CHAIRMAN ROGERS: Ladies and gentlemen, I now would like to call this first meeting of the Presidential Commission on the Space Shuttle Challenger Accident to order.
I want to make just a couple of preliminary remarks. As you know, this Commission was appointed by the President on Monday, and because of the time frame within which we are working, we wanted to start as expeditiously as possible, and the members of the Commission have been very accommodating and agreed to come to Washington yesterday.
We had a preliminary get-together to discuss our plans and where we were to go based upon the Executive Order, and we have, with the cooperation of NASA and the White House and other officials, been able to set up this meeting for this morning. The purpose of the meeting this morning is to be brought up to date on the events that have occurred since the accident, principally by officials from NASA. They have been very cooperative and have been working closely with us, and we are obviously going to rely in large part on the investigations that they have conducted and will conduct in the future.
On the other hand, as we said when the
 President announced the appointment of the Commission, we have our own responsibilities. We can seek other evidence, get any other information we may desire, and the NASA officials have been, as I say, very cooperative in that respect.
I would like to, by way of a beginning, refer to the Executive Order that created the Commission because we want to stick very closely to the instructions that we received from the President, and I will just read briefly the important part of that Executive Order.
It says "The Commission shall investigate the accident of the Space Shuttle Challenger which occurred on January 28, 1986, and the Commission shall:
"(1) Review the circumstances surrounding the accident to establish the probable cause or causes of the accident; and
"(2) Develop recommendations for corrective or other action based upon the Commission's findings and determinations.
"The Commission shall submit its final report to the President and to the Administrator of the National Aeronautics and Space Administration within 120 days of the date of this Order."
So our first task, it seems to me, and I think
other members of the Commission, is to deal with, one, review the circumstances surrounding the accident to establish the probable cause or causes of the accident.
Now, with that opening statement, keeping in mind that is our purpose this morning, to be brought up to date on the events that have occurred since the accident, we will call on NASA officials, and I guess the first witness is Dr. Graham, if the doctor will proceed to the podium.
Doctor, I will ask the Clerk to swear you in.
THE CLERK: Do you swear the testimony you are about to give before this Commission will be the truth, the whole truth, and nothing but the truth, so help you God?
DR. GRAHAM: I do.
DR. GRAHAM: Mr. Chairman, members of the President's Commission on the Space Shuttle Challenger Accident, NASA welcomes your role in considering and reviewing the facts and circumstances surrounding the accident of the Space Shuttle Challenger.
NASA continues to analyze the system design and data and, as we do, you can be certain that NASA will provide you with its complete and total cooperation. Along with the President, I look forward to receiving your report and to the resumption of space flight with our national Space Shuttle System.
I would like to introduce now Mr. Jesse Moore, who is NASA's Associate Administrator for Space Flight and also the Chairman of NASA's 51-L Data Design and Analysis Test Task Force. He will conduct the briefing.
THE CLERK: Do you swear the testimony you will give before this Commission will be the truth, the whole truth, and nothing but the truth, so help you God?
MR. MOORE: I do.
MR. MOORE: Mr. Chairman, members of the Commission, we are here today before you to discuss the Space Shuttle Challenger accident and to talk to you about where we stand today in terms of our analysis that we have done so far as a result of that accident, and supporting me here today are various members of the NASA centers involved, as well as members of the Astronaut Office down at the Johnson Space Center.
I would like to say that we tried, in preparing this document for you, to put it together to give you a sequence of how NASA goes about getting ready for a flight, what some of the background associated with the Space Shuttle System is, and then, finally, tell you where we are with respect to the overall investigation that we are currently working on right now.
We will have to apologize because we probably have some acronyms in our document here that may be kind of difficult. Some of the charts that may come on the television screens may be difficult to read, but we have
tried to put together the best set of information we could in the time available to do it.
I would like to now proceed with the agenda, please. [Ref. 2/6-1]
I plan to cover the overview, and then I would ask various members involved in the Space Shuttle System to cover respective parts of the Shuttle, and I will start out by asking Arnold Aldrich, who is the Manager of the National Space Transportation Program Office at the Johnson Space Center to talk about the orbiter system as well as to give you some background on the Shuttle and overall performance, and then I will call upon Dr. Judson A. Lovingood of the Marshall Space Flight Center to talk to you about the responsibilities of the systems that the Marshall Shuttle Projects Office have, and then I will ask Robert Sieck of the Kennedy Space Center to talk to you about the launch and landing operations at Kennedy.
I think what is also very important to this group is the design and development process that NASA follows in acquiring hardware and software before we fly it, and we will tell you about how we do that and the overall process, preparations with respect to that aspect.
Finally, we will close with our actual flight
preparation process: How do we get ready for a flight; who is involved in getting ready for a flight, and to try to give you some background information about the overall flight process involved in the Space Shuttle Program.
The next chart shows an organization chart showing how NASA is organized from the Administrator level down to what we call the field center level, and I won't spend a lot of time  going into great detail on this, but I will tell you that Dr. Graham is the Acting Administrator of NASA. I report directly to Dr. Graham. I am the Associate Administrator for Space Flight. And then reporting to me institutionally are four NASA centers involved in not only the Space Shuttle program but a number of other programs in NASA. The centers are the Lyndon B. Johnson Center in Houston, Texas. They are also the John F. Kennedy Space Center in Florida, the George C. Marshall Space Flight Center in Huntsville, Alabama, and the National Space Technology Labs in Mississippi. [Ref.2/6-2]
MR. MOORE: The next chart, please, will show a little bit more detail in terms of how I operate the Office of Space Flight. And in this chart I have four principal positions in my front office: a Deputy
position; a Deputy Associate Administrator for Technical Matters; and a Deputy Associate Administrator for Management. I have two staff functions, principal staff functions. One is looking at STS program integration, looking and making sure all elements of the program are integrated from a standpoint of program, policy and budget. Then I have a number of what I call line divisions that report to me that have various responsibilities which are listed on the chart, and I will just quickly try to let you have a feeling for what those are.
The box on the far left shows my Customer Services and Business Planning Division. That division principally interacts with the Shuttle customers to give them schedule information and planning information prior to our launches. Then I have a division called the STS, and here STS- you will see that quite a bit-stands for the Space Transportation System, Orbiter Division and Logistics Division. This division is responsible for the overall program aspects and policy aspects of the Shuttle Orbiter System, and the logistics to support the Shuttle Orbiter System, meaning all the hardware and the spares that we need to make sure the Shuttle flies.
CHAIRMAN ROGERS: What does STS stand for
MR. MOORE: I'm sorry, STS, you will hear that term quite a bit, stands for the Space Transportation System, and that is another way we use of talking about Space Shuttle. It is the Space Transportation System. If you look at the Space Shuttle, you can see the Space Shuttle here, and different people look at it in different ways. And some say the Space Shuttle is the orbiter only, but the Space Transportation System involves more than just the orbiter. It involves the external tank, it involves the solid rocket boosters, and all the people, facilities that we have to support it. And that is kind of what we call in broad terms the Space Transportation System.
CHAIRMAN ROGERS: Thank you.
MR. MOORE: In addition to our Orbiter Division we have a Propulsion Division, and this principally is, from a program standpoint, a budget and policy standpoint, responsible for the propulsive elements on the Shuttle, and those elements include the Shuttle main engines, of which there are three, the external tank which provides the fuel for the main engines on the Shuttle, and then the solid rocket boosters which provides the-a major part of the thrust during the initial ascent phase of the launch.
And then I have an STS Operations Division. This is responsible for, again, program and policy and budget related to how we operate the Shuttle in our launch operations down at the  Kennedy Space Center as well as in our flight operations activity that is involved and being performed at the Johnson Space Center.
There are other supporting divisions on the right-Resources, Advanced Programs, and Space Flight Development Systems. These are kind of supportive to the overall Space Transportation System, and then each of the centers listed below have various responsibilities.
And I think the next chart will kind of give you a feel for the overall management responsibilities.
MR. MOORE: You can see the Office of Space Flight kind of looked at from an overall management point of view and not so much from an institutional point of view. My office has responsibility for policy, advocacy of the program, budget and resources, marketing, and kind of ensuring that the overall corporate structure is maintained, and then external relations interfacing with the outside world as far as the overall Shuttle is concerned.
There is a Program Office at the Johnson Space Center called Level 2, and Arnold Aldrich, whom you will be hearing from in just a minute, is the manager of this overall office. His job is overall program management integration, which means making sure that the system all plays together, that everything is ready from a systems standpoint from an overall performance, that the hardware all matches and so forth. And then there is a customer service function down at the Level 2 office as well to make sure the cargo integration and work in that area is also done appropriately.
Then, reporting to the Level 2 program offices are various project elements at the four NASA centers that I talked to you about, and I will just quickly go through from left to right the various projects and the responsibilities for these projects are the responsibilities of, on the left, the Johnson Space Center has the responsibility for the Shuttle orbiter, for the orbiter crew equipment, meaning all the components and so forth necessary for the flight crew, and also the Astronaut Offices at the Johnson Space Center, for Flight Operations, meaning at liftoff, the flight of the Shuttle, and its orbital operations and its landing operations are basically the responsibility of the Johnson Space Center, and to
actually do the payload integration, making sure that the hardware we fly in the Shuttle is properly integrated into the cargo bay prior to our launch.
The Kennedy Space Center on the next box has the responsibility for ground support equipment such as all the launch pads and all the launch facilities that are required to support the launch of a Shuttle. They have responsibility for actually launching the Shuttle, the launch operations complex at the Kennedy Center does the actual countdown and so forth prior to a launch. And then they also do the hardware payload processing prior to installing, and they actually install the payload elements into the bay of a Shuttle.
At Marshall Space Flight Center they have the responsibility for the Shuttle main engines, for the external tank, for the solid rocket booster, and for Spacelab, which is a cargo element that flies inside of the Shuttle.
As far as the NSTL-again, NSTL is National Space Technology Laboratories-they basically provide us test facilities for testing the Shuttle main engines.
MR. MOORE: The next chart I'm just going to quickly let you look at. I don't intend to brief this
 in detail. What I have tried to do in this chart, you will see it discussed later by Mr. Aldrich. What I have tried to do in this chart is to give you a more detailed vertical cut from the previous chart, and on the right of the chart some of the specific functions that are done by this particular structure.
MR. MOORE: Now, the next several charts will talk about the planned evolution of the Shuttle program, and this is a plan which encompasses the 1981 timeframe through the 1986 timeframe, and I will try to show to you and to your Commission what flights have been done and the kinds of things that have been done during that period of time on the various missions.
There was a phase in the program that initiated in the April 1981 timeframe and ended in late 1982 called the Orbital Flight Test Phase.
MR. MOORE: During this phase we flew four Shuttle missions, STS missions, and as a part of those flights, we flew instrumented pallets-a pallet is a cargo element that sits inside of the cargo bay-to try to get some feel for how we could accommodate payloads in the Shuttle. We flew the RMS, another acronym-and that stands for the Remote Manipulator System,
-and that is the Shuttle's arm which we now fly routinely on most flights. We did fly our DOD, or Department of Defense, payload on one of the early flights, and we began doing some experimental flying on pharmaceuticals, doing some early experiments to see how those experiments would react to zero gravity.
Beginning in STS 5, which occurred in late 1982--
(Viewgraph.) [Ref. 2/6-8]
MR. MOORE: - we began what we called the early payload capability demonstration phase, and we looked at and we did fly a large number of different kinds of payloads to give us a feel for the capabilities of the Shuttle with respect to accommodating a number of different kinds of payloads. COMSAT is short for communications satellites, and in addition to the communications satellites, we flew several upper stages during that period of time. One is the PAM, or Payload Assist Module.
Let me pause. I think we put an acronym listing in the back of your book here, and we are going to try to make that as complete as we can because we in this business do an awful lot of talking in acronyms, and I apologize for that, but there are a couple of sheets in the back of the book with acronyms. We will
try to make that more complete as time goes on.
We also flew the IUS, the Inertial Upper Stage, and you should note that we had an Inertial Upper Stage on this particular mission, 51-L, and I will come back to that point later. We also flew Spacelabs, I talked about. We did an EVA, which is an extravehicular activity where a crewperson would go outside of the Shuttle, and we also did an MMU flight, or a Manned Maneuvering Unit flight, where we actually flew a powered system away from the Shuttle and returned back to the Shuttle.
We did rendezvous on orbit, we did satellite repair, we did-on the Solar Array, and we also did a refuelling demonstration on the program. Beyond that period of time we have entered into what we call the Payload Operational Phase where we have done satellite retrievals, where we  have flown some DOD, additional DOD, Department of Defense payloads, and we have also done some salvage rescue operations in space with the rescue of the SYNCOM satellite last year.
(Viewgraph.) [Ref. 2/6-9) & 10]
CHAIRMAN ROGERS: Up to that point, had the military, DOD, been involved in these programs?
MR. MOORE: The DOD has been involved in the Space Transportation System from the outset. In fact, they are working the launch pad facilities and have the responsibility now for the launch pad system development and facility development out at the Vandenberg Air Force Base. And the DOD plays a very strong role in the Shuttle program as far as working with NASA. There is a lot of interaction back and forth between the Department of Defense and NASA. A large contingent of the Department of Defense people are at the Johnson Space Center working hand in hand with our people, and we have also flown several dedicated missions on the Shuttle with the Department of Defense payloads on it.
So yes, the answer to your question is they are involved.
CHAIRMAN ROGERS: Has the role of the DOD changed at any point during this program?
MR. MOORE: Not in the recent past, sir. The role, in fact, it has gotten stronger. As time has gone on, I would say the role of the DOD is getting stronger in terms of their planned utilization of the Shuttle. We have plans in the latter part of this decade, the early part of the 1990s, where the DOD would plan to use a full one-third of the Shuttle capabilities.
So I would say the role is getting stronger,
and their commitment to the Vandenberg Air Force Base launch system out there which will give us polar orbit launch capability-we now can only launch from the Kennedy Space Center, and basically achieve inclinations around 28-1/2 degrees to about 57 degrees latitude. The launch facilities out on the west coast will now give us polar orbiting capability which the DOD is working on that facility development.
Now, in the system deployment phase, we are in the process of implementing our major elements of the system, and at the Kennedy Space Center we have been building Pad B, the Launch Pad B. Up until this last launch we had been launching off of Pad A, and this 51-L mission was our first launch off of Pad B. We had also been putting in place our second TDRS, which is our Tracking and Data Relay Satellite System. That was a major cargo element on this flight, and the Tracking and Data Relay Satellite System is intended to allow us to communicate almost continuously with satellites from the Shuttle to the ground as opposed to using a lot of ground stations and so forth that we have been using up until this time.
We have also been planning to fly, and we have not flown it yet, a filament-wound case, which is a graphite/epoxy case to replace the steel cases on the
solid rocket boosters. And if I could take a second, I will show you what these are.
These are the solid rocket boosters. These are steel cases here, and we have had a program underway in development to replace the steel cases with a graphite/epoxy case called filament wound case. The objective of doing that is to achieve more payload performance. We can get about 5,000 pounds more payload into orbit by going to a composite structure versus steel, and you will hear more about that later on.
The Vandenberg launch site I mentioned to you earlier, the improved engine life, or CENTAUR, the improved engine life is on the Shuttle main engine. We have a concern in the  program about lifetime associated with the Shuttle main engines, and we have been putting a lot of effort into trying to get ourselves into a position for improved lifetime. We are developing CENTAUR G prime which is an upper stage that fits into the Shuttle bay, and it was planned or is planned to be launched in-the first launch attempt was planned in the May timeframe of this year, to launch two planetary missions.
(Viewgraph.) [Ref. 2/6-9 & 10]
MR. MOORE: We are also planning this year to launch the third Tracking and Data Relay Satellite,
again to give us the global coverage I talked about. Space Telescope is planned to be launched this year, a scientific payload. We are building the mobile launch platform, MLP-3, and the mobile platform is basically what our Shuttle System here rolls out to the launch pad on. You have seen the large crawler with the big system that the Shuttle is anchored on at the launch pad. That is called a mobile launch platform. We now have two of those in operation at the Kennedy Space Center, and we have been in the process of developing a third one at the Kennedy Space Center for operation sometime later this year.
CENTAUR G prime is another upper stage which is a derivative of the G prime system, and it has a little lower performance capability, and it is being principally developed not only for NASA missions but also for the Department of Defense missions. I should point out that CENTAUR development program is a joint responsibility of NASA and the Department of Defense, the Air Force in particular.
CSOC, the last one, is a Consolidated Space Operations Center which we are in the process of planning with the Department of Defense. It is the responsibility of the Department of Defense to develop this capability, and it would take over and develop and
do some of the operations of the Shuttle from this particular capability in CSOC, and it is in the Colorado area, and it is planned to be operational in the early 1990s. So DOD would help us in the operations.
CHAIRMAN ROGERS: Would you mind giving us a little more information about Pad B and Pad A? You said Pad B was the first time you had used that?
MR. MOORE: Yes, sir.
CHAIRMAN ROGERS: And were the differences between-I assume there are differences between Pad A and Pad B?
Can the Commission-will the Commission be given some information about the differences?
MR. MOORE: Yes, sir. Pad A has been our primary launch platform in the Shuttle program up until this flight, this flight being the 25th flight of the Space Shuttle. Pad B is adjacent to Pad A by some few miles, and it is in design approximately identical to Pad A, and this launch, as I said, was the first launch attempt from Pad B.
CHAIRMAN ROGERS: All before were from Pad A?
MR. MOORE: Yes, sir.
Mr. Sieck, who will speak on the launch and landing operations at the Kennedy Space Center, can give you some additional information about Pad B this
afternoon when he talks, and we will be happy to provide the Commission any additional data that you so desire regarding the similarities and differences between Pad A and Pad B.
CHAIRMAN ROGERS: Thank you very much.
 MR. MOORE: The next several charts I won't spend a lot of time. I think they are mostly for your background, Mr. Chairman and Commission members.
(Viewgraph.) [Ref. 2/6-11]
MR. MOORE: These kind of plot as a function of time-and I apologize again for the line at the top. The chart did not come out very well, so you will have a hard time looking at the dates on this, but this chart basically was from the first launch of the Space Shuttle in April 1981 through the 1982 timeframe where we flew the STS-4.
The next chart-
(Viewgraph.) [Ref. 2/6-12]
MR. MOORE: - carries us into the latter part of 1983, and it shows the launches of STS-5 through STS-9, which is Spacelab. And there are a number of different kinds of payloads on here. Most of these payload names are satellites, communications satellites or other attached experiments like, for example, on STS-7, Palapa B-1 is an Indonesian satellite; SPAS-01 is
a German payload structure and so forth, so to give you a little feel for those particular cargo elements.
DR. FEYNMAN: On the chart it says first flight of OV-99. Is that the Challenger?
MR. MOORE: Yes, OV-99 is Challenger. Let me just give you the numbers. OV-102 is Orbiter Columbia. That was the first orbiter built and flown. OV-99 is the Shuttle Orbiter Challenger. It is the second one delivered. OV-103 is Discovery, and it was the third one built and delivered. And OV-104 is Atlantis, and we just recently received that last year, as a matter of fact, and it has had its inaugural flight last year.
There is an orbiter called Enterprise which was a structural test orbiter, and it has now been turned over to the Air and Space Museum, and so we now have four flight-configured-had four flight-configured orbiters until the tragic mishap with Challenger.
Continuing on with the payload capabilities demonstration phase.
(Viewgraph ) [Ref. 2/6-13]
MR. MOORE: Through 1984 and early '85 we flew STS-41-B, 41-C, 41-D, 41-G and 51-A, and maybe I can spend a few seconds trying to give you a little bit of the sense of the nomenclature of the 41's: A's, B's and
C's. And it is 41, the number four stands for the fiscal year of the flight. From October to September is the fiscal year, so it is scheduled in that period of time. One stands for the launch area we are using. One is the Kennedy Center Launch Area, and if we were launching out of Vandenberg that would be a two, and the As, Bs, Cs and Ds are kind of the sequences that we have planned the missions, although as things have occurred we have had to move a mission over another mission, and so you don't get exactly an alphabetized listing of the flights.
(Viewgraph.) [Ref. 2/6-14]
MR. MOORE: Our next chart here through the 1985 timeframe, and the early part of-well, I guess the next chart we will show you through the 1985, we flew STS-51-C, which was a dedicated Department of Defense mission, and we flew 51-D, 51-B, 51-G, F, and 51-I through the latter part of the 1985 timeframe. And as a matter of fact, 51-I, for a point of reference, I believe, was launched on November 27, in that timeframe, of 1985.
