CHAIRMAN ROGERS: The Commission will come to order, please.
Today the Commission will focus on the events leading to the decision to launch the Challenger. The Commission has already reviewed a good deal of information about the seals and the O-rings on the solid rocket boosters. It should be noted, however, that it is not yet clear that the joint area was the originating problem.
Therefore, it is important that all potential causes of the accident, including the external tank, be actively pursued.
In our sessions today and tomorrow, we want to present in a thoughtful and orderly manner the facts relating to the decision to launch the Challenger. Because of its importance I will ask witnesses to identify the time and place of any event that they are addressing and the names and positions of persons who participated.
 The Commission wants to be fair in the presentation of the facts because the subject matter may involve possible human error, as distinguished from equipment failure. The Commission will attempt to give a right of reply as soon as possible to any person who
believes he has been unfairly criticized or whose actions may have been inaccurately portrayed. During the last two weeks, the Commission has encouraged NASA to disclose a large number of facts and documents relating to the launch, which has been done. As a result, we believe the public is better able to understand and assess many aspects of the accident. We hope that this process will continue until all the facts are fully known and as much as possible fully understood.
While the Commission has the responsibility under its mandate from the President to investigate the accident and report its findings, the media plays a key role in the process by keeping the public informed. We believe it has performed this role well and with a high sense of responsibility.
If the Commission effectively performs its duties and the media performs its role of accurately reporting the facts as they develop, the public will be well served.
Witnesses who appear today will be able to comment on or clarify their testimony, as long as the substance is not altered. Of course, any additional evidence or additional material that might assist the Commission in the performance of its duties and
responsibilities will be welcome.
The first witness this morning will be Allen McDonald. Following Mr. McDonald and at the request of Morton Thiokol, the Commission will next hear Jerry Mason, who is executive vice president of Morton Thiokol.
Now I would like to call upon our Executive Director, Dr. Keel, who will make a few comments before we hear Mr. McDonald.
DR. KEEL: Mr. Chairman, for the benefit of the Commission we have put together a chronology of events relating to the period when the first temperature concerns were raised with respect to the Challenger, indicating the activities and also the participants as the Commission understands them, based upon testimony and documentation provided to the Commission.
This chronology has been provided to all of the witnesses, Mr. Chairman, so they will have an opportunity to understand our reconstruction of those events and to clarify them, and also, as appropriate, to identify the nature of the discussions at each of these meetings and activities, starting approximately from the scrub of the originally planned launch of Challenger for January 27th at 9:38 a.m., ranging up to the launch of the Challenger on January 28th at 11:38 a.m.
CHAIRMAN ROGERS: And if there are corrections
that have to be made on this document, we will make them as we go along. It is as accurate as we can make it at the present time.
Now I would like to call on Mr. McDonald, please. Mr. McDonald, I think probably if you take the middle chair it might be best. And I think to be consistent, let's swear all the witnesses in again.
CHAIRMAN ROGERS: Mr. McDonald, you're now employed by Morton Thiokol, Inc.?
MR. McDONALD: That is correct.
CHAIRMAN ROGERS: And how long have you been employed by them?
MR. McDONALD: I've been with Morton Thiokol a little over 26 years.
CHAIRMAN ROGERS: And you're an engineer?
MR. McDONALD: Yes. I have a bachelor's degree in chemical engineering from Montana State University and a master's degree in engineering administration from the University of Utah.
CHAIRMAN ROGERS: And can you give us some history of your employment with Thiokol?
MR. McDONALD: I am currently the director of the space shuttle solid rocket motor project. My responsibilities are for technical, cost, and schedule performance of the steel case motors that are flown out of Kennedy, and also the development and qualification of the filament wound case solid rocket motor to be flown out on Vandenberg Air Force Base.
I have had this position for a little less than two years. I started as director in March of 1984
of the shuttle SRM project. Prior to that, I was the manager of the project engineering division at Morton Thiokol, at which I had technical responsibility from a project engineering standpoint for all of the programs in the plant, with the exception of the space shuttle.
That included the Peacekeeper, the MX stage one, Trident 1 C-4 production, Trident 2 development, the HAARM Mark 104 standard missile, MD-2, the improved performance space motor 2. I finished a contract on qualification of a long life motor for SHRAM. I had all of the independent research and development, advanced technology programs with the rocket propulsion laboratory, and also some work on air bag, air cushion restraint systems.
I had that job I guess for about three, four years prior to coming into the shuttle program, and prior to that I was the manager of the propellant development department for a few years. And prior to that I was the manager of the project engineering group for advanced development and development projects.
I started with Thiokol in 1959, after graduating from Montana State University, and my first job was involved in designing the external insulation for the stage one of the Minuteman. I did that design and I was then chosen as a group leader for flight test
of the Minuteman, and participated in the flight tests, about the first 20 flights of the Minuteman, out of the Cape.
Subsequent to that, I spent considerable time working as the chief engineer on development of some controllable solid rocket motor concepts for several years, and worked on a lot of advanced development programs, before I became involved in the Trident program in the early seventies.
CHAIRMAN ROGERS: For the last three or four years, where have you spent your time?
MR. McDONALD: The last couple of years, of course, I spent my time as director of the solid rocket motor project, which involves a considerable amount of coordination relative to production of the shuttle solid rocket motors, assessment of the flight readiness reviews for the space shuttle solid rocket motors.
I am the chairman of the senior material review board for the SRM. That senior material review board has to review all of the discrepancies on any of the hardware that's considered as criticality one or any that is outside the experience base of our previous experience.
As chairman of that board, there are members from our quality group, our engineering group, NASA
Marshall representatives, but I have to sign every one of those that they're ready for flight.
And I am also a co-chairman of the problem review board with Marshall Space Flight Center, relative to any problems that are identified from returned hardware that come back to the Cape and what actions are taken to understand those problems and provide fixes for those and prevent them from occurring.
My activities in the past year to a large extent have been involved with design certification of the filament wound case solid rocket motor. I am also the co-chairman of the design certification team, represented by Thiokol and Marshall at the SRM level for that, and that has taken a considerable amount of my time this past summer in a series of reviews for certifying the graphite composite case for Vandenberg.
CHAIRMAN ROGERS: Now, how much time did you spend in the performance of those duties at Kennedy Space Center?
MR. McDONALD: Well, I have been alternating with my supervisor, the vice president, space booster programs, Mr. Joe Kilminster.
CHAIRMAN ROGERS: Mister who?
MR. McDONALD: Joe Kilminster.
CHAIRMAN ROGERS: And what is his title?
MR. McDONALD: He is the vice president of the space booster programs. And he and I have been alternating going to the Cape, supporting the launches of the SRM's.
CHAIRMAN ROGERS: Is he your immediate supervisor?
MR. McDONALD: He is my immediate supervisor, yes.
CHAIRMAN ROGERS: And you alternated going to the Cape?
MR. McDONALD: Yes.
CHAIRMAN ROGERS: Now, how did that work?
MR. McDONALD: That works out fairly well. We both, of course, have a fairly heavy demand on our time, with all of the reviews in the shuttle process, primarily with the trips to Huntsville and the Marshall Space Flight Center.
 I attended, of course, the STS 51-L. He was at the prior flight. And our charter is to attend the L minus one meeting.
CHAIRMAN ROGERS: 51-L is the Challenger launch?
MR. McDONALD: That is correct.
CHAIRMAN ROGERS: And you were there at that time. Was he, Mr. Kilminster, there at the previous launch?
MR. McDONALD: He was at the previous launch, yes.
CHAIRMAN ROGERS: What about the one before that?
MR. McDONALD: The one before that I was at, and he was at the one, I think, before that. We have been fairly well alternating.
CHAIRMAN ROGERS: And what were your responsibilities when you were there at the Cape at the time of the launch?
MR. McDONALD: Well, at the time of the launch I was in the firing room two launch control center. There are seats there for the monitors of many of the functions on the solid rocket boosters, as well as a TV monitor.
The Marshall Space Flight Center has a group at their console that involves the primary contractors for all of the subsystems. The SRB has one monitor, and they have people from USBI who provide part of the hardware for the SRB and for the shuttle.
We also have a monitor from our support to the space shuttle processing contractor, that is right next to that monitor, and Mr. Carver Kennedy, our vice president of our space operations at the Cape, was at
that monitor that's right next to the Marshall monitor, and I was sitting with him at the time of the launch.
CHAIRMAN ROGERS: I wasn't speaking so much about the Challenger launch as I was generally speaking. Generally speaking, when you or Mr. Kilminster are at Kennedy, you speak for the company, is that it?
MR. McDONALD: Yes. Generally, the process is, before launch there is an L minus one meeting the day before the launch, at which time all of the problems that were still open prior to the L minus one review are reviewed with Jess Moore and his board, and are assured that they are all closed out and we are ready for the launch.
Subsequent to that meeting, there is a poll that is taken. He takes an oral poll of everyone that is involved in the launch, including, as well as the propulsion systems, but the payload and everyone else. And every contractor that is involved in that has to answer to the poll as to whether they are ready to go ahead and launch.
I attended that meeting. As you know, the L minus one meeting was conducted, I believe, on Saturday or something.
CHAIRMAN ROGERS: Yes. I would like to, if you don't mind, come to that chronologically in just a
But, so at those meetings when you were there, you spoke for Thiokol?
MR. McDONALD: Yes, I spoke for Thiokol.
 CHAIRMAN ROGERS: And how long had you been there prior to the launch of the Challenger, physically located at Kennedy?
MR. McDONALD: I was at Marshall Space Flight Center earlier in the week on some negotiations for a subsequent contract, and had went down to Kennedy on, I believe it was, the Thursday before the launch.
CHAIRMAN ROGERS: Could you give some explanation of the relationship between yourself and Marshall before you went to Kennedy?
MR. McDONALD: I'm not sure what you mean by "relationship."
CHAIRMAN ROGERS: Well, what function was Marshall performing at that time, and what were you doing in representing Thiokol?
MR. McDONALD: Well, Marshall has overall responsibility for all of the propulsion subsystems on the shuttle, and we are part of the SRB team. I work directly with Larry Weir, who is the project manager for Marshall on the solid rocket motor, and he works for Larry Mulloy, who is the project manager on the SRB,
which includes the solid rocket motor and the aft skirt, TVA system, and the parachute recovery system that makes up the whole SRB.
And I always attend or Joe Kilminster attends the launches with Mr. Mulloy, and he has the representatives also from the other subcontractors for USBI, and in case there's any questions that come up, that we can either resolve there or get resolution to prior to launch.
CHAIRMAN ROGERS: Just for the record, where is Marshall located?
MR. McDONALD: Marshall is located in Huntsville, Alabama.
CHAIRMAN ROGERS: And when did you leave Huntsville, Alabama, to go to Cape Kennedy on this occasion?
MR. McDONALD: I think it was Wednesday or Thursday afternoon before the launch.
CHAIRMAN ROGERS: Did you go by yourself or with someone?
MR. McDONALD: I went by myself.
CHAIRMAN ROGERS: Now, I want to give you an opportunity to give a full description of the events the day before, the 27th, and the day of the launch. But before I do that, I understand that you made some notes after the accident which put on paper some of your
recollections of the events preceding the accident. Is that correct?
MR. McDONALD: That is correct.
CHAIRMAN ROGERS: And you have those notes now?
MR. McDONALD: Yes, I have those notes. [Ref. 2/25-1]
CHAIRMAN ROGERS: I would like to explain to you that you are at liberty to refer to those notes in any way you want to.
And now, beginning with the first recollection you have of the weather problem and how it came to your attention, give us a full account of the events of that day and the following day, the 27th and the 28th. And we will try not to interrupt you, except possibly for clarification.
And I want you to feel free to tell everything you recall about it, and then after that we may ask some questions to try to amplify any answers that you may give.
MR. McDONALD: Well, I had first become aware of the concern of the low temperatures that were projected for the Cape, it was late in the afternoon of the 27th. I was at Carver Kennedy's house. He is a vice president of, as I mentioned, our space operations center at the Cape, and supports the stocking of the
And I had a call from Bob Ebeling. He is the manager of our ignition system and final assembly, and he works for me as program manager at Thiokol in Utah. And he called me and said that they had just received some word earlier that the weatherman was projecting temperatures as low as 18 degrees Fahrenheit some time in the early morning hours of the 28th, and that they had some meetings with some of the engineering people and had some concerns about the O-rings getting to those kinds of temperatures.
And he wanted to make me aware of that and also wanted to get some more updated and better information on what the actual temperature history was going to be predicted, so that they could make some calculations on what they expected the real temperature the O-rings may see.
CHAIRMAN ROGERS: He was calling from Utah?
MR. McDONALD: He was calling from Utah.
I told him that I would get that temperature data for him and call him back. Carver Kennedy then, when I hung up, called the launch operations center to get the predicted temperatures from pad B, as well as what the temperature history had been during the day up until that time.
CHAIRMAN ROGERS: And pad B was the area where the launch was going to take place?
MR. McDONALD: Pad B was the pad the Challenger was to fly off of, and this was the first time it would fly off of that pad.
He obtained those temperatures from the launch operations center, and they basically said that they felt it was going to get near freezing or freezing before midnight. It could get as low as 22 degrees as a minimum in the early morning hours, probably around 6:00 o'clock, and that they were predicting a temperature of about 26 degrees at the intended launch time, about 9:38 the next morning.
I took that data and called back to the plant and sent it to Bob Ebeling and relayed that to him, and told him he ought to use this temperature data for his predictions, and that I thought this was very serious and to make sure that he had the vice president of engineering involved in this and all of his people; that I wanted them to put together some calculations and a presentation of material.
CHAIRMAN ROGERS: Who's the vice president of engineering?
MR. McDONALD: Mr. Bob Lung is our vice president of engineering at our Morton Thiokol facility in
To make sure he was involved in this, and that this decision should be an engineering decision, not a program management decision. And I told him that I would like him to make sure they prepared some charts and were in a position to recommend a launch temperature, just don't recommend a launch, but recommend a launch temperature, and to have the rationale for supporting that launch temperature.
I then hung up and I called Mr. Mulloy. He was staying at the Holiday Inn in Merritt Island and they couldn't reach him, and so I called Cecil Houston - Cecil Houston is the resident manager for the Marshall Space Flight Center office at KSC - and told him about our concerns with the low temperatures and the potential problem with the O-rings.
 And he said that he would set up a teleconference. He had a four-wire system next to his office. His office is right across from the VAB in the trailer complex C over there. And he would set up a four-wire teleconference involving the engineering people at Marshall Space Flight Center at Huntsville, our people back at Thiokol in Utah; and that I should come down to his office and participate at Kennedy from there, and that he would get back with me and let me know when that time would be.
I waited for a short period of time, I don't know exactly how long. It wasn't very long, and he called back and told me that he had contacted the parties and it was all set up for 8:15 p.m. eastern time for that teleconference.
I relayed that message on back to the plant and told them that we have to have charts at that time faxed out to Kennedy as well as Marshall that we could discuss for that teleconference.
CHAIRMAN ROGERS: Could you explain what "charts" means?
MR. McDONALD: Well, their charts, any data that we had for showing why we had concerns on the O-rings at low temperatures, what our history has been, what, any calculations we might be able to make relative to their performance, supporting rationale for what is an acceptable temperature, what might not be an acceptable temperature, and to review that. IR'~ '/t t-:~1
And these would all be on charts that we would send by a fax machine so that people could read those and we could discuss those as the rationale for either recommending a launch or not.
I arrived at the Kennedy Space Center at about 8:15, and when I arrived there at the Kennedy Space Center the others that had already arrived were Larry
Mulloy, who was there - he is the manager, the project manager for the SRB for Marshall. Stan Reinartz was there and he is the manager of the shuttle project office. He's Larry Mulloy's boss.
Cecil Houston was there, the resident manager for Marshall. And Jack Buchanan was there. He happens to be our manager, Morton Thiokol's manager of our launch support services office at Kennedy.
The telecon hadn't started yet. It came on the network shortly after I got there. But I was told to hold on because the charts had not been received either at Marshall or at Kennedy at that time, and we waited I guess for probably another half-hour before those charts finally came through and we could reproduce them.
In fact, they hadn't all even been received yet. There were some conclusion and recommendation charts that didn't come for about a half hour or even later than that.
CHAIRMAN ROGERS: Was it essentially a telephone conference, or was there actually a network of pictures?
MR. McDONALD: It was a telephone conference, just telephone. You could hear the voices from the other two places as well as our own. However, the way those
teleconferences work, there are buttons that you can push and that will mute out you speaking if someone else is speaking, and you can usually hear it better when you don't have your own mikes open. So there is a lot of conversations, I am sure, at all of the facilities at one time which you can't hear.
But I will relay on what I heard on the conference as best I can. The teleconference started I guess close to 9:00 o'clock and, even though all the charts weren't there, we were told to begin  and that Morton Thiokol should take the lead and go through the charts that they had sent to both centers.
The charts were presented by the engineering people from Thiokol, in fact by the people that had made those particular charts. Some of them were typed. some of them were handwritten. And they discussed their concerns with the low temperatures relative to the possible effects on the O-rings, primarily the timing function to seal the O-rings.
They presented a history of some of the data that we had accumulated both in static test and in flight tests relative to temperatures and the performance of the O-rings, and reviewed the history of all of our erosion with any O-rings in the field joints, any blow-by of the primary O-ring with soot or
products of combustion or decomposition that we had noted, and the performance of the secondary O-rings.
And there was an exchange amongst the technical people on that data as to what it meant and discussions. But the real exchange never really came until the conclusions and recommendations came in.
At that point in time, our vice president, Mr. Bob Lund, presented those charts and he presented the charts on the conclusions and recommendations. And the bottom line was that the engineering people would not recommend a launch below 53 degrees Fahrenheit. The basis for that recommendation was primarily our concern with a launch that had occurred about a year earlier, in January of 1985, I believe it was 51-C.
It was our motor number SRM-15, and that particular motor had a couple of field joints that not only had some erosion, but they had some fairly severe blow-by of the primary seals, fairly heavy soot over a fairly large arc, very deep and black.
And even though we could see no measureable erosion on the secondary O-ring, it was a heat effect, and by that, the sheen was gone off of the O-ring seal. That was, you couldn't measure any, but the sheen was gone, and because of that we were concerned with launching beyond our experience base, below that
Well, that temperature brought a lot of strong comments and reaction from several of the NASA officials. I believe it was Mr. Mulloy made some comments about when we will ever fly if we have to live with that some time in the future; and also commented that, we are trying to establish new launch commit criteria and we can't do that, you don't do that the night before a launch, that is a predetermined set of constraints and we can't do that.
And other comments were made about whether we could ever fly out of Vandenberg 24 flights a year, because it wasn't uncommon to have 53 degrees in the early morning hours where a lot of the launches occur.
One of the comments that came - and this is by voice recognition; I believe it was from Mr. Hardy at Marshall Space Flight Center - was that he was appalled at that recommendation. However, he also said that he certainly wouldn't fly without Thiokol's concurrence.
CHAIRMAN ROGERS: He said he would not fly - -
Mr. McDONALD: He would not fly without Thiokol's concurrence, even though he was appalled at that recommendation.
I believe it was Stan Reinartz made a comment that he was under the impression that the solid rocket motors were qualified from 40 to 90
degrees, and that 53 degree recommendation certainly was inconsistent with that.
Some place in the conversation about the impact of 53 degrees, I believe Cecil Houston at some time commented that it wouldn't be until about Thursday that we would have morning temperatures probably in the fifties. So he didn't seem to be as alarmed about when we could get to that temperature.
There were several challenges relative to, it was felt how conclusive the effect of temperature was on this whole problem of O-ring erosion or soot blow-by. And the challenge came from looking at the total data, because even though we were as concerned about this flight, which was the coldest ever at that time, from Florida a year earlier there was a flight back in the late fall of '85, I think it was probably October, 61-A, was our SRM-22 set, that had some blow-by of the O-rings, no erosion of the primary O-rings, in fact a couple of them.
And, this happened to be a launch that had the highest temperature, and so there was some concern that the data was inconclusive; and also that we had some motors that were static tested as low as 36 degrees Fahrenheit, DM-4 I believe, and it showed not only no O-ring erosion, but no blow-by.
Well, some of the comments that came back from that, and I believe it was Roger Boisjoly commented that he felt that there was a significant difference in the observation of the actual soot that passed the primary O-ring on the SRM-15 set, that was the cold one, versus the one that was warm; that there was a much larger arc between the two O-rings from the effect of the soot, it was much blacker. It penetrated all the way up to the secondary O-ring, and of course we had some heat effect there.
And he thought there was a significant difference, and that well could be the difference just due to temperature.
I commented at that time about the static test history. I told him I did not feel that that was a valid data, for a couple of reasons. One, on the static test motors, we keep the static test motors in an environmental building essentially during the buildup, assembly, and checkout of all the instrumentation, and that environmental building is kept at 70 to 72 degrees, and that building is then rolled back on a track about six hours before the static test. So it wasn't exposed very long to the cold temperatures.
Secondly, in the static test motors we went in and actually repaired and filled holes in the putty.
These holes are formed by the assembly of the rocket motor. As you form the tang and clevis, there's air trapped in there, and that air has got to go someplace. And sometimes that air will go up through the putty. We have seen this.
And also, when you run the leak check on the two seals, if you get any blow-by during the leak check it may tend to propagate those. And in the static test motors, some of these were observed and they went in and filled those inside the motor prior to static test.
So I told him I didn't feel that that data was conclusive and they shouldn't use that for deciding what the O-ring performance was.
At that time there was other discussion on some of the charts that we had that was somewhat inconclusive. We had a chart that had some sub-scale data, where we had run some tests on blow-by with some sub-scale O-rings that actually had the full-scale diameter, 280  thousandths, but they were smaller. That was the cross-section of the O-ring, they are smaller diameter hardware.
And they were cold gas tests, and we were attempting to try to measure what kind of blowby one might get with the pressurization rates you see in the motor. And we were using argon as the working fluid and
also some freon, and we had run some tests at around ambient 30 degrees in those and did not see any difference.
And so there was some conflicting data that said that it wouldn't make any difference. But that, I want to remind everyone, was a cold test.
At that time, I commented at the time that I felt that lower temperatures were in the direction of badness for both O-rings, because it slows down the timing function for both of those, but the effect is much worse for the primary O-ring compared to the secondary O-ring, because the leak check forces the primary O-ring in the wrong side of the O-ring groove, while it forces the secondary O-ring in the proper direction; and this fact should be weighed and considered in making an evaluation as to what the recommended temperature should be.
I was looking at a chart at that time that we had. In fact, it is a chart that I had made with some help of our engineering people back last summer, in a presentation I had made here in Washington to the headquarters people on August 19th.
And it was a chart that showed that there is really three phases or three regions of concern during the ignition transient relative to the performance of
the O-ring. The first phase of that is a condition where the O-ring, the primary O-ring, is pressurized and starts the energizing process and actually has to move from the forward face of the O-ring groove, because that is where it's at as a result of the leak check, and then it has to move back and seal on the back face.
And this process we felt took place in the early part of the ignition transient, someplace before it got to 200 psi. And in cold weather what's going to affect that, of course, is the grease that is in that area also is very viscous and stiff. The O-ring itself is stiff.
We knew that the cold temperature shrank the O-ring some, and from our resiliency tests, which are tests that basically show how the O-ring responds when you have it under some compression and release that load, it shows that it gets cold and stiff, it doesn't want to respond very well.
And I looked at it something like a flat tire on the bottom. I remember when we used to drive nylon tires; when it was cold I would get out and there was a flat spot on them.
And that O-ring having to move, it either has got to slide or it has got to roll somewhat. It is not a very big dimension it moves in. It is 20 or 30
thousandths. But certainly it can't be as good as when you don't have that.
Also, being hard, it then has to extrude into the gap between the two O-ring seals, and the harder it is I'm sure it's harder to extrude in the gap, which means it may take a higher pressure to do that, which also takes a longer time.
I felt that, based upon what we had done in the past, we had concluded that this blow-by phenomenon had really occurred in this first part of the pressurization cycle, and I think there was good evidence that it had because the soot that appeared between the two O-rings was exactly that, it was soot; and we analyzed it, but it didn't see any heat effect on the metal at all.
 In some cases it discolored the grease, but didn't really burn it. Some of it was the products of the grease. You could not see any real effect on the secondary O-ring. So it couldn't have happened very long and it couldn't happen under very severe conditions.
But at the same time, the temperature effects were concerning, that maybe we were going into another timing regime. However, if we felt that we had a good margin there and we felt that we do have a good
secondary seal during this time - I think there has been some misconception about the redundancy of the secondary seal. The secondary seal is indeed redundant until the metal parts between the tang and the clevis actually rotate. It is a full redundant seal and during this time period it is redundant, and that is important.
But once those metal parts rotate and you have a problem of resiliency, it may not be. And so that is why I was concerned about that area. But if we could convince ourselves that the data said it wouldn't make that much difference in that part of the phase, then it would be a reasonable recommendation to say that we wouldn't expect much different performance.
Shortly thereafter, Thiokol was asked about their recommendation. I believe Joe Kilminster was asked himself what his recommendation would be, since it was engineering that recommended not flying at 53. And he said that he would not go against our recommendation, he couldn't go against it.
But based upon the controversy relative to how conclusive the effects of temperature actually were on this phenomenon, we were asked to reassess and re-evaluate that data, and we decided we would do that. And the people at Utah said that, well, they would like
to have a caucus for about five minutes and go off the line.
CHAIRMAN ROGERS: Could I ask you to stop there just for a moment and go back. We will come to the caucus in a minute, but go back and explain what was said to convey the decision of no launch? I gather at that point the decision by Thiokol was to recommend against a launch?
MR. McDONALD: That is correct, that it was at that point, the recommendation was not to launch below 53 degrees.
CHAIRMAN ROGERS: Who did the talking on that subject?
MR. McDONALD: That was Bob Lund, vice president of engineering, who presented that position.
CHAIRMAN :ROGERS: Were you able to ascertain from that conversation how the engineers as a group stood on that?
MR. McDONALD: Well, the engineers as a group, I can't speak for the group. I was not there, but I did hear the engineers that presented the charts, that they actually presented as part of that. that supported the 53 degree recommendation. And I felt they were very strong in their conviction as to why they felt uncomfortable to go outside that experience base.
CHAIRMAN ROGERS: And who were they?
MR. McDONALD: Roger Boisjoly I think was one of the strongest ones, and Arnie Thompson, that presented those positions and presented the charts.
CHAIRMAN ROGERS: And Mr. Lund himself at the time?
 MR. McDONALD: Yes. Mr. Lund himself at the time didn't present the detailed technical charts, but he did present the conclusions and recommendations, and that was his recommendation as vice president of engineering.
CHAIRMAN ROGERS: Was anyone who was on the telecon from Thiokol's side recommending launch?
MR. McDONALD: At that time, no, there was no one that recommended launch. And I don't recall there was anyone at either Marshall or Thiokol from NASA that didn't agree that cold temperatures went in the wrong direction, didn't help anything. But no one from Thiokol at that time recommended launch.
CHAIRMAN ROGERS: And what were the comments by NASA officials about that recommendation. as you recall?
