were preparing in real time.
Listed there were our understanding of those people who were involved. I think that Mr. Malloy's presentation is a more complete list. This would be incomplete as far as those who were involved.
(Viewgraph.) [Ref. 2/14-5]
MR. LUND: The thing that we were most concerned about from an engineering standpoint was reflected in the history of O-ring damage on the SRM field joints.
As noted on this chart, the top five notations here are the joints and the locations in the joints, in the motors, of Motor 61-A and 51-C: the erosion depth that occurred in those motors, the perimeter around the circumference of the O-ring that was effected by that erosion, and, of course, the nominal diameter of the
O-ring. And then, if you took the O-ring and looked at at top view, looking down, this would be the length of that erosion. And then we looked for what we called heat affected zone, where you see some discoloration of the O-ring.
What brought the concern - -
DR. COVERT: Mr. Lund, on the chart I have, there is another column that is not on the viewgraph.
MR. LUND: Let me tell you what that - -
DR. COVERT: I'm just curious, what plus-, and minus-, are with respect to 36 degrees or something like that. I need to tie the two together with what I know.
GENERAL KUTYNA: Three sixty is the bottom on the SRB.
DR. COVERT: Three sixty is the bottom, so that's minus Z. Okay. Thank you, Don.
MR. LUND: Now, of chief concern were these five at the top. Those were the ones that experienced blow-by. The way we can tell what blow-by is, is we look for discoloration in the area aft of the primary O-ring. In the two instances, the one that was the most severe was the 51-C. There was black material between the two O-rings. And in the 61, there was some black material, but it was not anywhere near the amount that we experienced on 51-C. Also listed there for our
consideration was the fact that on other motors we had had O-ring erosion, but no blow-by.
 Now, what was not listed on the chart that night, but what was discussed in the meeting, was the fact that this motor was about, well, it was at 75 degrees, for a calculated O-ring temperature at the time of the launch.
This motor was at 53 degrees at the time of the launch.
DR. FEYNMAN: That says none. What was the matter with 61?
MR. LUND: It had blow-by. There was black products past the primary O-ring.
I think that's the message of that chart.
MR. CRIPPEN: Excuse me, sir.
Can we look at that chart and see the three cases of - what have you got there? Nine - and still say that there was no temperature correlation?
MR. LUND: The temperatures on the other motors, on 41, was 64 degrees. I'm sorry. I don't have, these are the overnight low temperatures. That's the data I have. These are the overnight low temperatures on the night before launch - was 64 on 41-D; 51 on 41-C; 56 on 41-B; 60 on STS-2.
GENERAL KUTYNA: And 53 on 51-C.
MR. LUND: Let me review that again.
What I have given you is the overnight low temperatures. I don't have at my disposal the calculated - -
GENERAL KUTYNA: What was it on 51-C, the overnight low?
MR. LUND: 51-C was 34.
DR. COVERT: And how about 61-A?
MR. LUND: Eighty-three.
DR. WHEELON: So the one where you had no erosion was the highest temperature by quite a bit?
Sixty-one-A had a relatively high temperature and overnight ambient temperature, and yet it had no erosion?
MR. LUND: But it had blow-by.
DR. WHEELON: The others were all in the forties and fifties?
MR. LUND: The overnight lows were in the fifties and sixties.
MR. KILMINSTER: I would like to correct one statement that was made about the caulking location on the right hand. For the right hand SRB, that is correct. Zero is in the minus-, position. For the left-hand, it is in the plus-, position.
MR. CRIPPEN: Unfortunately, some people use Z
in different directions. Could you be a little bit clearer?
MR. KILMINSTER: Minus Z is away from the orbiter. Plus Z is toward the orbiter.
(Viewgraph.) [Ref. 2/14-6]
MR. LUND: What I would like to do is, is there anyone in here who is not familiar with that chart? We have had enough of that chart.
CHAIRMAN ROGERS: Yes, we have been over it several times.
(Viewgraph.) [Ref. 2/14-7]
MR. LUND: This chart has been previously reviewed. As was noted, the field joint was our highest concern. What we were concerned about is the erosion penetration of the primary seal, and if it penetrates, we want a very reliable secondary seal.
 We had talked about the fact that that is a function of how quickly the pressure comes up in the motor. The radial expansion and the axial expansion of the steel deforms the joint. That is shown over here.
So we are concerned about the timing of how those seals seat and the rate of rise of pressure within the motor.
Now in steady state of course, if we have erosion penetrating this primary seal, there is a
possibility that this seal would not be there, and we could have blow-by and gas escape.
MR. SUTTER: I'm confused with that statement.
I thought the decision was if you had the primary blow, the secondary would hold? That it was a simplex seal?
MR. LUND: Only if this was in position early in the ignition process.
MR. SUTTER: I thought NASA's position said that a simplex seal is okay, which means that if the primary is gone, the secondary is holding. That is what I thought NASA was leaning on.
VICE CHAIRMAN ARMSTRONG: I think, to clarify that position a little bit, when we reviewed this at the Tuesday meeting, I guess it was, they pointed out that the reason it went from criticality 1-R to criticality 1 was that during testing - not firing, but testing - of the flexure, here (indicating), they found that they get this particular situation, and the secondary seal might not seat, in which case they only had one seal, the primary seal, and that is what caused the change.
It wasn't a firing test that did this, as I understand it.
MR. LUND: That is correct.
VICE CHAIRMAN ARMSTRONG: But it was static
testing that made them to go this criticality 1 as opposed to criticality 1-R, that is, this particular characteristic right here.
MR. SUTTER: But, during these conversations, with the concern over temperature that surfaced, I thought that the chart said it is still okay because you've got the simplex seal, which is a secondary seal. Am I confused?
VICE CHAIRMAN ARMSTRONG: No. That's true.
MR. LUND: We'll talk a little bit more about that in just a second. All I'm saying is that in a normal motor operation, you could experience this sort of thing. It could happen. That is a worst case.
DR. COVERT: Sir, have you ever taken this joint apart and examined the pin for wear or abrasion or scarfing of any kind, that would indicate that there is a bending of the nature that has been shown in that sketch?
MR. LUND: Maybe Mr. Boisjoly can talk about that. He's worked hard on that.
MR. BOISJOLY: Yes. I've taken many of them apart at the Cape, when they return from flight, and there is no indication in the pins at all that they've even been rubbed or even been used, for that matter. The only time the pins get pushed out of the recycle flow is when they have slight pitting, due to corrosion
or something on that nature. We would take them out of the flow.
But, as far as wear marks, the only wear marks that have ever been seen on any pins are those units that were taken purposely as engineering test units to burst, and then you started to see the shear effect and the rotation effects on the pins.
 DR. COVERT: I'm thinking about fretting.
MR. BOISJOLY: There is no indication on any pins I'd ever seen.
DR. COVERT: Are the pins that loose that it's possible to get a deflection without fretting?
MR. BOISJOLY: No, I don't think so.
MR. LUND: I agree with that.
(Viewgraph.) [Ref. 2/14-8]
MR. LUND: This next chart then summarized our concerns in the list.
First of all, the temperature lower than the current data base results in changing primary O-ring sealing-timing function. We were concerned that, the O-ring was going to move at a different rate.
We had some indication of that with 15-A and 15-B, with the black in the area between the O-rings.
We also know with the temperature that the O-ring does contract, and there is a 2 or 3 mil
contraction of the rubber itself at the lower temperature.
We know that the O-ring was harder at lower temperature.
We indicated that, of course, the grease is there, and it has a higher viscosity at the lower temperature.
Our feeling was, then, from all of that, that we would have a higher O-ring pressure actuation time.
Our concern was if the actuation time increased, the threshold of secondary seal pressurization capability is approached; and if the threshold is reached, then the secondary seal may not be capable of being pressurized.
Are there any questions on that chart?
MR. WAITE: So, you're saying you may not have any seals?
MR. LUND: Several things had to happen to cause that to occur.
MR. WAITE: Okay.
I want to get back to Mr. Sutter's point, that the primary seal concept was based on the fact that the secondary seal had been seated by the initial pressure check. You don't show that.
MR. LUND: In the seating process, if you have
the instant blow-by, because you would have a pressure at the secondary O-ring at time zero.
MR. WAITE: No. We're talking about pre-launch, pre-operation procedures which seat the secondary O-ring.
MR. LUND: Oh, the leak check.
MR. BOISJOLY: That shows in the top chart, the position of the secondary O-ring.
MR. LUND: The secondary is here, as a result of the leak check.
MR. WAITE: But in terms of the discussion we've been going through this morning, if you're talking about a primary seal, it is the secondary seal that is the primary seal.
MR. LUND: There is a scenario that would draw that conclusion. That is correct.
MR. WAITE: I'm having trouble with your scenario with that second seal, upset like that.
MR. LUND: If the primary O-ring seals, then this could result.
MR. WAITE: Even though it had been seated before?
MR. LUND: You see, the resiliency and the cold temperature and the rotation would tend to make you do that.
Now, the pressure force, even if this came through, the pressure force may be sufficient to push it in. But, in a worst case scenario, it could be up there if the primary seals.
MR. WAITE: Do you agree with that?
MR. SUTTER: I'm slightly confused.
MR. WAITE: Are you saying this scenario calls for a change in the secondary seal from its previous condition?
MR. LUND: This scenario is the one that has drawn all the attention for several years, that the gas comes down, actuates the primary seal, and it seals. As the rotation occurs, there is a possibility that the secondary seal would lose squeeze and be capable of having blow-by, if it ever burned through the primary.
It is not an easy concept.