(Viewgraph.) [Ref. 2/6-15]
MR. MOORE: In the next chart, the 61-A, 51-J was another DOD dedicated flight. 61-A was a Spacelab flight. 61-B was, the payloads were the communications
 satellites, and then the last flight before 51-L that we flew was STS-61-C, and we flew that in early January, and it also had communications satellites on it, among other cargo elements.
And then the flight that we are here to discuss, the 51-L mission, the Challenger incident, was planned, was launched on the 28th of January. That kind of gives you, Mr. Chairman, an early overview of some of the flight history and some of the very top-level structure of how NASA is organized, and what we have done in the Shuttle program to now.
If it pleases you, I would like to proceed with the 51-L mission summary and talk to you a little bit about the events of the day during the launch, where we are in the investigation work that we have done to date, what teams we have formed, and where we plan to go from here.
CHAIRMAN ROGERS: Mr. Moore, let's see if any Commission members have any questions.
DR. WALKER: I had one question. Why is 51-L after some of the sixties?
MR. MOORE: It was originally scheduled to be in an alphabetized sequence, but because of some of the cargo changes and so forth, we moved that nomenclature into the next fiscal year, and we just held the
nomenclature. Once you develop your documentation for a flight, it is awfully difficult several months before that time to go back and change all of your nomenclature. And so our principle is to hold the nomenclature, even though it may appear out of sequence in terms of the chronology of numbers and the alphabet.
CHAIRMAN ROGERS: All 24 of these flights were without accident, or were there minor accidents, and if so, how many?
MR. MOORE: The 24 flights to date have been without any major accident at all. We have a category called anomalies during a flight, like we may lose a power element or we may have something look anomalous on a flight, but no major accident. We have had a launch that has shut down on the launch pad, which is called a launch abort. The system is designed so that if things are not right before the solid rocket boosters light off, it will automatically go into a shutdown sequence. We had an occurrence of that. We also had an occurrence of a main engine which was shut down during ascent prior to reaching orbit, but we did reach orbit successfully, and the system operated as it was supposed to operate.
There have been a number of electronic problems, like we have had some problems with computers on board not functioning properly, and we have had some
problems with fuel cells, but there have been no major accidents in the Space Shuttle program to date up until this last flight.
CHAIRMAN ROGERS: Did you find that the performance improved with each launch or remained about the same?
MR. MOORE: I think our performance in terms of the liftoff performance and in terms of the orbital performance, we knew more about the envelope we were operating under, and we have been pretty accurately staying in that. And so I would say the performance has not by design drastically improved. I think we have been able to characterize the performance more as a function of our launch experience as opposed to it improving as a function of time.
CHAIRMAN ROGERS: I assume that you have rather complete records of each one of these flights.
MR. MOORE: Yes, sir, we have. As you will hear during the day, Mr. Chairman, we do a complete, thorough documentation of each flight, getting ready to each flight, and as the  Commission so desires, we will be more than happy to provide you with all of the information you need in those areas.
CHAIRMAN ROGERS: And do those reports show whether one flight seemed to be more successful than
And I am directing my comment-did you find that the performance was improved with each flight or not? Were you more worried in later flights or about the same, based on experience?
MR. MOORE: I don't think that we have relaxed at all in the program, and I don't think we have been more worried about the performance. I think we have gotten probably more confidence as a function of our overall performance on these things, but some of the events that we talked about, like the engine shutdown on the launch pad, that certainly worried us about the main engines because you need them to get to orbit, and we put together extensive review teams to find out what we could do about the engines program, and we have done a lot of work on that, and you will hear some more about the engine activities.
But as a function of time, I think our performance has been better characterized in terms of understanding the Shuttle system from a total system point of view is the way I would describe it.
DR. WALKER: I have one other question.
When were the graphite/epoxy casings to be phased into the program?
MR. MOORE: They are scheduled to be flown on the initial Vandenberg launch site flight, which is now targeted for the middle of the summer. It is mid July at this point in time is the current plan. So we have not flown any elements of the filament wound case, the graphite/epoxy cases up until this point in time.
DR. WALKER: Once you use them, was the plan to abandon the steel casings?
MR. MOORE: No, it is not. We have a major question that the program is looking at right now, and we probably won't get any good data on that until later downstream, and our question, among others that is on the table about the graphite/epoxy cases today, is can we reuse them?
You know, we currently reuse the steel cases. The Shuttle returns, it has its engines on the back, the SRBs are returned. They have parachutes on them. We go back and retrieve the SRBs and go through a refurbishment cycle on them to reuse them. For the graphite/epoxy cases, we are doing some of our final testing at this point in time, and we are not sure whether or not we can reuse those filament-wound cases after we fly them and they come back and impact the ocean. We have not made a determination like that, so we are not planning to get out of the steel case SRB business at this point in time. We have a lot of
additional work to go on the filament-wound cases.
MR. HOTZ: Mr. Moore, have you made any design changes in the steel casings of the SRBs since the beginning of the program?
MR. MOORE: I think there have been some very minor design changes in the SRB, and I think Mr. Judson Lovingood from the Marshall Space Flight Center will talk about that as he comes up here this afternoon or later on this morning. He will give you a detailed rundown of the chronology of the SRBs, the external tank and the main engines.
CHAIRMAN ROGERS: How many times can you reuse the booster?
 MR. MOORE: We have not set a real high use limit. We probably, I think-and Bill Lucas, maybe you can help me on this-20 times, Mr. Commissioner, is the current plan for the reuse of the steel cases on the SRBs.
CHAIRMAN ROGERS: What is the largest number of uses?
MR. MOORE: I think the largest-and again, I am recalling from memory-is about three to four times. This particular flight, 51-L, as I recall, had maximum of two uses of any of the components, possibly three, if my memory serves me correctly.
MR. SUTTER: I have one short question. The flights are characterized, the first flights were test flights to check the Shuttle system, and then the second phase was capabilities demo phase.
In the first flights which were labeled flight tests, was there a documentation of what was trying to be accomplished, what instrumentation was required, and then after those flights, was there a documentation of what the flights proved?
MR. MOORE: Yes, sir. We have very, very extensive documentation on all those flights, what we learned from those flights and what were changed as we left from the orbital flight test phase into the other phases of the program. We maintain very, very extensive records of all the flights.
MR. SUTTER: And at the conclusion of those flights were the objectives pretty well achieved?
MR. MOORE: In general, I would say the objectives of those flights were met. Each flight data was analyzed in great detail and fed back in to the program designers to look at what they actually achieved versus what they expected. And again, we will be able-we will be happy to make available to the Commission any data that the Commission so desires relative to any of the flights up until now.
Now, if I might, Mr. Chairman, I would like to move into the 51-L mission which is the mission we are talking about, Challenger's tragic mission, and I would like to start out by giving you a very brief look at what the cargo elements were on board. (Viewgraph) [Ref. 2/6-16]
MR. MOORE: I have talked about these, but let me talk to you again quickly. The largest payload component on board, and I should point out that the shuttle cargo bay, you are going to hear more about the dimensional characteristics and performance characteristics of the shuttle, but I should point out that the shuttle cargo bay is 15 feet in diameter and 60 feet long, to give you some feel of the dimensionality of the cargo bay, and we have flown a maximum of eight people in the shuttle up until this point in time.
On this flight, we had the Tracking and Data Relay Satellite. This was to be the second Tracking and Data Relay Satellite deployed. There is one on orbit now, and it was supported by an Inertial Upper Stage developed by the Air Force and used by NASA for the deployment of the satellite from low earth orbit where the shuttle takes you, up to the geosynchronous orbit where the Tracking and Data Relay Satellite has a requirement.
We also had on board a payload called Spartan-Halley. This was a structural element that actually sat across the shuttle bay attached to the cargo bay and supported several science instruments to do some observations of Comet Halley. And then we had in the crew compartment or the middeck area, we
 had the experiments associated with the Teacher-in-Space Program.
We had an experiment called CHAMP, Comet Halley Active Monitoring Program, a fluid dynamics experiment, some student experiments looking at different kinds of things from high school students, The Radiation Monitoring Experiment, and a Phase Partitioning Experiment.
Most of those sat in the middeck area of the orbiter, and you will hear some more about that particular area, and where the lockers are and so forth for putting those kinds of experiments. They are fairly small experiments.
(Viewgraph.) [Ref. 2/6-17]
MR. MOORE: The next chart shows the layout of the major elements of the cargo, and it showed the TDRS-B/IUS sitting in the cargo bay, the Spartan-Halley on the impasse, the support structure. It also shows on there an acronym which I talked about before called the RMS, which is the Remote Manipulator System. That is the arm on board.
The arm was planned to be used on this flight to pick the Spartan system up, deploy it overboard, leave it in orbit for a couple of days, rendezvous back with it, pick it up, and store it back into the cargo
bay and return back to the earth.
GENERAL KUTYNA: Jess, may I ask, how many remote manipulator arms do you have? Is that the only one?
MR. MOORE: No, we have another arm, and also we have a program with the Canadians for possibly refurbishing another one.
DR. WALKER: Could you say a word about the IUS?
MR. MOORE: Yes. The IUS is a two-stage solid inertial upper stage. It is solid rockets, and the TDRS in this case, I believe, is 5,000 or 6,000 pounds, and its purpose was basically to boost it from low earth orbit, which was about 140 or 50 nautical miles up to its position in geostationary orbit, which is about 22,000 miles. So it provides the propulsion to basically boost the Tracking and Data Relay Satellite up to its final orbital destination in geosynchronous orbit.
It is a two-stage rocket system. The first stage burns, and then after it burns it separates, and then it burns a second stage, and at the end of the second stage burn the IUS second stage separates from the TDRS and then the Tracking and Data Relay Satellite provides its own navigation and its own orbital adjustments with its own propulsion system on board.
(Viewgraph.) [Ref. 2/6-18]
MR. MOORE: The next chart gives you a quick summary of the STS 51-L mission profile. This shows the liftoff. In the case of 51-L the liftoff occurred at 11:38 a.m. on the 28th. We go through what we call a High Q phase or a high dynamic pressure phase for the flight, and then we go through planned SRB staging, and that SRB staging is about two minutes, and this 51-L mission was planned for 128 seconds, and at that point in time we had planned to stage off the SRBs, continue with the tank on the orbiter.
Remember, the tank provides the fuel to the shuttle main engines until we achieve our orbital destination some 150 or so miles into space. The tank stays with the orbiter or is planned to stay with the orbiter on this flight for about 523 seconds, after which time it has essentially depleted itself of its fuel. We shut the engines down, and some ten to eighteen seconds later we then separate the external tank from the orbiter, and then we plan to go about our orbital profile.
 That plans to give you some kind of feel for the profile. We had a six-plus day mission plan, and we had planned to land at the Kennedy Space Center on six plus a few hours, six days plus a few hours, so the
day-by-day mission profile is given to you in your upper righthand portion of this vu-graph.
DR. RIDE: You might say something about the Max Q phase of the flight.
MR. MOORE: The Max Q is the maximum dynamic phase. We see that we planned in the launch profile. We go through a throttling down of the main engines during that period of time, and we are concerned about loads on the orbiter, and so we throttle our main engines down, and this particular flight had a nominal engine profile of flying at like 104 percent of rated power, where we have flown a large, large part of our flights to this date.
We throttle down during that period of time to some lower percentage, and then after we have gone through that phase of the flight, we will begin to throttle back up again and hold that throttle setting until we get to geosynchronous orbit.
We are trying to minimize the loads on the total shuttle system during the time it is seeing its maximum dynamic pressure.
DR. FEYNMAN: Was there any special extra heavy load on this particular flight higher than other flights?
MR. MOORE: We do not think so, sir. In terms
of the prelaunch calculations, we get wind data prior to launch. We look at day of launch winds even an hour or so right before launch and try to get wind profiles and any kind of loads like that, and we have load indicators on the orbiter that are sensitive to different kinds of winds, whether you are getting a tailwind or a sidewind, and all of our calculations during that day had indicated that our loads condition was okay.
MR. HOTZ: Is there any change in the thrust of the solid rocket boosters when you are throttling back the main engines?
MR. MOORE: No, sir. The way the liftoff works is the shuttle main engines come on at approximately six seconds prior to what we call liftoff. We bring those engines up to their near nominal thrust level. We check those engines to make sure we have full redundancy on all the engines.
We have redundant systems on the engines, and once that check is made, a signal is sent to the solids to ignite the solids, and that happens about, as I said, about six to seven seconds after you have ignited the main engines.
Once the solids are ignited, then it lifts off the launchpad, and the solids are designed to provide stable thrusting during that period of time until they
are separated, in this case 128 seconds after liftoff.
MR. HOTZ: They don't change during the entire burn?
MR. MOORE: They are not planned to be changed during the entire burn. Now, we do have a thrust cone on the back of each of the solids, and there is a little gimbaling motion in case we do get a little bit of loading effect.
We can change the gimbal on there to change the orientation of the thrust, but the planned thrust of the solids is to have a matched pair of solids, a balanced thrust during the entire flight.
MR. HOTZ: Thank you.
 MR. ACHESON: Mr. Moore, at some point in the presentation today will we be briefed the test procedures, the preflight test procedures of all of the elements?
MR. MOORE: Yes, sir.
MR. ACHESON: And the contractor test procedures?
MR. MOORE: Sir, our briefing under the shuttle systems, when we begin to talk about l orbiter, we begin to talk about all of the propulsive elements of the shuttle system.
We will talk about the test procedures, the
NASA people involved, the NASA structure involved, the contractors involved, and then we will talk about our design approach, our certification approach, our testing approach.
We will also talk about the entire process that we use to get ready for a shuttle launch, and how that is tiered up from flight hardware and flight software point of view until it comes up to my level at NASA Headquarters. We will give you very, very much detail on that during the course of the day.
(Viewgraph.) [Ref. 2/6-19]
MR. MOORE: The next chart shows some specific mission data on STS 51-L, launch data on 51-L, January 28th, 1986. The orbiter is OV-99 Challenger. And we had a planned liftoff time of 9:38. Now, we had a three-hour launch window, and for a lot of our flights we don't have the luxury of a very long time to launch in terms of meeting payload requirements.
Some launch windows are like 50 minutes, and others are like an hour and a half or two hours. This launch we had three hours to launch. The throttle setting on the main engines were 104 percent of rated power level, and we have flown many times at 104 percent, and the abort thrust setting in case we had a problem going uphill was 104 percent as well. We keep
the same engine thrust. The inclination of the orbit we had planned was 28.45 degrees, and we had planned to achieve an orbital altitude of 153 and a half nautical miles circular.
DR. FEYNMAN: What is the inclination? What angle is that?
MR. MOORE: It is basically the inclination of the orbit relative to the latitude of where we are launching out of Kennedy, and it is the inclination relative to the-say, polar inclination. You are at 90 degrees. You are basically going around the earth, over the poles of the earth, and you can allow the earth to spin.
You have got an inclined orbit here like the 28 and a half degrees, and so you are not getting full coverage of the earth, so if you are plus or minus 28 and a half degrees latitude coverage in effect and your orbit is like a sine wave which walks across a still map if you were to plot continuous maps of the orbit.
One of the considerations among others that we have to do in this program is to look at our landing sites, not only for end-of-mission landing sites, which is a concern, but also abort once around, which is a condition where something could happen during the powered flight phase of the profile and not allow us to achieve
a full stable orbit.
In that case, we could go once around the earth and come back. Edwards was a planned landing if we had an abort of that nature. We look at weather alternates as well.
The Kennedy Space Center has inclement weather on a fairly high frequency-witness the last launch prior to 51-L-in terms of clouds or in terms of rain, and we have very stringent rules about what landing requirements are on the system, and so we have a weather alternate.
 We also have a trans-Atlantic abort capability in the event we lose an engine during a certain phase of the flight.
We have runways and people and systems on standby in places in Africa and also places in Spain where the shuttle could land if such a problem like that occurred, and in this case for Mission 51-L we had runway availability in Dakar, Senegal, and also in Casablanca, Morocco.
Both of those runways were considered viable trans-Atlantic landing sites in the event we had a problem, and we look at that on a real time basis during the preparations for launch and during the actual launch count.
We also have what we call an RTLS. Let me say
before I mention this there is a whole number of abort kinds of capabilities in the system. We are not planning to go into great detail today on that, but we will be happy to provide you with additional data on kind of the abort modes in the shuttle program.
We also have one other capability called RTLS. That stands for Return to Launch Site, and that is in the event again during a certain phase of the projectory if we have a problem, we can return back to the Kennedy Space Center. After that particular problem has been noticed, and after we have separated the solids, you can come back to the Kennedy Space Center and land there.
So, a constraint for launch is that we have good weather at the shuttle landing strip at the Kennedy Space Center for some 30 to 40 minutes after a launch to make sure that we have a capability if that event occurred to land at the Kennedy Space Center.
DR. RIDE: It might be helpful to go into a little bit more of the things that you might do an RTLS for or the constraints on an RTLS.
MR. MOORE: Arnie is planning to cover that, Sally, during his discussions today about what an RTLS and what other abort modes might be, but that is a good point. We will do that.
Flight duration, as I mentioned, was six days.
(Viewgraph.) [Ref. 2/6-20]
MR. MOORE: Now, I would like to tell you a little bit about launch date chronology leading up to our launch on the 28th, and this will give you a feel, a very preliminary feel, about the meetings that we have in terms of getting ready for a launch and who participates in that, and I am sure we will want to spend some more time on that as time goes on.
The first day we met at the Kennedy Space Center was on January 25th. Prior to that time there had been a number of meetings that a lot of the project people and even myself had participated in, talking about are we ready to launch Challenger on the 25th, at that point in time, or the 26th, I guess, was when that was scheduled, and we all agreed, so we all met at the Kennedy Space Center on the 25th of January, anticipating a launch on Sunday, and that was the 26th.
We have what we call an L-1 Day Review. Participants include myself, my senior managers, and my NASA Center people, directors, the contractor senior people, where we sit around the table and review the status of the system prior to launching. That meeting occurred at 11:00 a.m., and the major outcome of that
meeting was that we had a weather problem, potential weather problem, on Sunday.
We decided at that point in time to hold a meeting Saturday afternoon or late Saturday evening, I should say, 9:30.
 We met again with essentially the same type of people there, although not as large, and at that time we got our weather reports, and we decided the weather for the next day was no go. We had no optimism for the weatherman that said the rain was going to stop, or we would have an attempt to get off, and it takes an effort to get the team up, and so we decided to bet on the weatherman's forecast, and decided not to launch that day.
Well, it turns out the early part of Sunday morning for about an hour was a reasonable time. The frontal system had not reached Florida yet, and so we didn't win that call in terms of the weather, but it was a no go on Saturday night.
DR. FEYNMAN: Would you explain why we are so sensitive to the weather?
MR. MOORE: Yes, there are several reasons. I mentioned the return to the landing site. We need to have visibility if we get into a situation where we need to return to the landing site after launch, and the
pilots and the commanders need to be able to see the runway and so forth. So you need a ceiling limitation on it.
We also need to maintain specifications on wind velocity so we don't exceed crosswinds. Landing on a runway and getting too high of a crosswind may cause us to deviate off of the runway and so forth, so we have a crosswind limit. During assent, assuming a nominal flight, a chief concern is damage to tiles due to rain. We have had experiences in seeing what the effects of a brief shower can do in terms of the tiles. The tiles are thermal insulation blocks, very thick. A lot of them are very thick on the bottom of the orbiter. But if you have a raindrop and you are going at a very high velocity, it tends to erode the tiles, pock the tiles, and that causes us a grave concern regarding the thermal protection.
In addition to that, you are worried about the turnaround time of the orbiters as well, because with the kind of tile damage that one could get in rain, you have an awful lot of work to do to go back and replace tiles back on the system. So there are a number of concerns that weather enters into, and it is a major factor in our assessment of whether or not we are ready
CHAIRMAN ROGERS: Mr. Moore, in that connection, I notice a press report that one of the contractors said that they gave a warning of some sort about the cold weather. Could you deal with that, please?
MR. MOORE: Yes. I am going to continue on with this chart, which will deal with that cold weather question in a fair amount of detail, Mr. Chairman.
CHAIRMAN ROGERS: Fine.