MR. McDONALD: Well, as I recall, there were some fairly strong comments about being appalled by the recommendation, about trying to institute new launch
commit criteria at the last minute, about when we will ever get this launch off.
I thought those were fairly strong comments.
CHAIRMAN ROGERS: And those are comments, according to your recollection, that were made by whom?
MR. McDONALD: Well, the comments relative to the launch commit criteria and when we will ever get this off was made by Mr. Larry Mulloy. The comment about being appalled was George Hardy, who was at Marshall. I think I recognized his voice, but that was by voice recognition.
CHAIRMAN ROGERS: And so it was decided - and are there any other questions that any other member of the Commission has up to that point?
GENERAL KUTYNA: Mr. McDonald, I have one question. Before you went off the net, did you ask or make a comment about the secondary O-ring seal seating?
MR. McDONALD: Was I asked to make one?
GENERAL KUTYNA: No, did you make a comment?
MR. McDONALD: I did make a comment, yes.
GENERAL KUTYNA: Could you recall that comment, please?
MR. McDONALD: Yes. I think I read it to you, and I would be glad to do that again. I made the comment that lower temperatures are in the direction of
badness for both O-rings, because it slows down the timing function, but the effect is much worse for the primary O-ring compared to the secondary O-ring because the leak check forces the primary O-ring into the wrong side of the groove, while the secondary O-ring goes in the right direction; and this condition should be evaluated in making the final decision for recommending the lowest acceptable temperature for launch.
That was the comment I made.
GENERAL KUTYNA: That confused some people. Some of the witnesses I spoke to thought that that was a comment in support of the launch, the fact that the secondary O-ring seal would seat.
MR. McDONALD: Well, that comment is a good news-bad news comment. There is good news and there is bad news. The good news is that the secondary seal is in the right position, but that is not unique to temperature. It is always that way.
 The bad news is that the primary seal is the one we are depending on for the full ignition transient, and it is going to be a lot worse than it was. But even the secondary, as I mentioned, wouldn't be as good cold as it would be normally.
GENERAL KUTYNA: But by this comment you were not supporting the launch?
MR. McDONALD: No, not by that comment I wasn't supporting the launch. I was just saying it is an important consideration and I felt that if we could run some calculations to show that the temperature did not affect the timing, then that would be supportive of the launch.
If it did - and that was a concern, if we push that timing out long enough, we had a chart in there that said if that timing goes beyond that 200 psi regime while you're still eroding the primary O-ring, that for whatever reason if you ever bypass it at that time you can't depend on the secondary, and that is what is important.
GENERAL KUTYNA: Thank you.
CHAIRMAN ROGERS: So at the time of the caucus, then, you never favored launch?
MR. McDONALD: No.
CHAIRMAN ROGERS: And you made it clear that you were opposed to launch?
MR. McDONALD: Well, I never said I was opposed to the launch. I just made a few comments about why I thought some of the data was not appropriate, like the static tests, for saying the O-rings were good to 36 degrees. I made this comment about the lower temperatures affecting both O-rings, but it affects them
a little bit differently because one of them, it is a dynamic O-ring, it moves. One of them has a lot more movement and effects on it than the other one does, because it has to move across the groove.
I made those comments.
CHAIRMAN ROGERS: But you accepted the recommendation?
MR. McDONALD: I accepted the recommendation, yes. I thought it was the appropriate recommendation.
CHAIRMAN ROGERS: In other words, you accepted the recommendation of no launch that was made by your company?
MR. McDONALD: That is correct.
CHAIRMAN ROGERS: Mr. Armstrong.
VICE CHAIRMAN ARMSTRONG: Would you be surprised if your comments were interpret-ed by both your own company personnel and Marshall personnel as being supportive of the Marshall position?
MR. McDONALD: Yes, I would be surprised at that, yes. I wouldn't be surprised that that would be evaluated as the effect of that, but I would be surprised that it was interpreted as supporting.
VICE CHAIRMAN ARMSTRONG: Thank you.
MR. RUMMEL: Mr. McDonald, you mentioned a 40 to 90 degree qualification limit. Was that referring to
ambient air temperatures?
MR. McDONALD: Well, I had a discussion about that later. It was my impression that the motor itself was qualified from 40 to 90 degrees for operating, and we got into a discussion in  fact during the caucus, that was supposed to last for five minutes, that lasted for about a half an hour, on that very subject.
I told the people that were there from NASA that I, first of all, didn't agree that the motor was even qualified for 40 to 90 relative to all of its elements and subsystems. I wasn't there in the qualification of the steel case motor, but I just recently went through that process in the filament wound case SRM, and I am not aware of the testing or analysis that the O-rings were good to those temperatures, and that therefore it is part of the elements.
And the way I interpreted the spec is that all of the components and elements that make up the SRM should be qualified to those temperatures. Larry Mulloy at that time told me: Well, no, the 40 degrees refers to a propellant mean bulk temperature, and the propellant mean bulk temperature was being predicted to be 55 degrees for that launch; and that as long as the propellant mean bulk temperature wasn't below 40 degrees that you could expose the other parts of the motor to
lower temperatures, as long as you didn't drop the propellant mean bulk temperature outside of the 40 degrees.
I responded, I told him I thought that was absolutely ridiculous, because you could expose that motor to very severe cold temperatures, subzero temperatures, for a fairly long period of time, and you wouldn't change the propellant mean bulk temperature at all. It is just such a massive amount of propellant and insulator there that it takes a long time to do that, and I'm sure that the spec really didn't mean that.
And so my interpretation was certainly different than his.
MR. RUMMEL: Was there in fact a minimum temperature established by specification or by rote or in some manner that related to the O-rings or the joint at that time?
MR. McDONALD: Well, I wasn't aware of one for the O-rings. I found out later that there was - our specification refers to a higher level specification, which is level two at Johnson. I think that's the 07700 spec, that says that the shuttle vehicle has to be capable of launching in 31 to 99 degrees, or something like that; and therefore, since it is a higher level spec, that we should be able to comply with that.
But I'm not aware that all of the elements and subsystems were ever qualified to that.
MR. RUMMEL: What do you mean by "higher level spec"? Could you explain that?
MR. McDONALD: That specification comes down from the Johnson Space Center, who is responsible for the overall preparation of the vehicle, the shuttle vehicle, and what it is capable of operating in, the environments, both pre-flight and flight. And that specification for the overall vehicle gets incorporated as part of the lower level specifications that go through level three, which is Marshall Space Flight Center, to the various elements.
And they refer to that, and when they refer to that the way the system is supposed to work is, you're supposed to comply with your own specification plus any higher level specifications that may involve the entire shuttle system.
And I was unaware of that, frankly, that that criteria was in there. I'm still a little puzzled about it, because it doesn't have any timing limitation on it, either, whether it's 31 degrees for five minutes or 40 days.
MR. RUMMEL: Was there a Thiokol design temperature limit at the time this motor was designed
with respect to low temperatures?
MR. McDONALD: I really can't answer that, because I wasn't involved in the original design qualification.
CHAIRMAN ROGERS: If I may, I would like to continue, and we can come to some of these other questions. I would like to continue the chronology, because we were going fine and you stopped about the caucus.
Mr. Armstrong has a question.
VICE CHAIRMAN ARMSTRONG: One question, involving your answer that you just gave. Had Morton Thiokol to your knowledge ever informed NASA that the launch commit criteria were inadequate or did not in fact cover the kinds of conditions that you were concerned about?
MR. McDONALD: I am not aware that they ever did, not to my knowledge.
VICE CHAIRMAN ARMSTRONG: And so we're really talking about an event that was within the launch commit criteria, but outside what your experience base was?
MR. McDONALD: Well, I guess I don't even - I'm not convinced of that, either. I didn't learn about the 31 degree thing until some time afterwards.
But we were told to make this evaluation on
the basis of launching at 0938 in the morning, where the predicted temperature was 26 degrees Fahrenheit. That was the predicted temperature, and that was the decision that was made, whether we could launch at that time. So I'm not sure where that came from either.
CHAIRMAN ROGERS: Dr. Ride.
DR. RIDE: Yes, just one follow-up to Neil's question. Are you aware of NASA ever asking Thiokol to qualify the SRM or the SRB to 31 degrees?
MR. McDONALD: I'm not aware of it, but again, I wasn't in that part of the program. They may have. I can't say.
CHAIRMAN ROGERS: If we may now, let's go back. You said that a suggestion was made that you have a recess for five minutes. Who made that suggestion?
MR. McDONALD: That suggestion was made from someone at Thiokol. I can't recall whether that was Joe. I think it was probably Joe Kilminster, but I'm not sure.
CHAIRMAN ROGERS: Okay. Now what happened? You said that that lasted almost a half an hour instead of five minutes?
MR. McDONALD: That is correct.
CHAIRMAN ROGERS: And during that time what did you do and who were you with?
MR. McDONALD: Well, I was in the conference
room at Kennedy with Mr. Reinartz and Mr. Mulloy and Mr. Houston and Jack Buchanan still. And I gave you my conversation about interpretation of the qualification temperature there.
I also commented at that time that, I suggested that maybe we consider a late afternoon launch. I didn't feel good about the low temperature launch, because when I had first come down to Kennedy the original schedule was to launch that in the late afternoon, I think quarter to 4:00 or something like that. And based upon the weather report I heard, the temperatures would be 48 to 50 degrees in the late afternoon.
So I said, why don't we go to a late afternoon launch, and I was told that was considered, but it was rejected because of some problem either with visibility or weather at one of the transAtlantic abort sites. I think it was Dakar or Casablanca, one of those.
 I really expected - and the reason it was taking so long for this five minute caucus is that we were either trying to find some more information to support our recommendation or that we were trying to run some kind of calculations to determine how far away from that we could go, because clearly 26 degrees is a long way from 53.
I personally felt we certainly wouldn't go below 40, because I thought my interpretation of the qualification was correct and we wouldn't do that. But the reason it took so long was the engineers were reassessing all of the data they had and finding any more that they may have, and trying to quantify more. A lot of that data was very qualitative.
And finally, the people from Thiokol in Utah did come back on the line, after about a half an hour, and I believe it was Joe Kilminster who came on the line and said that, even though we had some concerns about the lower temperatures, that we would recommend that they proceed with the launch, based on the fact that we felt the temperature data that we had was not totally conclusive.
And he outlined several concerns still that we had relative to the effect of temperature, but also some rationales why we felt it was safe to proceed.
CHAIRMAN ROGERS: Can you relate what he said?
MR. McDONALD: Well, it was the information basically that ended up finally on the faxed statement relative to our concerns about the O-rings being colder and harder, but that we also had some data that was inconclusive relative to temperature, and I'm sure it
was the warmer temperature launch when we had some blow-by.
I didn't see anything that I recognized that was new information, but maybe they had some. And I felt all the engineers were certainly there that had generated the original data and evaluated it, and maybe they had reconsidered or re-evaluated the data they had and tried to quantify it and felt it was probably okay.
When he completed that he was asked, I believe it was by Mr. Hardy, I'm not sure, to put that rationale in writing and to sign it, make sure they get it down to the Cape, I think by morning, early morning.
And I was sitting across the table from Larry Mulloy at the time and I said I felt that I was the one who was going to have to sign it, because I was at the Cape; and I said I wouldn't sign it. I couldn't; it would have to come from the plant.
Joe Kilminster said that he would draft a letter or a statement and send it down, and he would do it tonight. He wouldn't wait until the morning. And I was instructed to stay there until that came down; and that he would also send it out to Marshall, and it would be a few minutes before that would come down. [Ref. 2/25-2]
He went off line at that time, and I asked Cecil Houston where the fax was, and he told me it was
at the other end of the building. I had a conversation with people at Thiokol just before they went off the line: Would they send that information in to Jack Buchanan's office, which was the fax machine right next to that we had, or were they going to send it in to the Marshall office, they had a Pitney-Bowes machine or something?
And they said: We will send it on the same one we sent all this other material, because they had the right number, and it happened to be the Marshall one, which was at the other end of the building. And so I said, fine, I would wait.
 Again, it took some time for that fax to get there, and so all of the parties who were in the meeting were still sitting there. And we started to talk about some things.
I told them I didn't feel very good about this recommendation, and I recognized it is very difficult to quantify at which temperature these seals may be acceptable and where they aren't acceptable based upon that data. Some of it certainly was inconclusive, there was no doubt in my mind, and that is a difficult thing to quantify.
But even though I didn't agree with the 40 degree qualification of the motor, that all elements
were qualified to that, it was my understanding that there were a lot of people at both NASA and Thiokol signed up to that, the design certification process, the critical design reviews, and I was absolutely surprised that NASA would accept any recommendation below 40 degrees Fahrenheit, especially when the predicted temperature was as low as 26 degrees Fahrenheit.
I told them: I may be naive about what generates launch commit criteria, but I was under the impression that that was generated based upon the qualification of all elements or subsystems of the space shuttle, and that anything that was outside that qualification was a launch commit criteria, and we never went outside that envelope, and I don't know why NASA would ever launch below 40 degrees Fahrenheit if that is what the SRM was qualified to.
In fact, I made the direct statement that if anything happened to this launch, I told them I sure wouldn't want to be the person that had to stand in front of a board of inquiry to explain why we launched this outside of the qualification of the solid rocket motor or any shuttle system.
When I made that statement, no one commented on that. I was still very upset, and so I asked that they reconsider this decision, for three reasons not one
but for three. And I said, if I were the launch director I would cancel this launch, for three reasons, not just one:
The first one being the concern of the cold O-rings that we just discussed, but there were two others. I had just left Carver Kennedy's house in Titusville, Florida, and he's responsible not only for stacking of the SRM's, he's responsible for the retrieval operations.
And he had been in communication with someone that was at hangar AF, I believe, that contacts the booster recovery ships at sea, and they had told him that the booster recovery ships were in an absolute survival mode, was how they put it; that they were in seas that were as high as 30 feet. There were winds at 50 knots sustained, gusting to 70 knots, pitching the boat as much as 30 degrees.
They even felt the rough seas may have damaged some of the retrieval equipment on the back of the ship. They were steering directly into the wind, heading for shore at about three knots, and they had been doing that for some time. There was no way that they would be able to support an early morning launch, because they wouldn't be in the recovery area.
I then reminded everyone in the room that
there are some firsts on this launch. This was the first time that we were going to use the new electronic control system for separating the nozzle extension cone on the SRB's at apogee, rather than just before water impact, while it is under full main parachute, and we were going to separate the parachutes at water impact for the very first time on this launch; and that, based on  the sea states that I had just heard, it appeared to me that it was going to be nearly impossible to recover that hardware, either the parachutes or the thrustums.
That there was also, I felt that they were putting the boosters at some risk as far as recovery was concerned, because the ships were steering away.
I also said that the third reason for not launching is the formation of ice. I knew that the sound suppression system was a water system, and I felt there was probably a lot of ice around there. And I'm no expert on all these matters, but I do feel that there may be a chance that that changing acoustics may be a problem with debris. It may have some effect on the structures. I didn't know, but I didn't think it was prudent to launch under that kind of a condition.
I was told that you know, there really weren't my problems and I really shouldn't concern myself with
these. But I said, you know, all three of these together should be more than sufficient to cancel the launch, if the one we had discussed earlier wasn't.
The NASA people who were there said that, well, they would pass these on, and they could tell I was disturbed and they would pass those on as concerns, and that they would do it in an advisory capacity.
I was then asked by Mr. Mulloy where the signed fax was, because some time had transpired since the teleconference had ended and it still wasn't there. And so I said, okay, I will go check on that, and I went down to the other end of the building, to this fax machine.
And there was nothing there that had come out yet, and I really wondered if it was working. And it was getting kind of late, and so I stayed down there I guess for about ten minutes. And it finally came in.
I brought the fax back - it was a single sheet of paper - to Jack Buchanan's office, where we reproduced copies for everyone. And I walked into, I think it was, Cecil Houston's office there and there was a telecon being conducted, and I believe it was with Arnie Aldrich.
And they were in the middle of this telecon and they were discussing the conditions of the booster
recovery ships and the high sea states and the fact that they were in a survival mode. And I recall that Arnie Aldrich asked Larry Mulloy if he felt there was any risk to recovering the boosters because of this. And he said, no, he didn't think there was any significant risk in recovering the boosters, because they had beacons and monitors, and they were going to have aircraft in the area also; but that there was a high probability that they would not recover the parachutes or the thrustums.
And the conclusion was that, I guess, they would have to make a decision to launch on the basis that they would have a high probability of not recovering that hardware.
But they weren't compromising the recovery of the boosters significantly. And I remember Arnie asking Larry the value of that hardware, and I think he gave some number close to a million dollars and asked him if he could afford to lose it and support the schedules of the program. And he said that he had sufficient inventory to do that.
But Arnie also told him that in no way have those ships attempt to turn around in those kinds of conditions, and the safety of the ships was important, to try to support that launch, and to turn around too soon, so to tell them to continue on towards shore until
it was really safe to turn around.
 They then briefly discussed the ice issue, about the ice, and there was a concern raised there. And Arnie, I believe it was Arnie, responded that they had discussed that issue earlier in the day. So it was a fairly brief conversation.
CHAIRMAN ROGERS: Arnie is Mr. Aldrich?
MR. McDONALD: Yes, Mr. Aldrich. They also made it clear that they were acting in advisory capacity only they weren't making some recommendations, they were acting in advisory capacity, but they wanted to be aware of this information. I didn't hear anything discussed about the O-ring seal problem. I presume that was done while I was down waiting for that fax, because that was the first concern.
CHAIRMAN ROGERS: But you're not sure of that?
MR. McDONALD: I'm not sure, I presumed it was because I got in on the middle of the conversation on the boosters and heard the ice. So I don't know. And finally the conversation concluded and the recommendation was to proceed on with the launch.
I stayed around a few more minutes and talked to Jack Buchanan for a few minutes, and then went back to Carver's house in Titusville, where I stayed, and got in there, I guess, a little before 1:00 sometime. And I guess that's all I have to say.
CHAIRMAN ROGERS: A couple of questions.
One, when you first appeared before the Commission I remember your explaining the fact that the company originally had recommended against the launch. And then you testified that after the caucus they came back and changed their mind and said go ahead with the launch. You said it was based upon inconclusive data.
I remember asking you how could they have changed their mind based upon inconclusive data. Can you explain that?
MR. McDONALD: Well, I can't explain that. That was the comment that was made, that the data was inconclusive relative to the effects of the temperature, and I prefer you ask those questions of those that made that decision. I don't know. I wasn't there. I wasn't there when all of that data was reassessed and evaluated and what the conclusions were drawn.
CHAIRMAN ROGERS: One other question. Dr. Keel asked at the conclusion of your testimony in executive session whether you felt that you were under pressure or had been under pressure or the company had been under pressure to reverse its decision, and I think your answer was yes. Do you remember that?
MR. McDONALD: Yes, definitely. There was no doubt in my mind I felt some pressure. I feel that I have a responsible management position, and I felt pressure.
CHAIRMAN ROGERS: Would you explain the reasons for feeling pressure?
MR. McDONALD: Well, I have been in many flight readiness reviews, probably as many as anyone, in the past year and a half at Thiokol, and I have had to
get up and stand before, I think, a very critical audience at Marshall, and a very good one, justifying why our hardware was ready to fly. I have to get up and explain every major defect and why we can fly with that defect.
And for the most part they are very minor - very, very minor. And I have been hassled about how I'm sure that that is okay to fly with. You know, such things as losing vacuum in a carbon cloth part in the nozzle while the part is basically cured. It is a critical process.
 There is a lot of those critical processes, and I have to address every one of those in great detail as to why I am sure that that part has not been compromised. And it has been that way through all of the reviews I've ever had, and that is the way it should be. And it is not pleasant, but that is the way it should be.
And I was surprised here at this particular meeting that the tone of the meeting was just the opposite of that. I didn't have to prove that I was ready to fly. In fact, I think Bob Crippen made the most accurate statement I ever heard. His conclusion from that meeting was the philosophy seemed to have changed because he had the same impression I did, that
the contractor always had to get up and stand up and prove that his hardware was ready to fly. In this case, we had to prove it wasn't, and that is a big difference. I felt that was pressure.
CHAIRMAN ROGERS: And can you explain a little more what source the pressure came from in your mind?
MR. McDONALD: Well, I think the strong statements that were made by Mr. Mulloy, and even some of those, the people at Marshall that were on there - Mr. Hardy - were I think fairly strong statements that I took as pressure about when we will ever fly this thing and the launch-commit criteria that we can't generate at the last minute, and appalled by our recommendation to fly at temperatures as high as 53 degrees. And that, to me, that was pressure to me.
It may not have been interpreted by others, but it was pressure to me.
CHAIRMAN ROGERS: Any other pressure that you want to refer to at this time or at any time?
MR. McDONALD: No. I just felt that the way the comments were made, as strong as they were made, and the fact that the conditions for justifying this launch were so much different than anything I'd been involved with before.
CHAIRMAN ROGERS: As far as the Telefax was
concerned, would you normally have signed that Telefax, or was the procedure that was followed the normal procedure?
MR. McDONALD: Well, I'm not sure, I guess, what the normal procedure is. I felt that since I was there representing the senior official at the Cape that I'm the one that usually is responsible for that. I know at the L-1, when we have a normal launch, there is a poll that is conducted by Jess Moore of all the contractors, whether they are ready to fly, and I am the guy there that has to get up and say yeah, Thiokol's hardware is ready to fly.
I felt that was my responsibility. That's why I'm there. I can't recall whether we were asked to sign anything like that before. We have a presentation that is given at every flight readiness review that is signed off by the principal parties. Joe Kilminster usually signs all of those on the formal review, but if anything comes up afterwards it has been done on an oral basis.
But I don't know. I've never been put in that position, and I don't know if Joe has. I don't believe he has.
CHAIRMAN ROGERS: So, the fact that a written decision was requested, as far as you were concerned, was not a normal way to do it?
MR. McDONALD: It was not normal as far as I was concerned.
CHAIRMAN ROGERS: And, as I recall your testimony, you testified that you made it clear that you would not sign a written statement approving the launch. Am I correct?
 MR. McDONALD: Yes, that is correct. And I think that has been misinterpreted, at least by the press. They said that I was overruled by my supervisor. That is not true at all. I chose not to sign that. He didn't overrule me. I felt that that decision, when I started, was an engineering decision by the people that understood the problem the best, that had all of the data and facts, and they are the ones who should recommend it. And that is why I made that.
It wasn't that I was overruled.
CHAIRMAN ROGERS: Thank you very much. I am sure other Commission members will have questions.
VICE CHAIRMAN ARMSTRONG: You were talking about the 40-degree qualification of various components of the solid rocket booster, and I was aware of the 40-degree limit on the mean bulk temperature. But was there anything else that the 40 degrees referred to?
MR. McDONALD: Well, in the spec, going back
after the fact and looking at it, that is what it had. What it refers to is the propellant mean bulk temperature.
I guess that is, in my opinion, it's an oversight, maybe, in the spec, or the launch temperature of 31 to 99 should be stronger in there to apply to all components, and by qualification it either has to be qualified by test or some analysis, and that means every element. And I'm not aware that all of those elements were qualified to that temperature.
I know we bought O-rings that said they are good to minus-30, but I never saw the analysis, and the application that we used them in that says that they are good to that, and that is a difference. It is a material problem versus a design problem.
VICE CHAIRMAN ARMSTRONG: I understand that, and I understand the 40 degrees was intended to protect against grain cracking and the consequences of that. But what I didn't quite understand is why you said you wouldn't recommend any time launching below 40 degrees.
MR. McDONALD: Well, the reason I said that is I felt that is what everyone had signed up to, as what this thing was really qualified from an operating standpoint. Now the motor does get exposed to much lower temperatures. We have a criteria in our
specification to expose that to much lower temperatures, sub-zero temperatures in the 60-mile winds coming across Wyoming, because we ship these things from Utah down to the Cape. So in the transportation mode they are subjected to some very severe temperatures for some periods of time.
And there has been analysis to show that they will withstand those temperatures as long as you don't operate them at those temperatures. The 40 degrees, they won't crack. There is no problem there. That is a, primarily a performance standpoint. You lost total impulse and performance the lower the temperatures go. If you get below 40 you start losing performance out of the shuttle and that is why that number came about.
As far as the capability of - grain structural capability, it can withstand a lot colder temperatures than that, and we have analysis where the transportation and storage shows that, and it has good margins of safety, very high margins of safety for exposure to lower temperatures.
It is just that things like the O-rings and some of these other components, I am not aware that we have really analyzed or tested those well enough to understand how they would operate in that kind of a temperature. There is a difference between exposing
them and storing them versus operating them.
VICE CHAIRMAN ARMSTRONG: Thank you.
DR. WALKER: I have a question just referring back to the static test that you mentioned at 36 degrees which was used as a justification. Was there analysis to indicate what the O-ring temperature during the test was?
MR. McDONALD: Well, it was done after the fact, and I believe in the presentation that was made on the night before the launch they calculated like 47 degrees is what they presented as what they expected the O-ring temperature to have really been when that was static tested.
DR. WALKER: I have a couple of other questions regarding the conference. Was there a specific request by NASA to reconsider, or was the reconsideration as a result of the implications of the remarks made by the NASA people in the conference?
MR. McDONALD: Do you mean the reconsideration of what?
DR. WALKER: Of the initial decision not to launch. The initial recommendation of Thiokol was not to launch, and then that was reconsidered. Did anyone from NASA explicitly ask for reconsideration, or did the reconsideration occur because of the negative remarks
and comments on that decision?
MR. McDONALD: Well, I think it was the latter. I can't fully recall whether they directed us to do that or not, but they had concluded that the temperature data was inconclusive, and I don't know whether we volunteered to reassess it or they said we need to. It is not clear to me on that. I'm not sure.
DR. WALKER: One further question in regard to the signature on the sheet which was faxed from Mr. Kilminster. Was there a specific request for that to be signed, and who made that request?
MR. McDONALD: Yes, there was a specific request for that to be signed. I believe it was George Hardy. It may have been Larry Mulloy. But I think it was George Hardy had requested that.
MR. ACHESON: Mr. McDonald, did you consider bringing your concerns about the final recommendation to the personal attention of Mr. Moore or Mr. Aldrich or Dr. Lucas?
MR. McDONALD: Well, I'm very familiar with the process by which these things are reviewed, and I was absolutely positive and sure that they were brought to their attention, because that is the way things go. I talked to the SRB project manager. I talked to his boss, the shuttle project manager, the shuttle project
office, and I was assured that those all went through those reviews.
I had no doubt in my mind that they had.
MR. ACHESON: Thank you.
DR. FEYNMAN: You indicated that NASA folk indicated that they would pass your concerns along, and I presume that you thought that - there were three concerns that you were talking about - the O-rings, the ocean, sea and the ice. But could they have simply meant the last two concerns, the sea and the ice? That is one question.
And the other is who were the NASA folk that promised to pass your concerns along?
MR. McDONALD: I guess you could maybe interpret that I thought it would be all three, but the people were Mr. Mulloy and Mr. Reinartz that would pass those on, and I presume they passed them all on. I didn't see any reason why they wouldn't.
 MR. HOTZ: Mr. McDonald, you mentioned earlier that you thought this decision on launching should be an engineering decision and not a program management decision. How would you characterize the final decision to launch from Thiokol? Was it engineering or was it management?