CHAIRMAN ROGERS: Okay, Mr. Lund.
Proceed with your presentation.
(Viewgraph.) [Ref. 2/14-9]
MR. LUND: This was a summary chart prepared by the next presenter.
In essence, he's just reiterated the same thing we had seen, that the SRM 15 had the worst blow-by, must worse visually than SRM 22. Twenty-two had blow-by and we also experienced, of course - then
also blow-by. And that was also discussed this morning.
(Viewgraph.) [Ref. 2/14-10]
MR. LUND: I would like to show you now the hardness data on the O-ring. This is the Shore A reading.
The hardness goes from 77 to 96, as you go from 70 down to 10 degrees.
DR. FEYNMAN: What is the hardness data - the amount of force you need to change it?
MR. LUND: Yes. You push on it and measure the amount of push.
DR. FEYNMAN: It has nothing to do with time?
MR. LUND: No. It's just hardness.
DR. WHEELON: Is that like a standard Brinell hardness test?
MR. LUND: It's like a Rockwell A on rubber.
(Viewgraph.) [Ref. 2/14-11]
MR. LUND: This is a result of some of the resiliency testing that we're running. During the initial pressurization rate of the solid rocket motor, pressure comes up relatively slowly for the first hundred milliseconds or so, and then goes more quickly, and then turns over and goes slowly again.
If we took a secant across the total time, we would have a rate of movement of the two metal parts that the O-ring is trying to seal of about 3.2 inches
Your time is much shorter, and so are the deflections, so that is the equivalent time.
And so we put into our tensile testing machine a two-inch-per-minute rate. We compressed the O-ring in a groove - and let me get those exact - and "squozed" the O-ring. Forty thousandths is very representative of what the squeeze is, as we squash the O-ring between the two metal parts.
CHAIRMAN ROGERS: When you say "we," was this an old test?
 MR. LUND: Yes.
This has been done previously.
And then we moved the head of this tensile machine away from the O-ring at two inches per minute.
VICE CHAIRMAN ARMSTRONG: At what point is it moving two inches per minute?
MR. LUND: The O-ring is in a groove, and we squash it down 40/1,OOOths, and then we moved the head of the tensile machine away from the O-ring at two inches per minute to try to simulate -
VICE CHAIRMAN ARMSTRONG: It doesn't lie within a groove when you're doing this? This is just a push against the machine?
MR. LUND: Yes. The machine forms the other seating surface that would occur in a rocket motor.
What this said was that at 100 degrees, as that head came back to its original position, I'm sorry, not to its original position, but to within 5/1,OOOths of its original position, still maintaining the squeeze, that at a high temperature, at 100 degrees, the O-ring came right back.
It followed the machine right up. At 75 degrees, it took several seconds to recover. And, as we went lower in temperature, it took much longer to recover.
DR. WHEELON: That's pretty nonlinear. How do you account for that?
MR. LUND: It is the modulus of the rubber. Those polymers do that.
DR. FEYNMAN: The rubber - ordinarily in materials, like steel or something when you squash it, you are compressing the molecules together and they simply expand back. When you stretch a piece of rubber, the reason that it responds is because of dynamic motion. It is trying to shake molecules and pull something; like, you take a long chain across a room, which has a lot of tennis balls bouncing in it. The chain will be "ponged" by the balls and pulled
together. If the balls are slowed up, and low temperature means slowed up, then there is much less ponging and much less pulling back together, and the same way responding.
I used the expansion. But you can do the same thing with compression. If you compress it out of shape, it goes back into shape because of thermal notion, really, not because of spring. And when the thermal temperatures change, it goes back very, very much lower.
It is very characteristic of materials of this kind, that have this enormous effect. Temperature has such enormous effect.
DR. COVERT: Does it follow the square root?
DR. FEYNMAN: No. It's E to the minus A over T. It is exponentially. So, at 32 degrees on the scale, you probably wouldn't be able to measure the time. It would be too late to wait for the hour, or whatever.
MR. LUND: Now, keep in mind that resiliency is not the only issue. But you have the pressure load coming in and the pressurization of the motor kicking that O-ring up and saying go with me.
So this is one factor.
(Viewgraph.) [Ref. 2/14-12]
DR. FEYNMAN: But if there is a gap left, is there really any pressure remaining to push?
Suppose the O-ring did return, and there's a little gulf, and the gas comes. Why wouldn't that push it?
 DR. COVERT: Because there's a lower pressure at the minimum area point.
MR. LUND: There's a nozzling effect, and the pressure is going to go down. If the pressure is half that, it is out in the chamber it's feeding, and it would suck it. That is one of the reasons O-rings work.
(Viewgraph.) [Ref. 2/14-12]
MR. LUND: Here are the results of the blow-by test.
This blow-by test fixture is simply a little ten inch rig that has simulated in it the actual geometry of the seating surfaces, only instead of being 146 inches in diameter, it is 10 inches in diameter, the O-ring diameters, the grooves. The gap widths are all the same.
What we wanted to do in this test is, first, by the same technique that is used in the motor, put pressure between the seals, to push them into the position that they actually occur in the rocket motor. Then, through another channel in the test vehicle, we pressurize, like the motor does. We loaded the
pressurization medium with argon, and ran a couple of tests at each one of these temperatures, and there was no indication of leakage that we could tell, with the argon. And we worried about the sensitivity of that.
We are in the process of using Freon 14, which is much easier to detect and categorize at much lower leakage rates.
CHAIRMAN ROGERS: I assume this is one you are doing now?
MR. LUND: It has been done now. We were right in the process of doing this at the time of the flight. And we had this done. We were in the process of doing this.
CHAIRMAN ROGERS: Was there any particular reason why you were doing it at the time of the flight?
MR. LUND: Oh, yes.
We have been working on this problem of this whole leakage O-ring scenario for some time.
MR. ACHESON: How many tests represent a reliable body of testing data?
MR. LUND: That is a tough question. I guess I couldn't quantify it.
I would certainly think that I would always want more than two.
CHAIRMAN ROGERS: When did this test start, or
these tests start?
MR. LUND: Arnie, can you answer that?
MR. THOMPSON: We started about eight weeks ago, I guess, or ten weeks, to build the apparatus, and we're developing the system and the techniques to measure blow-by.
CHAIRMAN ROGERS: And in these telecons that you had prior to launch, did you discuss the fact that you were then conducting tests on this?
MR. THOMPSON: This data here was presented in the telecon.
MR. CRIPPEN: Excuse me, sir. Can you tell me whether this test stimulates the flexure of the joint?
MR. LUND: No, it does not.
What we were trying to do was measure the blow-by at the early part of motor operation. At this point in time, we had not concluded the Freon 14 tests. We have completed them now.
DR. COVERT: What does a quick look say?
MR. LUND: No leakage down to in the area of zero degrees.
When you get down below zero, there is some leakage. So that would tell you that the engineering thought process is certainly in the right direction.
(Viewgraph.) [Ref. 2/14-13]
MR. LUND: This data was discussed very briefly in the telecon. All of this data was taken at 75 degrees.
What the intent here was is to indicate that when O-rings are squashed, "squozed" together, for long periods of time, that they will not return to their original form. They have a memory.
I might indicate that that scale is exactly reversed. This is really 70, 168, 500, and 1,000. But the answer is still the same, that there is some permanent set in all of these O-rings, as you store them for long periods of time.
That is another thing that was of concern to us, that there is permanent setting in the O-rings themselves.
DR. FEYNMAN: How big is the TO minus TS? Do you remember? The distance that you squoze it in the beginning? How much do you squeeze them when you do this?
MR. THOMPSON: Twenty-five percent.
DR. FEYNMAN: Thank you.
(Viewgraph.) [Ref. 2/14-13]
MR. LUND: We also carefully looked at the geometry on the "as built" dimensions, and compared the 15-A and B motors, where we had had erosion and
blow-by with the geometry of the motors that were to be flown. Two conclusions out of here. You can see the squeeze percent across 15. They range from about 11 to 16. You can also see that the one that had the highest squeeze had erosion, and the one that had the lowest squeeze did not have any erosion, which tells me that squeeze is not the only parameter affecting erosion.
We looked carefully at the squeezes here. They are in the same ballpark population, with the exception of the forward here (indicating) on the left hand, up front.
(Viewgraph.) [Ref. 2/14-14]
MR. LUND: These are the results of the thermal calculations that we performed. We went through our sequence of motors and picked those motors that we thought would give us the lowest operating temperature at the time of motor operation.
We then went back and looked at the environment that the motors were exposed to and picked out those motors that would give us the lowest O-ring temperature.
This is the list. The first four of these are static test motors that were static fired at the Wasatch Division.
You can see 15, 22, and 25.
This is the mean bulk temperature of the propellant.
This is the ambient temperature at the time of launch, or suggested launch.
Here are the results of the thermal calculations, indicating the temperatures that we would predict the O-ring to be at at the time of the launch.
MR. ACHESON: Why is there such an erratic relationship between the ambient and the O-ring temperature?
MR. LUND: It turns out that the fillum grain is a very nice oven or hand warmer for the case. The grain, of course, has a lot of rubber and has aluminum powder in it. It has a good heat capacity. But it is insulated. All those little aluminum particles are separated by polymers. And so, it is a good heat capacitor.
 But it contains a lot of heat.
Well, it transmits it slowly, too.
So, what you have to look at is how hot the grain is, what the temperature is, and you will always find that this is between them. They are being chilled and heated from two different sources, because we didn't have totally definitive velocities.
MR. ACHESON: Is there putty in between? I guess there is - at the time of this measurement?