MR. MOORE: Since we decided not to attempt the launch on the 26th, we called a meeting on the 26th itself at 2:00 o'clock in the afternoon, again an MMT meeting or Mission Management Team meeting, to sit down and see what the weather situation was projected to be, plus the status of our launch systems, including the launch pad and the shuttle system.
We decided after reviewing everything that launch was a confirmed go for Monday, the 27th, and that we confirmed that we were ready to attempt to launch on 9:37 a.m. on Monday, January 27th. Well, on Monday, January 27th, we did in fact get ready for the launch, and that involves making sure all of the systems have been checked out, the launch system is up, and making sure you have fueled up the external tank, which we do
 about seven or eight hours before the launch, and making sure you then bring the crew on board and make sure all the systems are ready for launch.
And so we started that late in the evening, started the final countdown and began a launch attempt for Monday morning at 9:30. We had a couple of initial delays during that attempt. There are a couple of microswitches on the orbiter that we need to receive closed indications of before we close out our requirement, and we were only getting one indication of a microswitch on there was closed, and so we went back and did a pressure check in the cabin to make sure that the seal was proper on the cabin door and you didn't have any leaks, and we convinced ourselves that that was okay.
Then we have a piece of GSE or Ground Support Equipment which attaches to the orbiter door to allow the technicians to close the door, and it is fastened on by some bolts and a nut plate that is attached to the orbiter Challenger's door, and it is fastened on in three places. One of the nut plates that is fastened onto the orbiter came loose, and we could not get the bolt off in a very timely manner, and so we sent some technicians out to actually take a hacksaw and pull this piece of Ground Support
That was successfully done to our satisfaction, but by the time we finished that, we had high crosswinds, and I mentioned crosswinds earlier on January 28th or 27th, and the high crosswinds, we had wind gusts up to 30 knots, and our limit is like 15 knots.
We have a limitation, a flight rule in the program that we did not launch because of the Return to Landing Site condition if crosswinds are too high. So the winds kept getting stronger that day, and after watching the wind patterns for some hour to an hour and a half, we decided to scrub that particular launch attempt for that day.
Then we called a Mission Management Team Meeting again, which is made up of the senior NASA managers, shuttle managers, Center directors in some cases, and contractor support people in other cases, at 2:00 in the afternoon on the 27th, and discussed should we attempt to launch on the 28th.
We had a fairly lengthy meeting, with the only concern being expressed that the weatherman had predicted the temperatures were going to be fairly cold that evening, down into the mid-20s. It was kind of the prediction.
And we talked about temperature concerns, and the main concern that came out of our meeting as far as temperature was, are the water systems or the support systems on the launch pad, the water pipes, eyewashes where technicians have water running to wash their eyes in the event they get contaminated on the launchpad and so forth, were these pipes going to freeze, and that was the major concern that the system had at that point in time.
Now the launch team guys were given the instructions to proceed with the launch for 9:38 in the morning, assuming there were no problems with tanking and getting the system working and ready, and because we had one waterpipe that broke on the launchpad, and I
think Bob Sieck can talk a little bit more about this than I can from Kennedy, we were an hour down in our launch attempt. So instead of 9:38 the earliest we could have launched was like 10:38, because our count was delayed about an hour. We had one pipe that burst.
 The other problem that we had and were concerned about all during this discussion was ice. We were concerned about ice buildup, and I think this is where you read the article, Mr. Chairman, about the ice concern. We were concerned about ice on the launch tower and that particular ice doing some damage to the orbiter surfaces and the orbiter tiles because of how fragile those tiles are from impacts and so forth.
There were technical meetings held to assess the ice situation. A major technical meeting was held involving a number of people that was chaired by Arnie Aldrich here of JSC. Their assessment came back that the system is okay, we should hold the launch for probably one more hour to allow a last-minute ice team to go out at about 20 minutes before launch and to validate the ice concerns, to go back and do another doublecheck of the ice, and that was done.
They came back and reported that everything was okay, and that we ought to go for launch, and a launch window then opened up at 11:38, I believe was the
time, on Tuesday morning.
DR. FEYNMAN: On the 27th you made a launch attempt?
MR. MOORE: Yes, sir.
DR. FEYNMAN: That means you put fuel into the tanks?
MR. MOORE: Yes, sir.
DR. FEYNMAN: Does it stay in the tanks all this time, or do you take it out?
MR. MOORE: No, sir. Immediately after we, so-called in our jargon, scrub, we start safing the vehicle. The crew stays on board and does a number of functions to get the vehicle in a safe condition to make sure all propellants and all electrical systems are properly safed. Other people go to the launchpad to start safing the launchpad, and then we allow the hazard and safety teams to go out and make sure it is all acceptable for people to come out and do the deservicing on the tank, and the fuel is drained out of the tank, and it will not be replenished again until we get ready to launch again, which is again some seven or so hours before the actual liftoff time.
DR. FEYNMAN: And all this time even when the tank is empty, the tank is standing there, and the rest of the equipment, in the weather?
MR. MOORE: Yes, sir.
DR. FEYNMAN: How early was it put out in the weather?
MR. MOORE: Sir, I am going to have to ask Bob Sieck. This tank and the entire stack on Challenger was moved out, I believe
MR. SIECK: December 21st.
MR. MOORE: It was moved out to the launch pad on December 21st, sir.
DR. WHEELON: At your meeting where you were concerned about the weather and the temperature, did you discuss and consider the impact that that weather might have, and the temperatures in particular, on the vehicle?
MR. MOORE: Yes, sir, that was discussed at the meeting, and I think the technical team meeting that Arnie chaired-Arnie can probably comment on the specifics of that, because he came back to me after the meeting was held on the temperature discussion and reported that everybody was okay from a temperature standpoint.
And I will ask Arnold Aldrich when he comes up to talk about that in a fair amount of detail, since Arnie chaired the meeting from all the parties involved in that particular session.
CHAIRMAN ROGERS: I thought that the report I
 read about temperature referred not to the outside of the space ship but to the booster rocket. The claim was, according to the newspaper, that there was concern that the cold temperature might have affected the booster rocket inside not outside.
MR. MOORE: That may be. The one paper or article I remember seeing, Mr. Chairman, was the article on the effects on the orbiter and so forth, and I will ask the people here who are in charge of the solid rocket booster to talk about any discussions that went on relative to that, and feel free to ask those questions to the members who have the responsibility for the various program elements as they discuss their systems.
CHAIRMAN ROGERS: What I refer to is not a rumor or just gossip. It was a statement by one of the contractors that was a quote that was issued.
MR. MOORE: Yes, sir.
DR. WHEELON: But, Jess, just to come back and be clear, at your meeting was the potential impact of low temperatures on the SRBs discussed with you? Was it dismissed or not discussed?
MR. MOORE: At the meeting that I had with Mr. Aldrich, who had come back after the review from his technical team meeting, it was not discussed at my
meeting. It was discussed at the meeting we had, the Mission Management Team meeting at 2:00 on the 27th of January. Is that right, Arnie? It was discussed by all of the people representing all of the systems. It was discussed on the 27th of January. Again, I will ask Arnie to give a little bit more details of that, since he was involved in that particular meeting on the orbiter.
DR. WHEELON: But it was not presented to you as a matter of potential concern?
MR. MOORE: It was not presented to me as a matter of concern. That is correct.
DR. WALKER: Mr. Moore, will you at some point tell us how many temperature sensors you had in the vehicle and where they were?
MR. MOORE: I will have to have the system design people do it, and let me ask the project element management down here if they would please talk about that to the extent they can.
Jud, can you do that from the Marshall side, and Arnie from the orbiter side?
(Viewgraph.) [Ref. 2/6-21]
MR. MOORE: Okay, the next chart shows the initial assessment after the launch, after the Challenger lifted off at 11:38 on January 28th. I
mentioned the fact that the launch had been delayed for a couple of hours. The launch processing equipment problems I talked about, the ice inspection of launch complex and ice removal. I did not have any concerns about the temperature expressed other than the concern on the complex, launch complex.
The actual flight, the ascent appeared normal based upon our initial quick looks for the first 73 seconds, and it went through its main program roll maneuver where the shuttle rolls from its initial launch configuration through its maximum dynamic pressure I talked about, and then the throttle down and throttle back up of the shuttle main engines.
The vehicle again appeared to be performing nominally at our 104 percent thrust at approximately 1,200 miles an hour at approximately 47,600 feet, when all our telemetry stopped, and at that point in time we observed the breakup from the ground. All of our controllers that we heard over the loop and all of the net had indicated that the flight was nominal were all of the calls that I had heard during the morning of the launch.
 (Viewgraph.)[Ref. 2/6-22]
MR. MOORE: What we initially put in place, the immediate actions that we took, we impounded
immediately all data and information from this flight at all sites. We have a contingency plan in NASA, and each center has a contingency plan on STS contingency events of this nature, and immediately I then was requested by Dr. Graham to form a Mishap Investigation Board.
I immediately put that into effect, and I had members, the director of the Kennedy Space Center, the director of the Marshall Space Flight Center, Arnold Aldrich, the National STS Program manager at Johnson, and Walt Williams, a former NASA employee, a special assistant to the NASA administrator, as immediate members, and additionally I added in the next couple of days Bob Crippen of the Astronaut Office at Johnson Space Center, and I also added Joe Curran, who is director of the Space and Light Sciences from the Johnson Space Center. As ex officio members on my group,
I added John O'Brien, chief counsel at NASA, and Milt Silviera, who is the chief engineer at NASA. Jim Harrington was my director of STS integration. He was the executive secretary. And shortly after this formation, we immediately put into effect a number of teams to start action.
I have listed those teams on this chart, and I will quickly just run through them. I think you can read them, and they are probably self-explanatory, but
some of them, I think, probably are worthy of some mention.
(Viewgraph.) [Ref. 2/6-23]
MR. MOORE: The Flight Data Trajectory and Com Team was immediately formed, a team to do the analysis of the launchpad facility at beach area, and I should point out, Mr. Chairman and Commission members, that we have held all the data, impounded all the data, kept the configurations the same as it was the day of the incident, and we will be working with your Commission as well as our own activities before releasing any of those types of information.
DR. WHEELON: Just before you get too far away from it, could we go back to the trajectory circumstances surrounding the accident? You have indicated in the handout that you were at 47,600 feet, going approximately 1,200 miles per hour. You have just gone through maximum dynamic pressure. To what level did you throttle down during that period?
MR. MOORE: I will have to recall my memory, but we do have a throttle profile. Let me look at my information. We throttle down initially from 104 percent, and I will be happy to give you a copy of this throttle profile. We throttled down from 104 percent at
20 seconds to 94 percent, and that is held until 36 seconds, and then at 39 seconds, between 36 and 39 seconds we throttle down to 65 percent and hold that from 39 seconds until 52 seconds, and then from 52 seconds to 57 seconds we throttle up to 104 percent.
DR. WHEELON: Was that the usual throttle-up, throttle-down profile?
MR. MOORE: It varies depending upon the loads and so forth that we have got in the system, you know, the cargo elements and the kind of profile that we have to fly to achieve it, but we always generally go through a throttle bucket of that general type, and we will be happy to get you the specific.
DR. WHEELON: But to your knowledge there was nothing that distinguished this profile from those flown previously except for the payload compensation?
 MR. MOORE: No, sir, to my knowledge there was nothing unique or that distinguished this, and let me say that we are doing-right now a lot of work is going on in looking at the detailed trajectory calculations. It takes-the Marshall Space Flight Center gets data. The Cape gets data. Johnson is the lead in this thing, and they have got all of that flight data, and we have a major team going and looking at synching up all of the trajectory data during the
various mission phases and mission events that went on.
DR. WHEELON: What was the Mach number at this time?
MR. MOORE: About 1.8, I believe, if my memory serves me correct.
MR. SUTTER: Depending upon the load and everything, isn't there a variation in the loads as you go through this, rather dynamic?
MR. MOORE: There is a variation in the load, and we use a parameter called Q alpha, which is dynamic pressure versus an angle of attack to look at the load calculations, and also have instrumentation that we look at, and look at various load points on the wings and the various surfaces of the orbiter, and do that calculation based upon a given kind of wind profile.
We put balloons up starting at like 36 hours before launch to 24, down to about an hour or so before launch to get wind profile data. That is fed back into our computer programs to give us load indications, to see if we have got any exceedences on any parts of the orbiter.
MR. SUTTER: So during this flight then the load versus time and compared to other flights is something that will be known?
MR. MOORE: That is correct. Yes, sir. We will know that very,
very precisely, and as to our knowledge on the day of launch, we did not have any loading sequences on any of the indications and trajectory analyses we had.
DR. WALKER: Is the throttle controlled by the crew?
MR. MOORE: The throttle is automatic.
DR. WALKER: Thank you.
DR. RIDE: The throttle can be controlled by the crew, but on a nominal ascent it is not.
MR. MOORE: Sally knows very well. Excuse me. A nominal throttle is automatic by the general purpose computer system on board which basically flies the flight profile.
There are a number of other teams we put in place, photography teams, data analysis, pedigree teams looking at the hardware, looking at the processing of this hardware. The quality records, the manufacturing records, and so forth on that are all being put in place.
Looking at security, in terms of anything that would be anomalous as far as security, range safety, public affairs. We have got a team on the flight crew with Bob Overmeyer chairing that from JSC. Marshall has a team on the main propulsion system, and the flight vehicle impoundment has also been formed.
We formed some additional teams on salvage and recovery, and our philosophy in the recovery of all the debris or wreckage from this tragic event has been to identify as best we could the areas and to delicately move when recovering, the parts that we possibly can without doing any additional damage.
We have, as you will see on the next chart, the next slides, a lot of support from a lot of different people in this whole area.
The other thing I want to mention to you is that we are forming a devil's advocate team, and that devil's advocate team is a TBD over there, which means To Be Determined. I have not  named the members of that team, and that will be a team which will set off and support my activities and think up scenarios that may have occurred on this mission that will not be intimately involved into the detailed scenario analysis that we are doing with our own teams in place here. There will be a team set off to the side and hopefully do some independent thinking to make sure we are not letting anything fall through the cracks.
(Viewgraph.) [Ref. 2/6-24]
MR. MOORE: The status as of today, we have reviewed some data, and our analysis does continue. As I said earlier, we are putting a very, very detailed time line of all events together. The initial time lines that we saw right after the occurrence were kind of first order time lines, and we are going back and developing and constructing the high-speed data to look at it.
We are enhancing all of our photography that we can, and we are concentrating a lot of that photography on the righthand solid rocket booster. As you probably have seen, we have released some photos which-I have three of them in here-which would indicate a plume in the righthand solid rocket booster.
The salvage and recovery operations is proceeding. I would like to just say, Mr. Chairman, that we have had extensive cooperation from all branches of the military, and we very much appreciate that, and also extensive cooperation from the National Transportation Safety Board, who have just been invaluable to us in helping us and assisting us in this grave incident that we are going through.
The wreckage analysis and reassembly is proceeding well, and we have essentially from a
procedural standpoint turned that over to the National Transportation Safety Board. They are working with us in laying out areas where we are trying to preserve as much of a wreckage as we can, and laying it out in some manner that we hope will give us some clues in terms of what kind of anomalies we did experience on this flight.
The next three charts show the three photos that we released, and again I apologize. We are working on getting each member of the Commission quality photos to replace the photos that did not turn out. In the interest of time I was not able to put any better photos.
You can see them on the monitor here. This photo was taken at about-and you are looking at the righthand solid rocket booster here, and it may be difficult to see on your screen, but the external tank outline is here. The solid rocket booster is shown here.
These are some reflections, we believe. We also think this is a reflection, but again these are very, very preliminary, and we are not prepared to conclude exactly what all of these are. These appear to be the engine plumes, and you can see the tail of the orbiter here at this point in time, and that photograph was observed at 58.3 seconds. [Ref. 2/6-25]
(Viewgraph.) [Ref. 2/6-26]
MR. MOORE: The next chart will show what appears to be a plume in this area, in the area of the righthand solid coming out at a time of 59.8 seconds.
(Viewgraph.) [Ref. 2/6-27]
MR. MOORE: And the final chart shows the plume has basically grown and merged into the tail from the engines and the other solid, and it basically looks like it has moved quite a bit here, and that occurred at 73 seconds, just milliseconds from the tragic event.
CHAIRMAN ROGERS: Would you mind showing us on the model where that plume is?
 MR. MOORE: Let me make one comment. I can't show you exactly where it is, because we don't know exactly. I can show you the vicinity of where it is, is what I will attempt to do.
This is the righthand solid rocket booster, and it appears that the plume is in this area in here. Somewhere in this area is where it would appear, and until we complete our detailed photographic enhancements with the best laboratories that we can get to support us through the overlays and make sure the trajectory siting and the angles of the cameras are all pinned down, it is going to be very difficult to pin it down any closer than to just say that it appears in this area right in here.
MR. HOTZ: Which segment of the solid rocket would that be?
MR. MOORE: We do not know. This is an aft segment here, and there is an aft center segment right in here that is joined together in this area. This is the structural attach point here to the external tank, and we don't know whether it is the aft center segment. We don't know whether it is the aft segment. We don't know for sure it is the SRB.
I will caution you, it appears in that area, but we are not ruling out anything at this point. I just can't say that other than there appears to be a plume in that area. That is basically all the data that we have at this point in time until we do our high-speed photography enhancement and begin to try to pin that down some more.
DR. WALKER: Could you show us where the seams are in the solid rocket booster, approximately?
MR. MOORE: I can attempt to do that. You are going to see that laid out in quite a bit of detail when the Marshall people talk about the solid rocket booster and so forth.
DR. WALKER: I can wait until then.
MR. MOORE: Would you, please? Thank you.
(Viewgraph.) [Ref. 2/6-28]
MR. MOORE: Now, my final chart, Mr. Chairman and members of the Commission, is to tell you that the activities we initiated on that tragic Tuesday at NASA are continuing. We are doing everything we possibly can to analyze the data from this occurrence and put in place a mechanism to fully assess and evaluate and determine the problems associated with this particular mission.
Yesterday I was designated by Dr. Graham to be the chairman of the 51-L Design Data and Design Analysis Task Force. We are continuing to analyze the facts and circumstances and to identify any design issues that we can surrounding this incident, and we are authorized to use any technical and scientific resources within NASA and any available external resources that we possibly can that we feel the need to call upon to solve this problem, and we would be happy to support you and the members of this Commission in any way you deem fit, and we are planning to proceed forthright in our analysis and detailed evaluation of this tragic event. And that is all the charts that I have prepared this morning, Mr. Chairman.
CHAIRMAN ROGERS: Thank you very much, Mr. Moore, for a very good briefing. We appreciate it.
MR. MOORE: With your permission, I will
introduce Arnold Aldrich from the Johnson Space Center, and he will go through a process of covering the other elements that I cited earlier.
 CHAIRMAN ROGERS: I would like to suggest that we take a five-minute recess, if you don't mind, before we get started.
(Whereupon, a brief recess was taken.)
CHAIRMAN ROGERS: Ladies and gentlemen, we will come to order, please.
Would you please swear Mr, Aldrich in?
Mr. Aldrich, proceed.
[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. 2/6-1] AGENDA [of Jesse Moore's testimony].
 [Ref. 2/6-2] ORGANIZATION CHART [NASA chart; From Administrator to field center levels].
 [Ref. 2/6-3] OFFICE OF SPACE FLIGHT CHART [NASA; Organization chart]. [Ref. 2/6-4] STS MANAGEMENT RESPONSIBILITIES CHART [NASA; Organization chart].
 [Ref. 2/6-5] NATIONAL STS PROGRAM MANAGEMENT RELATIONSHIPS [Management responsibilities]. [Ref. 2/6-6] PLANNED EVOLUTION OF THE NATIONAL STS PROGRAM [December 1985; Covering period from 1981 to 1986; Orbital Fligh Test Phase; Payload Capabilities Demo Phase; Payload Operational Phase; System Deployment Phase- see following charts.]
 [Ref. 2/6-7] NATIONAL STS PROGRAM ORBITAL FLIGHT TEST PHASE [Flights STS-1 through STS-4]. [Ref. 2/6-8] NATIONAL STS PROGRAM PAYLOAD CAPABILITIES DEMO PHASE [Flights STS-5 through STS-9].
 [Ref. 2/6-9 & 10] NATIONAL STS PROGRAM PAYLOAD OPERATIONAL PHASE [Flights STS 51-C through STS 51-I].