MR. McDONALD: I guess I would have to
characterize it as a management decision, the final decision.
MR. HOTZ: Thank you.
DR. RIDE: I have got a couple of questions on Criticality 1s. Did I understand you to say that you chair the board on Criticality 1s on the SRM from Thiokol?
MR. McDONALD: Yes, on all defects that are affected by that, yes.
DR. RIDE: Could you give us your understanding of the meaning of Criticality 1 and just an estimate of how many parts in the SRM system are classified as Crit 1?
MR. McDONALD: I don't have the number for you, but there is a tremendous amount of Crit 1s on the SRM, primarily because the motor doesn't have very many redundant features. The solid rocket motors don't. And, of course, a lot of it is structure and structure all becomes Crit 1 if it fails.
DR. RIDE: Could you define a Crit 1?
MR. McDONALD: Crit 1 is a single point failure that if that element fails there is no recovery. You lose the hardware and it is catastrophic. There is a lot of elements in the SRM that are under that category. Relative to the O-ring
seals, the redundancy was built in, because that was a critical element, as the pressure seal, in order to provide that redundancy.
I think there is some confusion of late as to what that Crit 1 and 1R was relative to the seals and how it was removed. I wasn't involved at the time, but it was found that because this joint rotated that if you took all of the worst engineering tolerances and dimensions that were allowed by the prints - and that means the maximum clevis opening you could have to start with, the smallest and thinnest tang that you could put into that clevis opening, the minimum O-ring that you could put in there with the maximum size of the grooves you could possibly put in there - that you put all of those combinations together, you could show that you would actually lose squeeze on the secondary O-ring once you pressurized the system and the joint rotated.
And, therefore, if you ever had to call upon that O-ring as a redundant system during that time period, you couldn't depend on it.
Now I went back and had an assessment made of have we flown any hardware in that condition, because I was a bit shocked about that, as much as anyone, when I first found that out, which was, by the way, last August
when I made that presentation here at NASA headquarters. I was unaware of it myself, that we had such condition, that we were flying with a Crit 1 on that part of the hardware.
Based on the information that I have received on all of the joints ever flown on the shuttle, there was only one time where we had a tolerance stackup of a joint that would have fallen from a Criticality 1R to a 1, and that was on STS 4. We had never had one since. We didn't have one before that. We always had adequate squeeze from the hardware when it rotates to maintain it as a Criticality 1R.
 DR. RIDE: I'm not quite sure I understand that, because I thought that the piece of paper in the critical items list specifically lists the primary O-ring as a Criticality 1.
MR. McDONALD: Yes, it does. and the reason it does that is because the drawing tolerances allow you to install hardware that may come together on a worst case basis that cannot guarantee a secondary seal. And, therefore, if you use all of the hardware that is in the inventory or you could possibly have in the inventory and build to acceptable prints, you could end up with a very small fraction.
It is a very small fraction that could go
together that way, and therefore that document was written to cover all that. But in reality other than that one case we never assembled hardware that way. We haven't had the thinnest tangs with the widest open clevises with the minimum O-rings ever put together. That is a concern, and the seal is a very serious concern, in my opinion, because that decision was made at the time based upon what we knew about joint rotation.
Since that time, we're getting this information on resiliency and the effects of temperature, which were never put into that at that time, that brings that question back out in front. I told you we didn't fly from a Criticality 1R and 1. Well, that is true, based upon the decisions and the information that was known that changed it from a 1R to a 1 just upon the tolerances and dimensions.
As far as the resiliency thing, I can't assess that yet well enough to know, but I do know we never stacked hardware together that had tolerances so bad that we didn't have contact of the secondary O-ring other than one joint.
DR. RIDE: But, just to be clear, I guess, you don't on a joint-by-joint basis go back to the NASA board and kind of reclamma the Crit 1 and turn it back into a 1R, do you? It is always classified as a
Criticality 1 on the primary seal?
MR. McDONALD: That's absolutely right. You are correct. Now we do, as part of our flight readiness review, present those joints that we are mating and what those O-ring squeezes are on every flight.
DR. RIDE: Did any discussion of the primary seal as a Criticality 1 come up during your meetings on L-1?
MR. McDONALD: No, they didn't.
DR. RIDE: Thank you.
DR. FEYNMAN: You suggested that the secondary seal would not be much affected by the temperature, but now you are telling us that because of the complete or nearly complete loss of resilience - that is, the tendency to spring back - the secondary seal would require very little rotation to open. Do I understand that correctly?
MR. McDONALD: I said it wouldn't be as affected as much as the primary seal because it doesn't have to move from one end of the slot to the other. But as far as the effect of resilience, you are absolutely correct. It still has the same problem. As far as extruding in the gap, it has still got the same problem.
DR. FEYNMAN: We were talking about- -
somewhere there was a discussion about the secondary seal being redundant until the metal parts rotate. When the pressure starts to build up, it can't move the primary seal until there is some pressure, and then there's a very small pressure, perhaps, and a very small rotation.
Isn't it true that the rotation is more or less proportional to the pressure, or is there some delay of some sort? Why is there a time delay between the two?
MR. McDONALD: There is some delay because the joint is stiff enough that under certain pressures you just don't move it at all until you have to build up some pressure to make any rotation. So there is a delay in that time period. But at some point in time it becomes a direct function of the pressure.
DR. FEYNMAN: Isn't the laws of elasticity such that everything is proportionate to the force and all of the spaces are proportional to the force? Wouldn't it be true that at every pressure there is some rotation and the rotation is more or less proportional to the pressure?
MR. McDONALD: Well, I think when you are down to a few psi or 50 psi, I don't think you are rotating anything.
DR. FEYNMAN: You are rotating it one-tenth as much as you rotate it at 500 psi; is that right?
MR. McDONALD: Well, the structure is so stiff that I can't believe you rotate it at all at 50 psi. You are moving the O-ring seal back into the groove, however.
CHAIRMAN ROGERS: Just to go back to the Criticality 1 so that I can understand it a little better, in, what, 1985, a change was made?
DR. RIDE: 1983.
CHAIRMAN ROGERS: I guess it was 1982 or 1983. At that point, it was listed as Criticality 1 with an R. Is that right?
MR. McDONALD: That is correct.
CHAIRMAN ROGERS: Now, does that mean that it was decided that if there was a failure in that seam, O-ring, that the mission and the crew would be destroyed, the whole thing would be a catastrophe? But at that point the R meant that there was a redundancy there, that you had two rings and each at that point was considered to support the other, or at least one was a backup for the other?
MR. McDONALD: That is correct.
CHAIRMAN ROGERS: That is what "R" meant?
MR. McDONALD: That is correct. The "R"
CHAIRMAN ROGERS: Now at that time experience merely demonstrated that the analysis which you had been using up to that point may not have been correct, so that instead of having both a primary and a secondary seal which provided redundancy, you came to the conclusion you didn't have a redundancy. Therefore, it was changed to Criticality 1; the "R" was removed. Is that correct?
MR. McDONALD: That is correct.
CHAIRMAN ROGERS: And so from that point on, I believe it was in - what is the date - December 1982, those shuttles have been flown on the basis of Criticality 1, so if there was a failure of that seal a catastrophe could result because there was no redundancy; is that correct?
 MR. McDONALD: Well, I guess that is the interpretation of that. But recognizing the actual hardware that was put together and what we knew at that time, I don't believe that that was true.
But what was true was that the drawings, as I mentioned, allowed the condition where that, you could fly that hardware in that condition.
DR. RIDE: But, just to be clear, what the CIL says is that the primary O-ring is a Criticality 1 and
you're not allowed to consider the secondary O-ring as a backup to that?
MR. McDONALD: That is true, Sally. That's absolutely correct. That is what is meant.
CHAIRMAN ROGERS: And that was known by everyone, I assume, who was working on the program - or most of the top people working on the program. Would that be true?
MR. McDONALD: Well, I kind of thought I was one of the top people working on the program, and I didn't know that until August of 1985 when I put that presentation together. I presume it was. I did find out that there was some disagreement between both Thiokol and Marshall in interpreting that relative to the joint rotation.
The joint rotation that was used for concluding that was obtained from two different sources. One of those sources was from the structural test article 1, the first structural test article - and this was way before my time. But where this test article was taken to Marshall and it is basically a forward segment - it is unloaded - and an aft segment. And where they input both the prelaunch loads and they put flight loads and all that business into the test article.
And this test is run horizontally and they measure through the leak check port, I understand, or some places, the actual rotation of these parts. And they got some fairly high numbers, up around 60/1,OOOths, I believe, is what they said it rotated. We had run some tests ourselves in a vertical assembly during the hydro test, and measured some of the rotations and got numbers like 30 to 40/1,OOOths. So there was some disagreement as to which numbers were correct.
Some of our people felt that the horizontal assembly may have made the structural test article numbers not representative and the vertical assembly was better. And in fact, because of that disagreement, we are in the process - and started early last summer at the direction of Marshall - to come up with what is called a referee test, to do some very careful instrumentation in a vertical assembly to get a better handle on the exact amount of joint rotation.
Those joint rotations that are used are those that are predicted for the maximum expected operating pressure, which, by the way, we have never obtained, fortunately - and I hope we never do. But that is a 3 sigma out there someplace. But that still is a point of controversy as to what that number really is, because
the CIL, I believe, the critical items list, that changed that from a 1 redundancy to a 1 not only assumed the MEOP but I believe it assumed the larger rotation, which is about 50 percent more than some of the data that we got from vertical.
So I still don't fully understand that. What I do understand is that it was made at the time when temperature effects were not known. And the resiliency problem, as Dr. Feynman brought up, I think is a more serious one.
CHAIRMAN ROGERS: Going back, though, beginning in 1985, when you realized that the Criticality 1 was on the critical items list, you knew from that point on that a single failure would be a catastrophe as far as the mission was concerned?
 MR. McDONALD: Well, as I mentioned earlier, you have to postulate what your failure mechanism is, and I felt very strongly that the blow-by that we had observed indeed was on the early part of the ignition transient. I think we all felt that way. We modeled that, by the way, I think fairly reasonably on the erosion.
And at that point in time, when the hardware really hasn't had a chance to rotate, taking the temperature effects out now, that we do indeed have a
good, redundant seal, because if we lose the primary O-ring at that time that secondary seal is in a better shape than the primary to really seal. It hasn't come off its land at all, if you ignore the resiliency problem.
DR. FEYNMAN: That is your opinion. In a different scenario, suppose the pressure is increasing for some reason in the primary seal. Just to understand what the situation is, the primary seal begins to erode, and by the time the pressure gets to some figure like 600 or 700 psi, which is I think just below the maximum operating pressure, it finally erodes all the way through so that the gas can pass through the primary seal.
Would you think there was a reasonable probability that the whole thing would fail because the rotation by that time was enough that the secondary seal can't hold it?
MR. McDONALD: Yes, I think there was, and that was our assessment in August - that there was a reasonable probability.
DR. FEYNMAN: Okay. That you first knew or thought of in August 1985?
MR. McDONALD: That is correct.
DR. FEYNMAN: Not before?
MR. McDONALD: That is correct.
CHAIRMAN ROGERS: Following up on that, wouldn't you assume that other people who had been working on the program and working on the seal and the O-rings would understand that, too?
MR. McDONALD: Yes. I think there is another important piece of information. Back in the end of April 1985 - I forget the exact flight, but it was the last one in April - we had a problem with the O-ring seal in the nozzle.
That flight, after it came back, the nozzle was still attached to the aft segment and we disassembled the segments when they were brought back to the port. And then they are put on rail cars and sent back to Utah and we never got the segment back until, I don't know, sometime in the latter part of June or something. This flight was at the very end of April.
We disassembled that nozzle and we found that we had violated the primary seal, in fact in three locations, and burned completely through. The secondary seal also had eroded like 32/ 1,000ths, but it held and it did its job. That was in a nozzle joint.
The primary seal in the nozzle joint is a bore seal quite similar to the field joint. Tolerances are a little different. But the secondary seal is a face
seal. They are both somewhat dynamic seals, but it is more of a static than the bore seals. The face seal is torqued down with bolts and it obviously did its job.
And our conclusion was, in that particular instance, was that even though we passed the leak check that the vacuum putty may have masked that leak check. We were using at that time a pressure, a stabilizing pressure, to run that leak check at 100 psi. We had had some data earlier that showed us that the consistency of that putty is quite variable, and you can actually  - the putty will become a good sealant in many cases and it can hold as much as 100 psi for a good period of time. Sometimes it will blow through and sometimes it won't.
And so our concern was that maybe we were not really checking the O-ring seals. We were checking the putty and we wanted to make sure we were checking the O-ring seals. We jacked the pressure up to 200 psi and that was the last flight where we were still under the 100 psi, which was the previous requirements, to stabilize at 100. And then once you have stabilized it for a period of time there, you drop the pressure completely again and you bring it up to 50 psi, and that is what you run the leak check out for about ten minutes. And we only allow a one psi drop.
In that particular set of hardware, since that was the last one we ran at 100 psi because the change hadn't gotten through with all of the paperwork system on what we understood about how putty behaves under pressure. as we went to 200 psi for the field joints at that time, we just hadn't gotten the nozzle, we concluded that the putty may well have masked that leak check, because it was at 100, and therefore we may have had some defect in that seal that we didn't detect.
And as a result, that seal leaked at ignition from time zero, and when that happens you get severe erosion in the O-ring, because you get the jet impingement that we have been calculating, which is directly onto the O-ring seal, like a flat plate. But when you bypass the O-ring in a leak like that, it actually chokes at that point, so you're forming a throat and it erodes very rapidly from underneath, as well as jet impingement, and you lose quite a bit of the seal.
We lost most of the seal, in fact. But the nozzle seal is very good, the secondary seal, because it is around the corner and it expands and goes down around the corner. And it eroded some of the secondary seal.
We ran a lot of analysis after that, because that was the first time that we had observed erosion of
a primary seal. We developed our models to predict erosion, what would happen in blow-by erosion, and it was because of that that we found that hardware.
And it was late in June and it was into July that we got all that data together. and we went down to Marshall and had very detailed reviews, because that was a serious concern to everyone that we had violated the primary seal that was in the nozzle joint.
But we were asked to come to Washington, to headquarters, and review that. It was a very serious concern. It was at that time that I got together with the engineering people and said, we need to put the whole story together on all the pressure seals, because I and several others still felt that, even though that problem happened with the nozzle, the field joint was a more serious concern, because I felt very good about the secondary seal and the nozzle; 1 didn't with the field joint.
And I put together a presentation for August that I think showed where our real concerns were and why we felt the highest priority was the field joint even though we had just experienced that problem with the nozzle, we felt we had corrected the problem with the nozzle because all subsequent flights had the 200 psi leak check, so that we could not miss a possible defective seal or a contamination that may have
prevented that seal from seating in the first place.
 But that was some of the background that I think really turned up the gain on the whole seal issue, from about April, really, and June on. Prior to that time, we were doing a lot of work to better understand this rotation business, but we have done a tremendous amount of work.
In fact, you may have read in the press, and it is true, that we actually went to an SAE conference last fall, a couple of our top engineers went there, to try to get help from the whole seal industry and SAE about the field joint: Is there a better way to seal that joint?
CHAIRMAN ROGERS: What does "SAE" mean?
MR. McDONALD: The Society of Automotive Engineers.
And we did a lot of work to try to get help from the outside, as well as do the work that we had inside. And I think that is all relevant to the discussion.
CHAIRMAN ROGERS: Were you surprised that some of the top people in the decisionmaking process didn't know about this at all?
MR. McDONALD: Didn't know about the CIL or the criticality one or what?
CHAIRMAN ROGERS: Well, the whole thing, the concern on your part and on the part of Thiokol's engineers, that the original decision had been not to launch and all of that.
MR. McDONALD: I'm very surprised at that. I hardly believe that. The issue is so controversial I thought that I'm sure that they were aware of it. I have a hard time believing they didn't.
MR. SUTTER: Could I ask one question? In talking about criticality one and going to 1R, I think you made the comment that you would have to have all of the tolerances going in the wrong direction to meet that condition, but you did say that one unit did meet that condition?
MR. McDONALD: Yes, to the best of my knowledge. And I had some record search done. I was told that there was a condition in the - I think it was the forward field joint of the STS-4 someplace, that was in that condition.
MR. SUTTER: What if that launch had been done at a cold temperature? Wouldn't it have maybe taken it over the edge?
MR. McDONALD: I don't know. It is possible. I certainly don't feel good about that.
MR. SUTTER: The reason I ask the question, it
seemed to me that if it was a Criticality 1 item then everybody should treat it as Criticality 1 and not rationalize that it may not ever happen.
MR. McDONALD: I agree with that.
MR. SUTTER: You think everybody else agrees with that?
MR. McDONALD: I think our engineering people agree with that, and that is why the recommendation we had made originally. That was the basis for that recommendation. We felt that we had observed a condition a year earlier that we did feel was attributed to temperature in some way or another and it was not a good condition, and we didn't want to go much beyond that, because, even though that one was successful, it certainly wasn't a good condition.
MR. ACHESON: Mr. McDonald, was it NASA or Thiokol that originally initiated the change from Criticality 1R to Criticality 1 for the primary O-ring?
MR. McDONALD: I have to tell you, based upon what I was told, because I wasn't involved in that change, but I was told that that was NASA-initiated.
MR. ACHESON: What experience led to that change, do you know?
MR. McDONALD: I am not sure of what
experience led to the change. I presume it was the understanding from the joint rotation data and the drawing tolerances of all of these parts that that condition could exist someplace in the hardware, and therefore if we were going to fly the hardware as it was designed that, either through refurbishment or new hardware that was within those tolerances, may be matched together some time to give us a condition like that.
But I think you would have to ask the people that were involved in that particular decision.
MR. ACHESON: How do you account for what appears to be the fact that between December 1982 and the middle of 1985, when Thiokol became concerned about the erosion and the blow-by, that flights did not occur seemingly during that time that led to the same concern?
MR. McDONALD: I can't explain that. I certainly didn't know about it until August 1985.1 don't know. I think that everyone was concerned, at least from the standpoint that we always had to present data on the joints that we were mating to show that we had adequate squeeze and all.
That data was presented, and I'm sure the people were concerned about that.
MR. ACHESON: Thank you.
CHAIRMAN ROGERS: If there are no other questions, we will have a ten minute recess.
CHAIRMAN ROGERS: Will the Commission come to order, please.
If I could ask Mr. Mason to take the stand.
[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. 2/25-1 1 of 24] Typed version of handwritten notes of A. J. McDonald, Manager Shuttle Rocket Motor Project, Morton Thiokol, Inc. [Ref. 2/25-1 1 of 24] Typed version of handwritten notes of A. J. McDonald, Manager Shuttle Rocket Motor Project, Morton Thiokol, Inc. -continued.
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 [Ref. 2/25-1 15 of 24] Jan.27 Morton Thiokol Inc. Recommendation. Signed A.J. McDonald. [Ref. 2/25-1 16 of 24] How Should We Attack This Problem? - A.McDonald hand-written notes.
 [Ref. 2/25-1 17 of 24] Environment Before Launch (A)- A.McDonald hand-written notes.
 [Ref. 2/25-1 18 of 24] Environment Before Launch (A) Cont. - A.McDonald hand-written notes.
 [Ref. 2/25-1 19 of 24] Environment During SSME Buildup (B)- A.McDonald hand-written notes. [Ref. 2/25-1 20 of 24] Environment During SRB Ignition and Liftoff (C)- A.McDonald hand-written notes.
 [Ref. 2/25-1 21 of 24] Environment From Liftoff to Problem Time (D)- A.McDonald hand-written notes. [Ref. 2/25-1 22 of 24] Problem Time (~58.3 sec) (E)- A.McDonald hand-written notes.
 [Ref. 2/25-1 23 of 24] Environment After SRB Burnthrough and Prior to ET Explosion (F) - A.McDonald hand-written notes. [Ref. 2/25-1 24 of 24] Other Possibilities (F) - A.McDonald hand-written notes.
 [Ref. 2/25-2] MTI ASSESSMENT OF TEMPERATURE CONCERN ON SRM-25 (51L)
LAUNCH. Signed: Joe Kilminster.
CHAIRMAN ROGERS: Mr. Mason, you requested that you appear after Mr. McDonald, and we are glad to welcome you, and go ahead and proceed any way you would like.
MR. MASON: Thank you, Mr. Chairman. We have given you a handout there, and I wanted to start on page 18. We had originally thought to provide some technical background, but that could be covered later.
(Viewgraph.) [Ref. 2/25-3]
CHAIRMAN ROGERS: Could I say that we have of course received quite a lot of this information in executive session, and we will certainly be pleased to look at the information on this first 18 pages. But proceed in any way you would like.
MR. MASON: Thank you. My intent here is to explain the organizational structure and those people that participated in the discussions, and then go through the chronology of the occurrences that night on the 27th of January.
First off, I am the Senior Vice President of Wasatch Operations. We have on the chart you have there selected only those people that participated in
I might point out that there are three divisions reporting to me: the space division, under Mr. Wiggins, who is listed there; and there are also a tactical and strategic division reporting to me. Mr. Lund, who shows there as vice president, engineering, provides engineering services for all three divisions.
We have covered just the space division in detail. You will see that Mr. Kilminster reports to Mr. Wiggins, and he is the head, he is the vice president of the space booster programs. And of course, you've just heard from Mr. McDonald, and reporting to him are Messrs. Ebeling and Russell. And then, from the KSC offices, Jack Buchanan, also reporting to Mr. Kilminster.
Within the engineering organization, there is a space shuttle project engineering group under Mr. Brinton, and Mr. Macbeth reports to him. Then the other part of engineering, engineering design organization, you will see the people listed there. I don't need to read them, but they were all participants in the discussion.
We added a couple of notes here we thought were pertinent. One is that we do have a flight readiness review at Morton-Thiokol before Marshall has
their flight readiness reviews, and Mr. Wiggins chairs that flight readiness review group. And the results of that flight readiness review are signed off both by Mr. Kilminster and Mr. Brinton to indicate that we are ready to fly.
Then Mr. Kilminster then attends the flight readiness reviews of NASA.
One other point we made here, which was also discussed by Mr. McDonald, and that is that he and Mr. Kilminster have been alternating as the attendees at the launches.
Now, as I go through the chronology you will see the names of various people here, and you will find them all in this chart. But I will try to point out where they fit as I go through the chronology.
(Viewgraph.) [Ref. 2/25-4]
We have the times here listed both in the Eastern Standard and Mountain Standard time, and the significant occurrences as we move through it. At 1:00 o'clock Eastern Time, Mr. Macbeth and Mr. Arnie Thompson and Charlie Saderholm all received calls from Boyd Brinton, who was at Marshall.
And that is something I ought to point out, that throughout this discussion Mr. Brinton, who is the manager of space shuttle project engineering, was at
Marshall Space Flight Center, as was Mr. Speas. And as you know, Mr. McDonald was at Kennedy, as was Mr. Buchanan. The rest of the people we have listed here then were all at Wasatch in Utah.
As a result of the call at 1:00 o'clock, Mr. Ebeling and Ketner were notified, and Mr. Saderholm started the bulk temperature analysis of the propellant and Brian Russell arranged a meeting in Mr. Ebeling's office.
They convened that meeting in Mr. Ebeling's office, and the attendees are as listed there. During that meeting they discussed the O-ring resiliency data at 50, 75, and 100 degrees. They talked about the amount of blow-by and erosion that had been seen on the 51-C, which was the previous coldest launch.
CHAIRMAN ROGERS: Were you at those meetings?
MR. MASON: I was not at that meeting, no, sir.
CHAIRMAN ROGERS: So this is hearsay as far as you're concerned?
MR. MASON: That is right. I do get to where I entered the picture here in a moment. This was an effort to get an overview of what happened and where, to try make the rest of the testimony flow a little better.
They did look at the other launch and static test temperatures and concluded that they did have a concern. They broke that meeting up and started to do some work. Mr. Maw was to run the calculation of what the O-ring temperature would be if the ambient were 18 degrees, and Mr. Ebeling notified Mr. Kilminster of the concern that they had.
And Mr. Kilminster asked Mr. Ebeling to get the engineering management, including Mr. Lund, involved, and to notify both Mr. McDonald and Mr. Brinton of the Marshall concern.
CHAIRMAN ROGERS: I assume that there was no recording made of these meetings and this is reconstructed from conversations you have had with other people?
MR. MASON: That is correct. We did talk to all of the people involved, so we felt we had a consensus of the sequence.
 Then Mr. Buchanan called to give us some temperature predictions at that time. They were predicting 34 degrees at launch time at 9:38.
Then Mr. Thompson briefed Jack Kapp on his concerns. Then Mr. McDonald called from Kennedy, hoping to have a telecon between Morton Thiokol and NASA on those concerns. There were people called to the
conference room to support the telecon, and that required interrupting the meeting that was at that point under way in Mr. Lund's office.
(Viewgraph.) [Ref. 2/25-5]
CHAIRMAN ROGERS: Well, just for semantics, you say people called to support the telecon. Do you mean to take part in the telecon?
MR. MASON: Correct. The conference room we have there has microphones so that you can be in the conference room and anyone can talk and be picked up.
CHAIRMAN ROGERS: My question really has to do with the word "support." Where you say "conference to support telecon" and "interrupted to support telecon," do you mean take part in the telecon?
MR. MASON: To take part, that is correct.
That telecon then proceeded with the people that are listed there, some 13, including the people at Marshall and at Kennedy. At the time that started, they notified Mr. Kilminster that it was starting.
(Viewgraph.) [Ref. 2/25-6]
At the same time, essentially, he received a call from - that LSS - that means launch support services. That is the people who work for Mr. Buchanan down at Kennedy. They called and gave him an updated overnight temperature prediction on a two hour basis,
every two hours they gave him what the temperature was going to be.
CHAIRMAN ROGERS: Were any notes or records kept of this conference, or is this all reconstructed from memory?
MR. MASON: Well, I don't know of any specific notes, although there may be. I guess I would have to answer it that way.
I know the calculations that were run. Those calculations exist, because they took those on an every two hour basis, and had started using 18 degrees and then proceeded to use the more updated temperatures, because ultimately we were told it was forecast to be a 29 degree O-ring temperature.
In any event, those concerns that existed were discussed, and they amounted to the fact that the previous coldest launch had given us the greatest blow-by and that, coupled with concern about the stiffer O-ring that would exist at a lower temperature, was the focus of the discussion.
It was just that, a discussion. And so it was decided, and NASA requested that we put together an organized analysis or organize the data and write down what our concerns were, so that it could be reviewed in a more careful fashion.
So there was a telecon then scheduled for 6:15 to do that, and at that point Mr. Kilminster called Mr. Wiggins and me - we were in another meeting in our Brigham City plant - and told us that there were concerns and that the telecon was going to start at 6:15. And so we - -
 MR. SUTTER: Excuse me. A quick question. You had data where you had reached a conclusion. What was the purpose of NASA asking you to better organize that data? Was that for them to review it and reach some of their own decisions, or just to see if your thinking was proper?
MR. MASON: At this point we had not reached a conclusion. During the part that I'm covering here, we had had the discussion.
MR. SUTTER: I still don't understand why they needed the data better organized at this point.