MR. LUND: There is putty in the gap, upstream of the O-rings.
MR. ACHESON: So, wouldn't that prevent the temperature of the bulk from warming?
MR. LUND: No, just conduction. The grain, the propellant is attached to a rubber insulator that is attached to the case. So it is just a conduction effect.
We also looked to see what the effect of the convective part of the heat transfer was. We didn't have definitive winds for each of those launches, and so we just took a look and said well, what is the effect of varying that wind? And you can see it makes some difference, but not a tremendous differences in the temperature at the O-ring.
GENERAL KUTYNA: A quick point.
The night before, when we drained the external tank, we did not drain all the hydrogen out of it, which sometimes happens. You had hydrogen in there, ice cold. Would that have made that a little bit cooler because you had that hydrogen?
MR. LUND: Yes, sir.
VICE CHAIRMAN ARMSTRONG: One question.
Clearly, you had a concern about temperature, and so on. Did you ever consider or take thought of controlling the temperature at the seals, or to changing
of the material of the seals to something that had different characteristics?
MR. LUND: Those thoughts have gone through our minds. There has been no positive action along those lines.
(Viewgraph.) [Ref. 2/14-15]
MR. LUND: So our engineering opinion, looking at that data, was, first of all, of course, that temperature of the O-ring is not the only parameter controlling blow-by. That was quite apparent to us. But we did know that SRM-15 with blow-by had an O-ring temperature that was low. We thought that was a contributing factor.
We had the four development motors from the previous chart that had no blow-by, that were tested lower than the SAM-15, in the area of 47 to 52 degrees. But, as was mentioned before this morning, because of the assembly problems, we had gone in and packed that putty, so we felt that it was a more representative case of the flight motors at that point in time. And we were concerned that we had done the right thing at that point in time, in looking back.
DR. WALKER: Let me understand that.
The motors had putty packing which resulted in better performance, better performance than the flight
MR. LUND: The flight motors.
 DR. WALKER: But I thought this morning, or earlier, rather, Mr. Mason indicated that he didn't think that packing the putty in the flight motors would really improve the performance because you couldn't necessarily see. There is evidently a difference of opinion.
MR. LUND: There is one of those that, you know, every engineer would have an opinion on that.
MR. MASON: Excuse me. I think the point was that if you packed the putty and you know there is a hole there, you would have filled it. But it doesn't assure you that you don't create one.
One of the primary ways of creating one is in the leak test. So, in the static test vehicle, you have the opportunity to run the leak test and make sure that if you have created any leaks, that they are plugged. Whereas, in the flight vehicle, you don't have that opportunity.
So, what we figured was we had a higher probability that we had plugged any leaks in the static test motor because, when we put it together and we knew we had a chance of creating the voids, and we knew that we had potentially created them with the leak test, so
we went in and plugged those. And so, we just figured that there was a lower probability of a blow-through in the static test motor than there would be in a flight motor.
So we didn't want to deceive ourselves by assuming that the static test motor was exactly the same as a flight motor.
DR. WALKER: I guess the question I had was if you thought packing the putty was a good idea, why didn't you suggest packing the putty after the leak test for the flight motors? Is it just too difficult, because the flight motors were not accessible and you couldn't get inside easily?
MR. MASON: Fundamentally, that is correct.
You would have to take the igniter out and go down into the motor.
DR. WALKER: It just wasn't a practical thing to do?
MR. MASON: That is correct.
MR. LUND: We concluded that at about 50 degrees Fahrenheit, that blow-by could be experienced in those case joints.
We looked at the temperature and we were seeing numbers at that point in time of those kinds of temperatures. We concluded that we really don't have
data that would indicate SRM-25 is different than SAM-15.
MR. SUTTER: Just to show you how confused I am reading what that says and going back to the point that the secondary seal may not be working, I would conclude that you shouldn't fly.
MR. LUND: Let's go to the next chart.
MR. SUTTER: Am I confused?
MR. LUND: No, let's go to the next chart.
MR. SUTTER: Am I confused?
(Viewgraph.) [Ref. 2/14-16]
MR. LUND: So, our recommendation was that we should maintain the O-ring temperature at greater than or equal to 53 degrees Fahrenheit at launch. We didn't feel that we had the data, as Mr. Mason pointed out, to really go down below, based upon the development motor because of the putty packing problem, and our engineering recommendation was to project the ambient temperatures, or conditions, the wind and the temperature, to determine the launch time.
DR. COVERT: Mr. Lund, what is the action time on the igniter, as it gets colder?
 MR. BRINTON: About 450 to 500 milliseconds.
DR. COVERT: Then it is lower, as it gets colder?
MR. LUND: No. It is longer.
DR. COVERT: That is what I mean - it spreads out.
MR. LUND: It is slower, to slightly longer
DR. COVERT: And the primary grain ignites with greater difficulty, I suppose?
MR. LUND: That is a fair statement.
DR. WALKER: So, could we conclude then that, in addition to the two engineers who seemed to be the best experts on the O-rings, that you also were recommending against launch?
MR. LUND: Yes, sir, at that point in time.
DR. FEYNMAN: At this point in time is the caucus, because that's what we're looking at?
MR. LUND: That is what we're looking at, the charts that were presented in the caucus.
MR. SUTTER: Didn't the chart before this say SRM-15 had blow-by?
MR. LUND: Yes.
MR. SUTTER: What does it mean that it worked?
MR. LUND: There was no violation of the primary seal, other than the instantaneous blowby and a little bit of gas. The seal functioned.
MR. SUTTER: I thought, though, that if you're concerned that the secondary seal may have a chance at not working, you sure wouldn't want to tolerate any blow-by in the primary seal. Then how can you say it worked to meet your criteria?
MR. LUND: I don't have a good answer to that.
MR. WAITE: You see, because when you say that secondary seal potentially can be upset by deflections, which disturbs the initial pressure check position, then there is no seal, if you have blow-by on that parameter?
MR. LUND: If you have blow-by. I think Roger said it best - every seal blows by. There is probably always some blow-by in the seating process.
VICE CHAIRMAN ARMSTRONG: That is at the low pressure?
MR. LUND: As the pressure is just rising.
VICE CHAIRMAN ARMSTRONG: If it's rising, you get a little blow-by before it seats?
MR. LUND: Yes, so "blow-by" is a qualitative thing.
MR. WAITE: The blow-by is excessive?
MR. LUND: If the blow-by is excessive, then you would have erosion and you would blow-by the O-ring.
DR. COVERT: Ron, I think we'd all better remember that we're talking about margins. There's nothing absolute about this. The real question is, as Roger put it, who's going to win the race. Is the seal going to seat before it erodes away, or is it not? And the question is how big is the margin between them?
MR. LUND: That's right.
MR. WAITE: I think I understand the mechanism. I'm just trying to understand what they're saying.
DR. WALKER: Could I ask a question.
 Do you know if there is erosion and blow-by in the Titan seals, General Kutyna, and can we get that history?
GENERAL KUTYNA: I do not know. I've asked for that history.
CHAIRMAN ROGERS: Okay.
If there are no further questions, thank you very much.
Now, Mr. Boisjoly we realize you don't have a prepared statement to give and we will have other opportunities to talk to you, I'm sure. We just want to get a preliminary statement. You've already said on the record that you did not favor the launch. Could you tell us a little bit more about your involvement and the discussions in detail?
[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. Also note that the references below are the same as the ones shown on pp. 645-651 (previous reference section above!)- Chris Gamble, html editor ]
 [Ref. 2/14-4] Temperature concern on SRM Joints- 27 Jan 1986. [Ref. 2/14-5] HISTORY OF O-RING DAMAGE ON SRM FIELD JOINTS.
 [Ref. 2/14-6] PRIMARY CONCERNS (continued). [Ref. 2/14-7] PRIMARY CONCERNS.
 [Ref. 2/14-8] FIELD JOINT PRIMARY CONCERNS SRM 25.
 [Ref. 2/14-9] Blowby history.
 [Ref. 2/14-10] O-ring (viton) shore hardness versus temperature [Ref. 2/14-11] Secondary O-ring resiliency.
 [Ref. 2/14-12] Blow-by tests (preliminary).
 [Ref. 2/14-13] Field joint O-ring squeeze (primary seal).
 [Ref. 2/14-14] History of O-ring temperatures.
 [Ref. 2/14-15] Conclusions.
 [Ref. 2/14-16] Recommendations.
MR. BOISJOLY: Yes.
I wrote some notes here. I have to confess that right now, my mind is basically like a sponge, with everything that has been going on after the incident and prior to the incident. So, I just had a sequence-down here, and I would just like to hit the highlights, if that's okay.
CHAIRMAN ROGERS: Yes, that's fine.
We have all been under a lot of pressure, too, so we understand that you may be tired.
But go ahead.
MR. BOISJOLY: Okay.
I first heard about the cold temperature at 1:00 p.m., the day before the launch, and we immediately, including myself - -
CHAIRMAN ROGERS: Do you want to give your name?
MR. BOISJOLY: My name is Roger Boisjoly, and I'm in the Structures Section. I work directly for Jack Kapp, and I have been involved in these seals and the joints basically since I've come to work for Thiokol, which was some five and a half years ago.
CHAIRMAN ROGERS: Thank you.
MR. BOISJOLY: Okay.
I first heard of the cold temperatures prior to launch at 1:00 o'clock on the day before launch, and from past experience, namely the SRM-15 launch, of which I was on the inspection team at the Cape, it just concerned me terribly.