 [Ref. 2/6-11] NATIONAL STS PROGRAM ORBITAL FLIGHT TEST PHASE [Flights STS-1 through STS-4- identical chart as Ref. 2/6-7]. [Ref. 2/6-12] NATIONAL STS PROGRAM PAYLOAD CAPABILITIES DEMO PHASE [Flights STS-5 through STS-9; chart identical to Ref. 2/6-8].
 [Ref. 2/6-13] NATIONAL STS PROGRAM PAYLOAD CAPABILITIES DEMO PHASE [For the year 1984; Flights STS 41-B through STS 51-A]. [Ref. 2/6-14] NATIONAL STS PROGRAM PAYLOAD OPERATIONAL PHASE [For the year 1985; Flights STS 51-C through 51-I].
 [Ref. 2/6-15] NATIONAL STS PROGRAM PAYLOAD OPERATIONAL PHASE [End of 1985, early 1986; Flights STS 51-J through STS 61-C].
 [Ref. 2/6-16] STS 51-L CARGO ELEMENTS.
 [Ref. 2/6-17] NATIONAL STS PROGRAM STS 51-L CARGO CONFIGURATION. [Ref. 2/6-18] STS 51-L MISSION PROFILE [From launch to landing].
 [Ref. 2/6-19] STS 51-L MISSION DATA.
 [Ref. 2/6-20] [STS 51-L] LAUNCH DATE CHRONOLOGY.
 [Ref. 2/6-21] STS 51-L MISSION ACCIDENT INITIAL ASSESSMENT. [Ref. 2/6-22] IMMEDIATE ACTIONS TAKEN.
 [Ref. 2/6-23] [STS 51-L investigative] TEAMS & ADDITIONAL TEAMS.
 [Ref. 2/6-24] STATUS [of investigation as of February 6, 1986].
 [Ref. 2/6-25] [NOT REPRODUCIBLE]. [Ref. 2/6-26] [NOT REPRODUCIBLE].
 [Ref. 2/6-27] [NOT REPRODUCIBLE]. [Ref. 2/6-28] [Investigation] ACTIVITIES CONTINUING.
MR. ALDRICH: Chairman Rogers, members of the Commission, my name is Arnold Aldrich, and I am manager of the National Space Transportation Systems Program Office at the Johnson Space Center.
(Viewgraph). [Ref. 2/6-29]
MR. ALDRICH: I am going to describe for you a little bit about the program management again to show you where I fit in the structure that Jesse described, and then I will describe the STS system elements, some of the system element performance, and then some of the orbiter subsystems.
Following me, Dr. Lovingood will describe the propulsion elements responsible by the Marshall Space Flight Center, and Bob Sieck will describe the launch and landing facilities that make up other portions of the STS system.
(Viewgraph). [Ref. 2/6-30]
MR. ALDRICH: The next chart deals with the program management relationships. We just passed over this chart. Level 1 control of the program is done here in Washington under Jesse, Associate Administrator for
Space Flight. They determine top level program requirements, budgets, schedules, policy for the agency on the Space Shuttle Program, and they deal with large budget items that would affect primary requirements in the overall program and the overall program schedules.
My office, as program manager at the Johnson Space Center, is management and integration of all program elements in support of the Level 1 organization. We do integrated flight system and ground system requirements, schedules and budgets, control of all project interfaces, control of changes exceeding program budgets of the different projects across the center, and those that impact overall STS program requirements, interfaces, and schedules.
Below that are the Level 3 projects at each center, and I will say more about those on the subsequent pages. Level 4 is defined on this chart by the specific contracts with industry that will be described for the fabrication, design, and provision of the flight hardware and the ground hardware that supports the STS program.
(Viewgraph). [Ref. 2/6-31]
MR. ALDRICH: The next chart says a little more about the concept of the program office at JSC for the STS program. This is what NASA calls the lead
center concept. That is a relatively small staff at NASA Headquarters for policy, overall budget, and overall program direction. There is a large program office under myself at the Johnson  Space Center that is responsible for control and integration of all elements of the Space Shuttle System.
This work across the system is identified in the detailed work breakdown structure. It is supplied to all elements across the program, both government and contractor, for all activities and program management, the office manager's projects at the various centers, and at those centers those projects that manage the contractors that provide the actual hardware that we are talking about here today.
Integration of this total system is identified as a government role. However, we also have contractor support in those areas, and I will identify them, some of the major contractor activities on a subsequent chart.
Project managers at the centers are also in a line responsibility and report through their directors to Jesse in an institutional fashion as well as through this program chain which I am describing to you within the Level 2 program office, we have a system, a very careful and detailed
documentation and control of all technical and management requirements for the program at all levels, and that will be discussed a little bit later in the day with some of the later briefings.
We also have very frequent communications nationwide within this program, and we use an extensive teleconferencing system, because travel is really impossible for the kind of day-to-day and continuous communications we use, and as was mentioned by Jesse, particularly in the last several years, we have very extensive involvement with the Department of Defense and the Air Force, both with their payloads and with the coming on line of the Vandenberg Launch Facility on the west coast.
(Viewgraph) [Ref. 2/6-32]
MR. ALDRICH: The next chart describes the structure of the government-industry team. That falls under the National Space Transportation System. Again, the overall policy and direction is the government at NASA Headquarters. My role as the JSC Lead Center is for program planning and control, system and cargo integration of the total system, operations and mission integration for the preparation and the flight of the Shuttle system. In executing those responsibilities-I am sorry for these acronyms; we tried a
chart with them spelled out, and they were very voluminous, and I have their names on a subsequent chart- Rockwell International Space Division is in charge of system and cargo integration and engineering in support of the STS program, and at the Johnson Space Center, also Rockwell International, the Rockwell support operations contract provides Shuttle engineering and operation support.
The Level 3 NASA projects of the National Space Transportation System, the orbiter, at JSC. Rockwell Space Division, Downey, California, is Prime. Space Shuttle Main Engines are the responsibility of the Marshall Space Flight Center, Rockwell International Rocketdyne Division is Prime. External tank, Marshall Space Flight Center, Martin Marietta Corporation, Michoud, Louisiana, near New Orleans, is a Prime Contractor.
Solid rocket boosters, United Space Booster Production Company is prime. Solid rocket motors are fabricated and refurbished by Morton-Thiokol in Brigham City, Utah, in support of the Marshall Center.
 The launch and landing facilities were developed in support of the Kennedy Space Center by a number of contractors, and in the last two years the Lockheed services operations contract is a consolidated contract that has those responsibilities in support of KSC.
The mission support at the Johnson Space Center for mission flight support, flight preparation, and crew training, Rockwell space operations contract is also a consolidated contract and that has recently come into being at the Johnson Space Center for consolidated contractor operations there.
DR. FEYNMAN: Could you tell me the difference between the solid rocket booster and a solid rocket motor?
MR. ALDRICH: Yes, sir. The solid rocket motor is the elements-well, I probably should let Dr. Lovingood give you that in detail, but basically the solid rocket motor are the elements with the propulsive grain in them, and the rest of the systems, the recovery systems, the gimballing systems, the electronics together make up the solid rocket booster as a total system.
(Viewgraph.) [Ref. 2/6-33]
MR. ALDRICH: This chart, in fact, deals with the elements of the STS program, the orbiter which I will be discussing in a few minutes, flight software, which goes in the orbiter but which controls all of the elements of the Space Shuttle System during the various phases of flight and even during ground checkout.
Main engine external tank and solid rocket
boosters. Flight crew equipment; have a significant activity in the program for spacesuits, for man maneuvering units which Jesse discussed, also for other crew equipments within the cockpit in support of the flight crew.
A number of cargo elements, and I will discuss some of those later, also for cargo integration of the various payloads that come from various places nationally and even internationally, integrating them into flyable cargoes to make them part of the National Transportation System. Launch and landing facilities and upper stages, and I believe Jesse described and gave you the names for each of these.
(Viewgraph.) [Ref. 2/6-34]
MR. ALDRICH: The next chart shows these pictorially. Again, it shows the solid boosters we just mentioned, the tank. The Space Shuttle main engines are shown behind the orbiter. The orbiter itself, there is cargo here. An element of the Space Transportation System is the Space Lab, which is provided by the European Space Agency and has been integrated by the Marshall Space Flight Center into the Space Shuttle.
The upper stages, the IUS, the Centaur we have talked about. The TOS is a proposed extension to that developed by private industry, and does not exist today
in the program. The three versions of the payload assist module each with additional capability depending upon the size and performance required for the given satellite or payload which is going to use it.
In addition, the launch and landing facilities at Kennedy are part of the Transportation System. The Control Center at Houston and later the Control Center to be built by the Air Force in Colorado Springs will be part of the National Transportation System. Mission planning and training activities at the Johnson Space Flight Center and other places around the nation, and a wide range of ground support facilities which I will discuss on the next chart.
 (Viewgraph.) [Ref. 2/6-35]
MR. ALDRICH: The next chart discusses ground support. I have mentioned on the launchpad the Kennedy support facilities, so the Shuttle is in direct communication with the Mission Control Center in Houston.
(Viewgraph.) [Ref. 2/6-36]
MR. ALDRICH: Also in support of the Control Center in Houston in the training and mission preparation phase are the simulation facilities and astronaut training facilities at Johnson Space Flight Center, and the payload operation control centers exist both within the
Mission Control Center in Houston and they exist at remote locations such as the Goddard Space Flight Center, at the JPL at the Marshall Space Flight Center, and in the future likely many other places.
In our past we have used a wide range of ground support facilities around the world for communications and tracking with the orbiter. We are currently evolving a Tracking and Data Relay System that Jesse talked about which is used to relay large amounts of voice telemetry and television information from the orbiter to the ground and communications and ground control to the orbiter.
Today there is one TDRS satellite in orbit that covers about half of each orbit of the earth, and we were in the process of deploying the second and third satellites in that system. The large antenna is the ground TDRS station which is located in New Mexico, which is the focal point for all of the TRDS satellites and relays the data to the various stations around the National Complex.
(Viewgraph.) [Ref. 2/6-37]
MR. ALDRICH: The next chart shows the physical national location of these different facilities. We are here at NASA Headquarters, at the Marshall Center. We have already discussed the ET, SRB,
and the SSME. They also provide the interface with the Department of Defense for providing the IUS upper stage and with the European Space Agency for the Space Lab.
Kennedy Space Center provides launch and landing operations and facilities. National Space Transportation Laboratory at Mississippi provides the main engine test firing facility. Dr. Lovingood will mention that in some detail. The Michoud assembly plant for the external tank is just east of New Orleans.
At the Johnson Space Center we have my program office that I am speaking to you today in support of. We also have the orbiter project focused at the Johnson Space Center and the mission control, mission design development and crew training activities are at the Johnson Space Center.
At White Sands we have an alternate landing site. We also have the TDRS ground station which works with the TDRS satellites. We also have an extension of the Johnson Space Center for hazardous orbital engine testing in California. The Downey Industrial Plant is responsible for orbiter design, development, manufacturing. In Canoga Park, the Rocketdyne Division of Rockwell International is responsible for developing the Space Shuttle main engines, design, develop, and manufacturing
 and tests. At Vandenberg Air Force Base we have launch and landing facilities on the verge of being operational. They have been developed and put in place and they are undergoing final testing at this time.
In the desert in California at Palmdale we do the detailed final assembly of the orbiter vehicles, and we also have the west coast primary landing site at Edwards Air Force Base. Brigham City, Utah, solid rocket motor, Morton-Thiokol does the construction, the pouring of the solid rocket motors, and the refurbishment of the used equipment, and reservicing for downstream flights.
In the future we will have at Colorado Springs the North American Aerospace Defense Command Control Facility. They are in support of the Air Force control of Shuttle missions.
I tried to go back and provide for you a basis of how the Shuttle program came to be. The Apollo program was flown in the 1960s, late 1960s and 1970s, and in the period 1967 to 1972 there was significant discussion nationally within and without NASA regarding the follow-on to the Apollo hardware.
The Apollo was scheduled to fly the sequence of missions that we have come to know the Apollo program did, also the Skylab missions and the Apollo-Soyuz test
project, and during this period between 1967 and 1972 there were a series of national and NASA task forces to look at the future generation vehicles that would be flown.
At that time there were extensive discussions and phase-in A and B studies for both the space station and for a reusable service vehicle to go back and forth from a space station, and at the end of that period in the 1972 time frame the basic characteristics of the Shuttle had been determined and defined coming out of those deliberations.
This chart then picks up with the National STS program development starting with the characteristics that were defined coming out of those series of activities which I am sure you will want to know more about, and which are very involved, and will require some research to put in the perspective you might like to see it from.
Anyway, in the 1972 time frame and slightly before that the first project to be begun was the Space Shuttle main engine project. It was started with a set of design characteristics, and not long after that the orbiter project, external tank project, and solid rocket booster projects were started in support of the total design concept for the National Space Transportation
The engineering, design, development testing, mockup, and all activities of hardware development proceeded through the early seventies, and the first orbiter was rolled out in 1976. That was Orbiter 101, the Enterprise. It was a flightworthy orbiter for aero flight, but it was not built for orbital flight, and in fact it was used at Edwards Air Force Base for a series of flight tests on the back of the carrier aircraft initially and then for a series of free flights in mid-to-late 1977 to demonstrate the approach and landing characteristics of the Shuttle and orbiter system.
(Viewgraph.) [Ref. 2/6-38]
In 1979 Orbiter 102, Columbia, was delivered to the Kennedy Space Center. It was brought into the Kennedy facilities which had been developed and brought along during this timeframe, and processing there continued to the first manned orbital flight in 1981.
 Since that time we have had a series of test flights. STS-1 through 4 were called test flights, and in fact, the Columbia vehicle was extensively instrumented, and it was configured uniquely in a way I will describe shortly as a test flight vehicle. It has since been refurbished, and since that time other orbiters have flown a series of operational flights that Jesse Moore described to you.
The next chart-
(Viewgraph.) [Ref. 2/6-39]
MR. ALDRICH: -describes the characteristics of the Space Shuttle System at a broad level. I have deleted the solid rocket booster and external tank because they are covered more precisely and in more detail on the presentations of Dr. Lovingood.
The overall length of the Space Shuttle System is 184 feet. It is 76 feet wide if you look at it as it is shown in this chart. It has a capability for payload weight of 65,000 pounds due east out of the Kennedy Launch Center, 32,000 pounds in a polar trajectory out of
the east coast. The 104 is a southerly launch azimuth out of the west coast launch facility, and it represents the mission which would correspond to the maximum performance out of that location.
The system weights represent the weights of the total vehicle on those inclinations on those max payload flights, 4.49 million pounds at liftoff and 4.49 million pounds at liftoff from the west coast.
In a minute I will come back to this chart. I would like to talk to you for a minute, first, about the Space Shuttle stack before I talk in detail about the orbiter vehicle.
I am going to use this mike over here and talk a minute to the model. In fact, I could come and talk to your model if that would be preferable.
We have defined several times in this briefing the characteristics of the Space Shuttle flight system and used the names of each of these. I would like to point out how they join together. The solid rockets are each joined forward and aft to the external tank. They are not connected to the orbiter. When the vehicle is stacked on the launch pad, the only part of the system that is load-carrying on the launch pad is the base of the solid rocket motors.
They are first mounted, the external tank is
put between them and connected here. Then the orbiter is mounted to the external tank, two places in the back and one place forward, and those carry all the structural loads for the entire system at liftoff and through the ascent phase of flight. Also connected to the orbiter, under the orbiter wing, are two large propellant lines, 17 inches in diameter. The one on the port side carries liquid hydrogen from the hydrogen tank in the back part of the external tank. The one on the right side carries liquid oxygen from the oxygen tank at the forward end, inside the external tank.
You asked several questions regarding abort profiles, and abort profiles for this vehicle are complex and complicated. I would like to try to outline for you a little bit about the way the vehicle can fly and the way it can separate.
At liftoff, as Jesse stated, we first light the Space Shuttle main engines, three engines in the back of the orbiter, using fuel from the tank, oxygen and hydrogen from the tank. They are allowed to run until they come up to full thrust, a little greater than five seconds, and a large amount of ground complex and the onboard orbiter computing complex checks a large number of details and parameters about the main engines to be sure that everything is proper-that the main engines
 are performing right, the tank is performing right.
If all of those checks automatically pass, the solid rocket boosters are ignited and the release mechanisms, the pyrotechnics that release the solids at the base are released, and the Shuttle System rises.
CHAIRMAN ROGERS: And that takes six seconds?
MR. ALDRICH: That takes roughly six seconds.
There is an exact time line, and we will be presenting that to you in detail.
Once the Shuttle System starts off the launch pad, there is no capability in the system to separate these rockets until they reach burnout. They will burn for two minutes and eight or nine seconds, and the system must stay together. There is not a capability built into the vehicle that would allow these to separate. There is a capability available to the flight crew to separate at this interface the orbiter from the tank, but that is thought to be unacceptable during the first stage when the booster rockets are on and thrusting. So essentially the first two minutes and a little more of flight, the stack is intended and designed to stay together, and it must stay together to fly successfully.
MR. HOTZ: Mr. Aldrich, why is it unacceptable to separate the orbiter at that stage?
MR. ALDRICH: It is unacceptable because of
the separation dynamics and the rupture of the propellant lines. You cannot perform the kind of a clean separation required for safety in the proximity of these vehicles at the velocities and the thrust levels they are undergoing, the atmosphere they are flying through. In that regime, it is the design characteristic of the total system.
MR. HOTZ: Do you mean you would have raw fuel spilling out?
MR. ALDRICH: Yes, and you would have contact between the various elements, particularly the orbiter wings and the back part of the orbiter, and it is thought to be unsurvivable.
VICE CHAIRMAN ARMSTRONG: It is physically possible to do that, but it has been proven that it can't be safe?
MR. ALDRICH: All analysis indicates there is no likelihood of it being successful.
MR. RUMMEL: Mr. Aldrich, in what manner do the boosters separate? Are there explosive bolts or what?
MR. ALDRICH: Yes, at two minutes and eight seconds the thrust tailoff is sensed in the orbiter in its computer, and at that time a time sequence to release the booster is set up, and signals are sent from the
orbiter to the solid rockets to fire pyrotechnics fore and aft to cause the rockets to separate. There are separation motors in the forward end of the rockets to pull them away in a correct dynamic sense.
CHAIRMAN ROGERS: During the two-minute period, is it possible to abort through the orbiter?
MR. ALDRICH: I am now going to, if you will let me, and I don't have a series of charts on this because of how complicated they are.
CHAIRMAN ROGERS: I didn't mean to interrupt. Go ahead.
MR. ALDRICH: You can abort, as Sally asked previously, for certain conditions. You can start an abort, but the vehicle won't do anything yet, and the intended aborts are built around failures in the main engine system, the liquid propellant systems and their controls. If you have  a failure of a main engine, it is well detected by the crew and by the ground support, and you can call for a return-to-launch-site abort. That would be logged in the computer, the computer would be set up to execute it, but everything waits until the solids take you to altitude. At that time the solids will separate in the sequence I described, and then the vehicle flies downrange some 400 miles, maybe 10 to 15 additional minutes, while all of the tank propellant is
expelled through these engines.
As a precursor to setting up the conditions for this return-to-launch-site abort to be successful, towards the end of that burn downrange, using the propellants and the thrust of the main engines, the vehicle turns and actually points heads up back towards Florida. When the tank is essentially depleted, automatic signals are sent to close off the propellant lines and to separate the orbiter, and the orbiter then does a similar approach to the one we are familiar with with orbit back to the Kennedy Space Center for approach and landing.
DR. WALKER: So the propellant is expelled but not burned?
MR. ALDRICH: No, it is burned. You burn the system on two engines all the way downrange until it is gone, and then you turn around and come back because you don't have enough to burn to orbit. That is the return-to-launch-site abort, and it applies during the first 240 seconds of-no, 240 is not right. It is longer than that-the first four minutes, either before or after separation you can set that abort up, but it will occur after the solids separate, and if you have a main engine anomaly after the solids separate, at that time you can start the RTLS, and it will go through
that same sequence and come back.
DR. RIDE: And you can also only do an RTLS if you have lost just one main engine. So if you lose all three main engines, RTLS isn't a viable abort mode.
MR. ALDRICH: Once you get through the four minutes, there's a period where you now don't have the energy conditions right to come back, and you have a forward abort, and Jesse mentioned the sites in Spain and on the coast of Africa. We have what is called a trans-Atlantic abort, and where you can use a very similar sequence to the one I just described. You still separate the solids, you still burn all the propellant out of the tanks, but you fly across and land across the ocean.
