The Report of the Presidential Commission on the Space Shuttle Challenger Accident - The Tragedy of Mission 51-L in 1986 - Volume 5 Hearings Part Two
National Aeronautics and Space Administration (NASA), World Spaceflight News, Presidential Commission on the Space Shuttle Challenger Accident, Rogers Commission
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Report of the Presidential Commission on the Space Shuttle Challenger Accident
June 6th, 1986
Washington, D.C.
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IN MEMORIAM
"The future is not free: the story of all human progress is one of a struggle against all odds. We learned again that this America, which Abraham Lincoln called the last, best hope of man on Earth, was built on heroism and noble sacrifice. It was built by men and women like our seven star voyagers, who answered a call beyond duty, who gave more than was expected or required and who gave it little thought of worldly reward."
President Ronald Reagan * January 31, 1986
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Francis R. (Dick) Scobee - Commander
Michael John Smith - Pilot
Ellison S. Onizuka - Mission Specialist One
Judith Arlene Resnik - Mission Specialist Two
Ronald Erwin McNair - Mission Specialist Three
S. Christa McAuliffe - Payload Specialist One
Gregory Bruce Jarvis - Payload Specialist Two
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Report of the Presidential Commission on the Space Shuttle Challenger Accident - Volume 5 - Hearings of the Presidential Commission on the Space Shuttle Challenger Accident: February 6, 1986 to February 25, 1986
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SECTION 6 - MARCH 21, 1986 SESSION. (part 1 of 2)
SECTION 7 - MARCH 21, 1986 SESSION. (part 2 of 2)
SECTION 8 - APRIL 3, 1986 SESSION
SECTION 9 - MAY 2, 1986 SESSION. (part 1 of 2)
SECTION 10 - MAY 2, 1986 SESSION. (part 2 of 2)
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VOLUME 5
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MARCH 21, 1986 SESSION. (part 1 of 2)
James R. Thompson.
Colonel Edward O'Connor . D. Germany, C. Stevenson, G. McDonough and G. Erickson.
Roberts Ryan, Jerrol W. Littles and Harold Scofield.
Garry M. Lyles and Frederick D. Bachtel.
Jerrol W. Littles.
PRESIDENTIAL COMMISSION ON THE SPACE SHUTTLE CHALLENGER ACCIDENT-FRIDAY, MARCH 21,1986
Dean Acheson Auditorium
Department of State
Washington, D.C.
The Commission met, pursuant to notice, at 9:40 a.m.
PRESENT:
WILLIAM P. ROGERS, Chairman, Presiding
NEIL A. ARMSTRONG, Vice Chairman
DR. SALLY RIDE
DR. ALBERT WHEELON
ROBERT RUMMEL
DR. ARTHUR WALKER
DAVID C. ACHESON
MAJOR GENERAL DONALD KUTYNA
ROBERT HOTZ
DR. EUGENE COVERT
ALSO PRESENT:
AL KEEL, Commission Executive Director
PROCEEDINGS
CHAIRMAN ROGERS: The Commission will come to order, please.
Since our last public hearing at the Kennedy Space Center the Commission, working in part through subcommittees, has made considerable progress in its investigation of the Challenger incident. The Commission has worked very closely with Admiral Richard Truly and his assistant, J.R. Thompson, as well as with the NASA investigative panels, and has been given excellent help and cooperation in all respects.
This session today is for the purpose of updating the information that the Commission has received and to inform the public as accurately as possible of the progress that has been made to date.
Now we will call on Mr. J.R. Thompson to be our first witness.
(Witness sworn.)
TESTIMONY OF JAMES R. THOMPSON, JR., VICE CHAIRMAN, STS-51L DATA AND DESIGN ANALYSIS TASK FORCE, CAPE CANAVERAL, FLORIDA
CHAIRMAN ROGERS: Mr. Thompson, will you identify yourself and say a few words about your present assignment.
MR. THOMPSON: My name is J.R. Thompson. I'm with Princeton University and I'm on temporary assignment to NASA headquarters, reporting directly to Admiral Truly.