MR. MASON: Well, we were providing it verbally over the telecon. They didn't have it in front of them. And so we were talking about things like curves and that sort of thing, that they didn't have the direct visibility of.
And we had not yet reached any conclusion. We were just saying that we were concerned because it was
cold. So the request was to get that data and fax them down, so that they could look at it at the same time that we were looking at it.
And when Mr. Wiggins and I were notified, they were in the process of putting together what data was needed for the discussion. And at the same time, Mr. Lund was trying to prepare some conclusions and recommendations. So the chart preparation and the conclusions and recommendations were going on simultaneously.
And Mr. Wiggins and I then arrived as that was going on and, as it turned out, we were not able to get all of the charts together in time to start the telecon. We got the first charts faxed down there by 6:30 and the last charts didn't get down there until 7:20.
And so we were working this in a real time basis. We did start the discussion again at 7:00.
(Viewgraph.) [Ref. 2/25-7]
The engineers that had prepared some of the charts discussed their charts, and ultimately Mr. Lund discussed the conclusion and recommendations chart. The fundamental issue, however, was the concern about what effect the cold would have on getting the primary O-ring to move into its sealing position and seal.
And if it needs clarification later, Mr. Lund
has some charts to explain that. But when we run the leak test, the primary O-ring is moved into the furthest point away from its sealing position, and that is maybe 20 thousandths of an inch or so, whereas the secondary is moved towards its sealing position.
And the concern was whether the cold and the stiffness of the O-ring and the grease would delay the movement of the primary O-ring so that it would not seat properly and there would be blow-by and perhaps damage to the secondary O-ring.
We looked at the erosion history we had to see what correlation there was with temperature, and there really wasn't any correlation. There was also a review of the blow-by history, which Mr. McDonald has covered very well, and the correlation that appeared there was that we had blow-by in both 75 and 53 degrees, but it was much more severe at 53 degrees, and so it was thought that that was evidence that the cold did in fact affect the performance of the O-ring.
Now, we looked at data on the hardness of the O-ring as an indication of how stiff and difficult it might be for the O-ring to move.
(Viewgraph.) [Ref. 2/25-8]
And we determined that from 50 degrees to 30 degrees, a 20 degree drop, it would increase the
hardness by about ten percent. In fact, that put it in the range of - when we discussed this that night, early in the program we were deciding what hardness we wanted and we had used some 90 durometer O-rings in some of the hydrostatic tests. We ultimately ended up with the 80 durometer O-ring.
But it was pointed out that we had some experience with that O-ring which was harder.
DR. FEYNMAN: What you mean by hardness is it's difficult to squash it into the tiny crack that it is supposed to go into? What is the feature of hardness? It is not resiliency; it is the difficulty of pushing it into a corner?
MR. MASON: Well, it was thought that that stiffness might make it move more slowly, moving across the gap, and then it would be harder to extrude it in. However, once it sealed, being slower to extrude per se wouldn't be a problem, once it sealed.
The points we're talking about, of course, were the points that were discussed back and forth that night.
We did look at the temperature history on our previous tests and flights, and we discussed the fact that we had run a sub-scale blow-by test at 30 degrees which had shown no blow-by. That was only an indicator,
because that was a cold test and it was with a fixed joint gap, and so it was just another point of data that we had to put in our heads.
MR. HOTZ: Mr. Mason, was that a vertical or a horizontal test rig that you ran the subscale test on?
MR. MASON: I don't know.
MR. HOTZ: Could you find out for us, please?
MR. MASON: Yes, sir. There are several fellows here that know, I'm sure.
VOICE: It was a vertical test rig.
MR. MASON: Out of that discussion, we got to the point where we just - we couldn't make a clear conclusion of the effect of temperature on the O-ring performance. And a number of the engineers felt that on that basis we ought to just stay where we were in our flight history and, with the information we had at that point and as far as we had proceeded in our thought process, that appeared to be the right thing to do.
And so we proceeded to present that information.
CHAIRMAN ROGERS: Isn't it fair to say, though, that all of the engineers felt that way?
MR. MASON: No, sir.
CHAIRMAN ROGERS: Which ones favored - -
MR. MASON: At that point it was not a pro-con
sort of discussion. It was, where are we in our thought process, and where we were in our thought process was that what we've discussed to date says let's stay with our experience.
CHAIRMAN ROGERS: But what I mean is, didn't all the engineers agree with that?
MR. MASON: I would say that at that point we all agreed with that, that it wasn't engineering or anyone else. We had just looked at what we had and went through our thought process, and at that point we felt that that was the recommendation that we got.
CHAIRMAN ROGERS: The position, though, that you took unanimously was the engineering position, was to base the recommendation on previous flight history, and you cite 51-C, which  was the coldest launch that had been made and where you had had the most trouble, isn't that right?
MR. MASON: That's right.
(Viewgraph.) [Ref. 2/25-9]
The next comments then were essentially, as Mr. McDonald said, that Mr. Mulloy said he disagreed because he didn't feel that we had shown any correlation between blow-by and erosion with temperature, and that therefore the rationale that had been used when we decided to fly in the first place was still a valid
And Mr. Hardy expressed surprise at the recommendation because it was above the qualification temperature. However, he said he wouldn't recommend flying against our recommendation.
And then Mr. McDonald came on and said that he too had a concern about the cold, and he pointed out that the secondary O-ring was in the position to seal, where it didn't have to move as the primary did, and that this point ought to be considered.
With that discussion, we were - let's say we felt that we needed to have further discussions to see if these comments would in fact cause us to have any change in our position. And so we decided to do that off the net, and we asked for a caucus.
(Viewgraph.) [Ref. 2/25-10]
Now, in the caucus we revisited all of our previous discussions, and the important things that came out of that was that, as we had recognized, we did have the possibility that the primary O-ring might be slower to move into the seating position and that was our concern, and that is what we had focused on originally.
The fact that we couldn't show direct correlation with the O-ring temperature was discussed, but we still felt that there was some concern about it
We then recognized that, if the primary did move more slowly, that we could get some blowby and erosion on the primary. But we had pointed out to us in that caucus a point that had not come across clearly in our earlier discussions, and that is that we had run tests where we deliberately cut large pieces out of the O-rings to see what the threshold of sealing was, and we found we could go to 125 thousandths of a cut out of the O-ring and it would still seal.
DR. FEYNMAN: Mr. Mason, was that a static test or a dynamic test?
MR. MASON: It is done by blowing the pressure against the O-ring, and it was done both cold and hot.
DR. FEYNMAN: But not in a moving joint?
MR. MASON: That is correct. And I might follow that. Through the whole discussion we were concerned about or we recognized that the O-ring, either primary or secondary, would have to seal before the joint had time to expand.
Now, the gas pressure gets to the O-ring before the joint has a chance to expand. But the question was, with the slower movement of the O-ring, would it still be there and seat before the joint expanded.
MR. HOTZ: Mr. Mason, what kind of time frame were you talking about there, in the time it takes to get there?
 MR. MASON: Well, the charts that we had said that if you seat in 160 milliseconds that - well, let's see. This goes back to that 1R versus 1 discussion we had, that what that boiled down to was that during the first 160 milliseconds the joint is still closed enough that the secondary O-ring actually provides redundancy.
Up to 300 milliseconds, there is less certainty, and above that there is a serious question about that.
Now, again, that chart was based on the worst conditions as far as joint conditions were concerned, that is tolerances. And what we had here we knew was a fairly nominal compression condition.
DR. RIDE: Excuse me. Did you just say that is the first 160 milliseconds that joint is officially classified as a Criticality 1R?
MR. MASON: It is not officially, no, ma'am.
DR. RIDE: That's right. It is just a Criticality 1, so even during the first 160 milliseconds you are not allowed to consider the secondary seal a backup to the primary seal by the critical items list.
MR. MASON: Well, I don't certainly want to
debate that point. What we did, what we considered, we considered that when it was established that it went from 1R to 1 it was identified that we were losing redundancy after the ignition transient.
And we did consider, and that is where I'm headed, that there was some protection during the ignition transient from the secondary O-ring.
CHAIRMAN ROGERS: I'm not sure I understand your answer to Dr. Ride's question.
MR. MASON: Well, let me try again.
DR. RIDE: Well, it sounds to me like you're trying to exercise some kind of engineering judgment on whether you can consider this a 1R or a 1, and I just don't think that the system allows that. I think that once something is classified as a Criticality 1, that sets a red flag in everyone's mind that that is an extremely dangerous situation.
And I'm just not sure that you're allowed to go back and rationalize it as, well, during this 100 milliseconds we may have a secondary seal, we may be allowed to consider it a redundant seal, we may have protection to a Criticality 1 system.
MR. MASON: Well, I really can't address the propriety of it as far as the system is concerned. I would have to state what we did, and we had recognized
when the criticality was changed from 1R to 1 that it was done because we didn't have a fulltime redundant seal.
And at the time of this discussion we were not addressing the thing from a lR/1 viewpoint. We were addressing it from what we knew of how the joint performed, and what we knew was that early in the ignition transient that the secondary in fact did function until the joint rotated.
CHAIRMAN ROGERS: But isn't that in effect changing the critical items list? I mean, as Dr. Ride says - and her list shows there was no redundancy, and if I understand your answer you're saying that, we as a management team decided there was redundancy.
MR. MASON: We did consider that as a factor in our decision process. And let me say first, I didn't get to the thing in the right sequence. Our primary concern and the thing we addressed in our earlier conversation was getting - making sure the primary O-ring would seal.
 And when we had this further discussion it was pointed out that we had run the test which showed that we could tolerate about three times as much erosion in the primary O-ring as we had previously experienced, in
fact experienced in that 51-C, I should say, in that cold test.
So we felt we had a substantial margin because we had the ability to tolerate much more erosion than we had, and that the erosion was driven by the volume of gas that could be passed past that O-ring, and that that we felt was limited, so that it was very unlikely that it could get beyond the three times the erosion, or beyond the three times the erosion we had seen before.
DR. FEYNMAN: Could I ask some questions. Doesn't the erosion partly depend upon the speed of the gas, the size of the hole through which it comes, and other matters? And do you have some kind of calculation that shows that you couldn't get more erosion than the amount that you got in 51-C?
MR. MASON: I don't know whether we have that calculation that tells us what that limit is or not.
DR. FEYNMAN: What made you think that 51-C was the maximum erosion that you could reasonably expect?
MR. MASON: We didn't feel that that was the maximum we could expect. We said that if there was a temperature effect that made it move slower, we might get some more erosion. And we felt that the factor of three times was not likely to be exceeded.
DR. FEYNMAN: Well, let me explain. I'm not interested at the moment in the temperature. I'm going to criticize the original decision that you can operate at 53 degrees, which is a different point of view than what we're talking about, based upon the idea that you've already seen that you have one-third the amount of erosion necessary to split the primary ring at a time when the secondary has a high probability of not being sealable, as Mr. McDonald said.
And I would like to know how you judge, by having seen one-third of an O-ring disintegrated in one flight, that it is very unlikely that you would get three times that erosion on another flight under the same circumstances?
MR. MASON: Well, that is the judgment issue that we finally got down to.
DR. FEYNMAN: I am trying to understand your judgment.
MR. MASON: When we had the previous erosion, to get that we had to fill all of the cavity that was there, all of the annular cavity. So there wasn't any way to get any more, substantially any more gas flow.
DR. FEYNMAN: Doesn't it depend upon the speed of the gas and the temperature? Doesn't it depend maybe upon the complexity of the hole that goes through the
putty, so that it would be a matter of accident how much you got?
Could it, for example, have been that you got one-third the amount of erosion, for instance, because the putty hole was smaller and longer with a reasonable probability?
MR. MASON: Well, the engineers, which are here, have - I don't have off the top of my head the numbers, but we did run tests with focused jets, which focused the most amount, to see how much erosion we would get. And I believe they can do a better job of correlating that than I
I can comment that my understanding of it was that it would appear that, because there is a limited volume and we had looked at what a highly focused jet would erode, that the combination  of that knowledge made us feel that the probability of getting three times the erosion was very unlikely.
DR. FEYNMAN: Thank you.
MR. WALKER: Sir, isn't it true that the amount of erosion you can tolerate actually depends upon the particular rocket motor you're dealing with, because the amount of compression can vary on the particular O-ring depending upon where you are within the tolerances of the two pieces which make up that rocket
And had you analyzed the particular amount of compression on 51-L, these particular joints, to see whether or not that was the average amount of compression and how much erosion of the O-ring you could actually tolerate?
MR. MASON: Yes, we did look at the compression on that testimony joint, and we compared it, as a matter of fact, with the compression that we had had on the previous cold launch. And the compression was essentially nominal. As I recall, it was around 40 thousandths. And so we did consider that.
DR. RIDE: Let me go back to this for just a second. We have got a Criticality 1 system and there is some question in your minds whether it will perform at the temperatures that are predicted at launch. Around 29 or 30 degrees is what you are basing your judgments on.
What test data did you have to show, or any test data at all on joint rotation or the timing function, or even seal erosion, down at 30 degrees, that would allow you to make a reasonable engineering judgment that this Criticality 1 item was safe to fly?
MR. MASON: Well, it was the various items that I mentioned. We had the durometer of the O-ring
down to below 20 degrees. I don't remember exactly, but it was down well below the temperatures. And we could see what the change in durometer was with temperature.
We did have the two tests we had run with the fixed joint at 30 degrees to indicate that the O-ring would seal if it moved in in the right timing.
DR. RIDE: But you said that at the time you weren't putting much emphasis on those tests. For one, they were fixed plates, and for another thing, you were using the argon gas and not the freon by that time.
MR. MASON: We were trying to avoid overemphasizing that test. We wanted to make sure we recognize it wasn't a totally representative test because it didn't have the joint rotation. On the other hand, we felt, because it was at the temperature and did indicate that the O-ring would seal if the timing was proper, so that the O-ring was in position before the joint rotated, we expected the seal - we expected it to seal.
DR. RIDE: Did you have data that indicated how the joint rotated at those temperatures?
MR. MASON: We know how the joint rotates. I don't believe there is any real effect of temperature on the joint rotation. If anything, it would slow it down.
DR. RIDE: Had that analysis been done?
MR. MASON: The joint rotation, the analysis to see what the temperature effect on the joint rotation is?
DR. RIDE: Yes.
MR. MASON: I do not believe that has been done.
 DR. RIDE: How about any tests or analysis to determine what the timing function would be at those temperatures? Had those been done at the time?
MR. MASON: Well, they had not been done at the time. We were in the process of devising the tests to try to establish that.
DR. RIDE: So those tests hadn't been done when you made this decision?
MR. MASON: They had not been done. Well, I had better not go beyond my knowledge of the subject. I don't know personally how far we had progressed.
I can say this. We didn't have enough information that we could quantify the effect of the cold.
DR. RIDE: You said that previously you had a factor of three safety in seal erosion. That sounds to me like you were willing to accept damage to a Criticality 1 system. Did you have any prediction of what the seal erosion would be or any, again, test or
analysis on what seal erosion would be under these conditions, or were you extrapolating from the 53 degree temperature, and did you have a model to do that extrapolation?
MR. MASON: Well, that is a lot of questions. We had done some modeling of the flow in the - the flow effect on the O-ring, and I'm not qualified to really talk about that in detail, but the engineers when they get here can provide more detail on that.
I have lost track. I would try to answer all of your questions. I have lost track. Could you ask me again?
DR. RIDE: Okay. The first one I guess I was asking about was the seal erosion. Do you know whether you had any test data on the seal erosion?
MR. MASON: Well, I know we had a lot of information, as I said, where we had focused, deliberately focused hot gases to see how fast it would erode and what kind of gas flow rates were necessary. And that is on erosion.
DR. RIDE: Let me ask a different sort of question. Were you willing to accept damage to a Criticality 1 system? It sounds as though you were willing to allow erosion on the primary O-ring.
MR. MASON: The answer has to be yes, and let
me explain that. The position we were in is, the first thing that has to happen is you have to have the blow hole through the putty, and our experience is that that happens like five percent of the time. I don't have that number exactly, but if you look at our history in the flight motors that is like five percent of the time.
When that happens, you can either get no effect, just simply hot gas pressurizes the O-ring, or you can get blow-by and then the O-ring seats, or you can get erosion.
And we had erosion, if memory serves me, four times in the some 144 joints that we had had. And so we recognized that we might get some erosion. We also recognized that it was a low frequency event, but the possibility existed, and that if it did happen, we had erosion, that it would in our opinion seal because of the extra margin that we had identified by running the tests on the amount of flow it would take to get enough erosion to actually keep the primary from seating.
DR. RIDE: I guess what I'm really trying to understand is whether you really had the engineering data or an engineering analysis to back up the decision that this Criticality 1 system was safe to fly at those temperatures.
You know, what we've seen in the charts so far is that the data was inconclusive and so you said go ahead.
MR. MASON: I'm sorry, I hope I didn't convey that. But the reasons for the discussion was the fact that we didn't have enough data to quantify the effect of the cold, and that was the heart of our discussion, is how much effect is the cold going to have on the performance.
MR. SUTTER: Could I ask a question? Your engineers with the data they had and with the concern with the temperatures did reach a tentative conclusion at least that, why not wait for at least a temperature that had already been flown. I guess you were responsible, your engineers were responsible, for the design and the testing and qualification of that design, and I would assume the interpretation of the data.
And therefore I am extremely puzzled why a NASA person could disagree and ask you to review the decision your engineers had reached, since it seems to me theirs was the responsibility for the design.
MR. MASON: Well, let's say the request to reassess was not a major factor in my view. The fact that we were picking a temperature based purely on the one test or the one flight, and we had had static tests
at other temperatures, and Mr. McDonald explained why we didn't consider those conclusive - but it was difficult to say that 53 degrees was exactly the temperature that you ought to fly at.
And when Mr. McDonald made the point about the secondary O-ring being in a favorable position, we felt that it was appropriate to consider that point, and that is the reason that we said, well, let's make sure that we have considered everything.
And the two things that came out of that assessment were: One, that we did have - we believed that we had a margin, a substantial margin, of allowable erosion and still have that primary ring seat and seal properly.
We didn't know for sure what the effect of that cold was on the time to move, but we said if in fact it does delay moving and it cause blow-by, then the secondary ring is already in position and the blow-by has to occur - if it occurs, it occurs immediately. The blow-by occurs on pressurization.
And so under those conditions, if you were to have blow-by you would be seating the secondary.
Now, I understand the point about the 1R versus 1. I simply have to be honest and say that that is the way we were looking at it then, that during the
ignition transient that the secondary really could function, and we had never said that it couldn't function on the ignition transient. Even when we wrote the CIL, we had indicated that.
In any event, we did expect the primary to seat. We expected it to seat because we had some tolerance of its ability to erode and still seat and seal. And so that was our thought process.
Now, the discussion was a free and open discussion with all of the people there, and I believe that it was not - well, at that point it was clear to me we were not going to get a unanimous decision. And so the question was, did we have a reasonable position to go to 53 degrees or did we have confidence that we could fly with a 29 degree O-ring.
And the people who were there had heard all of the discussion, and so I concluded it was appropriate to talk, to get a poll of the chief engineer and the chief program manager, and Mr.  Wiggins, who has the division responsibility, to see how they felt, whether they felt that we could safe]y fly with all of the information that had been presented. And we did conduct that poll, and we did conclude that it was safe to launch.
CHAIRMAN ROGERS: Could you tell us what the
poll showed? You say that you and Mr. Kilminster and Mr. Wiggins and Mr. Lund were unanimous. How about the others?
MR. MASON: We only polled the management people, because we had already established that we were not going to be unanimous, and we had already heard -
CHAIRMAN ROGERS: That wasn't the question. The question was what about the others. You testified before that you thought probably all of the engineers were against the launch, and now you say you took a poll and you only polled the managers. You didn't ask the engineers how they felt after their review of the data?
MR. MASON: In that discussion I felt that everyone had represented their opinion, and there were a number that I felt indicated, as we did, that with the consideration of the erosion margin and, well, the very factors that I just talked about, that they also considered that to be a reasonable -
CHAIRMAN ROGERS: Did they express a change of mind? Did they say, well, I've changed my mind?
MR. MASON: Not per se, no. Excuse me, I just feel that it is the kind of discussion that we frequently have, in which all of the people express their opinions and they make them clear.
CHAIRMAN ROGERS: Did you ever have an experience
where all the engineers voted one way and management voted the other?
MR. MASON: That wasn't the case here.
CHAIRMAN ROGERS: What was the case here? It looks that way. It looks as if you said the managers you polled were unanimous and the engineers who were opposed to the launch were still apparently opposed to it.
MR. MASON: There were some engineers.
CHAIRMAN ROGERS: Which ones?
MR. MASON: Mr. Boisjoly and Mr. Thompson were the outspoken ones.
CHAIRMAN ROGERS: I'm asking which ones changed their minds. Before you testified that all the engineers were opposed to the launch, and now you went through this process you've just described to the Commission.
My question is, did any of the engineers change their minds, and if so which ones?
MR. MASON: Well, I would say then that I would have to look at the list here. Based upon the conversations that we had there, I felt that Mr. Macbeth and Kapp were supportive. And Mr. Brinton, who was at Marshall, it is harder to judge, because he didn't have a lot to say.
What we were faced with was that there were the outspoken individuals, and the rest participated to a lesser degree. But I believe that we are familiar enough with the people and their manner to be able to judge their feelings, and we heard what they had to say.
MR. WALKER: Mr. Mason, earlier in testimony in private session, you indicated that Mr. Boisjoly and Mr. Thompson were the most knowledgeable on the seals, is that correct?
MR. MASON: Yes.
 MR. WALKER: Then the two most knowledgeable engineers were still opposed, and my understanding is they were still strongly opposed. Why did you proceed in the light of your two experts being very strongly opposed?
MR. MASON: It's kind of a horse race as to who is the most expert on the subject, because there are different areas of expertise, some on the gas flow and some on the metal parts. We identified that Mr. Boisjoly and Thompson were both generally knowledgeable people on those joints, and they were people whose opinion we regarded.
However, Mr. Kapp has a long history on the joint and he is as knowledgeable in my opinion as they are, and Mr. Sayre to a lesser degree. So I would say
that we felt that, although they were outspoken, we listened to their reasons more than the intensity, and the reasons boiled down to the things that I said. The reason was the uncertainty about the rapidity with which that primary would move.
MR. ACHESON: Did Mr. Russell participate in the conversation, either on the telecon with NASA or in the caucus off-line that followed?
MR. MASON: Yes, he participated in both discussions, it is my recollection.
MR. ACHESON: What were his views as far as you can reconstruct them?
MR. MASON: I felt that he had similar thoughts that we did. He had concern about the uncertainty, but beyond that I would say that he was, if anything, neutral; that he was providing all of the information and was having some difficulty, as were the rest of us, trying to get a decision in which we had confidence.
MR. ACHESON: Now, during the telecon with NASA and during the private caucus off-line did anybody, either at NASA or at Thiokol, mention the change in the critical items list to Criticality 1?
MR. MASON: No, sir, that was not discussed. That was not an issue at that point.
MR. WALKER: I have a question about the temperatures. You said that you decided that 29 degrees was safe to launch. Did the discussion result in some lower temperature limit below which you would not have recommended a launch?
MR. MASON: I'm sorry? Are you saying would we - -
MR. WALKER: Your ultimate recommendation to NASA was that it was safe to launch, and I believe the predicted temperature of the O-rings was 29 degrees.
MR. MASON: That is correct.
MR. WALKER: Did your discussion result in the establishment of a temperature below which it would not have been safe to launch?
MR. MASON: No, we didn't pursue it below that. I think the initial concern when we heard 18 degrees and we were thinking that the O-ring might be that cold, that is how all of the discussion got started, and there was a lot of apprehension at 18 degrees.
And then it was later found that it was going to be somewhat warmer than that, but we didn't pursue the idea of getting any colder than 29 degrees.
MR. WALKER: Well, how critical was this? If the temperature turned out to be 28 degrees, would this
have made a big difference? The recommendation was based upon a prediction. Of course that was only a prediction at the time and you didn't know exactly what the weather was going to do and exactly what the temperature was going to be.
 And I would have thought that the recommendation would have been more specific, so that, depending on the exact conditions which prevailed when the launch occurred, the recommendation would have been one which could have been used to make a decision.
MR. MASON: Well, I can't argue with that reasoning. We were addressing the specific condition, not looking for a threshold.
MR. WALKER: But usually engineering decisions and calculations are pretty exact calculations, and you usually have a very specific number, and that is why there are launch criteria. And those numbers are specific numbers, they are not ranges.
And here evidently you had a range, but you didn't even specify what that range was. Wasn't that rather unusual?
MR. MASON: Yes, I would say it was, the fact that we were focused on that one point, and that is what we were addressing. Normally, if you were earlier, preparing for another launch or something, if the
question came up, you would in fact tend to bracket it.
We were faced with, we felt, a specific condition here, and that is the reason we addressed it that way.
MR. WALKER: So you didn't feel uncomfortable with this position?
MR. MASON: I didn't. I felt that, after we had hashed it out and understood it, that the inability to precisely quantify the movement of that primary O-ring was the concern that we had. And that is the additional knowledge that I would like to have had.
But I felt that, with what the things that I've already pointed out, that we had a reasonable basis for feeling that it was -
GENERAL KUTYNA: Mr. Mason, you have used the word "uncertainty" now four or five times in the last five minutes, and now you've just had the inability to quantify this thing. That is the best thing you had going for you. I mean, every launch has a risk, but you take that risk because something must be achieved.
What was driving here? What was to be achieved that caused you to go?
MR. MASON: Well -
GENERAL KUTYNA: Why couldn't you wait a day?
MR. MASON: Well, as far as waiting a day is
concerned, we wouldn't have gained any more information.
GENERAL KUTYNA: You would have gained temperature.
MR. MASON: That's true. And we had to decide whether we felt that it was safe to fly at 29 in order to respond to the question, should we fly. That was the question we were trying to answer.
MR. HOTZ: Mr. Mason, in responding to the General's question about the use of the word "inconclusive" and "uncertainty," in your whole presentation here today you were basing your decisions on inconclusive and uncertain information. And yet, my understanding of NASA's flight philosophy is that decisions to go or no-go are based on certainties and conclusions.
When did this change in philosophy affect your operations?
MR. MASON: Well, I would have to respond, I think it is a case of degree of uncertainty.
MR. HOTZ: Well, do you allow any degree of uncertainty before you launch?
MR. MASON: I believe that in any case in the design and testing and so forth of the whole system, there have to be some uncertainties. It is a question of
MR. HOTZ: But it seems to me there was a high degree of uncertainty in your calculations here.
MR. MASON: Well, there was.
MR. HOTZ: According to your own testimony.
MR. MASON: Well, that of course is the point that we were struggling with that night, was what degree of uncertainty is there. And the area of uncertainty was the moving of the primary O-ring.
MR. HOTZ: Well, how would you characterize it? A high degree, a low degree, or a medium degree of uncertainty?
MR. MASON: As far as the probability of seating is concerned, I thought there was a low degree of uncertainty.
CHAIRMAN ROGERS: Following up on that, Mr. Mason, Mr. Kilminster when he wrote the telefax said "temperature data not conclusive on predicting primary O-ring blow-by."