And so we started in motion to question the feasibility of launching at such a low temperature, especially when it was going to be predicted to be colder than the SAM-15.
So we spent the rest of the day raising these questions.
DR. WALKER: And the O-ring was your concern?
MR. BOISJOLY: Yes.
I felt we were very successful up until early evening, because it culminated in the recommendation not to fly, and that was the initial conclusion. I was quite pleased with that.
I presented and prepared charts 2-1, 2-2, 2-3, 4-1, and 5-1, and basically those were the charts where I had that exaggerated view showing the O-ring in joint rotation.
There was the summary that put a probabilistic sequence on the timing of the seals, and then I prepared
the chart of primary concerns.
I was basically concerned with how temperature, low temperature, affects the timing function and the ability of the seal to seal. Low temperature - and I stated this for over a year - is  away from the direction of goodness. I cannot quantify it, but I know that it is away from the direction of goodness.
I feel very strong, and I always have felt very strongly, that SRM-15 was telling us a message, and at the flight readiness review, we did not have any data to support anything but a generalized statement that said we feel that temperature was a contributor.
We did not make a major input in that. We did not make a major thing about it. But we said that we feel that temperature had something to do with that thing.
Subsequent to that, we designed a blow-by rig specifically to investigate the questions that were raised at the SRM-15 data review, subsequent to that data.
That blow-by test, as configured, was strictly configured to measure if we could put approximately a teaspoon or a tablespoon of cold gas past an O-ring at the low pressure regime of, say, 1 psi up to 50 psi, and if we
could get that past, we would have explained the blow-by phenomenon, and then the timing function would have come out of that and that said it was a function of temperature because it is a delay. You are seeing hot gas indications pass, which was the visual indication between the seals in SAM-15. That was the primary crux of the whole situation.
GENERAL KUTYNA: Why did you not improve the dynamics?
MR. BOISJOLY: That was coming. But we had not got into that at that point.
On the net that night, after I presented those feelings very strong - I get very emotional about these things - and I was quite strong over the net about it, as George Hardy remembers.
Somebody brought up about SAM-22. I was not personally at the Cape, and disassembled, seeing the hardware in 22. But one of my colleagues was, a younger engineer. And I questioned him about this.
He told me that the gas blow-by that was observed on that was grey, splotchy-type blow-by, over a specific arc length, which I don't remember at the moment. I made that point that on SRM-15 we had over 100 degrees of arc, and the blow-by was absolutely jet black. It was totally intermixed in a homogeneous
mixture in the grease. I attributed that to the pumping action of the joint as we were towing it back into the Cape. That is why it was totally homogeneous.
But we analyzed that chemically and found the products of combustion in it, we found the products of putty in it, we found the products of O-ring in it.
I made that point.
During the course of the evening, I also produced photos of the SAM-15, and my colleague produced photos of SAM-22. And you could visually see the difference in the amount of soot, as characterized past the O-ring seal.
I was asked then on the net to support my position with data, and I couldn't support my position with data. I had been trying to get data since October on O-ring resiliency, and I did not have it in my hand. We have had tremendous problems in trying to get a function generator and a machine to actually operate and characterize this particular pressurization function rate.
At that point, the telecon basically continued, and Mr. Lund presented his conclusions and recommendations.
So the formal part of the presentation was finished.
Listeners on the other line seemed not very pleased with the recommendation. In fact, somebody asked Mr. Hardy what he thought about it, about our recommendation, and Mr. Hardy said he was appalled at MTI's decision. However, he would not go against our recommendation not to fly. If the contractor recommended not to fly, he would not go against that. He would recommend not to fly also.
There was a very short discussion that ensued, and we had, we asked for a five minute caucus. Our people asked for a five minute caucus to discuss the situation. Those opposed to launching continued to press their case with MTI management, and those opposed to the launch that pressed this case in the caucus were basically myself and Mr. Thompson. And we did everything we could to continue to try and press for not launching describing - I took the photographic position of the evidence and Mr. Thompson was trying to further elaborate on the sealing characteristics of the seals. When we realized that we basically had stopped in the discussion and we could go no further because we were getting nowhere, we backed off, both of us. We just sat back down.
GENERAL KUTYNA: What was the motivation
driving those who were trying to overturn your opposition?
MR. BOISJOLY: They felt that we had not demonstrated, or I had not demonstrated, because I was the prime mover in SAM-15, because of my personal observations and involvement in the flight readiness reviews, they felt that I had not conclusively demonstrated that there was a tie-in between temperature and blow-by.
My main concern was if the timing function changed and that seal took longer to get there, then you might not have any seal left because it might be eroded before it seats. And then, if that timing function is such that it pushes you from the 170 millisecond region into the 330 second region, you might not have a secondary seal to pick up if the primary is gone. That was my major concern.
I can't quantify it. I just don't know how to quantify that. But I felt that the observations made were telling us that there was a message there telling us that temperature was a discriminator, and I couldn't get that point across.
I basically had no direct input into the final recommendation to launch and I was not polled.
I think Astronaut Crippen hit the tone of the
meeting exactly right on the head when he said that, the opposite was true of the way the meetings were normally conducted. We normally have to absolutely prove beyond a shadow of a doubt that we have the ability to fly, and it seemed like we were trying to prove, have proved that we had data to prove that we couldn't fly at this time, instead of the reverse. That was the tone of the meeting in my opinion.
CHAIRMAN ROGERS: Thank you very much - any questions?
DR. WALKER: Mr. Boisjoly, wait. I have one question. We are still grappling with this little puff of smoke. Do you have any opinions about that?
MR. BOISJOLY: Yes, I have an opinion. But it is just an opinion, mind you. If you get blow-by through both seals and you have erosion sufficient to do that, you may be seeing the products of the culmination of the hot gasses, the putty, the grease, the O-ring materials, blowing out the joint; but you still, because of the overwhelming amount of pressure being  forced on these seals, push the remaining part of an eroded seal into either/or the primary or the secondary.
Basically you can work this scenario both ways because if the primary seals, the secondary at some point in time, because it would have had it to be eroded
too, because it would have been off of the seat, would have been off the seat, and then if you lost integrity later on in flight of the primary seal, you blow-by and fail.
If you use this scenario, that the primary seal was eroded so badly that it never sealed in the action, but there was enough of the secondary seal left and it did seat in the extrusion gap, and then subsequently later in flight, due to loads or whatever it got spit out, then you would have the same effect.
So you can do it either way, with either seal - and that you can't quantify, because you're talking about a hot gas happening with a cold gas test firing.
DR. WALKER: Do you think it is possible, by looking at the volume and duration of that smoke, to estimate just how much material was eroded?
MR. BOISJOLY: I understand that people at Marshall are trying to do just that thing.
DR. WALKER: Is there any result of that?
Could someone at Marshall comment on that?
MR. HARDY: I don't have the results. That activity is underway, was underway two days ago, when I came down here. That is being done, and we do think that is quite critical in understanding the scenario.
CHAIRMAN ROGERS: Thank you very much.
DR. FEYNMAN: I just had one question, to try to understand a little more clearly what Mr. Lund showed us - maybe he should answer, I don't know - a series of graphs, of pictures that were supposedly occurring during the half hour caucus.
MR. BOISJOLY: No. That conclusion was the conclusion prior to the caucus.
DR. FEYNMAN: These were not the slides shown during the caucus?
MR. BOISJOLY: No, sir.
That whole presentation was a culmination before the caucus occurred.
MR. ACHESON: Is it practical to conduct a test with hot gas?
MR. BOISJOLY: Yes. In fact, as a result of the incident, we are going back, and one of the things we are trying to do is to take a full-scale joint and run a hot, 40 pound charged motor, and blow gas, hot gas, through it. We are also trying with cold gas to simulate the dynamics in that subscale test rate that would have the O-ring pressurized as the joint opening is added.
MR. ACHESON: Why wouldn't either or both of those variations in your test program have been instituted at the beginning of the test program?
MR. BOISJOLY: I guess, in all honesty, the data that we ran in resiliency showed on that chart at room temperature showed that in a normal ambient environment, that we did not have a problem, and we had a very sufficient erosion margin.
Now, one thing that wasn't put up on that chart that we did discuss was there was one test, because I was concerned and I asked one more test be run in the time frame that those resiliency tests were run, back about eight or nine months ago, I asked that the O-ring be squeezed 40/ 1,000ths of an inch, and just back off 10/1,OOOths of an inch. The rationale for doing that was to show what the effect of the secondary seal was at the ignition transient, beginning, namely, the  zero to 170 millisecond regime and spilling over into the next regime of 170 to 330. And that never lifted off.
That was the basis of my making that chart. I made that chart for the Washington presentation and I quantified that as best I could on the basis of that information, and I felt very comfortable with the fact that, if we were in that position of a launch that was above SAM-15, that we were okay for that region.
We had that as an experience base in our books, and that is why I was so adamantly opposed to go
outside of it.
DR. WALKER: Did you present that argument at this half-hour meeting?
MR. BOISJOLY: Yes.
CHAIRMAN ROGERS: Thank you very much.
Mr. Thompson, Do you want to give your name and position?
[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. 2/14-17 1 of 22] Summary Notes (typed) for January 27 and 28, 1986. Written 2/13/86 by R. Boisjoly. [Ref. 2/14-17 2 of 22] Summary Notes (typed) for January 27 and 28, 1986. Written 2/13/86 by R. Boisjoly.
 [Ref. 2/14-17 3 of 22] Summary Notes (typed) for January 27 and 28, 1986. Written 2/13/86 by R. Boisjoly.