MR. HOTZ: Mr. Aldrich, could you just recapitulate just a bit here? Is what you are telling us that for the first two minutes of flight, until the solids separate, there is no practical abort mode?
MR. ALDRICH: Yes, sir.
MR. HOTZ: Thank you.
MR. ALDRICH: A trans-Atlantic abort can cover a range of just a few seconds up to about a minute in the middle where the across-the-ocean sites are effective, and then you reach this abort once-around capability where you go all the way around and land in
California or back to Kennedy by going around the earth. And finally, you have abort-to-orbit where you have enough propulsion to make orbit but not enough to achieve the exact orbital parameters that you desire. That is the way that the abort profiles are executed.
There are many, many nuances of crew procedure and different conditions and combinations of sequences of failures that make it much more complicated than I have described it.
 CHAIRMAN ROGERS: I assume that any abort procedure requires a human decision; it is not done by machines?
MR. ALDRICH: That is, in fact, exactly correct, and that was discussed at length in the design phase of the program, and no scenario for automatic abort could be found to be as reliable as having the human interact.
I would also mention Columbia and the first four flights, in fact, the first five flights because Columbia flew one flight beyond the test phase. Both Columbia and Enterprise on the drop tests in the desert in California had only two crew members, and they had ejection seats in the pilot and commander seats, and those seats would be fired again by the crew and not automatically, but they would blow hatches out of the
top of the crew cabin and eject the crewmen out for parachute recovery.
Those were taken out of Columbia after flight 5. They have not been in any of the other orbiters except for Enterprise.
CHAIRMAN ROGERS: So I assume, then, that in the event of any accident that the safety of the crew depends upon the safety of the orbiter? I mean, there is no mechanism for using parachutes or any other escape mechanism?
MR. ALDRICH: These aborts that we are describing, RTLS, trans-Atlantic abort or trans-Pacific which are being developed, and the abort-once-around are all called intact aborts. They imply the survival of the orbiter, and an acceptable approach to one of our planned landing fields.
I believe I have described the characteristics of the Shuttle flight system in that discussion of aborts and how they go together and how they separate. Now let me describe-and if I could have the picture go one more chart, and we will look at the picture of the orbiter fleet.
(Viewgraph.) [Ref. 2/6-40]
MR. ALDRICH: This was the orbiter fleet up until last week, and there are some differences between
these four vehicles. Again, Jesse named them for you. Columbia was the first vehicle. I have described for you that it was a test vehicle, that it had ejection seats. It also had a very extensive amount of instrumentation on board. It had over 1,000 pounds of instrumentation racks in the cargo bay to take data on the environment and the performance of the orbiter during those first four flights, and that data has been widely used in rounding out the understanding of the Space Shuttle System. Columbia is also the heaviest orbiter. Columbia and Challenger were made, were manufactured earlier in the program than Atlantis and Discovery. There has been a weight reduction program that has allowed us to take approximately 5,000 pounds out of the Atlantis and Discovery vehicles that reside in Columbia, and 3,000 to 4,000 that did reside in Challenger.
During the last two years since STS-5, Columbia has been back at the manufacturing site in Palmdale, and it has been retrofitted to be of the same configuration as the other flight orbiters functionally. However, there is one additional difference between these four orbiters that you see here. Columbia and Challenger have an external thermal protection system that allowed them only to fly
trajectories out of the east coast. The trajectories out of the west coast have a higher heating entry profile, require additional TPS externally, and Columbia and Challenger are not designed  for that. They could be retrofitted for it, but it has not been determined to be a requirement of the program.
Atlantis and Discovery have TPS systems on board where they can be flown from either launch site, and of course, the plan has been to deliver Discovery initially for west coast launches.
Now, if I could go back a little bit to the chart that has the characteristics of the orbiter.
(Viewgraph.) [Ref. 2/6-41]
MR. ALDRICH: The orbiter was conceived, as I said, in the 1972 timeframe. It is about the size of a DC-9 aircraft. It has a fairly standard aircraft aluminum skin and stringer design, and there is not a lot of unique technology in the airframe of it. I will describe a little more about the airframe components in a minute, but the thing that makes it different for orbital space flight is primarily the Thermal Protection System, and that is, in general, added externally after the orbiter is built as a flight vehicle.
It is 122 feet long. It has a wing span of 78 feet. On its wheels, it is 57 feet high. Jesse pointed
out the payload bay is 15 feet by 60 feet. On an entry profile, it can come down the azimuth it is flying down. It can also fly cross range 1100 nautical miles in either direction to achieve a landing at a selected landing site.
Attached to it from the main engine project are three main engines, 470,000 pounds thrust each. On board the back of the orbiter also are OMS-stands for Orbital Maneuvering System- engines, 6,000 pounds each, two of them. I will show you where they are in a minute. And then for smaller corrections on orbit, for all the attitude control, there is a reaction control system- and I will describe that for you again in a minute-38 engines mounted at various places on the orbiter, and each of those engines has 870 pounds of thrust; 6 vernier engines for precise control, 25,000 pounds of thrust each.
The weight of the orbiter inert is 162,000 pounds, and that varies from orbiter to orbiter because, as I said, they have a range of difference of about 5,000 pounds dry weight.
At landing, without a payload but loaded with all of the consumables, that residual and all of the crew equipment and all of the cargo support equipment in orbit is about 175,000 pounds. And with the cargo we bring back,
we have generally been landing cargoes, 205,000 to 215,000 pounds at touchdown from the missions that Jesse described.
(Viewgraph.) [Ref. 2/6-42]
MR. ALDRICH: If I could go to the next chart, and it is a complicated chart regarding various orbiter subsystems, and perhaps I will come back to the model in a minute, or for a minute.
The engine systems that I described on board, of course, you know about the main engines. We talked about them all day. The OMS engines are these little black engines, and there is one on each side. They do orbital attitude changes of the orbiter. The reaction control engines, the 38 large and 6 small, are mounted on this device that sticks back from this pod which I will describe in a minute about its contents, and in a bay that is forward on the orbiter nose, and these black marks here are intended to be the ports that these engines fire out. In fact, there's 14 big engines and 2 small engines in front, 12 big engines and 2 small on each side, to compose the reaction control system.
In terms of the structure, this is what we call the forward fuselage. Inside of that is the crew cabin. This is the orbiter mid-body, the orbiter wings. Attached to the wings are the elevon
 aerosurfaces inboard on both sides and outboard on both sides for control during the approach and landing phases. They also are used for load relief during the ascent phase and they actually gimbal in conjunction with the main engines to provide balanced loading of the stack.
Down under the main engines is a device called a body flap. And it is an aerodynamic system that is trimmed in conjunction with the elevons for proper angle on approach and landing. The vertical stabilizer points upward, and it has a big aerosurface on the back. It is both a rudder and a speed brake. It swings in one direction for rudder control and opens in both directions for speed brake on landing approach and roll-out.
This is called the aft fuselage of the vehicle, and there are some major engine systems in there, and I will show you them briefly on a subsequent chart. This is the payload bay, of course. Most of the orbiter, as I said, is aluminum skin and stringer. The payload bay doors are graphite/epoxy. The pods here that contain these engine systems are graphite/epoxy, but all of the vehicle is covered with some form of TPS to protect either the aluminum or the graphite.
Payload bay doors have inside them devices
that move with the doors that are cooling radiators when the orbiter is on orbit. It has a large thermal load to release, and it is released through these radiators which are pointed, in general, towards dark space. Although they are not specifically pointed, they see enough dark space to provide total cooling for the orbiter and for the cargoes we fly.
This is the remote arm from Canada that was discussed earlier. We only have one, on the port side. The orbiter design would pick up one on the starboard side, but we have not put that implementation in place in the program to date.
Viewing windows forward and to the side. Also we have viewing windows on the top for alignment sightings, and there are viewing windows in the back of the bulkhead, forward bulkhead, for viewing the cargo. And as you have seen from our flights, we have TV cameras mounted in the four corners of the payload bay, on the join to the RMS, and on the tip of the RMS.
I will describe the thermal protection system in a little more detail on a subsequent chart.
On the underside of the orbiter we have wheel wells. We have two main landing gear on the outboard aft side of the mid fuselage, and we have a forward nose landing gear in a wheel well under this forward RCS system, at
the forward end of the vehicle. Other unique physical characteristics. All of the vehicle has a soft exterior insulation that we talked about with respect to the ice and the rain, except for the leading edges. This is a reinforced carbon-carbon nose cap, solid, and the leading edges of the wing are reinforced carbon-carbon and solid.
And that is the orbiter vehicle. Let me show you where some of the systems are.
The orbiter is a very complicated system, and it would take a long time to describe all of it in detail, but the way I selected some charts for this was to show you the basic structural elements and then to show you the systems particularly on board that have energy stored in them since stored energy is one of the things that could relate to what we have seen in the films and know about this incident.
(Viewgraph.) [Ref. 2/6-43]
MR. ALDRICH: The next chart shows the basic orbiter airframe as it is assembled. The crew compartment is shown on the upper left, and it is a welded structure that has full pressure  integrity. It has got the hatch and windows in it, and it fits inside the upper forward fuselage and the lower forward fuselage at the top and bottom of the page as they come
together. Then the forward reaction control system module is inserted as an engine system forward of this line, and the nosecap is added at the forward end.
The mid-fuselage is a big structure configured as shown here, and the forward fuselage segments are added to it, payload bay doors are added to it in assembly, and the wings from the side and through feed-throughs into the main structural members of the mid-fuselage.
And then the aft fuselage is added on the back end and contains some significant systems for propulsion and control of the vehicle. Two OMS pods, Orbital Maneuvering System pods, with their RCS elements also are added on the top of the aft fuselage, the body flap added in back, and the vertical stabilizer added to the top.
(Viewgraph.) [Ref. 2/6-44]
MR. ALDRICH: The next chart describes the thermal protection system, and I will describe that, and then I will deviate here and talk to you a little bit about the ice question that we had earlier.
I mentionned, and I am sorry this is so poorly color-coded, the reinforced carbon-carbon is the hardest parts of the TPS. It is on the nosecap and the leading edges where I showed you. The plan view of the orbiter is cut down the middle, so on the bottom part of this picture you have a representation of the top surface of the orbiter, and on the top portion you have a representation of the bottom view of the orbiter.
The bottom of the orbiter sees the highest temperatures, up to 2,800 degrees for some mission profiles during entry, and it has on it what we call black tiles. The real name for them is high temperature reusable surface insulation. They are largely silicon fiber, and they are manufactured. They are very lightweight, very easy to handle, very lightweight material.
The tiles on the total underbody of the vehicle are this high temperature reusable surface insulation. It ranges from half an inch up to two inches in thickness. It is very thick on the body flap, very thick on the forward end of the orbiter, and varies other places across the vehicle.
Coming around the sidewall and up to the top of the vehicle are the things we have called in the past white tiles. You have seen them, and they are white,
and they are low temperature reusable surface insulation, again silicon, different physical appearance, the same kind of material, and they are generally thinner than the big tiles on the bottom. They are also lighter weight.
Further upward and rearward on the vehicle, the areas shown in white are a nomex felt material with a white surface at the top about a half an inch thick, and those are put on in blanket form. These are the coolest areas of the vehicle during the entry phase.
Now, let's see. Let me divert to the question you asked about ice on the launch pad. The question had to do with both the meeting we had on the 27th to discuss the temperatures we might expect and then the discussion on the morning of the 28th with respect to ice and icicles, and they are two separate questions.
The day before, we had the mission management team with Jesse Moore and myself, and we discussed the temperatures and their effects, what they were predicted to be on the launch system and on the facilities, and the temperature ranges which were predicted, in the mid-20s, and warming into the morning the next day were thought to be, by all in attendance from my  understanding, at least, and what I believed to be well within the specification design of all of the flight
elements of the vehicle, and in fact, we had no concern expressed for the temperatures that the flight vehicle would see.
We were concerned about the facility because about a year ago, in January of 1985, we had a launch attempt with temperatures in this range, and we had problems with icing on the launch pad that caused some of the facility water systems to malfunction in such a way that the launch could not be continued, and we had to delay a day because of this ice.
So our discussion dealt primarily with the facility and the corrective actions from the previous event as to whether the facility would be adequate to support the countdown, the servicing and the launch, and Kennedy had changed procedures and had in place arrangements and mechanizations that we all felt would perhaps be more difficult than the normal countdown but they would support the full launch processing.
At that time we made the decision to proceed, assumed we might have some slowness in the processing activities, which we did experience. We had no concern for performance or safety of the flight articles at that time, nor do I even at this time, given what we know to be the specification, certification and design of the components that represent the flight system.
DR. WHEELON: A question, please.
Did you or your experts specifically consider the effect of the ambient temperature on the solid rocket motors, and did you judge that that was okay?
MR. ALDRICH: I would like to have you specifically ask that to the Marshall Project, Dr. Lovingood, when he is up. My answer would be yes, I am sure they did, but they ought to say that. They reported that all of their considerations for launch were acceptable and they were go for launch, which would include those temperatures, yes, sir.
DR. WHEELON: But that wasn't explicitly discussed with you?
MR. ALDRICH: It was not explicitly discussed as a concern, partly because it is really within the design characteristic of the Shuttle System, as I believe all of us understand it.
CHAIRMAN ROGERS: Do you remember any warning from I guess it was Morton-Thiokol to the effect that there might be a problem with a temperature in the booster?
MR. ALDRICH: I do not recall such a warning at that time. The following morning we had had the situation where we had some water lines break, and other water lines, the protective reaction to the low
temperatures was to let them flow during the night so that they wouldn't freeze and break, and we had this fairly large, extensive deliberation of what the ice meant to us. There was quite a large amount of ice, primarily on the north side of the launch complex where many of these water systems are and where the water was permitted to run as part of the procedure to avoid the freezing and rupturing of the lines. And on the south side of the launch pad where the launch system was, the flight system, there was significantly less ice, but it had been characterized by an ice team which we sent out on every launch and had been out on this launch.
In addition, the sun was rising, and on the south side of the vehicle, and we were already seeing melting in several of the areas on the vehicle. We made a detailed assessment of the reports of the ice team about where the ice was located, where it might fall, what it might impact  on the launch system, and the total context of that discussion had to do with the orbiter thermal protection system which has the soft elements that I have described to you.
There was no discussion or concern expressed about the falling of ice on any other system in either the launch complex or on the solid rocket boosters or external tank. There was a detailed assessment by the
team and reported to us of where the ice was located, and as I say, there were large amounts on the north side, smaller amounts on the south side. We calculated what ice might fall at ignition and what its trajectory might be in conjunction with the winds, and the total recommendation from all parties concerned was that we did not see a credible threat to the orbiter except for the Rockwell International orbiter contractor who in that meeting expressed some concern that there might be a slightly higher risk for the orbiter TPS because this was a condition we had no experience with before, that is, lifting off with ice on the launch pad.
VICE CHAIRMAN ARMSTRONG: Could I ask the source of the ice, what percentage was due to the ambient conditions and what was condensation on the vehicle that froze?
MR. ALDRICH: I can't give you a totally accurate report on that, but essentially the icing on the propellant lines and on the external tank was relatively normal, quite low, and well within the bounds that we had accepted on previous launches. All of the ice I'm talking about was on the launch facility which is off to the side of the vehicle and does not protrude out over any of the flight elements, or at least does not protrude out over the orbiter. There is an arm that
goes out over the nose of the external tank.
VICE CHAIRMAN ARMSTRONG: It was unusual because of the unique weather conditions?
MR. ALDRICH: It was unusual because of the weather conditions, and the corrective actions to drain the facility water on the launch pad causing great amounts of water to be in certain locations.
DR. WHEELON: Was there either a tape recording or a written record made of these deliberations prior to launch, and would that be available to this Commission?
MR. ALDRICH: We have asked for a detailed report of the specific configuration of the ice both during this initial inspection that led to this discussion and then I am about to tell you that we sent the team out a second time to reassess it, and there will be-the written report will include the findings that the second assessment and the clearing up of small amounts of ice on the platform. There was not a recording of the meeting in which we discussed the ice debris threat to the orbiter.
DR. WHEELON: Quite aside from the ice debris, was there a recording or minutes taken of the meeting where you made the deliberations as to whether to go ahead or not?
MR. ALDRICH: That is the same.
DR. WHEELON: You are focusing just on ice. I am not worried about ice. I am worried about a much broader class of issues. How do you record those deliberations?
MR. ALDRICH: The meeting where we elected to proceed was held the night before, the mission management team meeting that Jesse described, and all parties felt agreeable to go. The normal process during the countdown is that the countdown proceeds, assuming we are in a go posture, and at various points during the countdown we tag up on the operational loops and face  to face in the firing room to ascertain the facts that project elements that are monitoring the data and that are understanding the situation as we proceed are still in the go condition.
And this is done prior to minus 20 minutes in the count, and is done again at minus 9 minutes in the count as a matter of procedure.
DR. WHEELON: I think you are answering a different question than the one I asked, and that is these key meetings where you and Jesse made the decisions to go forward or to delay, as you had in days prior to the launch, was there a detailed record of those deliberations made or not?
MR. ALDRICH: To my knowledge, there is not a written record or a recording of those meetings.
DR. WHEELON: Thank you.
MR. SUTTER: In releasing one of the vehicles for flight, and especially now that some of the equipment has been gone through refurbishment, and it is done by people that do work for you, is there a formal documentation of releasing the vehicle for flight? Is there a formal method of doing it, and is it signed off like when they release an airplane for flight?
MR. ALDRICH: Yes, it is, and it is signed off in great detail. And one of the briefings later in the day will go through that flight readiness process. It is the series of meetings that led up to the ones that Jesse reported right in close at L-1 day. There is a formal flight readiness review that is extremely thorough, with formal commitments and sign-off of all NASA organizations and all contractors that support NASA for these elements.
MR. SUTTER: Going back to this temperature question, then, if one of the units was designed to a given temperature range, then whoever was responsible for that unit, if it was outside of that range, would have to make that known, and there would have to be some review board action on that?
MR. ALDRICH: Yes, sir, and that would occur
in our system.
MR. SUTTER: Okay.
DR. WHEELON: And there were no such exceptions?
MR. ALDRICH: There were no such exceptions.
DR. WHEELON: Thank you.
DR. RIDE: How does the ice team document what it sees? Do they take cameras out with them?
MR. ALDRICH: They take cameras, I believe, Sally. I have not seen pictures from the ice team, but our discussion was that it would be photo documented. They also take IR measurement devices and actually measure the temperature around the tank and the propellant lines where we have a concern for perhaps the formation of ice on the flight system, and this occurs on all flights, the concern for ice on the external tank. It has liquid hydrogen and liquid oxygen in it. It is serviced with insulated lines, and depending on the wind and the amount of humidity and the ambient temperature, you can see extensive icing for different conditions than only the low temperature case.
In fact, one of the reasons the tank, in my understanding, had a small amount of-it did not have a major sheet of ice on it. It had perhaps a slight amount of frosting. One of the reasons is that although
 the temperature is very low, the humidity was also very low.
This weather discussion we have been having was the result of a front that came through the Kennedy area with high winds, cold temperatures, and very low humidity.
I would go now to a couple of more discussions on the orbiter. I wanted to show you what was inside several of these elements.
(Viewgraph.) [Ref. 2/6-45]
MR. ALDRICH: The next chart shows what is inside the main propulsion system, inside the aft fuselage, which is primarily the main propulsion system. You can see here where the two 17-inch lines come into the bottom of the orbiter, the hydrogen, liquid hydrogen on the port side and the liquid oxygen on the starboard side, through the 17-inch lines and into a candelabra of individual lines that go to each of the three main engines.
In the lower right hand picture is a schematic of the oxygen from the forward end of the ET, hydrogen from the aft end flowing through these lines, and the orbiter interface to the main engines.
I would also point out, not very clearly visible here, but there is an extensive heavyweight load
structure built into the aft fuselage to carry the main thrust and loads from the main engines, and that structure is seen up in this area and around the propellant lines that are shown coming from the external tank.