Isn't that a very serious statement, saying that it was not conclusive? Isn't that another way of saying that there might be a conclusion that there was going to be primary O-ring blow-by?
MR. MASON: Well, what we did was say, since it wasn't conclusive, we were going to assume that it
would have a negative effect. That is the way we approached it.
CHAIRMAN ROGERS: In other words, this is a statement saying we expect primary O-ring blow-by.
MR. MASON: We said we can't tell how much effect temperature is going to have, and so we had better look at what can happen if in fact it does.
(Viewgraph.)IRt f . 2/~4-~t,I
CHAIRMAN ROGERS: Now, if that is the case, Dr. Ride's question is most relevant, because the critical items list said that you cannot rely on this redundancy. If you're predicting there's a possibility of primary O-ring blow-by, you are violating the critical items list.
MR. MASON: Well, we weren't predicting it, but we were saying because we weren't able to be certain - that the situation we were faced with is we have had blow-by on earlier flights. We had not had any reason to believe that we couldn't experience it again at any temperature.
That is where we were right then. And so we had to say that we can experience blow-by, because we had experienced it, and we had not yet been able to figure out what to do to prevent it. And so we knew that it could happen, and so we had to say, what's the
But even given the low probability, we still had to think, what's it going to mean if it does. And that is what we endeavored to do, was to think, what does it mean if it does, even if it is a low probability.
CHAIRMAN ROGERS: Well, I don't want to continue arguing, but it seems to me, though, that the critical items list says if that is the case it's going to result in a catastrophe, because there is no redundancy. That was the finding as I understand it. Am I correct, Dr. Ride?
DR. RIDE: Well, I guess that, just reading the critical items 'list, what it says is that it is the primary O-ring which is Criticality 1, not a Criticality 1-R.
 MR. MASON: If you just read it in that sense, yes. But if you know how it was generated, which was that it was not redundant full-time, that it was only redundant during the ignition transient and then it was non-redundant once the joint opened up - we knew that. We understood that, and that did enter our thinking.
CHAIRMAN ROGERS: Dr. Feynman.
DR. FEYNMAN: In discussing this idea that the secondary seal will seat, the principle is that is
located in the correct place because of the pressure put on during making a check, which is two days or so before launch. After the check has been made in the VAB building, this machine is put on a carrier and carried, and jiggled and so forth all the way out to the site, and it stands there for two days and is rained upon, and we have found in other cases that water gets into the seals.
Did you consider, when you were discussing these, the probability or the possibility that in all of this jiggling and the water inside there freezing, making ice, that it could have displaced the secondary seal, and that your idea that the secondary seal is in exactly the right place and will seat immediately during the short transient might have even more uncertainty? Were you considering that possibility?
MR. MASON: We were not considering the possibility of ice in the joint. We did not discuss the potential for how much the O-ring might move as a point of rolling it out, although I think the feeling is that that is a pretty stiff joint and doesn't see any real movement.
But we did not consider the possibility of ice in the joint.
CHAIRMAN ROGERS: Mr. Armstrong.
VICE CHAIRMAN ARMSTRONG: Typical approaches to performance expansions, envelope expansions in the case of airplanes or component performance envelope expansions, normally take the position, well, I've flown in these places and, based upon that and my analysis of the results of those flights, I would be willing to go this much farther for the next case.
But yet, your engineering group said they wouldn't be willing to go outside their existing experience base, or recommended that they not originally, and then you said, well, we will go this much more.
Was there before the fact any attempt, let's say, to provide a level of expansion which the company could stand behind?
MR. MASON: Well, there was work under way to get a better understanding of overall performance of that joint and the effect of rotation and the effect of temperature, the program that was kicked off after the August meeting at headquarters, where all of the joint designs and performance was reviewed.
Then there was a program plan put together to look at ways to improve the performance and to get a more full understanding. That was under way. We didn't have the data.
VICE CHAIRMAN ARMSTRONG: The reasons that didn't exist after you had flown, as you say, 144 joints or whatever, could you attribute that to some reason? Was it that you weren't interested or didn't think it was important, or that you didn't have the resources?
How would you characterize the fact that you were only as far along as you were
 MR. MASON: Well, this spans along a fairly long period of time, but there had been a fairly long period where we had made some improvements in the layup of the putty. We had put some controls on the time it could be exposed and that sort of thing.
We were trying to make some changes that were not at risk of going in the wrong direction, but we had high confidence we were going in the right direction, and we were having a long period not having any erosion or blow-by.
In spite of that and in the middle of that period, in the August time period we all concluded that we needed to proceed with an aggressive effort, and so there was, say, a little pull and tug there, in that at that time the performance was running pretty well, but at the same time the analysis said we needed to get on with some improvements.
And we were searching for improvements that we
could prove out without running any risks on the flight.
VICE CHAIRMAN ARMSTRONG: Mr. McDonald stated that he did feel some pressure in this meeting, and would you characterize your own feelings about pressure that may have influenced the decision process in any way?
MR. MASON: I've thought a lot about that, and there was some pressure, but I believe it is in the range of what we normally encounter. Whenever we're taking a position, NASA tests us on that position to explain it, justify it, that sort of thing. And that is the way I perceive we were being tested, is how supportive or how well can we justify our position.
And so we responded in that fashion. Now, I can say, I guess, that I get pressures in a lot of cases, for a lot of decisions, not just from NASA but from many people I deal with, my boss and so forth. And I think that I am able to treat that properly and make a sound decision independent of that.
VICE CHAIRMAN ARMSTRONG: Well, let me be more specific to follow up. Do you think schedule pressure or cost pressure had significant influences in this instance?
MR. MASON: Cost pressure definitely had no bearing on it. From a schedule standpoint, we take a
lot of pride in the fact that we have supported all of the launches to date, and if there was any pressure, we wanted to continue to do the job we had been doing.
And that kind of situation exists every time. We have to say, are we ready to fly or are we not, and we want to be ready to fly, but we want to make sure it's safe.
CHAIRMAN ROGERS: Did anybody get in touch with you, any calls of any kind, urging you to go ahead with this launch?
MR. MASON: No, sir.
CHAIRMAN ROGERS: As far as you know, were any calls made to anybody in Thiokol?
MR. MASON: To my knowledge there were none. The only conversations we had were the ones on the net that have already been reported.
CHAIRMAN ROGERS: Just one other question. Did you realize, and particularly in view of Mr. Hardy's point that they wouldn't launch unless you agreed, did you fully realize that in effect you were making the decision to launch, you and your colleagues?
MR. MASON: Yes, sir.
MR. WALKER: Mr. Chairman, I had two other brief questions.
I would just like to return to your analysis
of the data during your half an hour caucus in regard to the imprecision or uncertainty of the data. Is it not the case that the largest amount of blow-by was associated with the coldest launch, and that point was made by some of the engineers in the discussion?
Why did you not consider that conclusive?
MR. MASON: Well, we did consider it, but we didn't consider it conclusive, simply because we had had blow-by at the warmer temperatures and we had had erosion at varying temperatures.
MR. WALKER: But the largest amount of blow-by was at the lowest temperature.
MR. MASON: Actually, the erosion is more of a concern than the blow-by.
MR. WALKER: In fact, let's turn to the erosion. Mr. McDonald just stated that there was a case earlier in which the primary O-ring on the motor seal was, on the lowest seal, was eroded and only the secondary O-ring prevented a burn-through. And since you could not really rely on the secondary O-ring for the other seals, was that not also a very significant parameter?
I notice that is not mentioned at all in your analysis of your half an hour caucus.
MR. MASON: Of course, we were considering the
joint seal and, as Mr. McDonald pointed out, we had concluded that the most likely cause of the nozzle problem, the nozzle and joint problem, was the fact that we had tested at a low pressure and probably had not had a seal of the primary, we had not confirmed that seal.
And we had subsequently gone to a higher pressure, the 200 psi, to be sure that the seals were proper, rather than be masked by the putty. What we found was that at the lower pressures, down at 100 psi, the putty could actually hold the pressure and so you weren't certain that the primary was seating. So we had to go to the higher pressure, which we knew the putty would not hold, and with that we could be sure the O-ring was seating.
And so our feeling on the nozzle joint was that that problem had been a product of not having proper sealing of the primary O-ring, and it hadn't been tested adequately because it was masked by the putty.
MR. WALKER: But was that incident discussed during this half-hour caucus?
MR. MASON: It was not discussed, no, sir. We were talking about the joint. It was of course known by everyone that that had occurred.
MR. ACHESON: Mr. Mason, can you recall any previous occasion when your at least preliminary advice
to NASA had been not to launch and they wished to go ahead with the launch?
MR. MASON: No, sir, I do not.
MR. ACHESON: Was there any comment made during these conversations that you have described with NASA that this was a very unusual situation? Did anyone, for example, say that, it is odd that the shoe is on this foot?
MR. MASON: No, not in that fashion, no. The situation I felt sure, or feel sure, was clear, because of the conversations that had gone on and the discussions by all of the people about how they felt and the data they had was all on the net. And so it was understood where we were coming from.
MR. SUTTER: Could I ask one question? In the analysis to get ready for launch, there was this one statement that temperature concerns were maybe fuzzy because there was a blow-by or erosion at a 53 degree launch, but there was also one at 75 degrees. And I am just wondering  whether getting blow-by, erosion, at a very good, warm temperature where everything should be working quite well, wouldn't that raise concerns that maybe this system was running quite marginally, and then maybe temperature would really put it in a sub-marginal condition? That is one question.
And the other one I have is, in this package you gave us it looks, as you proceed through the checks of the motors, more erosion and blow-by was occurring more recently than in earlier times, and the design changes, like the reduction in the structural strength of the motors, of the cases, the increase of the thrust - was there a concern at Thiokol that perhaps as time was going on and the system was asking it to perform better, that perhaps a seal was getting in more trouble?
And I'm just trying to understand. Was there that concern, or were you becoming more relaxed?
MR. MASON: I would say when we put it all together in August we indicated that we had a concern and that we needed to work on an improvement. We also in that summary said that we felt that it was safe to continue to fly as long as we had the proper conditions, that is, the 200 psi leak test, proper assembly, and that sort of thing.
And so we endeavored to summarize where we were in that August meeting, because we looked at all three joints, we looked at the field joints, we looked at the nozzle joint, and we looked at the igniter joint.
We looked at all of our history, and including
the history that you have here, and made our assessment and identified that we ought to proceed in an orderly fashion, but aggressively, to make an improvement in the joint.
MR. SUTTER: Well, then in the August meeting, then, were there some ground rules laid down, like good inspections and other conditions to keep flying?
MR. MASON: Yes, and those were identified and those were in place.
MR. SUTTER: Do we have a record of what those conditions were?
MR. MASON: It is in the August 19 briefing that we have provided copies to the Commis-sion on.
MR. SUTTER: Did you cover anything on temperature?
MR. MASON: No. In fact, in the copies that we provided we also put in a February 10th set of pages reflecting the things that had happened since, and in there we said that that is the condition that we should have.
MR. ACHESON: Those are the blue pages, are they not?
MR. MASON: Correct.
CHAIRMAN ROGERS: Dr. Keel?
DR. KEEL: Mr. Mason, in testimony that the
Commission has received in executive session and also in personal notes made available, you were characterized as telling Mr. Lund in this caucus to take off his engineering hat and put on his management hat as part of that final management caucus.
And in fact, in your notes here from your presentation from your charts, you indicate that you have asked them to exercise best judgment and make management recommendation. Since Mr. Lund was your vice president of engineering and since he presented the charts and the recommendations not to launch outside of your experience base - that is, below a temperature of 53  degrees for the O-rings - in the previous 8:45 Eastern Standard Time teleconference, what did you have in mind when you asked him to take off his engineering hat and put on his management hat?
MR. MASON: I had in mind the fact that we had identified that we could not quantify the movement of that, the time for movement of the primary. We didn't have the data to do that, and therefore it was going to take a judgment, rather than a precise engineering calculation, in order to conclude what we needed to conclude.
MR. KEEL: What triggered the caucus that Thiokol asked for, according to the testimony, was the
fact that NASA had expressed surprise and concern about the impact of such a recommendation of not launching below a 53 degree Fahrenheit temperature for the O-ring, and particularly the impact on schedule.
During the 30 minute caucus, was there any part of your discussion that addressed that impact on schedule and what that meant to Thiokol, any management concern on that?
MR. MASON: Well, when you say what - what triggered the caucus was not NASA's expression of concern. In fact, there is a bit of irony, but from my viewpoint the primary trigger was Mr. McDonald's comment about the fact that the secondary was in a preferred position, and that is a point that we had not actively considered in our previous discussion.
DR. KEEL: Well, what's the answer to the question, though? I said we have previous testimony that that is what triggered it. Regardless of what triggered it, considering those concerns were expressed, was there discussion in the Thiokol caucus with respect to schedule and the impact of sticking to a 53 degree Fahrenheit temperature as a launch condition and what that meant?
MR. MASON: No, there was not.
DR. KEEL: No discussion of schedule impact.
MR. MASON: No. We simply addressed the issue of flight safety.
CHAIRMAN ROGERS: Mr. Mason, when you spoke to Mr. Lund and told him in effect to take off his engineering hat and put on his management hat, wasn't that pressure on your part to a subordinate that he should change his mind?
MR. MASON: Well, I hope not, but it could be interpreted that way.
CHAIRMAN ROGERS: Let's adjourn and reconvene at 2:00 p.m. And we plan to have Mr. Boisjoly and Mr. Thompson and Mr. Lund after lunch.
(Whereupon, at 1:00 p.m., the hearing in the above-entitled matter was recessed, to reconvene at 2:00 p.m. the same day.)
[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.2/25-3] MORTON THIOKOL 27 JAN 1986 - MEETING PARTICIPANTS.
 [Ref.2/25-4 1 of 2] 27 January 1986 Chronology at Morton Thiokol (Utah) [Ref.2/25-4 2 of 2] 27 January 1986 Chronology at Morton Thiokol (Utah) (Cont.)
 [Ref.2/25-5] 27 January 1986 Chronology at Morton Thiokol (Utah) (Cont.)
 [Ref.2/25-6] 27 January 1986 Chronology at Morton Thiokol (Utah) (Cont.)
 [Ref.2/25-7] 27 January 1986 Chronology at Morton Thiokol (Utah) (Cont.) [Ref.2/25-8] 27 January 1986 Chronology at Morton Thiokol (Utah) (Cont.)
 [Ref.2/25-9] 27 January 1986 Chronology at Morton Thiokol (Utah) (Cont.)
 [Ref.2/25-10] 27 January 1986 Chronology at Morton Thiokol (Utah)
CHAIRMAN ROGERS: The Commission will come to order, please.
CHAIRMAN ROGERS: Mr. Boisjoly, you are now presently employed by Morton Thiokol?
MR. BOISJOLY: Yes, I am.
CHAIRMAN ROGERS: And how long have you been employed by them?
MR. BOISJOLY: Approximately five and a half years.
CHAIRMAN ROGERS: How many?
MR. BOISJOLY: Five and a half years.
CHAIRMAN ROGERS: And what is your present position?
MR. BOISJOLY: I am a Senior Scientist is my title, and I am basically a staff member to the Manager of Applied Mechanics.
CHAIRMAN ROGERS: And what kind of work have you been doing for the last five years?
MR. BOISJOLY: I have been involved in the joints, I have gone down to the Cape and taken a significant amount of inspections of the solid rocket boosters as they have come back from flights. I have reported on that information, and that information has been used in the flight readiness reviews for the next flights. And I have also participated in some of the
structural analysis, and also was one of the primary drafters of the refurbishment specification on the cases themselves, particularly in the area of the joints.
I have given, made a videotape and have given a presentation at our plant, also at Vandenberg and KSC concerning the inspection characteristics of the joint surfaces themselves. I have been appointed as a member of the Special Seal Task Force that was initiated last August, and I am in that position currently.
CHAIRMAN ROGERS: You have been described in previous testimony as either the leading or a leading expert on the subject of seals and joints in the booster rocket, and I gather Mr. Thompson works with you in this connection?
MR. BOISJOLY: Arnie used to be my supervisor. I used to work for him until approximately two years ago, and I went out of that capacity, like I said, about two years ago.
 CHAIRMAN ROGERS: Mr. Thompson, do you want to give a little background of your own experience? How long have you been with Thiokol?
MR. THOMPSON: I have been with Thiokol 21 years.
CHAIRMAN ROGERS: How many, 31?
MR. THOMPSON: Twenty-one years.
CHAIRMAN ROGERS: And during that time - well, what is your present job?
MR. THOMPSON: I am Supervisor of Structures Design for rocket motor cases, metallic rocket motor cases.
CHAIRMAN ROGERS: How many men work for you now?
MR. THOMPSON: About 25 people.
CHAIRMAN ROGERS: Are they mostly engineers?
MR. THOMPSON: Yes, sir.
CHAIRMAN ROGERS: And have you had extensive experience in connection with the solid fuel booster rocket and the O-rings and the seals that we have been talking about?
MR. THOMPSON: Yes, I would say so. I have been involved for about seven or eight years in the case program. I first came into it right after the first hydroproof of the cylindrical sections.
CHAIRMAN ROGERS: Mr. Boisjoly, do you have engineers working for you or with you?
MR. BOISJOLY: No, I am strictly in a staff position at this present time.
CHAIRMAN ROGERS: Do you want to go back a little bit? You have been doing some extra work in connection with the seals and the O-rings.
Do you want to describe that to the
MR. BOISJOLY: Yes. As a result of my involvement in hardware inspections after the vehicles had flown at Kennedy, I got involved quite heavily in some of the flight readiness reviews that presented problem areas with the seals, namely, the erosion that was going on.
CHAIRMAN ROGERS: Do you want to move the microphone just a little bit closer, please?
MR. BOISJOLY: I was involved in going down to the Cape and inspecting the hardware after it flew, and any of the hardware that experienced problems with the seals, namely erosion, I was also involved in the preparation and sometimes the presentations and flight readiness reviews along with Al McDonald.
CHAIRMAN ROGERS: So you have made some of the actual inspections we have been talking about this morning in connection with erosion and blow-by and so forth?
MR. BOISJOLY: I was the person who was there when SRM-15 was disassembled. I was the person that inspected those joints and reported on those joints, took the samples of the blackened grease, characterized the degrees of arc that the blackened grease existed, directed the photographs taken of the joint, took the
samples for a chemical analysis back to Morton Thiokol for analysis of what the blackened condition actually was, and then prepared the presentations to give to Marshall on the condition of those joints.
CHAIRMAN ROGERS: So you had as much firsthand experience as probably anybody else in the field?
 MR. BOISJOLY: That is correct.
VICE CHAIRMAN ARMSTRONG: Perhaps you could characterize for us the concern and activities that went on with respect to the joints, starting back in the time before the August of 1985 time period, or wherever before that where you should start.
MR. BOISJOLY: Yes.
Just along about SRM-8 or thereabouts - and I could be off a vehicle or two either way - we had previously to that experienced putty going around the end of the clevis and up to the primary O-ring and actually sometimes into the groove, and there was some concern expressed about that situation because the putty has an asbestos filler in it which is a fibrous filler, and the concern was that the fibers might interfere with the sealing capability of the O-rings.
Therefore, a change was made to lay up the putty in a little bit different character on the end of the clevis leg such that when you mate it, you would not
see that characteristic amount of putty down there next to the O-ring. And by observation, that intent was successful because from that time on I never saw putty past the chamfer on the end of the clevis leg, and never around the corner on the radial surface and down toward the seal.
Then we would report on the erosion characteristics on the seals as we observed them. Like I said, we photographed them. We documented the degree of arc of any of the damage, both heat affected and erosion, and the erosion generally is very localized removal of the material in the O-rings, and it goes some distance longitudinally, and as the charts explain that you have, and we would report on that, and that became a focal point for discussion as a problem area for the next flight readiness review.
So basically that was my task at that time.
VICE CHAIRMAN ARMSTRONG: Was there an increase in concern in mid-1985 as a result of the observations that you and others had made?
MR. BOISJOLY: Yes. SRM-15 actually increased that concern because that was the first time we had actually penetrated a primary O-ring on a field joint with hot gas, and we had a witness of that event because the grease between the O-rings was blackened just like
coal for those arc lengths that were described in the charts, and that was so much more significant than had ever been seen before on any blow-by on any joint.
MR. FEYNMAN: When was that flight?
MR. BOISJOLY: That was a year ago last January, and the reason it was so vivid in my mind is because I was at the Cape prior to the launch, giving the presentation to approximately 130 people at the launch facility on the inspection techniques on the joint to be used to ensure that any defects which had been removed from the joint were removed in a manner such that the transition on the defect was very smooth, so that the elastomeric condition of the O-ring could actually get into those imperfections because it had been smoothed out. And being elastomer, it would do just that.
And I remember watching the launch, and the launch - I went out of the VAB, and it was an afternoon launch, my recollection is sometime between 1:00 and 2:00 o'clock in the afternoon, I'm not sure, but it was reasonably cool, but yet I went out without a suit coat. During the presentation of that vehicle, after it was inspected, it was calculated by the folks back at the plant, the heat transfer folks, that the seal temperature would have been approximately 53
degrees for that launch, and that was part of the characterization of the presentation in the flight readiness review for the next vehicle.
Now, that presentation was a very pointed discussion, a very detailed discussion, and quite frankly, I commented to Al McDonald once or twice that had I not been personally there and been personally witnessing what I had seen and presenting what I had physically seen, I don't think we could have been able to convince NASA to continue to fly.
I felt very strong about that fact because I spoke from conviction, and I was challenged by just about everybody in the room about what I had reported, and I was very grateful that I was there and was able to stick by my convictions because I had seen the condition of the joint.
GENERAL KUTYNA: Mr. Boisjoly, on 51-C, you saw a very blackened joint.
MR. BOISJOLY: Two of them.
GENERAL KUTYNA: Well, however, on 61-A, the temperature was 75 degrees, and that has been used to minimize the effects on 51-C, saying that it occurs at warm temperature also.
Would you explain the difference that you saw or heard of between the two joints?
MR. BOISJOLY: Yes. the difference, the SRM-22 that was used as a comparison basis was not one that I saw personally but a junior engineer, or a younger - I shouldn't say junior, but a younger engineer who works for Arnie had actually been at the Cape and seen those joints. I questioned him, and asked him to tell me in his words what he saw. What he told me was that he saw light grayish to dark grayish splotches that occurred over an arc length of approximately 40 degrees.
Then we discussed the photos. He had a photo of that joint, and I had a photo package of the SAM-15, and we put the photos side by side, and you could see that the SRM-15 joint had coal black color where we had photographed it, and the joint was as he described; it was not coal black, it was significantly lighter and a little bit splotchy. The splotchiness wasn't so definitive, but that is how he defined it to me.
Now, on that basis, I concluded, and so presented the night before the launch, that that was extremely significant. It was very significant because it was telling us that temperature was indeed a discriminator, and that although I couldn't quantify what that discriminator was from an actual threshold standpoint, in other words, I couldn't say you can fly
above this temperature. you can't fly below this temperature, I couldn't do that. I don't know of anybody that could do that with the data we had at the time, but I was extremely concerned, and my concern ran deeper than SAM-15. It ran as a result of the SRM-16 nozzle which the primary nozzle was compromised, and we presented that as having never sealed, and as having happened in the ignition transient, in launching that vehicle.
Now, that was characterized as a seal that never sealed because it either was not properly leak checked, because of what was explained before - I shouldn't say not properly leak checked, but it was leak checked at 100 psi, which we knew, we had data that said that putty could mask a leak check at that level. We also postulated that maybe there was nothing wrong with the leak check and maybe in the transfer of the O-ring in the groove, it had simply ridden up on a piece of contamination and never did seal.
But the fact was that now you introduced another phenomenon. You have impingement erosion and bypass erosion, and the O-ring material gets removed from the cross section of the  O-ring much, much faster when you have bypass erosion or blow-by, as people have been terming it.
We usually use the characteristic blow-by to define gas past it, and we use the other term to indicate that we are eroding at the same time. And so you can have blow-by without erosion, you can have blow-by with erosion.
Now, I don't remember the temperature of that particular vehicle, but that turned the gain up very, very high on the seal problem, extremely high in my mind. We were just playing with a dangerous situation.
So you have seen the packages that I have turned in, and you have probably read the memo that I wrote and expressed the concern that I had to make absolutely sure in everybody's mind that management was aware of my concerns, seeing that I was one of the fellows that was most involved with that particular situation.
VICE CHAIRMAN ARMSTRONG: Let me ask, since you are on the task force -
MR. BOISJOLY: Yes.
VICE CHAIRMAN ARMSTRONG: Tell us the history of the establishment of the task force and what they were charged to do.
MR. BOISJOLY: We were charged to look at alternate designs in the joint upstream of the O-rings themselves, and to also look at the seal design as it
relates to the secondary seal. And that was to try to come up with something that would replace the putty, would be of a vented design and assure that we got gas pressurization to the seal, the primary seal, also look at an alternative secondary seal design which would indeed follow the gap opening of the metal parts such that should a primary O-ring be compromised in any manner, that the secondary seal would be in a position because it was in contact with both sides of the metal parts, to be pressurized, pressure actuated, and cause the seal to be effected. And that was the primary task of this team.
VICE CHAIRMAN ARMSTRONG: To what extent were temperature considerations involved in the work of the task force?
MR. BOISJOLY: To the extent that we had run tests, or Arnie actually had them run at the lab, but I was aware of them, we had run tests on O-ring resiliency, and from the team standpoint we ceased to talk about an O-ring and started to talk about seal because some of the seals under investigation are not O-rings; they are cross sections that have metallic leaf springs in them such that you will get a mechanical assist to force the elastomer to remain in contact such that if you did violate a primary seal, you would be
capable of pressurization.
So with that information, we were looking at the whole regime. We were trying to get resiliency data run at the plant since last October, which I mentioned in my statement, and also that night mentioned over the phone, and we had trouble because we kept having machine breakdowns, we kept having priority problems, and here we were, three months later, and we still didn't have the data necessary for us to pursue it even further.
So that night we presented the information on the basis of what we knew, and what we knew - and I feel very strongly about it - is that we had a problem with temperature, and it was away from the direction of goodness, and that is my phrase because I can t quantify it, but I always use that. It is away from the direction of goodness. And we had run tests to show that  the seal never lifted off in a resiliency test at 100 degrees Fahrenheit. We had a data point that night that showed that the seal lifted off in the ignition cycle for 2 1/2 seconds, or 2.4 seconds at room temperature, 75 degrees. We showed that it lifted off and remained lifted off for in excess of 10 minutes, because we stopped the test at 10 minutes at 50 degrees.
Now, with that testing that was run initially, I through my concern and the joints that I had
witnessed, had asked them to please run one more, and that was to back off the instrom machine platens that had compressed the seal 10/1000 inch, and see what happens. And they did that, and it remained seated. That was my comfort zone. I am the one that made the chart that Al McDonald presented at Washington in August which said that if you go from zero to 170 milliseconds, you have a high probability of a good secondary seal. If you go from 170 to 330 milliseconds, you have a reduced probability of a secondary seal. And if you go beyond that point to full pressurization, you most assuredly might not have a secondary seal.