Mr. Chairman, this morning we would like to give you three task force team updates from the report we gave to the Commission, to the full Commission two weeks ago. The specific topics we would like to cover would be: An update on our salvage status. I think we have made a lot of progress in that area and Colonel Ed O'Connor will give you that briefing.
I think we have now almost completed our photo and time line status, and we would like to update that for you, and Dan Germany and his team will be providing the specific information on that.
We would like to focus most of today's discussion on the accident analysis team results and an update from the discussion we had several weeks ago.
Dr. Wayne Littles will lead that discussion and be supported by five additional engineers from the Marshall Space Flight Center.
In summary, I would like to report I think we have made a lot of progress. I think we've got a lot of work still in front of us, but I think it is coming together quite well. And I think over the next one to two weeks we will be seeing a lot of results of the test program that we have reviewed with your Commission.
CHAIRMAN ROGERS: Thank you very much, Mr. Thompson.
I would call Colonel O'Connor.
(Witness sworn.)
TESTIMONY OF COLONEL EDWARD O'CONNOR, CHAIRMAN, SEARCH, RECOVERY AND RECONSTRUCTION, CAPE CANAVERAL, FLORIDA
CHAIRMAN ROGERS: Colonel O'Connor, would you identify yourself and give the Commission some information about your present assignment.
COLONEL O'CONNOR: I'm Edward O'Connor, Colonel in the United States Air Force, assigned to the Eastern Space Missile Center, Patrick Air Force Base, Florida. I'm currently assigned to the task force as the leader of the search and recovery team that is in the process of recovering the debris of the shuttle.
CHAIRMAN ROGERS: You may proceed.
COLONEL O'CONNOR: I would like to give you at this time a quick update on the conditions we are facing at sea. The oceanographic features today are predominantly influenced by the weather and the springtime seasonal changes.
We expect that the problems we are having currently with recovery operations will diminish within the next few weeks, permitting us to bring up more components, particularly the right SRB. We are finding most of the right SRB components, as well as left SRB components, fairly close to the axis of the Gulf Stream, still in the depths of 220 to 1200 feet of water.
The current recovery operations include nine ships, one manned submersible, four sonars, and 27 divers. In light of the expected improvement of weather conditions and the completion of some of the analytic work in identifying probable locations of components, we are proceeding to bring another submersible into the recovery operation.
One of our most successful vessels has been the Sea Link II, which is a manned submersible supplied by the Harbor Branch Foundation. At this time we will bring in the Sea Link I, which is their other vessel, similarly equipped, which would speed up many of our recovery operations.
We have released the NR-1, which was a nuclear submarine which was characterizing many of our deep water contacts. If conditions require, we could bring this asset back in to complete the search of certain areas within the next ten days.
This chart indicates some of the changes we have had in our search area. You will recall we had an initial search area approximately 25 nautical miles by 10 nautical miles as a box. We then added a small truncated portion going out to the north.
Since that time, using the radar data, optical data, and some information supplied by the FAA area radars, we have included a few additional small boxes for location of specific components. We would expect that this would probably be the completion of our expansion of the search area for crucial components.
Next chart, please.
As of yesterday, our search area encompassed approximately 420 square nautical miles. We have done a sonar search of 400 square nautical miles, leaving just a small portion to be completed. We would expect that to be completed within the next week to ten days.
To date, we have made 571 significant sonar contacts. Each of these contacts has to be further identified through video or manned submersible operations. We have investigated 112 contacts. Shuttle components were found at 29 locations. We still need to check 459 different locations.
The recovery to date has resulted in approximately 20 percent of the orbiter being recovered and made available for analysis. We have significant portions of the main propulsion system and, as you are all aware, we are recovering portions of the crew module at this time.
In the area of the inertial upper stage, we now have 65 percent of that particular part of the payload complement. We have -less than one percent of the TDRS. The external tank right now is about ten percent complete, and the solid rocket motor-booster recovery has only brought about ten percent of the components to shore.
We have seen nothing of the Spartan Halley payload.