 [Ref. 2/14-17 4 of 22] Summary Notes (handwritten) for January 27 and 28, 1986. Written 2/13/86 by R. Boisjoly.
 [Ref. 2/14-17 5 of 22] Summary Notes (handwritten) for January 27 and 28, 1986. Written 2/13/86 by R. Boisjoly.
 [Ref. 2/14-17 6 of 22] Summary Notes (handwritten) for January 27 and 28, 1986. Written 2/13/86 by R. Boisjoly.
 [Ref. 2/14-17 7 of 22] Typed Version of Handwritten Notes of R. Boisjoly, Seal Task Force, Structure, Morton Thiokol, Inc. [Ref. 2/14-17 8 of 22] Typed Version of Handwritten Notes of R. Boisjoly, Seal Task Force, Structure, Morton Thiokol, Inc.- continued.
 [Ref. 2/14-17 9 of 22] Drawing/Calculation Sheet; Prepared by R. Boisjoly; Description: SRM-25 Field Joints. [Ref. 2/14-17 10 of 22] SRM Seal Erosion Team Minutes.
 [Ref. 2/14-17 11 of 22] SRM Seal Erosion Team Minutes- continued? [Ref. 2/14-17 12 of 22] SRM Seal Erosion Team Minutes- continued?
 [Ref. 2/14-17 13 of 22] SRM Seal Erosion Team Minutes- continued? [Ref. 2/14-17 14 of 22] Interoffice Memo, Morton Thiokol, Inc.; From: A.R. Thompson to S.R. Stein. Subject: SRM Flight Seal Recommendation.
 [Ref. 2/14-17 15 of 22] MTI Assessment of temperature concern on SRM-25 (51-L) launch. Signed: Joe Kilminster.[Ref. 2/14-17 16 of 22] Activity Report: SRM Seal Problem Task Team Status. Signed: R. Boisjoly. 10/4/85.
 [Ref. 2/14-17 17 of 22] Activity Report: SRM Seal Problem Task Team Status. Signed: R. Boisjoly. 10/4/85. - continued [Ref. 2/14-17 18 of 22] Interoffice Memo, Morton Thiokol, Inc.; From: R. K. Lund to Larry Sayer, John Wells, Ross Bowman, Grant Thompson, D.M. Cox, Boyd C. Brinton. Subject: Nozzle O-ring investigation task force.
 [Ref. 2/14-17 19 of 22] Interoffice Memo, Morton Thiokol, Inc.; From: R. K. Lund to Larry Sayer, John Wells, Ross Bowman, Grant Thompson, D.M. Cox, Boyd C. Brinton. Subject: Nozzle O-ring investigation task force.- continued. [Ref. 2/14-17 20 of 22] Progress Report: Applied Mechanics Department. Signed: R. Boisjoly.
 [Ref. 2/14-17 21 of 22] Interoffice Memo, Morton Thiokol, Inc.; From: R. Boisjoly to R.K. Lund. Subject: SRM O-Ring Erosion/Potential Failure Criticality. Dated: 31 July 1985.
 [Ref. 2/14-17 21 of
22] Interoffice Memo, Morton Thiokol,
Inc.; From: R. Boisjoly to R.K. Lund. Subject: SRM O-Ring
Erosion/Potential Failure Criticality. Dated: 31 July 1985. -
MR. THOMPSON: Arnold Thompson, Design Engineer, in the case design structural engineer.
CHAIRMAN ROGERS: The comments I made to Mr. Boisjoly apply, of course, to you. We know that.
You are not expected to make a presentation, but go ahead.
MR. THOMPSON: I understand.
I need to start out first by "Amending" what Mr. Boisjoly has said. His thoughts parallel mine very closely.
I would like to add some more features to this.
As many of you know - and I think it answers some questions that were presented during the course of this morning, and initially this case was thought to not open up. You've seen the pictures where the gap opens up, and the secondary and primary, and the analysis revealed that it, in fact, was not supposed to open up. After running some hydroproof, and, in fact, the first attempt at a burst pressure of the standard weight case, it leaked. In fact, it leaked at about 1,300 - 1,400 psi.
We ran some additional analysis, and
re-boundaried the pins, and it turns out that the pins and how you boundary those is very, very critical to the response of this opening up that we are talking about.
CHAIRMAN ROGERS: Could you give the dates of when you ran those - roughly?
MR. THOMPSON: Two or three years ago.
DR. WALKER: What do you mean, "boundaried the pins?"
MR. THOMPSON: The boundary conditions of how you follow the load lines through the pins indicates if you're modeling the axisymmetric case that we smear the pins out in it and give the stiffness appropriate to make it approximate the case.
Now, if the pin doesn't follow the load line, that affects very much the results.
DR. COVERT: In other words, they cannot make the model, the math model, they cannot grid it up with these 177 pins? They have to model it some other way? Is that correct?
MR. THOMPSON: We're now modeling with a three-dimensional analysis to try to attempt to follow the load line better. And so we didn't know it was going to open up. And it, in fact, did. And we have shown that, and by remodeling in some, we were able to get 10/1,OOOths, and then, by that time, the STA-1 came on the scene. That is where we first got our first
definitive measured data that opened up on the order of about 42/1,OOOths. And I think the MEOP at that time was 936.
 MR. BOISJOLY: That was the static. Not "STS-1"; STA-1.
MR. THOMPSON: STA-1. Thank you.
VICE CHAIRMAN ARMSTRONG: When you said it leaked, did it leak water?
MR. THOMPSON: It didn't leak. It opened up. And we had one pressure port that was down at the bottom. We put into it a pressure transducer so that we could follow the motion of it.
VICE CHAIRMAN ARMSTRONG: You said you had some tests leak at 1,300 - 1,400 psi?
MR. THOMPSON: Yes. We ran a hydroburst because it leaked very badly at that point.
VICE CHAIRMAN ARMSTRONG: And that was water?
MR. THOMPSON: Yes, it was water. It leaked so badly, we just shut the test down.
But that gave us a very, very close to our safety factor, our 1.4 safety factor, with 936, so that was sufficient at the time.
Later on, we ran the STA-1 test.
MR. SUTTER: I didn't understand your last statement.
You said you ran a test and you got a load and it was very close to 1.4.
Is that good or bad?
MR. THOMPSON: We have been asked to produce a 1.4 factor of safety and have a positive margin.
MR. SUTTER: But the load you got in this test was how close to that 1.4?
MR. THOMPSON: We were at, I don't remember all the numbers exactly, but it was 1385 psi, and it was 936. So it would be 936 times 1.4, would be the required number, and the 1,300 number came very close to that.
DR. WALKER: Pretty much at the 1.4?
MR. THOMPSON: Yes, very close.
DR. COVERT: 1.4 if I did it right, is 1320, and I'm not good at arithmetic.
MR. THOMPSON: But I think we were just slightly below the 1.4. And so, we proceeded in doing better modeling. And then, of course, the light-weight motor came in, where we took about 41/1,OOOths off the stiffeners and attachers, and about 20/1,OOOths off the cylindrical wall. And we then ran a test with those light weight cases. And we ran a verification where we attempted, once again, to measure the joint motion. Because, as you can see, it is very critical in the operation of this motor. And we, because of some bracketry problems on that, we got the measurements
that were somewhat high, we tried but the brackets were rotating, too, and we tried to go back and correct for that. But it was somewhat high.
And then subsequently we have run a bunch of tests where we have confirmed what we feel good about, on the order of 42/1,OOOths between the sealing diameters at 1004 psi. So these are kind of new things that have come on the scene.
We have tried to adjust for these things.
We put shims - first of all, we adjusted the tolerances. We looked at the tolerances of the case, the O-ring groove depth, and so forth, and we found that most of the population was within tighter tolerances. So we changed the drawing.
We found out that we could, by twisting some arms with the O-ring people, we could reduce the tolerances on the O-rings also, and so we did that.
And then, the next thing we did, we put shims in on the outside to force the tang over against the clevis, and these are some of the things that we have been doing in an attempt to counteract that, what you are seeing.
 DR. WALKER: That was to increase the squeeze on the O-ring?
MR. THOMPSON: Increase the squeeze. It has
two squeezes. One is when it is just sitting there, static, with the various pre-launch loads on it, and so forth. That is what we call a gathering squeeze. That, on a worst, is like 33/1,OOOths. And then, once the cases are pressurized, they go around, but not necessarily concentric, and so that can get as bad as 8/1,OOOths.
So we are really better off pressurizing.
But the issue that we're speaking of today is that of the opening and the rate of opening.
All of you I think are familiar with the pressure trace. You recall that it has kind of a toe on it, and then it comes up over the inflection point, and then it has a saturated curve on top.
Well, of course, the movement of this gland or the separation of this gland is very close to that same response.
I would like to speak first to the primary O-ring.
The primary O-ring has lots of energy to activate it and it probably does it very quickly. But it is kind of dependent, as Roger has said, on the stiffness of the material.
If you look at the relaxation data for rubber at cold temperatures and very high rates of loading, it
has a very stiff response, versus a higher response at higher temperatures. And we were loading on a fairly fast response. So we are in a transition range of this elastic material, and it has to flow. And if it has to flow, it has to deflect, and the deflection would be dependent upon the stiffness of the rubber.
If it is colder, it will move slower. Before an O-ring can seal, it has to go into the squeeze, into the extrusion gap. It has to fill in the little pores in the metal, in fact, even the lay of the lathe turnings, as it is turned in the machine.
Until it does that, you're going to get some blow-by.
There is just nothing that you can do about it until it is finally extruded into the gap.