Now, that was based on the information that I had at the time, and I just went in and estimated those from a pressure trace, pressure time trace, and made that judgment. And that was the basis of my concern, and that was also the basis of continuing to fly because it happens - either it happens or it doesn't happen right at the very first threshold of the ignition transient.
VICE CHAIRMAN ARMSTRONG: Mr. Thompson, in your group, were you or any of your people working this problem as well, or aware of this?
MR. THOMPSON: Yes, sir, we were. Right after the January witness of SAM-15, and the disastrous
effects, in my judgment, on the O-ring situation, and seeing lots of soot in both the primary O-rings of the field joints and between the primary and secondary field joints and the nozzle, it appeared to me that some additional tests needed to be run. And as Roger mentioned, the resilience test was one of the first because then, if we were getting soot blow-by by the primary O-ring, we had better be checking and making sure that our secondary is in good shape.
So we devised a test to squeeze an O-ring down a nominal amount and then come off it about two inches per minute in an instrom machine, and I would like to quantify that just a little bit because if one looks at the rate at which the surfaces separate, it is a nonlinear function. It has kind of a toe on it at first, and then it has a fairly high rate over an inflection point, and then kind of comes over the top. And if one takes a secant from time zero to the top point, which is about, oh, 42/1000 at .6 second, that secant was on the order of 3.2 inches per minute.
And the tests that we had run up to this point, including the night that we were discussing this, was 2 inches per minute. And additionally, the concern is if one looks at the steeper slope after you come off the toe through the inflection point, that that slope is
on the order of 10 inches per minute.
So what it means to me, and I hope to others, is that it is a very, very high rate shortly after it comes off, on the order of 100 to 200 milliseconds. So the message I believe, and I tried to convey, was for 100 milliseconds to 200 milliseconds, Roger has indicated 170, you really probably do have a pretty good chance for a seal. Thereafter you do not.
And so, to further answer the question - and I hope I'm not too long - is that blow-by, of course, was an issue. And I set up a series of tests to try and determine the factors that affect  blow-by, such as squeeze, such as temperature, and in fact, attempt to measure the blow-by using argon at first, and then subsequently we changed to freon because it is a better witness.
MR. SUTTER: Can I ask a question about these tests to measure the rate of gap opening, if that is the proper term?
Was this on an actual set of hardware, or was it a test vehicle, and how would tolerances influence that? Could you get quite a varied answer depending upon whether you had a tight joint or whether you had a system that was close to the other end of the tolerance?
MR. THOMPSON: Yes, sir. what we did, recognizing this is, first of all, it was a bench test, it was a three inch piece of O-ring, in fact, two inch piece of O-ring that was squeezed to about a nominal squeeze, which is like 40/1000. Many of our joints have about that squeeze. The particular one in question in the incident was 35/1000, 37/1000. And so we just merely would give it the squeeze, and then back off at the simulated rate that we could do on the instrom machine.
MR. SUTTER: Well, do you think you might get a variation in results on actual flight hardware then, depending upon the various production runs on the cases?
MR. THOMPSON: Yes, sir, we do. In fact, if you have additional squeeze, you not only have the two surfaces, the one surface pushing off, but if it is a lot of squeeze and a small O-ring groove, the side surface of the O-ring probably can also help, and that gives you additional energy to help it respond.
MR. SUTTER: Well, what about the other directions where the tolerances are on the other side?
MR. THOMPSON: We investigated tolerances and gaps, and we have set up a matrix to do that very thing. This was kind of a preliminary test we had run, and as Roger mentioned, we have refined the tests and
have some results now, but after the fact, and the tests included squeeze and included temperature, and it also, the variable rate that we think we really have in the motor, we have simulated that by input, using a function generator as an input to the instrom machine so that we could generate the actual motion as we saw it.
MR. SUTTER: But with the fact that the testing is somewhat late and that there's a lot of variables and there's been a lot of commentary on temperature, could you come up with a situation where temperature and tolerances could develop a submarginal joint and that of the 144 cases that have been fired, you could run the gamut from having very good ones to very bad ones?
MR. THOMPSON: Yes, sir, we could. We ran, as I say, a preliminary run that showed that it was a problem.
MR. SUTTER: But would all of the parties be aware that you could have wild variations, then, that - and couldn't this develop quite a concern on everybody's part that the system was pretty tender?
MR. THOMPSON: In my feeling, the system was tender, and this is the reason I objected that night.
MR. BOISJOLY: That was the point we tried to make that night, is because we didn't have sufficient
 MR. SUTTER: Well, my question gets around to why wouldn't everybody have that feeling that the situation was very tender, and why wouldn't everybody develop a feeling of great concern, and then by that means develop a very, very conservative attitude toward approaching a launch?
MR. BOISJOLY: That is what we thought happened when the original conclusions and recommendations were made because they were quite consistent with what we had presented prior to the meeting and prior to making the charts.
CHAIRMAN ROGERS: Can I interrupt just a second? I would like to come to the night of the launch and the launch itself, or the decisions, in a little while, but I would like to go back just a minute to some of the background before we get to that point, to show your concern as expressed to management.
I have here a letter which appears to be one signed by you dated July 31, 1985. And I will ask Dr. Keel to give it to you.
And I gather from the files that we have received from you, you wrote a series of letters or memos, I guess memos is a better way to describe it.
MR. BOISJOLY: Those were activity reports.
CHAIRMAN ROGERS: Expressing your concern about this problem of the seals and the O-rings and so forth.
And I would ask you, if you don't mind, to read that memorandum dated July 31, which you wrote to R. K. Lund, who is Vice President of Engineering. [Ref. 2/25-11]
Would you mind?
MR. BOISJOLY: Yes.
"This letter is written to ensure that management is fully aware of the seriousness of the current O-ring erosion problem in the SRM joints from an engineering standpoint. The mistakenly accepted position on the joint problem was to fly without fear of failure and to run a series of design evaluations which would ultimately lead to a solution or at least a significant reduction of the erosion problem.
"This position is now drastically changed as a result of the SAM-16A nozzle joint erosion which eroded a secondary O-ring with the primary O-ring never sealing. If the same scenario should occur in a field joint (and it could) then it is a jump ball as to the success or failure of the joint because the secondary O-ring cannot respond to the clevis opening rate and may not be capable of pressurization. The result would be a catastrophe of the highest order - loss of human life.
"An unofficial team (a memo defining the team and its purpose was never published) with leader was formed on 19 July 1985 and was tasked with solving the problem for both the short and the long term. This unofficial team is essentially nonexistent at this time. In my opinion, the team must be officially given the responsibility and the authority to execute the work that needs to be done on a non-interference basis (full time assignment until completed).
"It is my honest and very real fear that if we do not take immediate action to dedicate a team to solve the problem with the field joint having the number one priority, then we stand in jeopardy of losing a flight along with all of the launch pad facilities."
Then I signed it, and a manager that I worked for countersigned it as concurred.
CHAIRMAN ROGERS: Thank you.
 I assume, Mr. Thompson, you agree with the contents of that memorandum?
MR. THOMPSON: Absolutely, yes, sir.
CHAIRMAN ROGERS: Unless the Commission has any further questions, I would like to now go to the January 27 and January 28, to ask you, Mr. Boisjoly, to describe in your own words your first involvement in those discussions and what was said, who took part, and your position, and later on, your position.
MR. BOISJOLY: Okay. My first -
CHAIRMAN ROGERS: And can I say to you also, just before you start - I'm sorry to interrupt, but you did make notes on the 27th about the events at that time?
MR. BOISJOLY: Yes, I did. I made them after the meeting. [Ref. 2/14-15]
CHAIRMAN ROGERS: But on the same day.
MR. BOISJOLY: Yes, and then I made a few more notes on the day of the launch, prior to the launch, and then I made a short entry after the launch.
CHAIRMAN ROGERS: But the notes on the 27th and the 28th were made on those days?
MR. BOISJOLY: Yes, they were.
CHAIRMAN ROGERS: And the last one was made
after the accident?
MR. BOISJOLY: That is correct.
CHAIRMAN ROGERS: In your discussion you may refer to those notes, and if you have no objection, we may make them public.
MR. BOISJOLY: I kind of just paraphrased them and made them on three by five cards, but I think they essentially have the content of what is in those notes - my first knowledge about any temperature concern on the launch was approximately 1:00 p.m. on the 27th of January. There was a preliminary meeting held to discuss the concern at the low temperature for resiliency, soot blow-by, previous launch and static test temperatures, and there were several, well, there were quite a few people in that meeting, most of whom were engineers, some of whom were program management. I don't remember the names, honestly.
Anyway, that meeting concluded with the tempo that there was a valid concern for temperature, low temperature. I also heard sometime afterwards that it had been cold for several days, and what really impressed me about this piece of information was that it was opposite what SRM-15 had experienced, and that concerned me because when I got off the plane a year ago last January for the SRM-15 launch, it was very cold,
like 17 or 18 degrees when I got off the airplane at Orlando. The next few days, although it remained cold, it got warmer, and by launch time, like I said, it was probably in the 60s, but it did get warmer.
Now, what was concerning me about this piece of information was it was the reverse, it had been cold for several days and was getting colder. And that is why I noted that because that just turned the gain up on my concern because that was away from goodness again. SRM-15 that I am referring to was the coldest launch up to that point in time.
Okay, I felt we were very successful in convincing engineering and management of the problem. By now we heard that the overnight low was predicted to be 18 degrees Fahrenheit, and again my concern deepened because of what I just spoke, it was going the wrong direction from the past experience base.
A telecon was set up with Marshall Space Flight Center and Kennedy Space Center to present data over our concern about the low temperature. Now, there had been some meetings  in between, and quite frankly, I am almost a total blank because I was down in my office, I ran a calculation that showed that the O-ring shrinkage due to low temperatures and dropping from 75 degrees to 25 degrees, it was just a rough number, was
3/1000 inch, and that was due to both the shrinkage on the diameter and the effect of temperature stretching it around its circumference and thus causing the diameter to shrink down again. There was roughly a fifty-fifty split in those numbers, but the bottom line was it was about 3/ 1000 inch.
Okay, that shows me that squeeze wasn't really an effect. Squeeze was not an issue. It never has been an issue with me because if you look at all the eroded O-rings, they don't correlate with squeeze. The O-rings that you would expect to be eroded are those that have the lowest squeeze, and that is not the case. So squeeze was never an issue, but I ran the numbers anyway to assure myself that it was okay, which it was.
Okay, the telecon data - and I must emphasize this. We had very little time to prepare data for that telecon. When it was decided in a group in our conference room that we would take a systematic approach and assigned certain individuals certain tasks to prepare, we all scurried to our individual locations and prepared that information in a timely manner. That is why the charts for the most part are hand printed or hand written, because we didn't have time to get them even typed.
Each person during the telecon presented their
own charts. Just for the record, I presented Charts 2-1, 2-2, 2-3, and I also presented 3-1, which I did not prepare but which was sequenced right after one that I did, and I was asked just to present it, which I did. I presented 4-1 and 5-1. I expressed deep concern about launching at low temperature. I presented Chart 2-1 with emphasis - now, 2-1, if you want to see it, I have it, but basically that was the chart that summarized the primary concerns, and that was the chart that I pulled right out of the Washington presentation without changing one word of it because it was still applicable, and it addresses the highest concern of the field joint in both the ignition transient condition and the steady state condition, and it really sets down the rationale for why we were continuing to fly. Basically, if erosion penetrates the primary O-ring seal, there is a higher probability of no secondary seal capability in the steady state condition. And I had two sub-bullets under that which stated bench testing showed O-ring not capable of maintaining contact with metal parts, gap, opening rate to maximum operating pressure. I had another bullet which stated bench testing showed capability to maintain O-ring contact during initial phase (0 to 170 milliseconds of transient). That was my comfort basis of continuing to fly under normal
circumstances, normal being within the data base we had.
I emphasized when I presented that chart about the changing of the timing function of the O-ring as it attempted to seal. I was concerned that we may go from that first beginning region into that intermediate region, from 0 to 170 being the first region, and 170 to 330 being the intermediate region where we didn't have a high probability of sealing or seating.
I then presented Chart 2-2 with added concerns related to the timing function. And basically on that chart I started off talking about a lower temperature than current data base results in changing the primary O-ring sealing timing function, and I discussed the SRM-15 observations, namely, the 15A motor had 80 degrees arc of black grease between the O-rings, and make no mistake about it, when I say black, I mean black just like coal. It was jet black. And SRM-15B  had a 110 degree arc of black grease between the O-rings. We would have low O-ring squeeze due to low temperature which I had calculated earlier in the day. We would have higher O-ring shore hardness, and that is the characteristic similar to the hardness test that is done on metal except that it has a different anvil size, and when you press against the elastomeric material, that is
the measure of how far a standard size anvil will go into the particular elastomer, and it gives you a measure of relative hardness of the substance.
Now, that would be harder. And what that really means basically is that the harder the material is, it would be likened to trying to shove a brick into a crack versus a sponge. That is a good analogy for purposes of this discussion. I also mentioned that thicker grease, as a result of lower temperatures, would have a higher viscosity. It wouldn't be as slick and slippery as it would be at room temperature. And so it would be a little bit more difficult to move across it.
We would have higher O-ring pressure actuation time, in my opinion, and that is what I presented. If action time - and these are the two. These are the sum and substance of what I just presented. If action time increases, then the threshold of secondary seal pressurization capability is approached. That was my fear. If the threshold is reached, then secondary seal may not be capable of being pressurized, and that was the bottom line of everything that had been presented up to that point.
CHAIRMAN ROGERS: Did anybody take issue with you?
MR. BOISJOLY: Well, I am coming to that. I
also showed a chart of the joint with an exaggerated cross section to show the seal lifted off, which has been shown to everybody. I was asked, yes, at that point in time I was asked to quantify my concerns, and I said I couldn't. I couldn't quantify it. I had no data to quantify it, but I did say I knew that it was away from goodness in the current data base. Someone on the net commented that we had soot blow-by on SAM-22, which was launched at 75 degrees. I don't remember who made the comment, but that is where the first comment came in about the disparity between my conclusion and the observed data because SRM-22 had blow-by at essentially a room temperature launch.
I then said that SRM-15 had much more blow-by indication and that it was indeed telling us that lower temperature was a factor. This was supported by inspection of flown hardware by myself. I was asked again for data to support my claim, and I said I have none other than what is being presented, and I had been trying to get resilience data, Arnie and I both, since last October, and that statement was mentioned on the net.
Others in the room presented their charts, and the main telecon session concluded with Bob Lund, who is our Vice President of Engineering, presenting his
conclusions and recommendations charts which were based on our data input up to that point. Listeners on the telecon were not pleased with the conclusions and the recommendations.
CHAIRMAN ROGERS: What was the conclusion?
MR. BOISJOLY: The conclusions were that we should not fly outside of our data base, which was 53 degrees. Those were the conclusions. And we were quite pleased because we knew in advance, having participated in the preparation, what the conclusions were, and we felt very comfortable with that.
MR. ACHESON: Who presented that conclusion?
 MR. BOISJOLY: Mr. Bob Lund. He had prepared those charts. He had input from other people. He had actually physically prepared the charts. It was about that time that Mr. Hardy from Marshall was asked what he thought about the MTI recommendation, and he said he was appalled at the MTI decision. Mr. Hardy was also asked about launching, and he said no, not if the contractor recommended not launching, he would not go against the contractor and launch.
There was a short discussion that ensued about temperature not being a discriminator between SRM-15 and 22, and shortly after, I believe it was Mr. Kilminster asked if - excuse me. I'm getting confused here. Mr.
Kilminster was asked by NASA if he would launch, and he said no because the engineering recommendation was not to launch.
Then MTI management then asked for a five minute caucus. I'm not sure exactly who asked for that, but it was asked in such a manner that I remember it was asked for, a five minute caucus, which we put on - the line on mute and went offline with the rest of the net.
CHAIRMAN ROGERS: Mr. Boisjoly, at the time that you made the - that Thiokol made the recommendation not to launch, was that a unanimous recommendation as far as you knew?
MR. BOISJOLY: Yes. I have to make something clear. I have been distressed by the things that have been appearing in the paper and things that have been said in general, and there was never one positive, pro-launch statement ever made by anybody. There have been some feelings since then that folks have expressed that they would support the decision, but there was not one positive statement for launch ever made in that room.
Picking up where the caucus started -
CHAIRMAN ROGERS: Excuse me. Is that your recollection, too, Mr. Thompson?
MR. THOMPSON: Yes, particularly in the
caucus. I think Roger and I were the only people that expressed our views.
CHAIRMAN ROGERS: But nobody expressed a view that you should proceed with the launch at that time?
MR. THOMPSON: Not amongst the people that I was able to hear.
GENERAL KUTYNA: Mr. Boisjoly, you said there was some confusion in your mind as to Mr. McDonald's position at the time he came out with the comment about the secondary ring seating, that you should consider that?
MR. BOISJOLY: That is correct. When Al first came on the line and explained the situation about the primary and secondary O-ring and how the secondary O-ring was in position, I had a flash of confusion in my mind as to what he was saying, but I, having worked on the SRM-15 presentation and the SRM-16 presentation, realized exactly what he was trying to say. But I did have that tinge at the beginning, and so there was definite misunderstanding about Al's statement, there's no question in my mind, because I had it, and I was probably closer to that joint than most anybody else, and I had that tinge, and I so stated that to you.
Okay, the caucus was started by Mr. Mason stating that a management decision was necessary. Those of us who
were opposed the launch continued to speak out, and I am specifically speaking of Mr. Thompson and myself because in my recollection he and I were the only ones that vigorously continued to oppose the launch. And we were attempting to go back and rereview and try to make clear what we were trying to get across, and we couldn't understand why it was going to be reversed.
 So we spoke out and tried to explain once again the effects of low temperature. Arnie actually got up from his position which was down the table, and walked up the table and put a quad pad down in front of the table, in front of the management folks, and tried to sketch out once again what his concern was with the joint, and when he realized he wasn't getting through, he just stopped.
I tried one more time with the photos. I grabbed the photos, and I went up and discussed the photos once again and tried to make the point that it was my opinion from actual observations that temperature was indeed a discriminator and we should not ignore the physical evidence that we had observed.
And again, I brought up the point that SRM-15 had a 110 degree arc of black grease while SRM-22 had a relatively different amount, which was less and wasn't quite as black. I also stopped when it was apparent
that I couldn't get anybody to listen.
DR. WALKER: At this point did anyone else speak up in favor of the launch?
MR. BOISJOLY: No, sir. No one said anything, in my recollection, nobody said a word. It was then being discussed amongst the management folks. After Arnie and I had our last say, Mr. Mason said we have to make a management decision. He turned to Bob Lund and asked him to take off his engineering hat and put on his management hat. From this point on, management formulated the points to base their decision on. There was never one comment in favor, as I have said, of launching by any engineer or other nonmanagement person in the room before or after the caucus. I was not even asked to participate in giving any input to the final decision charts.
I went back on the net with the final charts or final chart, which was the rationale for launching, and that was presented by Mr. Kilminster. It was hand written on a notepad, and he read from that notepad. I did not agree with some of the statements that were being made to support the decision. I was never asked nor polled, and it was clearly a management decision from that point.
I must emphasize, I had my say, and I never
take any management right to take the input of an engineer and then make a decision based upon that input, and I truly believe that. I have worked at a lot of companies, and that has been done from time to time, and I truly believe that, and so there was no point in me doing anything any further than I had already attempted to do.
I did not see the final version of the chart until the next day. I just heard it read. I left the room feeling badly defeated, but I felt I really did all I could to stop the launch.
I felt personally that management was under a lot of pressure to launch and that they made a very tough decision, but I didn't agree with it.
One of my colleagues that was in the meeting summed it up best. This was a meeting where the determination was to launch, and it was up to us to prove beyond a shadow of a doubt that it was not safe to do so. This is in total reverse to what the position usually is in a preflight conversation or a flight readiness review. It is usually exactly opposite that.
DR. WALKER: Do you know the source of the pressure on management that you alluded to?
MR. BOISJOLY: Well, the comments made over the net is what I felt, I can't speak for them, but I
felt it - I felt the tone of the meeting exactly as I summed up, that we were being put in a position to prove that we should not launch rather than being put in the position and prove that we had enough data to launch. And I felt that very real.
DR. WALKER: These were the comments from the NASA people at Marshall and at KSC?
MR. BOISJOLY: Yes.
MR. FEYNMAN: I take it you were trying, you were asked to prove that the seal would fail?
MR. BOISJOLY: Yes.
MR. FEYNMAN: And of course, you couldn't, because as a matter of fact it didn't. That is, five of them didn't, and only one of them did, and if you had proved that they would have all failed, you would have found yourself incorrect and under criticism because five of them didn't fail.
MR. BOISJOLY: That is right. I was very concerned that the cold temperatures would change that timing and put us in another regime, and that was the whole basis of my fighting that night.
MR. FEYNMAN: It is just that the probability had been increased to a point where it was intolerable?
MR. BOISJOLY: That's right.
MR. ACHESON: Mr. Boisjoly, your correspondence in the summer of 1985 indicates that the
heightened sensitivity to the O-ring problem at Thiokol was really initiated by heightened sensitivity about it at NASA, and for example, reference is made to the problem that has escalated so badly in the eyes of everyone, especially our customer, NASA.
Now, was any mention made during the telecon net with NASA the evening of January 27 of how the NASA view had moved from this heightened sensitivity to the O-ring problem to the position that they were now putting forward at the January 27 telecon?
MR. BOISJOLY: No, that wasn't mentioned, but in fact, they were just as concerned as we, our counterparts that we worked with, that they were right on top of the seal task force team with us, and we had status reviews going on all the time. In fact, when any time we would hit a situation where they felt we weren't going quick enough, we ended up having a visit, and they would just be there and watch over our shoulders and make darned sure that we were proceeding in a timely manner. And so that to me told me that they were just as concerned about it as we were.
DR. WALKER: Mr. Boisjoly, could you tell me something more about the task team that was set up? You alluded to it in your letter of 31 July, and you asked that that team be reconstituted and made more urgent.
Did that happen?
MR. BOISJOLY: In a way.
DR. WALKER: Who was on that team?
MR. BOISJOLY: Don Ketner headed the team up. I was a member. Brian Russell was a member.
DR. WALKER: Were there any NASA members?
 MR. BOISJOLY: They had a counterpart team, yes. They had members of their team. Our main interface was with a gentleman named Jerry Peoples and Ron McIntosh, but they had their folks involved also.
DR. WALKER: You had meetings with representatives from both NASA and Thiokol?
MR. BOISJOLY: Yes, we did, when we outlined the plan on how we were going to proceed to fix this problem, they were part and parcel to that plan.
DR. WALKER: Now, this is the team that evolved a number of solutions to this problem, some of which have already been publicized.
MR. BOISJOLY: That is correct.
DR. WALKER: And some of those solutions were short term solutions, and others were long term solutions?
MR. BOISJOLY: We categorized them, at least I did in all my notes, as short term solutions, medium term solutions and long term solutions. And to give you
a flavor for what put what in what category was I considered a short term solution, for instance, a 292 diameter O-ring which would have afforded us 12/1000 more squeeze and still not have an overfill condition in the groove with the elastomeric material. Also couple that with selective shimming that would make the tang and clevis more concentric to one another, and take as much of the free volume gap on the outside away to make sure that we were putting more and more squeeze on the O-ring and less and less chance for the gap to open up to the rate that it is opening.
DR. WALKER: Do you have some estimate of how long the short term solutions would have taken?
MR. BOISJOLY: Yes. We had assembly tested a 292 O-ring in some static motor joints - excuse me, some inert motor joints, and put them together and found that we had good success with that. They are currently installed in the aft two field joints of the QM-5 test motor that was ready to fly or fire about two weeks ago at our plant. And so we had made that progress, and we were well on our way to showing that those seals would work in a joint.
And I must emphasize that the QM-5 motor is a filament wound case motor, and it is a joint with a capture feature on it that doesn't have the gap
opening. But the major issue on the 292 O-ring was the assembly characteristics of it, and we were getting like 12/1000 inch squeeze for free. Basically that was the short term issue that we could implement as quick as possible.
DR. WALKER: Did the team report on a regular basis to both NASA and Thiokol management?
MR. BOISJOLY: We had status reports with the Marshall folks at regular intervals, and we had a Friday teleconference at mid-day and statused the proceedings of that previous week with them.
DR. WALKER: So everyone in the telecon on January 27 was aware of the work of this team, the solutions that it had proposed?
MR. BOISJOLY: I don't know that everyone was, but there were a number of people that were, yes. I don't know. I cannot make the statement that everybody that was on the telecon knew about that. For instance, I had never heard Cecil Houston's name before. I didn't know that he was a Marshall type until I heard on the telecon afterwards that he was down at KSC. I had not met that gentleman, so I don't know if he knew it or not. And I don't know if some of  the other folks knew, but there were enough folks on that telecon that knew what the status was.
DR. WALKER: What about Mr. Malloy and Mr. Hardy? Do you know if they knew?
MR. BOISJOLY: I don't have sure knowledge of that, no, I don't know.
MR. FEYNMAN: I want to get away for a moment from the temperature question which comes up later, and go back to the earlier time when you were worrying about these things, and I would like to know whether already you felt that there was a serious problem in flying even at 53 degrees, where the following logic is possible, perhaps. And you can correct me.
If their primary ring would start to erode and would take enough time to erode that it takes, the pressure builds up to 600 psi or so, then if there is joint rotation from the result of that, the secondary seal may fail, if the erosion would get all the way through the primary seal. The erosion got through a third of the way of the primary seal in fact in 15C.
Do you feel that you understand the process of erosion well enough to know that it was unlikely to go three times as far?
MR. BOISJOLY: I think we need to clarify one thing. One third of the seal was not eroded. One third of the allowable erosion number occurred, and you really have to clarify that because we are talking about a seal
diameter that is 280 in diameter, okay, and we really eroded about 32/1000 inch on SAM-15, and the factor of three is being used against subscale data which showed that we were able to seal an eroded seal on a subscale rig that had 10 inch diameter seals, that up to an eighth of an inch. Then we had a window where we failed to seal, and then we had another one up to I believe it was 145/1000 or 147/1000 of an inch that also sealed.
And now, the analysis from the gas dynamics standpoint, which is out of my area, had been conducted, and they found an excellent math model of that erosion process, and it correlated extremely well with the subscale test data which had been run about a year before, and there were 27 tests that characterized that erosion. They ran most of them at 3 seconds, and then my recollection is there was one or two 5 second tests and one or two 20 some odd second tests to show that it was indeed at ignition transient, and what that test was all about was they had a metal orifice with a rectangular orifice that was 40/1000 wide and had different characteristic heights, and they ran a parametric study using those tests, that test rig, and determined what the erosion rate, or not the rate, but the erosion depth was as a function of the orifice
Then the math model was made and characterized that, and my recollection is they were within 12 percent of all of the test data, and they were very pleased at the characterization analytically of what was going on.
So from an erosion standpoint. I think it is fair to say that there was indeed sufficient margin, but that was not the issue. Erosion was not the issue. What was the issue is can you stand a longer period of time in an attempt to seal before the erosion eats you alive and you don't have a seal, period? Because once you get flow you have two types of erosions. You have blow-by erosion and impingement erosion. The 27 tests characterized impingement erosion only. There were no blow-bye in that.