(Viewgraph.) [Ref. 2/6-46]
MR. ALDRICH: The next chart shows the forward and the aft Reaction Control System. I mentioned a number of engines. I wanted to point out to you the amount of propellants and the type of propellants that are on board. In the forward Reaction Control System we have 477 pounds of nitrogen tetroxide in the starboard tank, 928 pounds of monomethyl hydrozene in the port tank. They are pressurized by a helium bottle, and they feed the thruster system I previously described to you. The two aft pods contain both the RCS system on each side and the OMS system. This chart lists the characteristics of the RCS. Again, the oxidizer tank, I believe it is the lower tank, in the forward end of the pod, contains almost 3,000 pounds of nitrogen tetroxide. The upper tank, the fuel tank, contains 1856 pounds of monomethyl hydrozene. This is pressurized by RCS helium bottles down at the upper corner of the other end of the pod, and the propellant flows to the RCS thrusters, and they can be interconnected so the
tanks on one side can feed the engines on the side or across on the other side as well.
The next chart shows the Orbiter Maneuvering System.
(Viewgraph.) [Ref. 2/6-47]
MR. ALDRICH: The way the charts are laid out, they deal with the OMS separately, even though it is the same component of the vehicle, and as you can see, there's 14,866 pounds of nitrogen tetroxide and 9,010 pounds of hydrozene in the lower Ox tank and the upper fuel tank, again pressurized by helium bottles, and they feed the big OMS engine either on this side or can be cross connected and feed the OMS engine on the other side.
(Viewgraph.) [Ref. 2/6-48]
MR. ALDRICH: The next chart describes the electrical power system within the orbiter. This shows the cargo bay, the mid-fuselage I have shown you before. All of the cargo fits within the U-shaped rings, and there is a liner, but under the liner, in the cargo bay are a number of  orbiter systems, and I have highlighted here the electrical power systems. The electrical power in the orbiter is generated by three fuel cells which are fed by cryogenic liquid oxygen and liquid hydrogen bottles. The configuration shown here
shows three oxygen tanks and three hydrogen tanks. We can increase that to either four or five of each for longer duration missions.
Again, there is a fair amount of fluid in these tanks. There is 781 pounds of oxygen per tank, 92 pounds of liquid hydrogen in the hydrogen tanks. They provide 2370 kilowatt hours of energy to the orbiter during the mission, and 168 pounds of oxygen for supplying the atmosphere in the orbiter cabin and keeping the cabin pressurized.
(Viewgraph.) [Ref. 2/6-49]
MR. ALDRICH: The next chart shows a little bit about the crew arrangement. This is looking down only on the crew module of the vehicle. The top two pictures show the upper level in the crew module, the flight deck. The lower two pictures show the mid-deck. For launch and entry there are four crew members seated approximately as shown here, on the flight deck, the commander on the left, pilot on the right, and mission or payload specialist seated in the back, and they can participate in some of the procedures in support of flying the vehicle from the forward consoles.
Once you go on orbit on the flight deck, more or less crew members can come up to the flight deck, and a large number of the consoles on the back end of the
flight deck deal with the payloads and the cargo, and they are operated by various mission and payload specialists.
DR. WALKER: Is the atmosphere in the crew quarters pure oxygen?
MR. ALDRICH: No, it's oxygen-nitrogen mix, roughly basic atmosphere, basic earth atmosphere. In the mid-deck you can see the configuration that was approximately what we had on the STS 51-L, two mission specialists in front of the airlock facing the module stowage, and one back by where it says the waste compartment is located. The other three crew seats shown in dotted are contingency configuration that can be used to extend the capacity of the vehicle. However, on this flight and on most flights, that is taken up with either three or four sleep stations as is shown on the right hand side of the page.
Locker storage is in front of these crewmen, and we stow there things for crew-provisions, food, clothing, communications equipment, camera equipment. We also stow some experiments and some flight activities in those areas.
Waste management compartment is back in the lower port corner, and the side hatch for exit and entry to the vehicle is shown on the port side. Airlock is
truly that. You enter the airlock from the cabin, don a space suit, decompress, open a hatch, and go out into the payload bay for external operations on orbit. The mid-deck picture on the right shows a little more detail of personal hygiene station, galley station, and tables that are set up once the orbital configuration is arranged on board.
(Viewgraph.) [Ref. 2/6-50]
MR. ALDRICH: The next chart discusses some major systems in the orbiter that I am not going to go into in great detail today. There is an extensive avionics system in the orbiter, and it controls not only the orbiter but the solid rocket boosters and the external tank, and it works in conjunction with the launch processing system.
 There are a series of avionics bays shown here. In the mid-deck portion of the cabin, there is a Bay 1 forward and Bay 2 forward. Bay 3 is in the back end of the crew compartment, and many of the major electronics components, including the general purpose computers that fly the Space Shuttle are located in that region.
Above them on a navigation fixed mount are the inertial measuring units for flying the Space Shuttle System and the star trackers for aligning it once you are on orbit. They are mounted in proximity with these
other electronics, and they are part of the total guidance and navigation system.
In the back end of the orbiter are three more electronic bays with, again, additional electronic devices that participate in guidance control of the vehicle and its systems, and they are shown roughly in the forward part of the aft fuselage module that I showed you previously mounted on the back side of the bulkhead. These subsystems provide for guidance and control of the total Space Shuttle for ascent, on-orbit and entry. Communications and tracking provide a series of different communications modes through S band and UHF, through an on-orbit Ku band system that has an extensively high data capacity. They provide the displays and controls to the flight crew who can interface to the vehicle systems through the avionics and through the computers. They provide for the electrical power distribution and the instrumentation throughout the vehicle, and they provide a series of data processors that both record data and instrumentation measurements on board and provide those to the ground.
Those are the basic systems of the orbiter that I was going to describe. There is one other high energy system on board. The system operates its elevons and its landing gear release and brakes and body flap and rudder speed brake with three hydraulic systems, which run around to the appropriate places on the vehicle.
Also, the throttling and control of the space shuttle main engine use the orbiter hydraulic systems. And to provide the orbiter power, there are three auxiliary power units mounted in the aft fuselage, and they have each 325 pounds of hydrozene in a tank to provide those APUs.
Those units are powered prelaunch for ascent to control the engines and the aero surfaces, and then pre the orbit for entry to control the aero flight for the approach and landing.
There are also a series of systems in the cargo bay that support the various cargo modules. There are electronics, there are beam structures to support the payloads. There are keel fittings, a wide range of instrumentation and communications systems that are put together in standard configuration so that they can support the widest range of cargo mixes that we fly in the space shuttle.
That is the briefing that I was going to give you on the shuttle configuration and on the orbiter, and I realize it is not nearly the depth to cover any of those things in detail. But I thought that would be a good start.
And I would be glad to answer any other question about the way the vehicle works or how it is integrated.
CHAIRMAN ROGERS: Well, thank you very much. It has been very helpful.
I wonder, was there anything about this launch, excluding the discussions about ice and weather, that caused any concern over and above the normal concern? Anything unusual about this launch that we should know about?
 MR. ALDRICH: I do not recall that there were any unusual things other than we had the situation with the hatch, where we did not get it off.
CHAIRMAN ROGERS: Which Mr. Moore referred to. But excluding that and excluding the questions of the weather, anything else that was discussed about this launch that was different from the previous launches?
MR. ALDRICH: No, sir, not to my knowledge.
I would add, that reminded me of one of the questions you asked earlier about the anomaly tracking.
As we first flew Columbia and had our initial flights with the orbiter, we did have quite a large number of anomalies in the space shuttle systems, and most of them were not of consequence to completing the mission or to doing the activities on board the way we intended to do them.
There were major engineering problems with the systems that are highly redundant, and some of the redundancy areas had anomalies, and the system accounted for it properly. We track each of those systems problems individually by item. It is researched, analyzed, and closed out formally to my level in the program to be sure we have treated it correctly and completely.
We have it signed off, and we keep a formal tracking system of all of these things that occur. And we have had anomalies on every flight. With the amount of instrumentation and redundant subsystems we have, we frequently have things that need corrective action. Every one has been tracked, every one is recorded and logged and available.
And a different response than Jess gave to your question about how our performance has been: We have seen significantly fewer anomalies on flights in the last year or two than we had early in the program.
There has been a significant correction of things we couldn't find until we flight-tested, and corrective actions.
In fact, the Atlantis vehicle, which has flown two times and was delivered in the spring of this last year, has been extremely clean and has had no significant anomaly as yet in any of its systems. So I think there is a great learning curve, particularly with respect to the orbiter, as we have flown and become familiar with the vehicles.
CHAIRMAN ROGERS: I assume that you are comparing the flight pattern of this launch with previous ones to see if there are any deviations from previous flights?
MR. ALDRICH: Yes, sir. We do do the exact characterizations of the winds and profile that Jess described. We do build a best trajectory from all the data available, and apply those best known external conditions to it, and we analyze completely, to the best of our ability, the exact loadings and the profile that the vehicle flew through.
I might add, we talked about throttling the main engines. There is in fact on board an adaptive control within the orbiter system. The solid rockets have very minor variances, depending upon a lot of
parameters. And the on-board system senses that and throttles the main engine to a precise level to account for that.
So what you predicted it might go to pre-flight may be slightly different. That is understood. That also will be factored into our total analysis of the ascent system performance.
CHAIRMAN ROGERS: At what point in the flight was the loss of power detected?
 MR. ALDRICH: We essentially lost all data with the vehicle at very close to 73 seconds, 73 and some tenths either way seconds. And loss of power and data presumably is the same thing. All contact with the ground was lost instantly at that time, and there is a great reconstruction of all events from data and from tracking and from photo.
And I haven't seen that yet. That is a fairly laborious job, but my expectation would be that it will coincide with the physical event that we saw.
DR. RIDE: Could you say something very briefly about the data lines between the SRBs and the shuttle, the shuttle computers?
MR. ALDRICH: Let me see if I can say what you want me to say.
The central control and computing for the
entire stack during ascent is in the computers in the orbiter. Some of the sensing equipment- for instance, there is a set of rate gyros at the top of each solid rocket motor. That is fed through the electronics system to the orbiter and it is factored into the orbiter guidance computations for the total stack.
There is also telemetry and measurements on various parts of the tank and the solid rocket booster, and those come back into the orbiter and are relayed or recorded in conjunction with the orbiter data stream. And for the separation sequences, commands go the other way, from the orbiter.
The orbiter guidance and navigation system senses when separation should occur, when engine throttling or gimballing should occur-not throttling of the solids, as was pointed out, but throttling of the main engines, but gimballing of both mains and solids-and those commands go through data lines to the solid rocket boosters and to the space shuttle main engines.
DR. WHEELON: Since I sense that our chairman may soon be calling a luncheon break and since that provides an opportunity to get some data, would it be possible to get from you or from your colleagues the nominal trajectory, powered flight trajectory parameters as anticipated for this
flight, not as actually measured? And specifically, what was-what did you expect would be the altitude versus time and the speed, the Mach number, the dynamic pressure, and the throttle position on the main engines?
Could you provide that?
MR. ALDRICH: Expected pre-flight and compared to what we found in-flight, yes, sir.
DR. WHEELON: I suspect you don't yet have the actuals, and if you do that's fine. But, I would be grateful for just the pre-flight nominal for this flight.
MR. ALDRICH: I will do that.
CHAIRMAN ROGERS: Mr. Acheson wondered if there was any way to make an estimate of how much further information you want to give to us today. The question is not designed to hurry you at all, and we are prepared to continue over until tomorrow. We just want to get some idea of what estimates you make and the time that would be involved.
Jess, can you address this?
MR. MOORE: Mr. Chairman, what we are prepared to do from here the rest of the afternoon is to go through the Marshall shuttle projects. As I mentioned earlier, the Marshall Space Flight Center is responsible
for the propulsive elements of the shuttle.  We have probably got about a 45-minute briefing or so on the propulsive elements, and maybe a little longer. I am kind of guessing. I didn't have time last night to go through a formal dry run.
Following that, I have a presentation by the Kennedy Space Center to tell you how the launch system is processed and all the steps to get ready for launch, and that probably can be done in about 35 to 40 minutes, depending upon questions. It is mostly photographs, to give you a feel for what we go through in getting ready for launch.
Beyond that, we have got about a 30-minute pitch that will address the design philosophy- requirements, certification, testing, analysis-that we go through in NASA for procuring hardware. And then I've got another presentation which is about another 30 minutes long that talks about our flight certification, preparations for flight, and talks about the flight certification process and the specifics associated with how we pool the resources of the NASA-industry shuttle team to get ready for a flight.
If I add those up very roughly in my mind, we are probably talking about another three hours-plus of briefings if the Commission would so desire.
CHAIRMAN ROGERS: Well, that's fine. We can extend over until tomorrow, and we don't want to hurry you at all.
And I think we will take a recess now for about an hour. I would like to suggest, though, on the presentations, that if you could relate your presentations a little more directly to the Challenger and what happened. Otherwise it becomes rather abstract.
And so, I don't want to discourage that aspect of it, but if you could relate it a little bit more to what happened here and what you did in connection with the Challenger, anything that was unusual, I think the Commission would appreciate that.
MR. MOORE: Yes, sir. What we tried to do for the Commission, Mr. Chairman, is also to give you some indication of how the systems are manufactured and how they are put together. And that specifically is applicable to Challenger, as well as the other elements of the shuttle program. So we will try to narrow our focus a little bit more on the specifics associated with Challenger and any differences that we possibly can highlight relative to this flight versus others.
CHAIRMAN ROGERS: Thank you very much.
Okay, we will adjourn until 1:30.
(Whereupon, at 12:40 p.m., the hearing was recessed, to reconvene at 1:30 p.m.)
[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. 2/6-29] NATIONAL SPACE TRANSPORTATION SYSTEMS PROGRAM MANAGEMENT. [Ref. 2/6-30] NATIONAL STS PROGRAM MANAGEMENT RELATIONSHIPS.
 [Ref. 2/6-31] NATIONAL STS PROGRAM ORGANIZATIONAL APPROACH.
 [Ref. 2/6-32] NATIONAL STS PROGRAM GOVERNMENT/INDUSTRY TEAM.
 [Ref. 2/6-33] NATIONAL STS PROGRAM SHUTTLE SYSTEMS ELEMENTS. [Ref. 2/6-34] THE NATIONAL SPACE TRANSPORTATION SYSTEM [Pictorial description of the previous reference, 2/6-33].
 [Ref. 2/6-35] NATIONAL STS PROGRAM DEVELOPMENT ACTIVITIES PHASE [From 1972 through operational flights, 1983]. [Ref. 2/6-36] GROUND BASED SUPPORT.
 [Ref. 2/6-37] NATIONAL STS PROGRAM FACILITY AND SUPPORT LOCATIONS [Map of the US with location of NASA centers & contractors supporting the STS program].
 [Ref. 2/6-38] NATIONAL STS PROGRAM DEVELOPMENT ACTIVITIES PHASE [From 1972 through operational flights, 1983; same chart as 2/6-35].
 [Ref. 2/6-39] SPACE SHUTTLE SYSTEM [Orbiter, ET and SRB].
 [Ref. 2/6-40] ORBITER FLEET [Columbia, Challenger, Discovery, Atlantis].
 [Ref. 2/6-41] SPACE SHUTTLE SYSTEM [characteristics]. [Ref. 2/6-42] MECHANICAL SUBSYSTEMS.
 [Ref. 2/6-43] SPACE SHUTTLE SPACECRAFT STRUCTURES.
 [Ref. 2/6-44] THERMAL PROTECTION SUBSYSTEM.
 [Ref. 2/6-45] MAIN PROPULSION SUBSYSTEM [SSME]. [Ref. 2/6-46] REACTION CONTROL SUBSYSTEM.
 [Ref. 2/6-47] ORBITAL MANEUVER SUBSYSTEM. [Ref. 2/6-48] ELECTRICAL POWER SUBSYSTEM.
 [Ref. 2/6-49] CREW CABIN ARRANGEMENT AND CREW FUNCTIONS.
 [Ref. 2/6-50] ORBITER AVIONICS SUBSYSTEM.
The Presidential Commission met, pursuant to luncheon recess, at 2:00 o'clock p.m.
- WILLIAM P. ROGERS, Chairman
- NEIL A. ARMSTRONG, Vice Chairman
- DR. SALLY RIDE
- DR. ALBERT WHEELON
- ROBERT RUMMEL
- DR. ARTHUR WALKER
- RICHARD FEYNMAN
- ROBERT HOTZ
- DAVID C. ACHESON
- MAJOR GENERAL DONALD KUTYNA
CHAIRMAN ROGERS: The Commission will come to order, please.
MR. MOORE: Mr. Chairman, members of the Commission, we would like to continue this proceeding now. I have asked our presenters here for the remainder of the afternoon to try to make their presentations as brief as possible, particularly the background kinds of presentations, and focus as much as we can on the relevancy to the incident on 51-L.
And with that, I would like to introduce the Deputy Manager of the Shuttle Projects Office at Marshall, and that is Dr. Jud Lovingood.
THE CLERK: Do you swear the testimony you will give before this Commission will be the truth, the whole truth, and nothing but the truth, so help you God?
DR. LOVINGOOD: I do.
CHAIRMAN ROGERS: You may proceed.
DR. LOVINGOOD: Mr. Chairman, Committee members, what I have been asked to do today is to give you a propulsion systems overview so that it will provide you with the background that you will need in the course of your investigation, and what I have done is I have given a very brief summary of the elements that Marshall has responsibility for, which are the external tank, the main engines, and the solid rocket booster. I hope that as a result of this briefing there may be some areas that you can identify that you do want to home in on, and then we will be able to provide you additional information if I can't answer it today.
So, with that I will start out by talking about the-
(Viewgraph.) [Ref. 2/6-51]
DR. LOVINGOOD: This is the agenda, which doesn't show up very well. Go to the next chart.
(Viewgraph.) [Ref. 2/6-52]
DR. LOVINGOOD: I think none of these are showing up on the screen. CHAIRMAN ROGERS: Well, we have the books. We
can follow it that way.
DR. LOVINGOOD: If you would look at those, and on these word charts, I will try to summarize basically what I am trying to say quickly.
We have two responsibilities, one in capability development, which is the early part of the program primarily, with some continuation into the operational phase which we are currently in, and then, of course, we have support to operations. We are responsible or were responsible for the development and certification of the external tank, the solid rocket booster and the Shuttle main engine. We are responsible for the propulsion system testing, which I will say more about, which is the testing of the complete propulsion system, including the external tank, the three main engines and the orbiter propulsion elements down at NSTL, the National Space Technology Laboratories. We have been involved in propulsion and ascent flight system integration activities with JSC. They have the lead, but we have been heavily involved in that activity with them because of the skills that we have at the Marshall Center.
And then performance improvements and productivity, and then in supporting the launches, we are responsible for producing the flight hardware and
logistics support at KSC and at Vandenberg, and we are involved heavily now in the activation of the Vandenberg facility as far as processing the vehicle, and then we are also looking at  operational improvements like producibility improvements, requirements reductions and simplifying the launch processing.
(Viewgraph.) [Ref. 2/6-53]
DR. LOVINGOOD: The next chart shows what I just said in pictorial form, and I won't dwell on that, and we will just go ahead and continue to the next chart.
(Viewgraph.) [Ref. 2/6-54]
DR. LOVINGOOD: The next one shows the organization that we have at Marshall for the Shuttle Projects. There is one Shuttle Projects manager that is responsible to the center director, and he has responsibility for all Marshall Shuttle activity. Under him is a project office for each element, and that is indicated down at the bottom, showing an External Tank Project Office, a Solid Rocket Booster Project Office, and a Flight Engine Project Office. In addition, we have a Development Engine Project Office which is involved in the engine improvements which Jesse Moore mentioned earlier.
Each of these project offices, if you will
note the remark I've got in the upper right hand corner, has a chief engineer which is assigned to report directly, functionally, on a day-to-day basis, to the project manager. His institutional home is our Science and Engineering Directorate which is a major institutional organization which reports to our center director.
Proceeding to the next chart-
(Viewgraph.) [Ref. 2/6-55]
DR. LOVINGOOD:-and then this is the engine project lead-in, and then go to the following one.
(Viewgraph.) [Ref. 2/6-56]
DR. LOVINGOOD: The SSME, and of course, there has been some discussion of SSME, which is the main engine on the Shuttle. It has already been discussed to some extent by Arnie and Jess. It is a liquid hydrogen/liquid oxygen engine. It is manufactured, or its prime contractor responsible for development, certification, manufacture and launch acceptance testing is the Rocketdyne division of Rockwell. Major subcontractors are Honeywell on the controller and Hydraulic Research, on the actuators that we use for the valve controls. Test sites are the National Space Technology Laboratories. We have two single-engine test stands at the Santa Susana laboratory, which is near Canoga
Park, where Rocketdyne is located.