So we have two things that are happening. One would have to translate a little bit. That's only on the order of 20/1,OOOths across the O-ring groove, maybe less. And then it has to form into the O-ring groove. Until such time, you are probably going to get some flow; at least you can't guarantee that you're not.
Now, on this particular motor, we know that when we launched with the O-ring temperature predicted to be 53 degrees, we had considerable blow-by. It was blackened for about 180 degrees.
Now we're proposing - and I'm thinking of the next day now - of launching at 29 degrees, and it was quite a ways out of our experience realm, as has been said many times today.
Now, let's talk about the secondary O-ring. I started to talk about it a minute ago.
The departure of those two surfaces is very similar in shape to the pressure trace. In the beginning, during the pressure buildup, and during the separation of these two things, it is rather slow. On a comparative rate, it is on the order of, maybe, about 1.2 inches per minute. And then it increases as you get to the inflection point.
It is as high as 10 inches per minute.
Then, when you go over the top, it backs off to 1 or 1.5 inches per minute.
 The reason we talk about inches per minute is because we are going to use an instron to do some work, and that is the way those people talk - rather, in inches per second.
What we had done, and the data we had available to us that night, was two inches per minute. Now, if we take a secant from time zero to the max pressure of 1,000 psi in 600 milliseconds, that secant is about 3.2 inches per minute. That was shown on the chart.
We tested at 2 inches per minute, because that is how instrons work, generally in decades of two, and at two inches per minute the resiliency of the O-ring is not sufficient to follow that velocity at room temperature. It will separate. But it won't separate until in the low velocity sections. So you've probably got, as has been mentioned here today, somewhere between 100 and 125 milliseconds while you're in the low velocity movement of this gland. And in that time you do have a secondary O-ring, as Roger indicated in the bracketing of various sequences during the rise in pressure. But in the early parts, you do have a secondary O-ring, and in the latter parts you do not.
Now, what has been alluded to earlier. We have devised a machine now where we can control the instron to give us exactly the shape, and we're doing that work now. In fact, a lot of that work has been done - which confirms much of the things that we're discussing here.
So, I guess, in a final summary, without talking too much, my view was that we were now launching at a lower temperature; we were going to get more blow-by; at 53 degrees we had considerable blow-by and now we're going to get more of it; and after the first hundred milliseconds, 125 milliseconds, we do not have a
secondary O-ring that is functional.
MR. RUMMEL: I have a question for clarification.
As I recall, the wall of the motor, I distinctly recall it was reduced in thickness during the course of this program. That would tend to increase the spread in the joint, would it not?
MR. THOMPSON: Very little. It is on the order of 1-2 mils and I'm speaking now from finite element analysis, after we had learned to boundary it, so that we could predict the correct STA-1 structural test article results. We used that type of boundary conditions and applied it t both wall thicknesses. It was very small. It was on the order of a few mils of additional opening.
MR. RUMMEL: That was actually tested? Or this is predicted?
MR. THOMPSON: Those were predicted numbers.
MR. SUTTER: These improvements resulted in tighter tolerances in the shims? Were the, in some of the flight vehicles?
MR. THOMPSON: I was trying to remember if they were, in fact, in all of the flight vehicles. I think shims were. It's about a 30/1,OOOth shim that take up some of that slop.
MR. SUTTER: Do you know when they were introduced - which flights?
MR. THOMPSON: I don't know.
Maybe Mr. Boisjoly recalls.
MR. MASON: Those were right from the first flight.
MR. SUTTER: So these were improvements from the beginning, and the joint basically has been the same?
MR. MASON: Yes.
DR. WALKER: Did you consider using a larger O-ring?
 MR. THOMPSON: You can go to about a 292 O-ring, without getting - and then, of course, you have to have a tolerance on that of plus 5, minus 3. And anything above a 292 with plus 5 on it, and if you go to the wall on the land, that is all that will fit in. We have considered a 295. In fact, we have assembled shells with a 295 in hardware, after firing the DM-1, our first static firing, and they went together fine.
DR. WALKER: Why didn't you go to the larger O-ring, then?
MR. THOMPSON: One problem in going to larger O-rings is in field joints - plant joints, excuse me. In the plant joints, if you put in the 295 and you take
the worst on worst, when the joint is raised to a temperature of 325 degrees during the curing of the insulation, it is an overfill condition because of the alpha problems with the case, and the rubber.
DR. WALKER: There is no reason why a field joint and a plant joint had to have the same O-ring, is there?
MR. THOMPSON: There were some QC people that were afraid of the confusion that might be developed between two nearly the same sized O-rings.
CHAIRMAN ROGERS: A couple of questions, if I may.
Was any consideration given to the possibility of water? I notice you said earlier on that there were some experiments with water. Any consideration given at this time to the possibility of water being dangerous?
It had been raining a good deal prior to this launch.
MR. THOMPSON: Well, it had been raining, and also we know that at one time we disassembled a motor when we had to make a nozzle change; and when we pulled out the pins, water came out. And we know that water does get in there, and we know that the temperatures most likely were below freezing. So there was a chance
of some ice.
I'm not sure that was a consideration that night, though.
CHAIRMAN ROGERS: Were there other engineers that would take issue with you on this matter, when it came to the launch question of whether to go or no go? Did you have others who opposed your point of view?
MR. THOMPSON: No, sir.
I have 24, 25 people, gals and guys, working for me, and I know none of them that would have opposed this viewpoint that are involved in the case, the case/nozzle joints.
CHAIRMAN ROGERS: All of those people would have said no to the launch?
MR. THOMPSON: My judgment is yes, that is true.
MR. ACHESON: Question, and maybe this question runs against the engineering culture. But what I'm wondering is when people run test programs that show these significant anomalies, some think related and some think maybe not related to temperature, why wouldn't MTI say to NASA we have some tests going on that show some inconclusive, but troubling, results, and we're not sure we know what to think about it. But until we decide what to think about it, you ought to be damn sure you
don't launch below X temperature, and that is an order. I mean, you are to accept that with our product.
Do contractors ever talk that way to the customers? If not, why not?
 I don't quite see why this spirit of scientific inquiry with neutral and anti-conclusory culture surrounding it should be allowed to continue so long when the worst case is pretty obvious and it had pretty bad results.
Of course, we don't know yet that this was the case, but if you believe that it could have been a catastrophic category in the worst case, when your test results were troubling, but not scientifically proven, I really don't understand why the customer isn't told to hold everything below some threshold condition.
MR. MASON: Sir, I probably should address that.
MR. ACHESON: And I don't mean just this launch.
MR. MASON: I understand. It's more of a policy issue, so I should probably address it, instead of Arnie. Let me try to do that.
I believe that we have provided full visibility of the testing, the analysis, and there has been a joint continuing review with NASA on the whole
question of the joint, and on every flight we have assessed that issue, looking at our most recent history or our total history, to see if there would be a concern on the subsequent flight.
We were really trying to acquire enough information to be able to identify if there was a threshold.
I think the fundamental answer to your question is we didn't know what the threshold was, we knew we needed more test data, and we are getting that so that the threshold could be identified.
We were looking at both what the capability of the existing joint was as well as at the same time looking for improvements.
While I've got the floor, we have in the motor that is about to be static tested, we are testing larger O-rings. That is one of the candidate improvements. And I will add to that that a lot of you already know that when you have something that is working and you have to contemplate a change, you have to be absolutely certain that the change is, in fact, an improvement; because the history of the business is that if you aren't very, very careful, what you think is an improvement may end up being worse. It has happened a number of times.
So I know there is concern about the time that we have taken to look at these improvements. But you have to be certain that they are improvements before you make the change.
CHAIRMAN ROGERS: I would like to go to a little more specific point. I mean, I think Dave's point is a good one. But the thing that is most troubling to me is if you had Mr. Thompson, who is a supervisor, and he says all of his people had doubts about whether this launch should take place, and it has been a matter of major concern all of this time, and you have evidence from the flight a year ago that there was blow-by, what was it that caused you to go ahead and approve it?
MR. MASON: Well, let's see. First off, to say that all of his people didn't even know that there was an issue, and so, I mean, it is really conjecture to determine what their position would have been. But, as far as what motivated us, it was logic said that 53 degrees is not a threshold.
If you ask anybody would 50 degrees be okay, I think everyone would sign up at 50 degrees. So, every flight which the program has had, has had to break some frontiers.
But when you go from STS-1 to STS-2, you went
into a temperature regime that you weren't in, and as you move down through the program, you are working to some degree in an extrapolated area.
DR. RIDE: The time you go through frontiers is during testing, not during the flights. That's the way it's supposed to work.
MR. MASON: Well, "demonstration" is a better word, at the demonstration. You fall on your analysis when you make your first flight, and your second flight you're falling on your analysis. You have not demonstrated everything that you're going to see.
I hope that is clear.
I'm trying to say that when we qualify in the first place, we don't test the full range of every piece of item, and we therefore take some data and extrapolate it by analysis.
So we don't have actually demonstrated capability on every facet of the motor.
DR. WALKER: We are talking about 25 degrees away from your experience.
MR. MASON: And that is certainly the reason that it had the extensive debate that it did.
DR. WALKER: And just recently, apparently, the previous launch was a situation where something was 2 degrees out of spec and the decision not to proceed might
have averted a catastrophe. So 25 degrees out of your experience is really rather a large extrapolation.
MR. ACHESON: It seems to me not a case where you are trying to set a threshold, but a case in which you have established a point which is 53 degrees, and everybody, as you say, would agree that's all right. And you've got some people who say anything substantially outside of that is troublesome and anything colder than that is more troublesome. And we think we see a parallelism between increasing coldness and increasing unreliability. That is the state of mind at MTI.