 And I might say, too, we ran tests on that same rig without an orifice and pressurized it exactly the same way on an unprotected O-ring, and there was not even the sheen missing on the O-ring. So the analysis characterized that very well and they understood it very well.
What it is, it is a volume filling problem as a function of time. The higher the volume, the more the time the hot gas flows, if you have a blow-by through the putty, that will enable you to get erosion, and I felt
very confident they had a good analytical handle on that.
MR. FEYNMAN: Thank you. I have another question now on the other side, which is that blow-by early on, that is, in the first whatever you call it, 170 milliseconds, during which it was supposed that the secondary ring would be close enough to the right place to be sealed, but now I am going to talk about the lower temperature.
Under those circumstances where the thing is standing around and it has no resilience, and in fact, when the engine goes off it swings or twangs back and forth and there are various stresses that have been there since the time the ring has been pushed into place by the test, which I now discover was 28 days earlier, not just three days earlier; isn't it possible that the secondary ring has gotten squoze or squeezed to a smaller size than it should be, and then when it bends back it leaves a hole, that there is no 170 milliseconds at all, that it is already too small because it has so low a resilience time and it takes so long to respond after it has been squeezed.
MR. BOISJOLY: That is possible. I had done a series of tests relating clevis opening problems back about three years ago where we had experienced a
phenomenon where the clevis was opening up, oh, maybe 3/1000 to 5/1000 inch over its original manufactured dimensions, and we tried to run that down and pin that down as to where that came from, and in the attempt to do that I ran a series of tests which took an empty cylinder segment, and I actually characterized when it was round what happened to the clevis, when I ovalized the case what happened to the clevis, when I took the case and put shims underneath the longitudinal direction, what happened to the clevis, and characteristically with very large numbers, like when I ovalized it to a value of approximately an inch, I could only affect the clevis gap opening say several thousandths of an inch.
And so, even though you get motion, it was not characterized as a major motion relative to the squeeze that we had. But in reference to temperature, which is what you are talking about, yes, you could have very well had that situation.
MR. HOTZ: Mr. Boisjoly, we have had some data, you probably know, on experience with water accumulating in the field joint while it is standing out there on the stack. As Dr. Feynman pointed out, 51-L stood out there for 28 days during which there were some heavy rainstorms, wind driven rain.
What would be the effect - and then we also had cold temperatures the night before and a couple of nights earlier. What would be the effect if water accumulated in the field joint and then froze during these hard freezes?
MR. BOISJOLY: Well, first of all, I had no prior, prelaunch knowledge of that occurring. I have since found out that there was a vehicle that they changed out one of the segments, and when they pulled the pin, water poured out of the joint. I did not know that prior to the launch.
We have been looking at that since the incident and actually have run a test, and the effect on the actual opening of the clevis, the actual spreading of the clevis itself was almost  nonmeasurable, and we attribute that I guess to the fact that you cannot fill the joint, by configuration, all the way up to the secondary O-ring.
Now, if you postulate that there was enough grease in there and you actually moved the grease with the ice, then you could move the O-ring. But that is speculation at this point. It looks from the design configuration of the joint that if you filled the joint with water, you would still have an air column that would probably be on the order of 5/8 to 7/10 inch high,
and you would simply compress the air column. And it appeared like you wouldn't be able to generate enough pressure to transfer the ring.
But in all fairness, we are running tests to find that out. We haven't completed them yet, or I should say Marshall is doing that.
MR. ACHESON: Mr. Boisjoly, were you at Thiokol when the design of the joint for these SRMs was developed?
MR. BOISJOLY: No, I was not.
MR. ACHESON: But you were there when SRM-8 was fired, were you not?
MR. BOISJOLY: Yes, I was there when SRM-1 was fired.
MR. ACHESON: Can you account for what appears to be a concentration of erosion and blow-by cases in these O-rings following SRM-8 as opposed to prior to SRM-8?
MR. BOISJOLY: That has been a topic of much discussion over the years, and there was a putty change. The original putty was a Randolph putty, and then they simply stopped making it - no, excuse me, not Randolph, Fuller-O'Brien, excuse me - and they simply stopped making it, and then we switched to a Randolph putty, and that is a simultaneous general area of time
sequence with the changes in the layup of the putty to bring it back around from the edge of the clevis so that we were sure there wasn't any putty down by the O-ring. But that hasn't fully tied together either because the first erosion that was ever indicated, to my knowledge, was on SRM-2, or STS-2, the second flight. In fact, the second flight had the most erosion of any of the O-rings in the field joint.
So we have been struggling with that because the data appears just totally random. If you look at the degree locations, if you look at the temperatures, if you look at - it is random in regards to erosion per se.
MR. ACHESON: Were you at Thiokol when the Critical Items List was amended in December 1982 to make it a Crit 1 instead of a Crit 1R?
MR. BOISJOLY: I was at Thiokol at that time, but you know, I don't even know what a CIL is. I am hearing all of this for the first time. I just don't know.
VICE CHAIRMAN ARMSTRONG: I would like to ask Mr. Thompson, from your point of view in the engineering group, did you feel that perhaps particular constraints needed to be established on the operation of the motor and the case and its joints that hadn't been, and for
example, temperature related or other function related? And was that passed up the line at all?
MR. THOMPSON: Yes, I did feel impressed to, back in the times of STA-1, which was structural test article, STA-1 structural test article, we discovered that the joint was opening up rather than closing as our original analysis had indicated, and it was up to 52/1000 at that time, for the primary O-ring. And in fact, it was quite a bit. I think at that point, at that same meeting, we went to Marshall and discussed the problem, and we also indicated, in fact, I think it was me that indicated that the secondary O-ring in certain worst on worst conditions pressurized  even without resilience considered, could be opened, could be noncontact with the adjoining surface.
And so we have been working with these problems for the last several years. And of course, you can immediately see our response, both Roger and myself, we know that we need an elastomeric seal very badly, more so than in many hydraulic applications, because if you look at the usual, probably a dynamic seal, but nonetheless, the requirements were for a 70 durometer O-ring at 1,000 psi. People want to talk about 6/1000 or 7/1000, and now we are talking about that type of clearance to start with, but coupled with another 50/1000 of motion. And so it
is an elastomeric problem of the first order, in my judgment.
And what is required is a visco-elastic type of phenomenon. As we all know, any visco-elastic material is very temperature sensitive.
VICE CHAIRMAN ARMSTRONG: Well, did you in fact, or do you know of specific recommendations being made with respect to establishing limitations of any type on launch?
MR. THOMPSON: Yes, sir. Several changes were made. We looked at the O-ring tolerances. We looked at the O-ring groove tolerances. We looked and we decreased on the side of goodness, as Roger would say, all of those things, and in addition to that, the shim - we called it a centering strip at that time - was 20/1000. We replaced that with an M type clip that goes over the pins in that area, and increased that to 32/1000.
And these are some of the things we have made in an attempt to make the joint better from where it was originally.
VICE CHAIRMAN ARMSTRONG: And all of the recommendations that you made, to your knowledge, were accepted and implemented?
MR. THOMPSON: No, sir, not all of them were
made. Recently, and as late as August of 1982, I wrote a memo to my management project engineering, indicated that we should stop flying until such point as we could double the squeeze on the O-rings. [Ref. 2/25-12]
CHAIRMAN ROGERS: What was the date of that?
MR. THOMPSON: About the 22nd of August 1985.
CHAIRMAN ROGERS: You said 1982, I think.
MR. THOMPSON: That was 1985. And my recommendation there was to double - I went through an example in the memo - I think it was SRM-20 - where if we went to the shim that Mr. Boisjoly has indicated, a full shim, which is about a 55/1000 shim versus a 32/1000 shim, coupled with a 292 O-ring, which is about the largest O-ring we can get in there with confidence that we are not going to nick it when we assemble, that this would about double the squeeze on the O-ring, which we felt was an important thing to do.
And I realized at that point that the O-ring committee that had been dispatched to discover these things had in fact discussed that. But it was my view that we needed to get it into the flight right away.
VICE CHAIRMAN ARMSTRONG: Were any recommendations made with respect to temperature of the seal area at launch, to your knowledge?
MR. THOMPSON: Not at that time. But that is
one of the reasons, is that if you get additional squeeze on it, particularly the secondary and the primary, the primary will have a better chance of seating with the additional squeeze, and the  secondary will get more help from the side walls of the O-ring groove and help its resiliency problem. And we know that additional squeeze also helps in extending the time that the O-ring is in contact with the seal.
MR. RUMMEL: Mr. Boisjoly mentioned the capture ring a few moments ago as having been included in one of the tests. At what point, if ever, was the capture ring seriously considered for adoption? And as I understand it - and I appreciate your comment on this - the capture ring is a flange which is intended to arrest the opening up of the two-seal - the area of the two seals.
When was that first seriously considered, or has it been seriously considered for production?
MR. THOMPSON: When it was first brought to my attention was in the design of the filament wound case. I believe someone from Marshall suggested it in the adaptors for the filament wound case, and it was I think roughly two and a half or three years ago. And it seemed like a good idea because what it does, it holds that inside flange in against the tang, and our
finite element analysis indicates that instead of opening on the order of 50/1000, it cuts it down to 5/1000 or 6/1000, which is in the direction that we need to be going.
MR. RUMMEL: Has that been considered for adoption, or has it been adopted?
MR. THOMPSON: Yes, sir. It particularly has come to recent attention because of the heads up program where we have discussed higher pressure going up to 1110 psi.
MR. HOTZ: Mr. Thompson, could you tell us what happened to those recommendations you made in August of 1982, or 1985 - I beg your pardon? Were they ever implemented?
MR. THOMPSON: No, sir, they were not.
MR. HOTZ: Do you have any idea of why not? Or did you ever receive a reply back from management explaining that?
MR. THOMPSON: No, sir, I did not. The person that I wrote it to, directly involved in management, has since transferred down into my group again, and so that may have been part of the problem. But management was aware of it because of questions and feedback that I received from it.
MR. HOTZ: But you got no formal response from
management on it.
MR. THOMPSON: That is correct.
MR. RUMMEL: On the capture flange, I have a couple of more questions.
Apparently it has been considered for some time, and I take it the installation of the flange is an integral part of the case, is that correct?
MR. THOMPSON: Yes, it is part of the tang, and as it comes in first, it engages first on a tapered basis, and then it comes into a cylindrical basis. At first it was attempted to have two tapers fit, but the tolerances became very unreasonable, and so we would engage first on two tapered surfaces and then come into a cylindrical engagement where we could maintain the same type of tolerances that we have on the sealing joint.
MR. RUMMEL: Would that involve a change in the forging process or the manufacturing process, or the forging billet?
MR. THOMPSON: Yes, sir. The inside bark on the forging was not quite sufficient to every time assure that we would be able to find the part.
MR. RUMMEL: Would a change of that magnitude have been practical for your company to undertake without the concurrence and authorization from NASA?
MR. THOMPSON: No. I think that would take a
high cooperation between ourselves and NASA because it is quite a large undertaking, of course. MR. RUMMEL: Well, could you clarify for me if that in fact has been undertaken and what the first implementation dates were or might be? Obviously it wasn't on 51-L.
MR. THOMPSON: I think that it is indicated to me that on a general effort, that it was on the order of 18 months, but on the basis of an extremely large effort, a wartime effort I think was the word that was used, it could be made available in 12 to 13 months.
MR. RUMMEL: Are any under process of being manufactured at the present time with the capture flange?
MR. THOMPSON: Yes, I think several forgings have been ordered, and I don't know if it is a full flight set or not. Some other people would have to answer that.
MR. BOISJOLY: I would like to address that on the seal team that was part of the long term fix - and there had been some forgings ordered, and the expected delivery was in February of 1987, and that was in the works, and that was part of the peripheral action, if you will, on the long term basis of the seal task team.
MR. RUMMEL: Have they been tested yet?
MR. BOISJOLY: No, sir, there hasn't been one
MR. RUMMEL: When is a test scheduled?
MR. BOISJOLY: The first delivery was scheduled for February of 1987, and so we wouldn't be able to test until after the hardware was received.
DR. WALKER: I would like to ask a question about the putty.
Do you or does anyone know what the impact of temperature is on the putty and the formation of blow holes?
MR. THOMPSON: We have the formation of blow-holes on assembly. Since then, during the investigation which we of course didn't know at the time we were making this decision, we have tested putty in a putty test fixture somewhat similar to what the motor has, only instead of pressurizing from the outside, as we usually do in running our seal pressure test, we pressurize from the inside, and in some cases, in the worst on worst small clearance basis, it held pressure for about 3200 seconds.
MR. BOISJOLY: I should amplify, the night of the launch, the only data we had in our possession on the putty was that we had run temperature tests down to 40 degrees, and that was the characterization that
determined the leak check pressure, to ensure that the leak check pressure was not masked by the putty, and we have held up to 100 psi with the putty, pressurized through the leak check port. And so we had temperature data at 40 degrees on the putty at that particular time, and we determined that 200 psi would be a conservative number that would bracket all of the testing that had been done, and we would have a leak check at 200 psi for 15 minutes with an open nitrogen gas source to ensure that the putty was not masking a leak in the O-ring, and we would drop to zero, repressurize to 50 psi, and run the actual low pressure leak check on the seal. Fifty psi is a very severe check on an O-ring seal at low pressure, holding that for ten minutes and allowing a one pound drop is a very, very small leak? on the order of an atomic energy type reactor leak.
 DR. WALKER: There is one thing that disturbs me somewhat about the qualification tests in regard to the putty. As I understand it, during qualification tests, the putty was actually smoothed out or there were attempts made to eliminate any imperfections in the putty, but in fact, during an actual launch, that is not done. So in that sense, qualification tests did not truly simulate launch conditions.
Did that disturb anyone?
MR. THOMPSON: Yes, sir, that is true. To assemble these motors under a horizontal condition, which we would do for the development motors and the qualification motors, the motors go out of round probably more so than they do during the normal stacking, vertical operation, and so the putty is probably moved more than it would be during normal stacking. And so probably more blow holes were generated, and you can see, we sometimes called them volcanoes in the putty.
DR. WALKER: You say probably? You don't really have any data?
Does anyone or has anyone actually photographed the condition of the putty or examined the putty when the vertical stacking is done, even early in the program?
I had heard that someone was lowered in a bosun's chair during the early phases of the program to examine the putty on a field joint.
Do you know whether that has ever occurred?
MR. THOMPSON: I don't have any detailed knowledge on that. We do know that as the tang is inserted into the clevis and the first and once the O-ring covers up on the tang, the sealing surface, that the residual air is compressed, and we know for a fact that
sometimes that air that is compressed will cause a blow-by just on tang insertion.
GENERAL KUTYNA: Mr. Boisjoly, I wonder if we could go back to a broader question. You talked about data that you couldn't get, resources that you didn't have. Mr. Thompson has mentioned a letter that he put in in August that he got no response to. You wrote an activity report on the 4th of October that characterized some of this.
Could you summarize some of the things you said in that activity report, the key points, please?
MR. BOISJOLY: I have just got to check to make sure I know which one you are speaking of.
GENERAL KUTYNA: It is titled SRM Seal Problem Task Team Status, and it starts out with "The team generally has been experiencing trouble."
MR. BOISJOLY: Okay, I have that. That was written October 4.
Do you want me to read it?
GENERAL KUTYNA: Well, the pertinent points; I would like you to make those points, if you would.
MR. BOISJOLY: I felt, as I stated in my original memo before the team was formed, that the only way that we could pull off a timely resolution to this problem was to have people dedicated to this problem
full time with full cooperation, and I felt that wasn't coming to pass. I felt very strongly that we were working towards a solution in a timely manner, but we were getting -
CHAIRMAN ROGERS: Could I interrupt just a second? You might as well read it. It is a short memorandum. Dr. Keel will give it to you.
 MR. BOISJOLY: This was an activity report that I turned in that said "SRM Seal Problem Task Team Status. The team generally has been experiencing trouble from the business-as-usual attitude from supporting organizations. Part of this is due to lack of understanding of how important this task team activity is, and the rest is due to pure operating procedure inertia which prevents timely results to a specific request.
"The team met with Joe Kilminster on 10/3/85 to discuss this problem. He wanted specific examples, which he was given, and he simply concluded that it was every team member's responsibility to flag problems that occurred to organizational supervision, and to work to remove the roadblock by getting the required support to solve the problem. The problem was further explained to require almost full time nursing of each task to ensure
that it is taken to completion by a support group. Joe simply agreed and said we should then nurse every task we have.
"He plain doesn't understand that there are not enough people to do that kind of nursing of each task, but he doesn't seem to mind directing that the task nevertheless gets done. For example, the team just found out that when we submit a request to purchase an item, that it goes through approximately six to eight people before a purchase order is written and the item actually ordered. The vendors we are working with on seals and spacer rings have responded to our requests in a timely manner, yet we, MTI, cannot get a purchase order to them in a timely manner.
"Our lab has been waiting for a function generator since 9/25/85. The paperwork authorizing the purchase was finished by Engineering on 9/24/85 and placed into the system. We have yet to receive the requested item."
The reason I made an issue of that is because we had heard it was on the shelf down in San Diego, it was simply a matter of picking it up and using it.
"This type of example is typical and results in lost resources that have been planned to do the test work for us in a timely manner. I, for one, resent working at full capacity all week long and then being
required to support activity on the weekend that could have been accomplished during the week. I might add that even NASA perceives that the team is being blocked in its engineering efforts to accomplish its tasks. NASA is sending an engineering representative to stay with us starting October 14. We feel that this is the direct result of their feeling that we, MTI, are not responding quickly enough on the seal problem.
"I should add that several of the team members requested that we be given a specific manufacturing engineer, a quality engineer, a safety engineer, and four to six technicians to allow us to do our task on a noninterference basis with the rest of the system. This request was deemed not necessary when Joe decided that the nursing of the task approach was directed.
"Finally, the basic problem boils down to the fact that all MTI problems have number one priority, and that upper management apparently feels that the SRM program is ours for sure, and the customer be damned."
And I signed it October 4, 1985. [Ref. 2/25-13]
CHAIRMAN ROGERS: May I turn the subject a little bit around now to another aspect of it? One of our responsibilities is to attempt to determine the cause or causes of the accident, and I guess both of you gentlemen have suggested in these memos that if certain
things were not done, a catastrophe might result.
Looking at the pictures that we now have available to us, which show a puff of black smoke during the first, less than the first second of the launch, which was about 25 feet high, what is your opinion? Is that consistent with the concern that you had that a catastrophe might occur in that joint?
MR. BOISJOLY: We should back up and give you a little bit of background information first. It was everybody's considered opinion, including mine - and I am not a solid rocket motor man. I don't know anything about the propellants or anything like that, but it was everybody's considered opinion that if we developed a problem, that we would blow it up on the pad, and that we would never even lift off the pad.
There has been a lot of speculation about the puff of smoke. It hasn't really been determined what it is, where it came from. It for sure - I mean, there is a lot of speculation, but if that was a joint, then that supports the seal - excuse me, the leak seal leak theory, which is to say that you had a puff of smoke or a puff of products of combustion pass both seals at a very early stage in the ignition transient; then you sealed with whatever remaining material you had left in the seals, and you can postulate this, be it either the
primary or the secondary, it would work both ways, and then at some time later, due to either going through a Max Q environment or vectoring of the nozzle, that you could - and vibration or aerodynamic forces, whatever you want to characterize, that there wasn't that much left, and it spit it out at that point in time and started to leak again.
That has not been really determined at this point that that - -
CHAIRMAN ROGERS: I understand. I was just really asking whether the first puff of black smoke which has been described as about 25 feet high, is not inconsistent with the theory that you have been concerned about.
MR. BOISJOLY: That's right.
CHAIRMAN ROGERS: Mr. Thompson, do you agree with the comments that Mr. Boisjoly made earlier about the discussions in the telecon and other discussions that you were engaged in?
MR. THOMPSON: Yes, sir. I think I am prepared to talk about these things, but I think it has been mentioned, and most of the points that I have have been brought out.
CHAIRMAN ROGERS: Well, why don't you, if you would like to, just look over your notes and see if there's anything you want to add because we would be
perfectly glad to have you go through the whole thing.
Maybe you can glance at them to see if you want to add anything.
MR. THOMPSON: Maybe I could just quickly summarize.
About 10:00 o'clock the morning of January 27 I received a phone call from Mr. Boyd Brinton. He is manager of project engineering, and he called me from Marshall and told me about the 18 degree temperature that was indicated that night, and this particular phone call was prompted by Mr. Larry Wear of MSFC, program manager, and indicating that they were both concerned about this. And they asked me how I felt and what my - if I felt concerned. And of course I told them that I did. And it went through a series of meetings up through engineering throughout the day, ending up finally in Mr. Lund's office, and we had concluded there that we would not launch if the temperature were anything lower than 53 degrees.
 So at this point I felt fairly content, and we met back over in the engineering conference room, we call the MIC room, and prepared to make charts, and you have heard much of this conversation. And I guess the only thing I would like to add to it is I also heard that Marshall's reaction was that they were appalled at
our recommendation, and I was very much surprised by this, having had the experiences over the years of how careful and conservative these people are, and I really admire them. And so I was extremely surprised and really not ready for this type of a recommendation.
And so I guess we had put together some things, probably we may have put together some more if we had any anticipation that our recommendations would not be accepted. But I think we pretty well got everything out on the table that we had in mind, and they indicated that the seal was not a function of temperature, and being a visco-elastic seal, it had to be a function of temperature, in my thinking, although I was unable to explain the SAM-22, where we got some soot there also, in a supposedly warm motor.
And during the caucus I, as Mr. Boisjoly has mentioned, and something that I am not usually accustomed to doing, sitting down between two managers and trying one more time to explain and make sure that I got my thoughts across to them. And after not completing that conversation but concluding that I probably wasn't being - I wasn't communicating, and that may be my fault, I am happy, not happy, but I readily admit that it may have been my type of explanation, I wasn't getting through.
I think that - just one last point. I think that we had seen erosion on SAM-15, erosion, but more important, we had seen blow-through, and it was fairly severe. We had blow-through on two field joints, and in fact, two nozzle joints also, we saw soot between the O-rings in four places that I recall, and that was 53 degrees, and it was my judgment that we had no reason to take the risk of shooting at an O-ring temperature that was lower than 53 degrees, and my recommendation in some of the former meetings was to just at least wait until the afternoon, and then, depending upon temperatures, perhaps wait another day. Ands I think that concludes my remarks.
CHAIRMAN ROGERS: Can you remember any time in your experience at Thiokol when the Engineering Group has been overruled in effect by management?
MR. THOMPSON: Nothing that comes immediately to my mind, sir.
CHAIRMAN ROGERS: Thank you.
MR. ACHESON: Mr. Boisjoly, the activity report of October 4, 1985, to whom was that directed?
MR. BOISJOLY: I turned that in to my immediate supervision for incorporation to go up through the ladder as it reports on a weekly basis.
MR. ACHESON: Who did you give it to, what
MR. BOISJOLY: My supervisor is Jack Kapp. I turned it in to his secretary.
MR. ACHESON: Were you given an opportunity to discuss it at any subsequent time with anybody in management?
MR. BOISJOLY: No, sir.
MR. ACHESON: Thank you.
 DR. RIDE: Just to be perfectly clear about this, is it fair to say that as engineers you don't believe that you had data or analysis to characterize the performance of the joint at a 30 degree temperature?
MR. BOISJOLY: That is correct.
CHAIRMAN ROGERS: Is that true of you, Mr. Thompson?
MR. THOMPSON: Yes, sir.
CHAIRMAN ROGERS: Okay.
Thank you very much.
Now we would ask Mr. Lund and Mr. Kilminster and Brian Russell to come up.
CHAIRMAN ROGERS: Mr. Lund, do you want to proceed and make any remarks or give any testimony you would care to, particularly in light of the testimony we
have had this morning and this afternoon?
[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.2/25-11 1 of 2] Morton Thiokol Interoffice memo; Subject: SRM O-Ring Erosion/Potential Failure Criticality; From: R.M. Boisjoly - 31 July 1985. [Ref.2/25-11 2 of 2] Morton Thiokol Interoffice memo; Subject: SRM O-Ring Erosion/Potential Failure Criticality; From: R.M. Boisjoly - 31 July 1985.
 [Ref.2/25-12] Morton Thiokol Interoffice memo; Subject: SRM Flight Seal Recommendation; From: A.R. Thompson 22 August 1985.
 [Ref.2/25-13 1 of 2] ACTIVITY REPORT- SRM Seal Problem Task Team Status- R. Boisjoly, 10/4/1985
 [Ref.2/25-13 2 of 2] ACTIVITY REPORT - SRM Seal Problem Task Team Status-
R. Boisjoly, 10/4/1985
MR. LUND: I'm not sure there's anything. We've been over so many things; if there are additional questions, I would certainly be happy to talk about that.
CHAIRMAN ROGERS: How do you explain the fact that you seemed to change your mind when you changed your hat?
MR. LUND: I guess we have got to go back a little further in the conversations than that. We have dealt with Marshall for a long time and have always been in the position of defending our position to make sure that we were ready to fly, and I guess I didn't realize until after that meeting and after several days that we had absolutely changed our position from what we had been before. But that evening I guess I had never had those kinds of things come from the people at Marshall that we had to prove to them that we weren't ready.
CHAIRMAN ROGERS: Do you want to move your mike a little bit closer, please?
MR. LUND: And so we got ourselves in the
thought process that we were trying to find some way to prove to them it wouldn't work, and we were unable to do that. We couldn't prove absolutely that that motor wouldn't work.
CHAIRMAN ROGERS: In other words, you honestly believed that you had a duty to prove that it would not work?
MR. LUND: Well, that is kind of the mode we got ourselves into that evening. It seems like we have always been in the opposite mode. I should have detected that, but I did not, but the roles kind of switched, and so after making, or listening to the verbal presentation in the afternoon, they asked what Thiokol's position was, and I looked around the room, and I was the senior person, and I said I don't want to fly. It looks to me like the story says 53 degrees is about it.
And of course, we were requested then to go back and do something more and prepare detailed charts to show that in more detail. And so we got busy then, and I gave assignments to a dozen or so people to go out and generate data that would in a workmanlike manner show the rationale and show the data that we had so that everyone would understand all the data and where it came from.
And we spent the next couple of hours beating the bushes trying to put together that data. And so we did that and began transmitting charts even late then, and then went through that rationale. And all of this time we were preparing the data, the data was coming in, and I was  trying to put together what I was concluding out of all this because there was some additional data that was being generated, and trying to understand and to absorb all of the data that was there, to again see what my thought processes were.
And so we stood at the white board there in the Management Information Center and as the data would come in we would try and say, now, what does this tell us, what does this tell us, and put together a rationale for what we wanted to do.
So it was in a real time mode, and we were trying to absorb the data and put together the story.
Well, as a result of that telecon, I gave the charts that made the recommendation that we wait until the motor got to 53 degrees. I didn't see anything different that I hadn't seen before. And of course, you have heard the story of what happened after that.
VICE CHAIRMAN ARMSTRONG: Let me ask a question about that 53 degrees.