(Viewgraph.) [Ref. 2/6-57]
DR. LOVINGOOD: The next chart shows the flow. As I mentioned, the engine is manufactured at Rocketdyne in Canoga Park. We acceptance test it at our designated test area at the National Space Technology Laboratories in Mississippi. We install them into the orbiter at KSC. In fact, the Marshall Space Flight Center delivers them to KSC, and then the installation in the orbiter, and then the launch processing from there on is the KSC responsibility. And between flight maintenance is done at KSC.
(Viewgraph.) [Ref. 2/6-58]
DR. LOVINGOOD: The next chart shows some interesting characteristics, and what I want to point out on there, it is a 470,000 pound thrust engine in vacuum. We call that the rated power level. Most of our flights up until now have been at 104 percent of rated power, with a few at 100 percent.
DR. FEYNMAN: Excuse me. I am sorry to interrupt you.
 I wanted to understand whether you, that is, your organization, checks the engine when it is manufactured. When it is going to be reused, is there another test made, or is the test made at the
DR. LOVINGOOD: If an engine is brought back on an orbiter to be flown again without any changeout of parts, then our assessment is made in terms of data that we get from the flight, and any anomalies that are found from post-flight inspections, which the inspections are done under the cognizance of KSC, but we get a report on that, and we have to disposition those anomalies before we fly it. In the case of a component changeout, we are responsible for the production of that new component, the acceptance test of it.
All components are acceptance tested by hot fire on a single engine.
DR. FEYNMAN: Thank you.
DR. LOVINGOOD: FPL is full power level, and that is 109 percent of the rated power level, and we have not flown at that power level yet. In fact, the improvements that we are making are to give us more margin in operating at 109 percent.
I want to point out the mixture ratio, which is the ratio of oxygen mass to hydrogen mass consumed by the engine is six, and down there, on life at the bottom of the chart, it shows that we have a specification requirement, and I want to emphasize that is the spec requirement of seven and a half hours or 55 starts, and
that has not yet been demonstrated.
And I have a subsequent chart that shows you what we have demonstrated.
And then we have a controller which I think has been mentioned today, and we are capable of throttling with that controller to 65 percent minimum. The controller accepts commands from the general purpose computers in the orbiter, the GPCs, and then makes the engine valves operate to provide the proper throttle setting.
Some design features we have-
(Viewgraph.) [Ref. 2/6-59]
DR. LOVINGOOD: -is that we do have a failsafe philosophy. The controller has redundant computers which control the mixture ratio and the chamber pressure, and the controller includes self-check monitoring capability to ensure proper engine operation. The design features redundancy in the engine control and the monitoring functions, and we have red lines that are established based on both analytical work and ground test experience.
The engine operation has been demonstrated in our ground test program, both development and certification. We fly the engine with the maintenance parameters and so forth, just like we have done it in
our ground test program. We have included off-nominal engine performance, and that is by varying the mixture ratio off of the nominal value of 6.0, and we have demonstrated various abort modes. There was some discussion of that this morning. We fired engines around 600 seconds, approximately, to demonstrate one of the abort modes, and approximately 800 seconds to demonstrate another abort mode. And we have also demonstrated off-nominal engine shutdown modes. Normally the shutdown, for example, is with hydraulic power from the auxiliary power units which Arnie mentioned, which are on the orbiter. In case of an emergency, we do have a  pneumatic shutdown system using a helium supply on the orbiter, and we have demonstrated that in ground tests.
And then, before we put an engine into the orbiter or a component, replace a component and install a new one in an engine, we do hot fire acceptance tests of those engines, as I have already mentioned.
(Viewgraph.) [Ref. 2/6-60]
CHAIRMAN ROGERS: Would it be possible to relate these functions to the Challenger?
DR. LOVINGOOD: Well, the way I would relate it to the Challenger is that we did go through the acceptance testing, our normal acceptance testing
and data reviews, looking at any material discrepancies that come out of manufacturing to make sure that we didn't have any problem. This was done before we flew the Challenger for the first time with this set of engines In fact, on things like hardware discrepancies from the plant, we have what we call a re-review of those discrepancies. That is part of our flight readiness review process. So we do a very thorough review of the hardware that we are flying.
As far as manufacturing anomalies. We look at process changes that might have been incorporated, we look at all the acceptance test data, and if it is a reflight, then we do the review of the post-flight inspection data from the previous flight as well as the previous flight data, and we always acceptance test.
DR. FEYNMAN: For example, was this Challenger, the one we are interested in, the flight we are interested in, a reflight of an engine or a new engine?
DR. LOVINGOOD: I believe that this, all three engines were being reflown. I'm almost 100 percent sure of that. And I don't believe we changed out any major components, but I will get you that for the record because I am not certain, but I will give you exactly what component changeouts were made for this flight.
CHAIRMAN ROGERS: Your records would show any anomalies in previous flights as far as these engines are concerned?
DR. LOVINGOOD: There could have been. We do have occasional anomalies which are sometimes dispositioned as being within our experience, something that shows up. We look at anything that looks unusual. In fact, sometimes people like to call them observations, but we always classify them as anomalies, and we thoroughly review those. So I am not certain. But I do know that whatever we saw in the data, that there is a documented rationale as to why that is no problem for flight.
CHAIRMAN ROGERS: In other words, you do have records to show any anomalies as far as Challenger is concerned?
DR. LOVINGOOD: That is correct.
CHAIRMAN ROGERS: Thank you.
GENERAL KUTYNA: Yet on this particular flight, we had less instrumentation than on previous flights, but these engines are very well instrumented, aren't they, to the point where if you saw an anomaly on climb-out, it would have registered and possibly even shut the engine down before anything disastrous occurred?
DR. LOVINGOOD: The instrumentation on this
 flight would be like it has been. It would be as much and in some cases more than we have had on previous flights. I don't think-we haven't subtracted any recently, and we have added some instrument data.
GENERAL KUTYNA: Did you see anything anomalous on climb-out on these engines?
DR. LOVINGOOD: No.
MR. RUMMEL: The engines would not have been shut down until after the accident occurred, if I understood this correctly this morning, is that right?
DR. LOVINGOOD: That is correct. The nominal shutdown time is around 500 seconds.
GENERAL KUTYNA: Let me push that point. Had there been an anomalous condition on the engine, it would have shut itself down prior to having anything disastrous happen?
DR. LOVINGOOD: There are red lines, and for the record, I will tell you what those red lines are. I have got a list of them here.
GENERAL KUTYNA: For example, we had an engine shutdown on the previous flight. It sensed something going wrong and it shut itself down before there was any problem.
DR. LOVINGOOD: Yes. I will tell you what
that was. We have red lines on fuel, the high pressure fuel pump turbine discharge temperature. We have two temperature sensors in the discharge of that turbine, and the red line is set at 1960 degrees, roughly. It is actually different on the two gauges because of the different coolant flow we have in there.
We also have red lines on the turbine discharge temperature on the high pressure oxygen pump. We have a coolant liner pressure red line in the fuel pump turbine. There is a fuel pump turbine coolant liner that has a red line in it on pressure. We have an intermediate seal pressure that is-the seal that separates the hot gases of the turbine from the LOX that we are pumping, this is on the high pressure LOX pump, and we have a high pressure LOX pump drain pressure as a red line. Those are the five red lines we have.
Now, the problem that led to the engine shutdown in flight was a failure of two of the two temperature sensors that we have, and we have a way that the controller monitors those temperature sensors to determine whether they are good sensors or not, whether they are qualified. If the determination of the controller is that they are not qualified-and it is based on the failure rate, how fast the sensor goes off-scale high-then the controller disqualifies that
sensor, and that sensor would not vote to cut.
What happened in the previous case when we had the shutdown was that the failure mode of that sensor was such that the controller did not recognize it as a bad sensor, and recognized it as a vote to cut, and so we ended up shutting the engine down.
GENERAL KUTYNA: But the bottom line is you really have a fail-safe system as far as those engines shutting themselves down.
DR. LOVINGOOD: That is correct. We have got redundancy, and it is fail-ops with the first one, and then fail-safe.
Okay. I think I was on Figure 11. [Ref. 2/6-60]
Prior to flight we have a ground certification test program and I have indicated here how we go about doing that. The current engines that we are flying were initially certified for ten missions, and that is taking two samples, two builds of that engine, and running through what  we call two CERT cycles, and a CERT cycle consists of 5,000 seconds of testing in 13 starts, and those CERT cycles represent the kind of mission profiles that we would fly in the missions.
If you add all that up for just one engine, that would be two cycles times 5,000 seconds, that would be 10,000 seconds, about roughly 500 seconds per
flight. That would be equivalent to 20 missions, and what we do is we divide that by two, we allow our ground test program to exceed flight by a factor of two. So in running 20 missions on the ground on two engines, we certify ready to fly ten missions.
When we change, make an engineering change in a component, generally or typically we require two samples of that, one CERT cycle, and say that qualifies the component for ten missions operating in that engine system that we have already got certified. But each change receives a thorough review by both NASA and the contractor to decide what kind of certification requirements there should be, and that is put into-that is documented in the paperwork, and that is a requirement that we complete that certification requirement or we must get a waiver with supporting rationale, if we do not, before we fly.
And then the ground test program develops parameters that we use in our maintenance, the post-flight inspections that we use, the inspection intervals, and then any removal and replacement schedule based upon life limits on certain piece parts in the engine that we know have a life limit which is less than what we have certified the basic engine for. And all of that, of course, is documented and it is documented in
our files as well as at KSC as far as what all of those between-flight inspections, maintenance and removals are.
And then this last bullet just says that we use a factor of two in our ground test over our flight.
(Viewgraph.) [Ref. 2/6-61]
DR. LOVINGOOD: And then the next chart shows with our current engines that we are flying, with our ground test program using a factor of two, we are certified to fly 15 flights for each engine that we put into the field at a mixture of 100 and 104 percent of rated power level.
This program did include some testing at 109 percent, some certification testing at 109 percent, and that certifies us to fly seven flights of that 15 at 109 percent.
And then the last two bullets down there just shows that we did that on Engine 2010 and Engine 2014 with a ground test of 40 missions on Engine 2010 and 30 missions on 2014, and then we take the smaller of those two numbers and divide by two to get to 15.
CHAIRMAN ROGERS: Is there anything about the testing of the Challenger engines that caused you any concern or which seemed to be different than previous tests?
DR. LOVINGOOD: No, I don't recall anything.
In fact, when the question came up this morning concerning this launch, I was trying to think, the question was asked whether there was anything other than weather considerations that made you more concerned, and that went through my mind at that time, and I don't know of anything off hand.
VICE CHAIRMAN ARMSTRONG: Do I understand correctly that 2010 and 2014 are engines that are used for testing only?
DR. LOVINGOOD: Engine 2010 and Engine 2014 were new engines that we had in our planning to use as ground certification engines, and that is a very controlled program. We don't do  development testing on those engines. If we've got a new part, we don't put it on there. It is a very controlled program, and we use the same specifications, so to speak, as far as maintenance and inspections are concerned, that we use when we fly. I mean, that is the intent of that, to fly the same way we do that certification program.
VICE CHAIRMAN ARMSTRONG: It is functionality and reliability kind of testing?
DR. LOVINGOOD: Exactly.
VICE CHAIRMAN ARMSTRONG: Thank you.
DR. LOVINGOOD: Okay. That is really all I had to say about the
I wanted to talk about this propulsion system test that we do, and that is what Figure 13 is relating to. This test, which is done on a test stand down in Mississippi, which includes a flight type external tank, and it has got the orbiter aft structure simulated, but it has got all the valves and the plumbing in the aft end of the orbiter for the propulsion system. And then it has got a cluster of three main engines on it.
Before we flew the first time we performed 12 successful tests in the time period I have indicated there, and then we also performed these, in addition to the static firings and hot firing, we performed the special propellant tanking test which had to do with loading procedures at KSC. And then our current plan, we have not run a test of that cluster at 109 percent. So the current plan is to run two static firings at 109 percent of rated power level, and then after we complete that we intend to convert that to another single engine test stand and convert that facility to another single engine facility.
That is all I plan to say about the engines and the main propulsion tests, and if there are no questions, I will go on to the solid rocket booster.
DR. FEYNMAN: I would like to know a little
bit more about the actual engines used on the Challenger. What new items had to be replaced after the engines had been used; if the engine is a reused engine, were there some parts that had to be replaced, or what kind of condition is it in relative to were there some special problems?
DR. LOVINGOOD: Are you talking about this particular flight?
DR. FEYNMAN: Yes.
DR. LOVINGOOD: I don't recall for sure. My recollection is-I have got to get that data. I recall that we didn't change anything, but I will provide that data to you, and if we changed out anything, I will tell you why we changed that out.
(Viewgraph.) [Ref. 2/6-62]
DR. LOVINGOOD: On the solid rocket booster, there were several questions raised this morning about that. Let me see, I have got some notes here.
We did make a change-well let me talk about the booster description first.
Go to Figure 15, and then I will try to respond to some of the questions that came up during Jess and Arnie's discussions.
(Viewgraph.) [Ref. 2/6-63]
Figure 15 shows an expanded view of the booster, and starting on the lefthand side of that chart and working your way across, you will note that we have the nosecap, which contains the pilot and drogue chute, and then we have the frustum, which contains the three main  parachutes. We have the forward skirt, which has the forward attach fitting to the external tank. and we also have avionics.
Then the next, moving on across there after the forward skirt, to the right of the forward skirt is the forward segment, and that is a motor case segment that is cast as shown there. In that configuration that was 327.5 (on the forward segment) inches long, and it has a forward bulkhead which is a pressure dome, and then we have what we call the forward mid segment or forward center segment, and then the aft mid segment, and then the aft segment, and the aft segment is shown there with a nozzle attached to it. And then we have the aft skirt, which contains the separation module, the thrust vector control system, and I think Arnie pretty well discussed that today.
Now, these segments are transported overland, and assembled by KSC. They are transferred from Morton-Thiokol in Wasatch to Kennedy Space Center, and the assembly is done there. I think the next chart
shows who the contractor--
GENERAL KUTYNA: Would you point out the previous problem you had with this booster, with the SRB and explain how you fixed that? What gave you confidence that that problem would not reoccur? You had problems with the nozzle and your burnthrough of the nozzle, as I recall.
DR. LOVINGOOD: We had on-it was STS-8. We had some pocketing in the nozzle, and that was-I don't recall exactly where it was. I think it was on the throat inlet. It was prior to the throat, upstream of the throat.
And we had made a process change prior to that time. We went back to our old process, and there was also some suspect material, a particular manufacturer of material, and we had extensive analysis and test data which supported the fact that that particular supplier of this material might have had volatiles in there or other parameters which could have led to this pocketing.
CHAIRMAN ROGERS: I don't understand that. Could you explain it a little to me? It doesn't have much meaning to me.
DR. LOVINGOOD: Well, I am not sure I can explain it.
GENERAL KUTYNA: Maybe we should try and say
you had air pockets in the material. Is that right?
DR. LOVINGOOD: Well, there were gases. I think there was just the chemical constitution of the materials, too, that indicated that this one supplier had components in there or constituents which were not good as far as this pocketing problem is concerned. The gas pocket, I think, is one of the things that led to the mechanism, and I am not familiar with the mechanism.
What I suggest we do, we could give you a detailed briefing, because that is all documented, and if you would like, we can give you a detailed briefing on exactly what we found.
GENERAL KUTYNA: As far as NASA is concerned, that problem is resolved? You found the problem was not a factor in this particular incident?
DR. LOVINGOOD: Thus far we don't see that as being a factor.
MR. HOTZ: Did you change manufacturers?
DR. LOVINGOOD: No. When I mentioned something about a supplier, we had two suppliers of this material, and the analysis showed that this one supplier's product was better, and we are using strictly that supplier's product. So there is no change.
MR. HOTZ: No, but you did drop a supplier, then?
 DR. LOVINGOOD: In that particular area of the nozzle.
CHAIRMAN ROGERS: Was that based upon negligence of the supplier?
DR. LOVINGOOD: No. It was within specification. And I think that it was just on one side of the spec in the way he had been manufacturing it, and we felt like if we could eliminate that, and we did go back to our old process, too, for curing the nozzle, and doing that, we could eliminate a problem, and we haven't had a recurrence like we did on that flight.
CHAIRMAN ROGERS: Is there a report on that? Did you make an inquiry and file a report on that whole incident?
DR. LOVINGOOD: Yes, we can get you a report.
CHAIRMAN ROGERS: And that is available to the Commission, I presume.
DR. LOVINGOOD: Yes.
CHAIRMAN ROGERS: Thank you.
DR. WALKER: Are you planning to discuss the way in which these sections are joined?
DR. LOVINGOOD: I had not planned to go into any detail on that. This is the aft attach ring to the external tank, and I think that was mentioned by Arnie. There is a field joint approximately right here, and the
field joint is what we call the joint between two segments that are cast individually, separately, and that joint is made at KSC.
There are factory joints. These segments, I believe, this particular segment here is about 27 feet long, so about halfway up, 13 and a half feet or so, there is a factory joint that is made at Thiokol. These have two O-rings in the joint. When you have a field joint, we have inhibitors there that inhibit the propellant burning on the face at that joint.
In the case of a factory joint, we have insulation that comes all the way across that, and we don't use the inhibitor.
GENERAL WALKER: Are these VITON O-rings?
DR. LOVINGOOD: I am not sure. I believe they are, but I am not certain. Yes, that is correct.
What we can do is, I had not planned to focus-the instructions I had for this was to just give you an overview. I had not planned to focus on any particular area, and that is why I am not prepared to do that.
CHAIRMAN ROGERS: Well, we can come back to that. We appreciate that we didn't give you much notice of the meeting, and so, proceed. We will be able to get that information.
GENERAL KUTYNA: How about the operating limits on this motor? Are you the proper one to discuss that?
DR. LOVINGOOD: What is the question?
GENERAL KUTYNA: How about the operating limits on this motor? It says in the manual that it ought to operate between about 40 and 90 degrees Fahrenheit. Of course, it was a lot colder than that.
DR. LOVINGOOD: The requirement is on propellant mean bulk temperature, and in fact I had that on a chart that it is one of our requirements, and it was predicted that the mean bulk temperature would be 55 degrees at launch, and it has been reported to me that that is what it was, about that value. So we do have a requirement to be between 40 and 90, and we were within that range.
 DR. KUTYNA: Do you have instrumentation that would give you that temperature, or do you predict it, or how do you know that the mean bulk was what it was? DR. LOVINGOOD: It is calculated based upon ambient.
(Viewgraph.) [Ref. 2/6-64]
DR. LOVINGOOD: Okay, Figure 16 shows the major suppliers on the booster. Of course, the motor is made by Morton-Thiokol. The booster assembly is-United Space Boosters Production Company, they are
currently called, does the assembly work of the aft skirt and of the forward skirt and the parachute frustum area and the nosecap, and I have got the suppliers down there for structures of the motors and so forth, and you can read through that list, and then we have done our testing at Morton-Thiokol's Wasatch Division as far as the large motor static firings are concerned. All that testing was done out there, and this is just a highlight, by the way. And then at Marshall Space Flight Center, we have done the structural testing on the booster, and also TPS, Thermal Protection System development and testing.
DR. WALKER: Could I just ask a question on terminology? Solid rocket motor refers to the fuel itself?
DR. LOVINGOOD: Let me show you on the next chart.
(Viewgraph.) [Ref. 2/6-65]
DR. LOVINGOOD: What I have got here, I thought this was going to be in color, but the solid rocket motor, our terminology for that is the part that is the responsibility of Morton-Thiokol, and that would be all of the segments from this forward bulkhead back including the nozzle, and this includes the casting of the propellants into those sections, and then there is
also a systems tunnel that runs along the motor case, and that is a Morton-Thiokol responsibility, so we call all this the solid rocket motor.
Now, when we put the aft skirt on with the thrust vector control system and the avionics, booster separation motors, when we add-which is a USBPC responsibility, and then when we add the forward skirt, the frustum and the nosecap with the parachutes, the avionics, the separation motors, and so forth, we call that whole assembly a solid rocket booster. So then there are two of these per mission. Does that explain our terminology?
DR. WALKER: Yes.
(Viewgraph.) [Ref. 2/6-66]
DR. LOVINGOOD: The next chart I don't plan to dwell on. It shows the characteristics. The main point there is, we have a mean thrust of 2,400,000 pounds per booster.