What I really don't quite see is why everybody took it so calmly.
MR. MASON: Well, it was not calmly nor was there a lack of concern.
We were trying to, we listened to all of the arguments, and we found ourselves in a position of some uncertainty that we were not able to quantify. And we had, as opposed to the 53 degree joint that had a blow-by, we had five joints that did not in that very same flight. And so, we, on a statistical basis, we were working with random occurrences. And taking a couple of random occurrences and trying to say there's a clear correlation didn't hold up.
Our intuition and, of course, some data, says the colder it is, the more risk there is. The real issue was how much colder before you run into a regime where you will get three times the erosion of the worst one we had seen. It wasn't as if what we had seen before was on the verge of failure. It was not. The blow-by, by itself, was not a failure mode. It has to lead to erosion. And the worst erosion we had seen was a third of what we were tolerating.
So our first thought was that, even if we had more blow-by, and it led to erosion, it would have to be three times as much as anything we had seen, and that seemed extremely unlikely.
MR. ACHESON: It seems to a layman that it comes down to a point of view that says the burden of proof is on the people who want to launch, this cold; and another point of view says the burden of proof is on the people who want to stop the launch. Then nobody can really decide how to resolve that. And so, it just got resolved either by persuasion or by some presumption in favor of launching or - I don't know how.
But I don't see either a mathematical or a logical process by which it got resolved.
 MR. MASON: Well, certainly since the incident we have been searching our minds and our souls on the
question of did we address it properly. You know everyone has said if I could have stopped it, I wish I had.
But here we are, trying to present the thought process that we went through that day, rather than what we could do over.
CHAIRMAN ROGERS: Well, I think everybody is sympathetic, and we understand. The problem that I'm having is when you talk about frontiers, I think we all understand that. I mean, this whole program has had a lot of frontiers, and we understand. But it doesn't seem to me that you were saying to yourself now we want to test this equipment because we're going to establish a new frontier.
It seems to me that the question was should we delay this launch or scrub it. And so, you really weren't thinking about a new frontier.
MR. MASON: That was a poor choice of words on my part.
What I was trying to convey was that we are always working somewhat in the extrapolated area.
CHAIRMAN ROGERS: But that is not this case.
I mean, here you have a lot of warning, and you've all been discussing the O-rings and seals, and you've all had concerns, and it's all over the papers.
All you have to do is look at it, as we have, and you can see that's been a major concern. And now you have a situation where there is a lot of concern and a lot of your people expressed a negative vote, and that our people in NASA don't even know about it.
I mean, that is unbelievable to me. At least, if there were a calculated decision and everybody said yes, we all know about it and we're willing to take the risk, and there is some risk, and I suppose you have to do that. Every flight has some risk. But this one seems to be so difficult to explain. It must be difficult to ask about it, as Bob said.
Well, do we have any other questions?
MR. REINARTZ: Mr. Chairman, I just wanted to ask Mr. Thompson one question.
Arnie, had you said during the end of your discussion that after 100 to 125 milliseconds you do not have a functional secondary O-ring?
MR. THOMPSON: Yes, sir.
MR. SUTTER: I have one question.
I'm really confused as to whether the secondary seal was considered by anybody to be effective or not. But the statement that was used states if the primary seal does not seat, the secondary seal will seat. I think that is a key issue.
What the hell is going on there - and was this criteria that was used - did the people know that stated that criteria - did they know this? And why didn't MTI and NASA have better communications on that very critical item?
I just don't understand it. And I have listened for two hours and I still don't understand it.
I think I hear two different things here.
It's sort of a hell of a way to run a railroad on a critical item like this.
CHAIRMAN ROGERS: Well, shall we go to the next item on the agenda? I guess that's all for today.
 MR. McDONALD: Since I caused this meeting to come about, I would like to testify, I guess. CHAIRMAN ROGERS: Surely.
VICE CHAIRMAN ARMSTRONG: I was just going to say that other Thiokol people might want to testify and should be given the opportunity.
CHAIRMAN ROGERS: Well, we have a little scheduling problem. Everybody will have an opportunity, but I think you should particularly have an opportunity, Al, and we will assure you you will all have an opportunity later on.
We do have a schedule we want to try to keep to. We're a little out of sync already. But, please,
MR. McDONALD: Since I was very involved in getting the issue brought to a head through the telecon and from the concerns at the plant, and I was at the meeting for Thiokol at Kennedy, since I was the senior member at Kennedy from Thiokol for this launch, as the presentation was being made by the members of Thiokol, there were some comments that were made, I think, that influenced some of the decisions that were made later.
Besides the comment being made that NASA was appalled by our recommendation, but they said they wouldn't fly without our concurrence, Mr. Mulloy jumped in and said that you guys are trying to establish new launch commit criteria, and you can't do that on the spur of the moment; those are predetermined constraints. I think that influenced some of the thinking.
In addition, Mr. Reinartz turned to me and said your 53 degree temperature recommendation isn't consistent with what I understand is the qualification temperature for the rocket motor, which I believe is 40 to 90 degrees, isn't it? And I told him yes, I think it is 40 to 90 degrees, but that the recommendation in this particular case was being made on our experience base,
and that the temperatures that were predicted were well below that.
I was very supportive of the decision that was made by the plant initially at 53 degrees, and, while they were off-line, reevaluating or reassessing this data, because the chart that Mr. Boisjoly had made that I was looking at, and I presented from last August, which was my grave concern about the whole situation, I got into a dialogue with the NASA people about such things as qualification and launch commit criteria.
The comment I made was it is my understanding that the motor was supposedly qualified to 40 to 90 degrees.
I've only been on the program less than three years, but I don't believe it was. I don't believe that all of those systems, elements, and subsystems were qualified to that temperature.
And Mr. Mulloy said well, 40 degrees is propellant mean bulk temperature, and we're well within that. That is a requirement. We're at 55 degrees for that - and that the other elements can be below that; that, as long as we don't fall out of the propellant mean bulk temperature. I told him I thought that was assinine because you could expose that large solid rocket motor to extremely low temperatures - I don't
care if it's 100 below zero for several hours - with that massive amount of propellant, which is a great insulator, and not change that propellant mean bulk temperature but only a few degrees, and I don't think the spec really meant that.
 But that was my interpretation because I had been working quite a bit on the filament wound case solid rocket motor. It was my impression that the qualification temperature was 40 to 90, and I knew everything wasn't qualified to that temperature, in my opinion that we were trying to qualify the case itself at 40 to 90 degrees for the filament wound case.
I then said I may be naive about what generates launch commit criteria, but it was my impression that launch commit criteria was based upon whatever the lowest temperature, or whatever loads, or whatever environment was imposed on any element or subsystem of the shuttle. And if you are operating outside of those, no matter which one it was, then you had violated some launch commit criteria.
That was my impression of what that was. And I still didn't understand how NASA could accept a recommendation to fly below 40 degrees. I could see why they took issue with the 53, but I could never see how they would take or accept a recommendation below 40
degrees, even though I didn't agree that the motor wasn't fully qualified to 40. I made the statement that if we're wrong and something goes wrong on this flight, I wouldn't want to have to be the person to stand up in front of board of inquiry and say that I went ahead and told them to go ahead and fly this thing outside what the motor was qualified to.
I made that very statement.
I was still very upset because when they came back on the line and said that we, Thiokol, would go ahead and fly after the caucus, I was bothered enough, because I believe, and Roger and I - and I have worked with him, I believe the same as he does - that I wanted to have one more reconsideration. I asked the folks at NASA for one more reconsideration not to fly. In fact, I said, can we fly in the afternoon? It was my impression when I came down here that the original launch schedule was 3:45 in the afternoon. It seems like it's an available window. According to the weather report I heard, it was going to be 48 to 50 degrees in the late afternoon.
The comment was made that, well, that was considered but there was some problem with one of the transatlantic abort landing sites, with bad visibility in late afternoon. So then I said well, if you don't accept
the discussion we had as a good enough reason not to fly, there are three good reasons not to fly, and those three, together, ought to be a good enough reason not to fly.
And I said we just discussed the O-ring as I left Titusville, from Mr. Carver Kennedy's house, who happens to be our Vice President of the Space Services for LSOC here. I was staying at his house. He had just gotten a report from the recovery ships. The recovery ships reported to him that they were in an absolute survival mode, that they were headed toward shore, and had been for some time, there was 30 foot seas, winds of 50 knots sustained, gusting to 70 knots, they were pitching 30 degrees. They even thought they may have done some damage to some of the retrieval equipment on the back of the ship. They were doing about three knots toward shore and they would not be in the recovery area to support the launch in the morning. And they did not dare even turn around or try to turn because of the tremendous seas.
And I said you know, that is, in my opinion, putting the boosters at risk, and I think we ought to remember also that this flight is the very first flight that we were going to sever the exit cone at apogee from the solid rocket motors, and it also was the very first
flight that we were going to sever the parachutes from the boosters on impact. And in my opinion, we were putting the recovery, the boosters, at risk. But we were certainly just throwing  away the parachutes, the frustums. You would never find those because the recovery ships will never get back in the area. And I think that is an important consideration.
The third consideration that we ought to consider is I know damn well in the morning there's going to be ice all around that place, and water, because we've got this sound suppression system and I don't understand how it all works. But I do know that maybe we ought to, maybe it will change the acoustics on the vehicles, the structures, or debris. I don't know. But it seems to me that that is another unknown that we shouldn't be delving into.