You stated that you - it has been often
stated that the recommendation was at this point in time to stay within your experience base, but I find that to be a peculiar recommendation in the operation of any kind of system because normally you say from our experience base, our data points, and our analysis, and our extrapolation, we would be willing at any time to go beyond our experience point out this far as a next step, and the only reason you would say "I would stay within my experience base" is that you had a problem at that point that said you dare not go any farther.
So could you clarify why you said that?
MR. LUND: It wasn't a question of that. It was a very definite question of conservatism. You know this program has people on it, and so I am very concerned about that, and I want to make sure that if there is any hint of a problem, that we are not extending that. And we didn't have any data at that point that would indicate that we should go beyond that.
Is that an answer to the question or do you want me to try again?
DR. RIDE: Maybe a slightly different way of asking that is normally, when you are trying to extrapolate beyond, maybe beyond your flight experience, you rely on your qualification testing program, and a
system or a subsystem is qualified to fly within a certain regime or a certain envelope. That would include environmental effects like temperature.
Did you have any sort of qualification range on the temperature of the SRM?
MR. LUND: Yes, we had development qual motors that were down in the 40s, as has been pointed out. The data, because of the horizontal assembly problems, what we were trying to do is to put them back to a condition that would resemble that that we would have in a vertical installation. And so we had gone in and repaired the putty, because when you put those together horizontally you can't do it the same way. You can't do it the same way.
And so although the intent was to put them back to the vertical, there is some doubt that you can really do that adequately. And so there is always the question, well, was it perfect? And the answer was, it was not.
And so my belief is that those 40 degree motors are probably valid and adequate, but there is the doubt.
DR. RIDE: So going down below, say, 47 degrees or 40 degrees, you could consider it, perhaps taking it below what the motor had been qualified to?
MR. LUND: Correct. I think one thing that we need to make very clear is, as we have talked about SRM-15 and SRM-22 being the ones that were the blow-by motors, and that we couldn't tell because of those, but we have got to keep in mind there were ten motors between those, 30 joints between those two temperatures that had no blow-by at all.
And so I think that as Marshall pointed out, I think Mr. Mulloy pointed out, he said, you know, the data is just not conclusive at all, and it wasn't because we had a low temperature motor and a high temperature motor, and we had ten motors in between that showed nothing.
MR. SUTTER: Could I ask a question on that? In looking at the earlier data it appears there is erosion and blow-by occurring more frequently later than sooner, and Mr. Boisjoly pointed out that during the year 1985, because of what he learned in looking at, inspecting that one motor that he looked at, he developed greater concern, and in line with Neil's question, did you want to stay with 53 rather than, say, exploring something slightly beyond that, because there was a greater concern developing, and was this concern - did you share Mr. Boisjoly's concern? Just why did you stay with 53 and not say explore a little
MR. LUND: Well, again, the conservative aspect of looking at what our experience has been, and that was the rationale that we presented to Marshall, is stay within the experience band, don't extend it.
MR. SUTTER: Well, how did you view - you mentioned ten motors without blow-by. In looking at the data that was handed out this morning, there are several cases of problems with various parts of the motors, and it seems to be more of it later rather than earlier.
MR. LUND: We haven't been able to identify those parameters that are causing that more pronounced effect.
MR. SUTTER: But if you look at that, since you had a problem that was developing to a greater extent, and it was an unknown reason as to why this problem would happen, I can't understand why there wasn't a greater area of concern developing.
MR. LUND: Well, there was, and that is why we had initiated all of this. What are we going to do with this joint, how are we going to investigate it, set up a special task team. I took one of my best supervisors and gave him the task of doing that. We assigned Mr. Boisjoly to the task team, and we put one of our best project engineers on it, and a program manager was assigned. We
implemented a full time activity to evaluate and do that.
MR. SUTTER: Well, one more question.
Since your people were responsible for the design and were responsible for the testing and were responsible for the qualification, when it came up to the point where there was a question of whether a launch should be made, shouldn't you alone or your organization alone be the one that says yes, or not? And why would there be a question coming from NASA because of not having data as well presented as they wanted? Why would they raise questions on your data, and why would you respond to that question? Why didn't you just tell them it's our decision, and this is it, and not respond to the pressure?
MR. LUND: As a quarterback on Monday morning, that is probably what I should have done, but you know, you work with people and you develop some confidence, and I have some  great confidence in those people at NASA we worked with. We have worked with them for a long, long time.
MR. SUTTER: But in what I think I have heard is that your experts were developing a greater and greater concern, including writing rather powerfully stated memos, and it is hard to understand why they
didn't get more attention.
VICE CHAIRMAN ARMSTRONG: I would like to continue that line of thought in response to your earlier answer about the ten motors between the 53 degrees and the 75 degrees. One conclusion might be from that data base is that you shouldn't operate at 75 degrees or 53 degrees, but you ought to stay within the temperature range of those motors which exhibited no erosion or blow-by.
So again, I am going to ask you the same question I asked before: what was conservative about saying 53 instead of a number other than that which might be higher or might be lower, depending upon how you approach the problem?
I am trying to understand your thought process.
MR. LUND: I guess all the engineering rationale said that cold was probably worse and warm was probably better, and all the physics of the situation, as we best understood it. And so we felt that, you know, the conservative thing to do would be to stay warmer.
VICE CHAIRMAN ARMSTRONG: But did you like 53 degrees? Did you like the results on the 53 degree flight?
MR. LUND: I would rather have a motor that has no erosion and no blow-by and looks perfect at the end of the motor firing.
VICE CHAIRMAN ARMSTRONG: Then might not you have taken the position that 57 would have been a number, or 62 or some other number?
MR. LUND: We have had motors down in the low 60s, and I guess there are some, just looking at my chart, in the low 60s at least that were perfect, and we have had some in the lower 50s that were not anywhere near as bad as SAM-15. So there is no clear dividing line, at least.
VICE CHAIRMAN ARMSTRONG: There's a lot of other factors other than temperature that might be involved, is that correct?
MR. LUND: That is correct. So we don't know what the effect of temperature was.
MR. SUTTER: Can I ask just one more question?
I heard these comments that some tests looked pretty good at 75 and others looked okay at 53, but was the qualification testing thorough enough for any proper data base to be in hand to really know what the critical variables are like the thrust of the motor, the tolerances of the metal joints, the tolerances of the
O-rings, or the application of the putty or the application of the seal?
Isn't one of your problems the fact that the qualification testing was inadequate?
MR. LUND: It seems like the size of the qualification program is inversely proportional to the size of the motor, which is called dollars, and there's no doubt about that. With small tactical motors it is not unusual to fire many, many, many, and the larger the motor, the smaller the qualification program, and to get a full statistical range of every parameter of that motor, I don't think there's enough money in the national treasury to do that.
So there is a practical limit to what you can do.
 MR. SUTTER: Well, can't you go from the partially qualified motors and make changes and go into another area of further unknown exploration like reducing the strength of the motor or increasing the thrust or changing the putty?
MR. LUND: There were qualification motors, of course, to do the strength or the thickness of the case and the thrust change.
MR. SUTTER: Well, were they adequate?
MR. LUND: In engineering opinion, yes.
DR. WALKER: I have a question on temperature.
Mr. McDonald testified that he had a discussion, I believe it was with Mr. Mulloy, about the meaning of the temperature range of 40 to 90 degrees, whether it would apply just to the bulk temperature of the motor or whether it would apply to every part of the Shuttle.
What is your understanding?
MR. LUND: If you would have asked me a month ago, I would have told you the motor is 40 to 90.
DR. WALKER: And so there is no qualification in your mind on the O-ring temperature? For example, the O-ring temperature could have been quite cold because the O-ring is certainly going to move in temperature with the metal case. The metal case could be quite a bit colder than the bulk temperature of the propellant if the weather had been cold.
MR. LUND: There were no full scale motors fired below 40.
DR. WALKER: But what I am asking is did you as the supplier of the system to the government have a specification on the O-ring temperature, or could the O-ring temperature have been anything?
MR. LUND: I don't believe there is a
specification on the O-ring temperature other than the material itself.
DR. WALKER: And what is that specification?
MR. LUND: Well, it is a specification that says the material can withstand these kinds of environments.
DR. WALKER: But it doesn't specify the operational aspect, does it?
MR. LUND: To my knowledge, no.
DR. WALKER: In fact, the Milspec says specifically that the O-rings should be qualified for whatever uses they are put to.
So did you take any steps to do that, that is, qualify the range of temperatures over which these O-rings were to be used?
MR. LUND: Yes. The development motors were fired from 40 to 84, and the qualification motors from 45 to 83.
DR. WALKER: So then 40 degrees was the temperature limit for the O-ring?
MR. LUND: In the full scale qual program, that is correct.
DR. WALKER: So when it was predicted that the temperature of the O-ring at launch of 51L was going to be 29 degrees, the O-ring was outside of the
qualification temperatures by some 10 degrees.
MR. LUND: That is correct.
DR. WALKER: Then how could you make a recommendation to launch if you were 10 degrees outside of your qualification?
 MR. LUND: Our original recommendation, of course, was not to launch.
DR. WALKER: Well, I understand that, but your final recommendation was to launch.
MR. LUND: Okay. What we need to do, then, is go through that rationale.
DR. WALKER: So you are going to answer my question then at the end of this discussion, hopefully?
MR. LUND: If you want me to go through it now, I would be glad to do that.
CHAIRMAN ROGERS: Well, I think we have heard what explanation you have given. I think the problem we are having, it is not convincing. I mean, let me, if you don't mind, I assume you have great confidence in your engineers Boisjoly and Thompson and the others, and they are probably as well qualified as anybody in the country in dealing with these problems of O-rings and seals and so forth, is that right?
MR. LUND: Yes.
CHAIRMAN ROGERS: And you had a long
discussion in the telecon, and you decided, all of you, I understand, all of you decided that for safety reasons you would oppose the launch. And thereafter, NASA, in one way or another, made it clear that they were displeased with that recommendation, and I assume that you knew when you made the recommendation that your recommendation in fact was going to determine whether that Shuttle would be launched or not because NASA had indicated to you that they would not fly unless they had a written report from Thiokol saying you approved the launch.
MR. LUND: I didn't know NASA would accept that.
CHAIRMAN ROGERS: You didn't know that?
MR. LUND: No.
CHAIRMAN ROGERS: Well, you must have known your recommendation was very important. You knew that if you voted against the launch it would not have been launched, didn't you?
MR. LUND: Well, we had voted prior to it, and they didn't accept it, so I couldn't forecast what NASA would do.
CHAIRMAN ROGERS: But you knew that that was the reason they asked you to reconsider. That is why you had the five minute recess, didn't you?
MR. LUND: That's a fair statement, yes.
CHAIRMAN ROGERS: Now, knowing that, and knowing that the safety of the crew was involved, and knowing your own people, the engineers that you respected, were still against the launch, what was it that occurred in your mind that satisfied you to say okay, let's take a chance?
MR. LUND: Well, I didn't say take a chance because I felt that there was some rationale that allowed us to go ahead.
CHAIRMAN ROGERS: Well, maybe that isn't fair. Then what was it that occurred in your mind that caused you to be willing to change your mind?
MR. LUND: I guess one of the big things was that we really didn't know whether temperature was the driver or not. We couldn't tell. We had hot motors that blew by and cold motors that blew by, and some very near either end that did not. The data was inconclusive, and so I had trouble justifying in my own mind and saying, by golly, temperature is a factor.
Second - -
DR. WALKER: May I interrupt for just a moment?
 Mr. Boisjoly has said that the thing which was compelling to him was that the blow-by a the coldest
motor was much more severe.
He has emphasized how black was the blow-by and how large an angle over which it occurred.
MR. LUND: But three or four degrees above that was zero.
DR. WALKER: So his discussion was not convincing to you?
MR. LUND: Well, it wasn't totally convincing because in two or three degrees it went from very, very bad to no problem, no blow-by.
MR. FEYNMAN: There were many seals that didn't have any problem, and so it is obviously a random effect. It depends upon whether or not you get a blow hole or you don't get a blow hole. So if within a particular flight it happens that all six seals don't get a blow hole, that's no information. The fact that - as far as I can understand this, it doesn't mean you are suddenly good because it worked and the next time when one goes off it's suddenly bad. It seems to me that it has to be understood as a probabilistic and confusing, complicated situation.
So you could never decide they are all going to break or they are all not going to break it's not the wonderful one-horse stray, and when you look at it that way, it is a question of increasing and decreasing probabilities that we have to consider rather than did it work or didn't it work.
And I would like you to explain it to me from that point of view.
MR. LUND: Well, the question still is, is temperature the thing that caused the SRM-15 effect?
MR. FEYNMAN: You have heard your engineers argue that there was an effect of temperature which looked like it made things worse. Is it not inconceivable that there is something else that sometimes produces blow-by, that there is more than one effect, and that temperature could still be an important effect and increase the probability in spite of the fact that at a high temperature it gets worse?
Is there any evidence that temperature is not an important matter just because at some high temperature you have an accident?
MR. LUND: Well, there is, as you point out, there are many variables in the thing, and it wasn't clear that temperature was the effect.
MR. FEYNMAN: But logically, from the point of view of the engineers, they were explaining why the temperature would have an effect, and when you don't have any data, you have to use reason, and they were giving reasons.
MR. LUND: That's right, and that is what we did as we included in our rationale the fact that sure enough, the temperature could be an effect.
Okay, it wasn't clear, but we said we will consider that to be so.
MR. RUMMEL: I have great difficulty with this. In the usual practice, when there is any real doubt about flight safety, whether it is aircraft or whatever, you simply don't fly, and it seems to me this is the reverse, and I just have great difficulty understanding the question that has been asked before, that is, understanding any answer. I just haven't heard it as to why, if there is doubt in your mind, why you went ahead, why you changed your mind. I just don't understand it, and I would appreciate very much if you could explain that.
 CHAIRMAN ROGERS: Maybe we ought to go to Mr. Kilminster, if you don't mind. He signed the Telefax, and we have asked Mr. Lund a lot of questions, and I think maybe in fairness to Mr. Lund, Mr. Kilminster, could you attempt to explain to the Commission why - I guess you changed your mind, too, didn't you?
MR. KILMINSTER: Yes, sir, based upon the discussion that we had and the rationale that was developed.
CHAIRMAN ROGERS: How can you say you changed
your mind when you say temperature and data not conclusive on predicting primary O-ring blow-by?
Did you have a feeling that you had to prove that it was - that the burden of proof was on you to show that it wasn't safe?
MR. KILMINSTER: No. I think we were asked to relook at the data, which we did.
CHAIRMAN ROGERS: Could you tell me what data it was that you looked at that was different from the data you had looked at first?
MR. KILMINSTER: There was one piece of data that we looked at which has been discussed before, and that was the erosion parameter, and the factor of three, but my evaluation was -
CHAIRMAN ROGERS: Is that the only new piece of data?
MR. KILMINSTER: That is really the only new piece of data that we had not previously discussed on the telephone, but I think that the data that we did show, the fact that we had subscale tests at 30 degrees showing no blow-by was an indicator. We, as Mr. Lund pointed out, had other flight motors at temperatures between the two in question, that is, 75 degrees and 53 degrees O-ring temperatures that had shown no blow-by, and we had static test motors at temperatures lower than
53 degrees that had no blow-by.
Now, I would like to discuss that just a moment.
CHAIRMAN ROGERS: Could you particularly, though, point out the new data because the purpose, as we understand it, for the recess was to find out if there was any new data, or were you just asked to change your mind based upon the data you had?
MR. KILMINSTER: I had one piece of data that was new in our discussion was that if we did have blow-by past the primary O-ring, as it was being positioned to seal, and recognizing the fact that the cold temperatures could cause that timing function to extend, then we had an opportunity perhaps of having some erosion occur. We looked at the erosion that had occurred on 51-C, and compared that to the data that we had developed, both from cold hydraulic oil testing and from hot subscale testing, that indicated that that very flight had a safety factor of three over what would have to have happened in order to get to an area of questionable sealing capability.
With that information in mind, then, and also the fact that we had had some analytical work done earlier to develop the limiting erosion parameters on O-rings, led me to believe that we were in the condition
of having a safe position for recommending a flight.
CHAIRMAN ROGERS: Excuse me. How come that data wasn't available the first time? How did it happen to show up at the recess?
 MR. KILMINSTER: Well, it was just a matter of a discussion that we had while we had the recess. When we said that well, if indeed the temperature is going to cause a longer time for the primary O-ring to function, and there is the possibility of additional erosion, then where do we stand relative to 51-C, and how much more margin did that exhibit?
CHAIRMAN ROGERS: So you really had the data there before?
MR. KILMINSTER: Yes.
CHAIRMAN ROGERS: You hadn't analyzed it. In other words, it was not new data. It was data that you hadn't properly analyzed, is that right?
MR. KILMINSTER: It was data that we hadn't prepared or discussed on the earlier telecon or the earlier portion of the telecon.
CHAIRMAN ROGERS: And that was through an oversight?
MR. KILMINSTER: Well, I don't know if it was oversight or just another piece of data that we were searching for in order to establish our position.
DR. RIDE: You are saying that you had a safety factor of three over the 51-C erosion problem. How were you attempting to analyze how the timing function would change and how much erosion that could possibly give you on 51-L?
MR. KILMINSTER: Only on a subjective basis that if, as has been stated, the timing function under cold condition was to extend, and if what was observed under 51-C, not only the blowby but the erosion, were combined, then we developed the rationale about that safety factor of three.
CHAIRMAN ROGERS: Mr. Kilminster, did you have any feeling of pressure being put on you by NASA, or were you just calmly reassessing?
MR. KILMINSTER: I felt that the pressure that was put on us was to go back and look at the data, look at the detailed information that had been presented to see if there was something that we were seeing that we were not representing on the phone.
CHAIRMAN ROGERS: You didn't feel they were trying to get you to change your mind?
MR. KILMINSTER: I did not feel a significant amount of pressure in that regard.
MR. ACHESON: Mr. Kilminster, have you had an opportunity to look at the correspondence of Mr.
Boisjoly written in the summer and autumn of 1985?
MR. KILMINSTER: No, I have not.
DR. WALKER: Mr. Boisjoly's memo to you of 31 July, you received that and read it, I presume.
MR. LUND: Yes, and we took immediate action on that and established the O-ring task team within a week or so of that memo.
DR. WALKER: Did you pass along Mr. Boisjoly's concerns to anyone at NASA?
MR. LUND: The normal process of that sort of information is through the project office and Mr. McDonald and so on were on that. That would be their task.
DR. WALKER: Well, then, you are saying that it would have been Mr. McDonald's responsibility to alert NASA that a key engineer thought a catastrophe was possible?
MR. LUND: I think NASA understood that clearly, and we have been working with them since that time on this whole problem.
DR. WALKER: I am not asking that. I am asking whether as a result of Mr. Boisjoly's memo to you, you or Mr. McDonald or anyone else at Thiokol alerted NASA to the concerns of this key engineer.
 MR. LUND: I did not call anyone at NASA
specifically but I saw that they were alerted because of their immediate response in working with us.
DR. WALKER: But are you aware of their having heard that a potential catastrophe was possible?
MR. LUND: I am not aware.
DR. COVERT: Mr. Kilminster, I would like to ask a couple of questions about the temperature, if I may, a sequence of questions.
You say that on this 40 to 90 degree launch or certification criteria, is this a cold soak, or is this some other kind of a temperature?
MR. KILMINSTER: The 40 to 90 degrees is a mean bulk temperature of the propellant, which means to me that we could have a motor where the propellant grain was soaked out to 40 degrees, or conversely, propellant grain was soaked out to 90 degrees.
DR. COVERT: What is the time constant on this case plus insulator and so forth to get to an equilibrium bulk temperature?
MR. KILMINSTER: We ran some calculations based upon equilibrium at the Cape, and I believe it is about 30 days.
DR. COVERT: So that it is possible to be exposed to a cold temperature and have sharp temperature gradients within the propellant or the insulator and so
part of it would be at a temperature far outside of what you think would be appropriate and the rest of it would still be warmer, shall we say?
MR. KILMINSTER: Yes, but I think that is limited by the other requirement which was spelled out in the Level II document that said 31 degrees to 99 degrees.
DR. COVERT: Is it possible that some of it could be at 26 degrees and other at 55 degrees, considering again a 21 to 30 day transient to get to the bulk temperature?
MR. KILMINSTER: That is not the way that I would read the combined two specifications or two requirements.
DR. COVERT: Is it possible that there is a difference between the behavior of the subscale motors at some temperature and the behavior of the large motors at the same temperature if one was in thermal equilibrium and the other was in some sort of a nonuniform temperature distribution?
MR. KILMINSTER: Yes, I would expect there could be some differences.
DR. COVERT: So there may be some doubt in your mind as to how exactly to apply the subscale motor data within the framework of the large scale motor if
you allow for the temperature transient?
MR. KILMINSTER: Yes, sir.
DR. COVERT: Thank you.
MR. ACHESON: I have a question for Mr. Lund or Mr. Russell.
When I was talking with you a few days ago at your plant, I think I am correct in recalling that one of you told me that if the temperature at the Cape on the day of launch had been in the 9 to 10 degrees above zero Fahrenheit range, there would be no question but that you would have stuck to a no-launch position.
Am I right in that recollection?
 MR. LUND: That is right. There's many, many things in the motor then that we would be concerned about.
MR. ACHESON: So you did recognize that temperature was a discriminator in an absolute sense. The only question was what the margin was.
MR. LUND: That's right.
MR. ACHESON: Below 53 degrees, is that correct?
MR. LUND: Yes.
MR. ACHESON: Were you acquainted at all with this correspondence which I assume you have had a chance to read, of Mr. Boisjoly, written in the summer and autumn of '85? It seems to say that management does not
have an adequately heightened sense of the urgency of the work to be done on the O-ring problem, the seal problem.
My question is were you aware of that feeling on his part at the time? Did it cause you concern? And what if anything did you do about it?
MR. LUND: I didn't meet with Mr. Boisjoly, I met with Don Ketner, who is the task team leader. He made recommendations to us, and I think we followed those recommendations, and did everything we could to help him with them.
Now, undoubtedly there are things that were bugging them that they didn't bring to my attention, that I didn't do anything about because I didn't know about them, but when they came, and Don Ketner, particularly, we worked very hard with him to try and establish and take corrective action as needed.
MR. ACHESON: Thank you.
VICE CHAIRMAN ARMSTRONG: I am sure that all of you and everybody associated with the Shuttle knew that it was NASA's intention to fly on a very rapid time schedule throughout the year, or build up to the point of that, and that they would have to launch on winter mornings and at other times.
In the process of evaluating the information
brought to you, did you at any time suggest to NASA that the launch commit criteria, the LCCs or other rules, may be insufficiently constraining, and that you ought to establish rules with respect to the SRM that kept you, one, either within your experience base, your qual test, or your extrapolations?
MR. LUND: We did not. Mr. McDonald evidently had some discussions with them along that line.
VICE CHAIRMAN ARMSTRONG: Thank you.
MR. ACHESON: Mr. Russell, I have a question for Mr. Russell.
Perhaps you would give us your recollection of the thought process followed in your mind in the change of position between the view presented in the telecon that Thiokol was opposed to a launch, and the subsequent conclusion of the caucus within the company.
MR. RUSSELL: I was part of the overall day's efforts that started off pretty early, as has been mentioned, and as the day developed, pretty much agreed with the recommendations, and as our presentation was made on the charts, the subsequent answers that came back, you have asked others if they felt pressure and undue pressure, and I felt some pressure with some of the comments. I thought our rationale was reasonable. I have seen many instances in the past where we have
used previous limits for data on putty that I am familiar with and other raw materials, for example, that we do not exceed our experience base in the usage of these materials. And so I felt that this was the proper thing to do, albeit our 53 degree experience, as has been mentioned, wasn't desirable, but we had deemed it acceptable at that time.
And the statements that seemed to me to put pressure or at least to make me feel the pressure were the responses of being appalled at our recommendations, the responses of when we should launch, how long do we have to wait, April? And also there was argument about what sort of rationale we could have for 53 degrees, and Mr. Armstrong made the point that what temperature could we make a strong statement on? And the data couldn't tell us which temperature other than 53 degrees, which had been our previously most successful low temperature. And so I felt some pressure based upon those comments.
I would like to add that my feeling as I believe it was Mr. Mulloy - and this is, again, by voice recognition, but after we had made our recommendation initially, he talked for about five minutes and explained in his mind why the data really didn't add up to the conclusions that we had made. And
I will have to admit at that time that it was a very logical presentation that he had made, and then there was talk back and forth as to what the data really meant, and as has been mentioned here, in the caucus there weren't any new data brought up that I recognized. We pretty much talked over the same types of things, and my feeling of it was that what some of us were understanding and what others were understanding and feeling important didn't really agree.
I didn't make - I think I can only recall making one comment in the caucus. I can't even remember what that was, and it was very brief, and I don't think it made a big impact at all. And the reason that I didn't make so many comments, despite what I felt, was that Roger and Arnie were making the points to the best they could, and I couldn't see a way of making them any better.
So we got to a point in the caucus where Mr. Mason said, and rightfully so, we are covering the same information, we are not talking about anything new here, and it's time for a decision.
And I maybe tend in my position to feel more pressure. I know these other gentlemen have many pressures from all sides, and I can't really speak for them, but I felt pressure that we were - and I don't
know if Roger was referring to me in his testimony, but he could have been because I had the feeling that we were - that it was a distinct feeling that we were in the position of having to prove that it was unsafe instead of the other way around, which was a totally new experience. And I believe I made that statement afterward. I know I did when I went home and talked about it with my wife.
But here again, I think it's impossible for me to say what might have swung the decision. But I felt in my mind that once we had done our very best to explain why we were concerned, and we meaning those in the camp who really felt strongly about the recommendation of 53 degrees, the decision was to be made, and a poll was then taken. And I remember distinctly at the time whether I would have the courage, if asked, and I thought I might be, what I would do and whether I would be alone. I didn't think I would be alone, but I was wondering if I would have the courage, I remember that distinctly, to stand up and say no.
 However, we were not asked as the engineering people. It was a management decision at the vice president's level, and they had heard all that they could hear, and I felt there was nothing more to say, that we could change anything, and also felt in my mind
that I didn't see - and I believe I mentioned this to you last week - that I didn't see a dangerous concern. I knew we were entering into increased risk, and I didn't feel comfortable doing that.
I was nervous. You asked how I slept that night, and I said I thought I slept okay, and my wife differed with that as I talked with her after that. But there was a nervousness there that we were increasing the risk, and I believe all of us knew that if it were increased to the level of an O-ring burnthrough, what the consequences would be. And I don't think there's any question in anyone's mind about that.
I don't know if I've answered the question. I guess your original question was what I thought was in the thought process, but that was what was in my thoughts.
MR. ACHESON: Thank you very much.
CHAIRMAN ROGERS: Thank you very much.
Just one other question and I think we would like to adjourn for the day.
Did either of you gentlemen, Mr. Kilminster or Mr. Lund, have any pressures, outside pressures? Did anybody call you or anybody suggest that you should vote to launch? Is there anything of that kind that the Commission should know about?
MR. KILMINSTER: No, sir.
CHAIRMAN ROGERS: Thank you very much.
We will adjourn for the day.
(Whereupon, at 4:25 p.m., the Commission recessed, to reconvene Wednesday, February 26,