(Viewgraph.) [Ref. 2/6-67]
DR. LOVINGOOD: Then the next chart, Figure 19, I do have a thrust time trace that I will show you which is a typical trace, and that will come up next, but I want to leave this chart up here until I get ready to talk about that, and I will show you how that is specified as a requirement. And then we have a thrust
vector requirement to be able to gimbal the nozzles for control during the first stage boost of plus or minus 88 degrees, and these were qualified with five development test static firings out at Thiokol and with four qualification test firings.
Then I have just listed, and I am just trying to highlight here sort of our approach on this motor. The structural integrity, as far as the design criteria is concerned on the hardware, we  have a 1.4 time limit load. That is, the limit load is the maximum predicted load from pressures, aerodynamics, engine thrust that you will see in flight, and we take a load 40 percent higher than that, and then that is what we design to, and then we do an ultimate load test, testing that structure to that value to make sure that it doesn't break.
And then on the propellant we have got a factor of two times the maximum expected load; and we verified that with subscale test and analysis. And on the insulation, the case insulation, we have a 1.5 factor times the predicted erosion, and on the nozzle insulation it is a factor of two times the predicted erosion.
DR. FEYNMAN: Excuse me. Predicted erosion is predicted erosion. The question is, in your experience
in measuring erosion, how much variation from predicted erosion is the average degree of variation to be expected? How good is the prediction?
DR. LOVINGOOD: The prediction is real good, with the exception of one case that we talked about earlier where we had that pocketing, and we are staying pretty much right in that same area.
DR. FEYNMAN: What is real good, 5 percent, 10 percent?
DR. LOVINGOOD: Like on the nozzle with a factor of two. That means you know you are good for another flight. You would have been good for another flight. I think we may have come off just a little bit.
DR. FEYNMAN: How good are the predictions for the amount of erosion, 5 percent accurate, 10 percent accurate?
DR. LOVINGOOD: I would say within 10 percent. It may be more accurate than that. Okay, and then I have got listed on this chart the fact that we do have a design environment for the propellant mean bulk temperature, a range of between 40 and 90 degrees.
DR. RIDE: Can I ask you a question just, I guess, relate it to the design environments? You must have a set of launch commit criteria for the SRBs and
the motors. Could we get those available to us, or do you have them?
DR. LOVINGOOD: Yes, I will make a list, and that was one of the questions that came up this morning. We do have an LCC, Launch Commit Criteria, on some temperatures in batteries, and I don't know what those values are or what the particular batteries are. We have got them on batteries. We have got them on the tank. We have got a nose cone temperature limit, but we can provide you a complete listing of that, and of course you know what that means. That means if you violate the LCC you don't launch or you get a waiver with supporting rationale which is documented in order to go ahead with the launch. So, we can provide a list of those.
CHAIRMAN ROGERS: Can you determine the temperature of the booster, inside temperature of the fuel in the booster?
DR. LOVINGOOD: Just by calculation. We don't have any measurement.
CHAIRMAN ROGERS: No instrument?
DR. LOVINGOOD: No.
MR. ACHESON: May I ask, in the design environment here, the temperature 40 to 90, does that mean it is designed to operate at that temperature, or
does it mean that it is designed not to undergo a physical or chemical change within those temperatures?
 DR. LOVINGOOD: I will have to get you an answer to that. I don't really know. I don't know what the genesis of that requirement is and what the design criterion is based on it. Let me mention here, too, something that came up this morning. We did do a motor case redesign. We reduced the wall thickness approximately 6 percent, the wall thickness.
CHAIRMAN ROGERS: You are speaking about the Challenger now?
DR. LOVINGOOD: Yes, but I will tell you now we made that change on STS-6, which means that we have had 18 flights, successful flights, if I did my arithmetic right, and of course that is two boosters, so 18 times two is 36, but we did make a change, and we reduced the wall thickness about 6 percent to lighten the case weight, and we did motor firings. We also did two motor firings, one development motor firing and one quality motor firing.
We didn't do it in order to certify that redesign. We did it because we made some additional-another change to get more performance out of the motor. We call it our high performance motor, and that was effective on STS-8, and what we did there was to
decrease the nozzle diameter by-I think it was a half an inch or quarter of an inch. No, a half an inch. I have got to get that for you. I forgot. And we extended the nozzle ten inches.
We also changed-we cut back on the inhibitor in the radial direction. We made the inhibitor less in order to get higher thrust at liftoff. So we made those changes, and we can provide you exactly what we did for the record, what those changes were.
DR. FEYNMAN: What is the inhibitor, a liner of some kind that goes around the propellant?
DR. LOVINGOOD: The inhibitor is at the field joints, where we cast the propellants in separate segments, and then the inhibitor is there to keep the surface, let's say the forward facing surface of the propellant from burning, and it is NBR. It is an NBR rubber, the material.
DR. WALKER: Does that inhibitor form a seal between adjacent sections?
DR. LOVINGOOD: No, it is not a seal. It is an insulation protection for the face of the propellant.
DR. WALKER: So the four sections of propellant are really separate entities?
DR. LOVINGOOD: That is right.
DR. WALKER: They don't connect with one another? They burn separately?
DR. LOVINGOOD: Well, it burns from the inside out, is the way the solid rocket motor burns, so all the segments are burning simultaneously that way.
DR. WALKER: But each is burning separately?
DR. LOVINGOOD: Yes, that is correct.
GENERAL KUTYNA: Jud, do you have a slide of the joints where these segments are joined? Do you have the technical detail of that?
DR. LOVINGOOD: No, I had planned to have some detail as backup but we didn't have backup for this briefing. That is the normal way we do things, and I thought it might come up.
GENERAL KUTYNA: Have you looked at these post-mission after you recovered them from the ocean to see if there is any damage at those joints from the previous flights?
DR. LOVINGOOD: We have seen some evidence of what we call blow by of those seals, some erosion of those seals. The primary seal. We have never seen any erosion of a secondary seal, but we have seen evidence of soot in between the two seals.
GENERAL KUTYNA: Was that any cause for
DR. LOVINGOOD: Oh, yes, that is an anomaly, and that was thoroughly worked, and that is completely documented on all the investigative work that we did on that, and we can get that for you.
CHAIRMAN ROGERS: If a committee or subcommittee of the Commission visits your operation, would you have the information there that you could answer specific questions about this more conveniently, and particularly about the Challenger as distinguished from the overall operation?
DR. LOVINGOOD: Yes, we would have more data there that we could get, plus we would have our experts in these areas that could talk much more intelligently than I can on the subject.
CHAIRMAN ROGERS: Well, we do not expect you-I mean, we understand that you didn't have much notice, and that you were to give an overview so you don't have to be apologetic, but we are just trying to figure out how to get the information ourselves, and that certainly would be one way we could do it, isn't it?
DR. LOVINGOOD: Yes, I think that would be a way.
CHAIRMAN ROGERS: Thank you.
(Viewgraph.) [Ref. 2/6-68]
DR. LOVINGOOD: The next figure shows the thrust time trace, and there is a higher thrust, as you can see, for about the first 20 seconds of flight, and then the thrust drops off. By the way, the two outside lines represent the band that we have to be within in order to achieve the proper performance on the motor, and these numbers here, I think the artist took a little license in the way this was plotted. These aren't exactly right. But anyhow, generally we lie right in the middle of that band. Sometimes we come up fairly close to the edge at some points.
But we have never to my knowledge gone outside of that band. So we have that kind of trace where the pressure drops down. The pressure here starts about 1,000 psi, and in this region here it drops down to about 600 psi chamber pressure, and then it starts back up nominally, and then it goes back down and then starts to tail off here, and then we separate when it gets to 50. That gives a signal to the GPCs to separate.
DR. WALKER: How uniform is the pressure inside of the motor?
DR. LOVINGOOD: I don't know. I know we have done a lot of analysis trying to understand, and I think early in the program we had some, maybe some acoustical
measures, measurements up on the forward dome, but that is information that we could give you, and I really don't have good knowledge of that.
(Viewgraph.) [Ref. 2/6-69]
DR. LOVINGOOD: The next chart, Figure 21, shows some considerations that I thought would be worthwhile to put out here. The fact that since this is a manned space flight program, that our designed safety factors relative to other solid rocket motors have been applied differently as indicated on that chart.
Like on the structures, we have 1.4 times the limit load, which is the maximum expected flight load, and generally on military weapons systems that is 1.25 or 1.15, and then on the insulation 1.5 times the predicted requirement on the case, two times the predicted requirement on  the nozzle, and that is usually one and a quarter on military systems, and we do proof test all of these segments to 112 percent of their maximum expected flight pressure.
And what that amounts to is-that is 80 percent of the 1.4 safety factor, and that is the convention in solid rocket motor technology.
VICE CHAIRMAN ARMSTRONG: Excuse me. On what do you apply this 112 percent proof test?
DR. LOVINGOOD: Segments.
VICE CHAIRMAN ARMSTRONG: Each production segment?
DR. LOVINGOOD: Each segment.
VICE CHAIRMAN ARMSTRONG: Thank you.
MR. RUMMEL: Does the term "limit load" apply to the ultimate strength of the material or the yield point or what?
DR. LOVINGOOD: That would be ultimate. That would be breaking up. The requirement is that you don't break up at less than 1.4 times the maximum expected load. You don't have an ultimate failure.
MR. RUMMEL: Thank you.
DR. LOVINGOOD: Then we have done x-ray and we did 100 percent x-ray of the propellant in the first 68 segments that were manufactured, and through that verified that the casting process that we were using provides proper propellant strength. Currently we use the process control that we verified with those 100 percent x-rays, and we do a random monthly x-ray of a segment, and then whenever we have a process anomaly or a process change or design change, then we do an x-ray for the segments, and then we still do a 100 percent x-ray of the nozzle ablator parts to be sure that there aren't any delams or voids or cracks.
MR. ACHESON: At what times are these x-rays
taken in comparison-that is, in relation to the dates of delivery and flight of mission?
DR. LOVINGOOD: I will have to get you that information. I can get you the information on these specific segments that we flew. I am not even sure of the manufacturing time. They may not have been 100 percent x-rayed because it may have been after we instituted this random sampling, but I will give you a typical example of when the x-ray was taken and when it was flown.
DR. WALKER: Are the three forward segments interchangeable?
DR. LOVINGOOD: The forwardmost segment, and I am not familiar with exactly how we do all of these segment changes, but the length of the forwardmost segment is longer, and also you have got a dome, a forward dome on that segment. So there is not complete interchangeability between the segments, but when we take these back and refurbish them, we do wash out the propellants and the liners and start all over again and then remake the factory joint, and I am just not sure how we can interchange those.
DR. WALKER: Thank you.
DR. LOVINGOOD: But that is kind of data that we can provide to you.
DR. WALKER: Thank you.
 Now, that is all I had on the booster. I want to comment that there were questions earlier- I think the gentleman who was asking the question has left. There was a question earlier about, I think he phrased it, a concern by Thiokol on low temperatures.
We did have a meeting with Thiokol. We had a telecom discussion with people in Huntsville, people at the Wasatch division, and people at KSC. And the discussion centered around the integrity of the O-rings under lower temperature.
We had the project managers from both Marshall and Thiokol in the discussion. We had the chief engineers from both places in the discussion. And Thiokol recommended to proceed on the launch, and so they did recommend the launch.
We had a meeting where there was some concern about the cold temperatures.
CHAIRMAN ROGERS: When was that meeting?
DR. LOVINGOOD: That was the 27th. That started around quarter to 5:00 central time.
(Viewgraph.) [Ref. 2/6-70]
DR. LOVINGOOD: Is there anything else on the booster?
CHAIRMAN ROGERS: I guess not.
DR. LOVINGOOD: Going on to the external tank
(Viewgraph.) [Ref. 2/6-71]
DR. LOVINGOOD: Arnie has talked a great deal already about this, and I think you realize that the LOX tank is forward, the oxygen tank is forward. And we have the inner tank, which has a large cross beam, which takes out the thrust from the SRMs. The SRMs are attached on the sides here to this large cross beam, and that is where all the thrust is reacted into the external tank, through the inner tank.
And then the hydrogen tank is the aft tank, which is separated from the oxygen tank by the inner tank area. And then we have the gaseous oxygen pressurization line that runs the length of the vehicle up to the top of the LOX tank.
We also have a cable tray that runs up to the top of the LOX tank, and that cable tray has wiring, wires, electrical wires, as well as it has a linear shaped charge in it. This feed line, the oxygen feed line, comes out of the inner tank. Well, it comes from the LOX tank into the inner tank and out at this point, and feeds down the side of the hydrogen tank external to the hydrogen tank, into the orbiter.
The hydrogen feed line comes directly out of the bulkhead in the orbiter. The hydrogen
pressurization and the oxygen pressurization lines are just adjacent to that feed line, the oxygen feed line, and then the cable tray.
And then I think Arnie has already discussed the attach structure that we have back here. This aft ring is where the orbiter loads are reacted, plus this thrust longeron, and it goes up into this next forward ring, and then the SRB rear attach points come also into that aft ring.
MR. FEYNMAN: What is the purpose of the linear shaped charge?
DR. LOVINGOOD: That is range safety destruct in the event there is a problem.
MR. FEYNMAN: Where is it located?
DR. LOVINGOOD: It's in the cable tray. I'm not really sure where the charge starts, but it runs up the vehicle. And I'm not sure of the total length, but it is actually in that cable tray.
 Okay, that is really all I wanted to say about the external tank. I think we have covered that.
MR. FEYNMAN: What loads is that designed to?
DR. LOVINGOOD: The external tank loads, when we first began the program we had a safety factor of 1.4 on all loads. We had a weight reduction program in which we took 8,000 pounds out of the tank, and we used various methods to get that 8,000 pounds out.
At the time that we did that exercise and that engineering analysis, we had already done loads testing on the standard weight tank that we started out with, and so we knew the load paths very well. And so what we did was we took loads which we considered to be well-defined loads-for example, a pressure load-and we said that since we know that load so well and with our experience at that time, plus the structural testing that we had already done, plus the proof testing that we do of those tanks, that we would design that structure to 1.25.
The other structure, which is determined by thrust, gimballing loads or aerodynamic loads, wind loads, are still-that structure is still designed to the 1.4.
MR. SUTTER: When did the lighter tanks get into service?
DR. LOVINGOOD: STS-8.
Well, I guess the next chart I had on the tank. Of course, Martin-Marietta is the prime contractor, and we've got major subcontractors as listed there. And then we did a lot of the testing, most of the testing, at Marshall, including the structural tests and modal survey tests and various thermal protection system activities, as I've got indicated there.
And I would say, too, that the requirements-and I don't think I have that on that chart. Do I have another chart?
(Viewgraph.) [Ref. 2/6-72]
Excuse me just a minute. I think I've got my charts all mixed up here.
Okay, chart 25. Well, this really answers the question, I guess, that was just asked. I've got down there three sigma loads, and that is a statistical term that doesn't mean anything. That's the maximum predicted flight loads. That is our requirement.
And there is a loads data book, and I think Dick Kohrs is going to talk about or Tom Moser I think is going to talk about how we do that as far as the requirements are concerned. But anyhow, it is designed to the maximum predicted flight loads, and then we do qualification tests to 1.25 and 1.4, as I just mentioned, depending upon the circumstance.
And then in that testing, we do it at cryogenic temperatures for the hydrogen tank and room temperature for the oxygen tank and the inner tank: and the propulsion system, as far as the interface requirements and delivering the proper propellants to the orbiter and to the main engine, is qualified by testing that we do.
But in particular, the main propulsion tests, which I have already mentioned, we have run 12 of them. And then thermal protection system: that is there to maintain the propellant quality, to make sure you've got proper temperatures for engine operation and avoid propellant boiloff and that sort of thing; to thermally protect the structure in certain areas, areas of high heating, like for example that we have an ablater underneath the LOX feed line over where we do have external mold line protuberances.
 And then also limit ice formation to prohibit damaging the orbiter, and we have qualified that through wind tunnel testing, both combined environments and also putting plasma arc heat sources on there to make sure that we've got the proper recession ranges.
CHAIRMAN ROGERS: As far as previous flights are concerned, has the external tank been successful or has it been a source of trouble, generally speaking
DR. LOVINGOOD: The external tank I personally feel like we have had very good success with. We have had some problems with some pressure transducers, and these are just fairly rare occurrences.
I think we have had like two LOX LH transducer bias shifts, just very small changes.
CHAIRMAN ROGERS: What does that mean?
DR. LOVINGOOD: Well, we have in the oxygen tank, we have four pressure transducers that measure the amount of pressure that is in the tank, and then those pressure sensors are used to control the gaseous oxygen control valves on the orbiter. And on the hydrogen tank, we also have pressure transducers, and they control gaseous hydrogen control valves, or they feed back information as to the pressure and then those valves open or close based upon what the pressure is.
The problem we have had is that we have had some-when we sit at one tanking load for a long period of time, the sensors tend to vibrate. And we're not really sure what the cause of it is, and we've found that the vibration is causing perhaps shorting between lines or contamination between the wiper and the coil.
And it has given us like a tenth of a psi or a half a psi offset. The main concern here is that we will violate a launch commit criteria, because we have-at T minus 31 seconds, we have to have three of these transducers before we go.
And so, we never have really considered that to be a problem as far as safety in flight was concerned.
DR. WALKER: Can I ask a question about venting? Are there vent valves when the tank is sitting
on the launch pad?
DR. LOVINGOOD: Yes. But I would like to defer that question to Bob Sieck. I think he could answer it much better than I could, about what happens on the pad.
CHAIRMAN ROGERS: Okay. If there are no further questions, thank you very much.
MR. MOORE: Mr. Chairman, we will, at your request, provide you any of the detailed briefings on the specific elements of this, at the center or wherever you need, to get more detailed information on the 51-L situations of hardware.
I asked our people to make sure that they gave the Commission today a good oversight and an overview of what each of the elements of the shuttle was.
CHAIRMAN ROGERS: Well, I'm sure that all Commission members understand that. And as I said, we appreciate the fact that you have been able to assemble all of this information on such short notice. So please don't be apologetic for not being able to answer all of these questions, which we'll have plenty of opportunity to ask later on.
MR. MOORE: Thank you, sir.
Next I would like to continue on with a major element of our program. That is the grounds operations
 work and getting ready for launch. The activities that you will see presented here by Mr. Robert
Sieck, our Director of Shuttle Operations at the Kennedy Space Center, will be applicable to STS 51-L, as they are in terms of how we process all of the particular flights.
[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. 2/6-51] Agenda [of testimony]. [Ref. 2/6-52] MSFC SPACE SHUTTLE ROLE.
 [Ref. 2/6-53] MSFC Space Shuttle Responsibilities.
 [Ref. 2/6-54] Marshall Space Flight Center Shuttle Projects Office [Organization chart].
 [Ref. 2/6-55] SPACE SHUTTLE MAIN ENGINE (SSME) PROJECT. [Ref. 2/6-56] SPACE SHUTTLE MAIN ENGINE.
 [Ref. 2/6-57] FLIGHT ENGINE FLOW. [Ref. 2/6-58] NOT REPRODUCIBLE.
 [Ref. 2/6-59] DESIGN. [Ref. 2/6-60] SSME CERTIFICATION VALIDATION OF HARDWARE FOR FLIGHT.
 [Ref. 2/6-61] CERTIFICATION AND LIFE CERTIFICATION EXTENSION PROGRAMS PHASE I ENGINE RESULTS.
 [Ref. 2/6-62] MAIN PROPULSION TEST PROGRAM SUMMARY.
 [Ref.2/6-63 1 of 2] [Ref.2/6-63 2 of 2] SOLID ROCKET BOOSTER (SRB) PROJECT [photo of SRB elements].
 [Ref. 2/6-64] SOLID ROCKET BOOSTER (SRB). [Ref. 2/6-65] SOLID ROCKET BOOSTER - SRB - [sketch of].
 [Ref. 2/6-66] SOLID ROCKET MOTOR characteristics. [Ref. 2/6-67] DESIGN REQUIREMENTS AND QUALIFICATION.
 [Ref. 2/6-68] TYPICAL THRUST PROFILE. [Ref. 2/6-69] SRM PROJECT PERFORMANCE.
 [Ref. 2/6-70] EXTERNAL TANK (ET) PROJECT. [Ref. 2/6-71] SPACE SHUTTLE LIGHTWEIGHT EXTERNAL TANK. [sketch of]
 [Ref. 2/6-72] EXTERNAL TANK.