I was told that, you know, these are not your concerns. And I said well, I am concerned about all of these, and I think those combined should be absolute criteria not to launch this thing because if I were the launch director, I wouldn't do it.
That is what I told them.
Well, I was waiting for the fax to come back because when the final recommendation was made by Thiokol to fly, they were told to put that in writing.
I told Mr. Mulloy I wouldn't sign that, it would have to come from the plant because normally I am responsible for telling whether the flight goes or not.
And so, I had deep concerns about that.
So I was told to stay and wait for the signed fax to come in, to deliver it to the attendees at the meeting here, and that is when we had a lot of this discussion.
So I believe the NASA people that were here decided that there were enough concerns that they would at least pass those on in an advisory capacity, as I was fairly emotional about it. And I went. They asked me where the fax was because it was just like the five minute caucus. The fax took another half hour or more.
And Mr. Houston told me where it was at. It was at the other end of the building. And they asked me where it was at, and so I left the end of the building to get the signed fax. And I waited. I wondered if the machine wasn't working or not. And I waited for it. And it took a while. And it finally came through.
I came back, and I believe they were in Mr. Houston's office or something. And they were on a telecon. I believe it was with Arnie Aldrich, but I'm not sure. I thought somebody said Arnie, and I heard them discussing the concerns and problems with the
recovery ships, and the survival mode at sea. And the discussion went along these lines, that the conclusion was that the ships were heading toward shore and would be way out of the launch area, and could not support a morning launch, and that if a decision were made to launch, it would have to be made on the basis that the recovery ships would not be in the area. And the problem associated with that Mr. Mulloy recognized there was a fairly high probability that because of that, we would lose the parachutes and the frustums, and he was asked, I believe, what the value of all that was. He gave some value like $660,000, where the parachutes and frustums - it was someplace, I guess, of around a million dollars of hardware.
He was asked if he could continue to support the flight schedule if we lost that much hardware, and he said yes, that he had sufficient. And then he was asked about whether we were putting the boosters at risk, and he said that he didn't think there was any significant risk of putting the boosters at risk, that we did have airplanes in the area and they've got beepers and things, and we could get them later.
And he was told well, for darn sure, don't have the ships try to turn around in the condition they're at, to go back there, and risk the ships, to be
in the area. They must continue on their course back in.
And then the next discussion that came up that I heard part of was about the water system and the freezing and the ice. I heard some comment basically that that was considered earlier and discussed. But I didn't hear anything about the O-ring discussion, and I presumed that that discussion happened while I was down at the fax machine, waiting for the fax to come in. And the gentlemen did make it clear that they were acting in an advisory capacity only, to make sure he was aware of this information.
And, at that time, I had given them, I went to Jack Buchanan's office and had copies of it made, of the fax that was signed, and gave it to them. And then I went home that night.
CHAIRMAN ROGERS: Thank you very much.
MR. ALDRICH: I would like to comment on that phone call.
I do not remember that with relation to this incident. There was a phone call to me that night of the status of the launch facility with respect to the temperatures and the discussion about the recovery ships not being able to hold station, and being well off station; and they headed into the weather, which was
taking them away from their home position - was discussed.
My first question was if it was safe for them to be out there at all for some other procedure than with respect to the ships themselves and the people on board. We should be concerned with their safety. And I was told that the ships had dual engines and that they were considered safe, but they couldn't guarantee to be in the position the following day.
We discussed a delay in recovering the rockets and the discussion proceeded that we would lose some of the equipment, but probably not the rockets themselves. And I determined at that time that that was not cause to call off the launch or to not proceed with the tanking.
The other discussion I had was about the facility, and it had to do with the earlier sessions we had, that is, that the temperatures were cold, they were proceeding slowly, more slowly than normal, and that there was expected to be ice on the facility, perhaps there already was ice on the facility.
That was the total content of that discussion, and there was no inference of threat to flight hardware, other than the potential for some difficulty or delay in recovering the solid rocket boosters.
The following morning, I went to the Control
Center, as I have described previously. I spent a large amount of time dealing with the question of ice on the launch facility and its implications and concerns for it.
At that time, I also checked on the status of the recovery ships. In fact, the seas offshore had subsided, and it was reported to me that it would not be a problem, that they would be in the proper position for launch.
CHAIRMAN ROGERS: Are there any questions?
DR. WALKER: I have a question. It is a question that I would like perhaps to have a response to later on.
I would like to understand how you go about developing criteria for launch, and if these always are initiated within NASA or whether the contractor can initiate things, what the procedure  is, and, in particular, why there was not a criteria for the O-ring seals, as opposed to the bulk temperature of the propellant?
MR. ALDRICH: We will clearly have to present that. The process is that each project develops for their equipment and hardware with that contractor. It is submitted to a review at the integrated project level and is approved up the line, and what we have in place is what has been entered into that project review and approved.
CHAIRMAN ROGERS: Okay.
I would like us, if there is no objection, I would like to recess the meeting now, and I think the Commission should consider the testimony that we have heard this morning very carefully and then decide our next step.
We will be in touch with all of you as we make some decisions.
DR. FEYNMAN: Sir, don't you think it is necessary to get all of the testimony from the Thiokol people that are here now, who wish to, that is, who wish to make a statement?
CHAIRMAN ROGERS: Well, I think - obviously, as far as the Chairman is concerned, we are prepared to listen to anybody that wants to testify. We are going to have to have a lot of testimony. We can't take it all today.
It may be if any Commission members or anyone else want to say something, fine. But we have had a pretty full morning, and there is a lot of material to digest, and there are a lot of questions to be asked and a lot of answers to be given. I guess I'm just saying that I'm not sure that, unless there is any particular - -
DR. WHEELON: Mr. Chairman, may I propose a
procedural thing, and that is that we turn individually to each one of the Thiokol people and establish today whether they have additional information that they can provide whenever available or pass at this point - just to get an explicit disclaimer from each one of them that they have nothing to give?
CHAIRMAN ROGERS: That's a good idea.
Does anybody from Thiokol want to add anything, either in this session or to the Committee staff?
Dr. Keel will be here and his assistants will be here. If you have anything you want to pass on, fine. If you want to say anything now, fine. But we do assure you that you will all have a chance to be heard more fully at a later date. We're not sure what that later date will be, but we will decide that pretty soon.
MR. ACHESON: Could I ask, for the record, what the requirements and constraints are presently governing the preservation of Thiokol records of this launch, and the system hardware and testing preceding this mission?
Is there an order outstanding or an impoundment?
MR. MASON: We have been instructed to impound all of the data having to do with the launch and have
done so. Much of it has been copied and sent to Marshall as part of the process, but it is all impounded in one area.
MR. ACHESON: It will physically be at Marshall?
 MR. MASON: Right now it's impounded at the plant and we're sending copies of whatever anyone wants for the investigation.
CHAIRMAN ROGERS: Is there any material in NASA on this general subject matter that we haven't seen?
MR. HARDY: Not that I'm aware of.
MR. ACHESON: How broadly does the impoundment order run?
MR. MASON: It covers anything to do with this specific launch, and the complete history of the motor, the fabrication and anything to do with that motor.
MR. ACHESON: Including test procedures and test records?
MR. MASON: Where they are applicable to that motor.
MR. ACHESON: Do you mean the SRB type or do you mean just the segments involved in this launch?
MR. MASON: Just the segments involved, the data for this specific launch is what is impounded right now.
DR. WALKER: I think our question would extend to all of the data, such as the test data, which is described on the O-rings; all data referring to tests concerning the operation of the O-rings, particularly their response to temperature. All of those data should be made available to the Commission.
MR. HARRINGTON: I'm Jim Harrington, Secretary of Jess Moore's Task Force. We, the day of the accident, instituted our contingency plans, which are covered under NASA documents. Our first action was to impound all data.
And so we instructed all of the NASA centers, and they, in turn, instructed all of the contractors to impound all data pertinent to the incident.
Now, specifically, some data that you talked about is test data run years ago, and may not have been covered by impoundment because it doesn't relate specifically to the incident.
MR. ACHESON: Well, isn't it clear that we want eventually to look at all of the data relating to the O-ring problem, at least, regardless of what sections it affected?
DR. WALKER: Could we request that NASA ask the contractors to preserve all such data and make it available?
MR. ALDRICH: Yes, sir.
We'll take that action.
DR. RIDE: I guess I would also like to ask the people from Marshall why they decided not to advise Mr. Aldrich of Thiokol's concerns?
MR. REINARTZ: I think, Sally, I would be glad to go through it again, but I think I indicated earlier through the basis for the decision not to bring that up as being a Level III item that did not violate waivers or constraints to the launch, and that was the basis for not going ahead and bringing it up at that time.
CHAIRMAN ROGERS: So, you have nothing to add to what you have testified?
MR. REINARTZ: No, sir.
DR. KEEL: Mr. Chairman, could I just ask one question, just not to embarrass anyone or put anyone on the spot at all, but just for the sake of establishing the record, so it is not left to inference?
The inference, Mr. McDonald, from your testimony is that you were under pressure, perhaps unusual pressure from NASA officials, to go ahead with the launch. Is that an accurate inference or not?
 MR. McDONALD: That is an accurate inference, yes.
CHAIRMAN ROGERS: And did I understand, too,
that you did not sign off on this one?
MR. McDONALD: No, I did not.
CHAIRMAN ROGERS: Was that unusual?
MR. McDONALD: I believe it was.
CHAIRMAN ROGERS: Thank you.
Let's adjourn for lunch.
Thank you very much.
[Whereupon, at 12:35 p.m., the meeting was adjourned.]