This chart lists the components that we have recovered from the 51-L accident. We have added a few new components on this list, predominantly in the crew module area. We have come up with some additional skin panels and some additional portions of the base heat shield.
In the area of the SRB's, we have the frustums, the drogue parachute, the rate and gyro system tunnels. At the end of this briefing, I will be covering the specific components of the right SRB that we have recovered at this time.
In the area of the external tank, we have found few additional portions of the external tank. That has not been a high priority search item at this area - at this time. But in the future we will be bringing more of that in. We have located some additional components on the ocean floor and we'll recover them at a later time.
I would like to discuss with you now for a few moments the right solid booster recovery status. We have formed a recovery team specifically to support the recovery of the right SRB components and their further analysis. This team is comprised of NASA engineers from both Kennedy Space Center and Marshall, a contractor team from the contractors involved, Thiokol and some of their other support contractors.
We have the design team in place to support all of our activities as quickly as possible when we recover the components. The identification of the critical hardware is being provided by this team, and they also suggest schemes for recovery and what things are important to them from an analytic standpoint.
The National Transportation Safety Board members of the team are also investigating the components recovered and are establishing investigative protocols to ensure the maximum evidence is recovered from any component.
In order to maximize the effectivity of the search and recovery activities, we have used many data sources. Many of the range radars were used. Optical data was used, and a lot of sonar mapping.
And a quick summary: We have completed the majority of the radar data analysis and data reduction. The optical data has also been reduced in a metric sense to help support the recovery operations. Sonar mapping is approximately 95 percent complete and we are now starting an SRB breakup analysis to better understand the breakup mechanism that occurred on the vehicle after command destruct, to better help locate the components on the ocean floor.
CHAIRMAN ROGERS: Colonel, are you in a position to make any estimates of how long it will take to complete the work you are doing?
COLONEL O'CONNOR: To recover the total right-hand SRB, assuming that we have some good weather and that our radar predictions are accurate, two to three weeks would let us get up many of the significant components that you would be interested in.
CHAIRMAN ROGERS: Thank you.
COLONEL O'CONNOR: I have one chart up there that I would like you to take a quick look at. This chart shows some of the radar and optical data that we have reduced, and it indicates what portions of the right SRB we have found to date.
As you can see, we have the frustum identified, parts of the skirt associated with the frustum, some portions of the center case elements. And at the rear of the vehicle, we have found a debris field which encompasses the majority of the aft segment and skirt.
It does not include the area of interest in that joint at this time. We are going to continue to look at that. There is one part there, slightly shaded in in the joint area, I will be discussing in a moment.
CHAIRMAN ROGERS: I wasn't clear. In the aft section, the shaded part, have you recovered all of that?
COLONEL O'CONNOR: No. We've located that on the bottom.
CHAIRMAN ROGERS: You have located it, I see.
COLONEL O'CONNOR: We will start recovery activity in that area early next week.
This chart indicates some of the design features we use for identifying the components. We use many of the index devices that NASA uses in the alignment and the stackup and manufacture of the vehicle, hole patterns and dimensions, paint markings, part and serial numbers if they are available. In many cases on the SRB, these part and serial numbers are not available on the components that we have.
Seeing they were manufactured as large segments, they would only occur in one or two places on the case. If the case breaks into many pieces, that gives us a difficult time associating a particular piece with a particular SRB
Many of the internal features are also assisting us, such as propellant profiles, and some of the inhibitor characteristics, such as depth and shape and the manufacturing records for scratches and blemishes on the case, are also being used to help characterize and help locate these components.
The right solid rocket booster components that we have located are quickly listed here. This coincides also with the chart on the wall and indicates those that are recovered: the two case cylinders, the ET attach segment, which we are not exactly sure which SRB is associated with at this time; it has not been recovered, and we will discuss that a little more - and part of the frustum have been located and also recovered.
There is a chart now-and I believe you will have to turn two charts to get to it, and it is a more detailed breakup or breakdown of the central part of this chart, indicating the type of radar tracking that led us to look into that area and the concentration of right SRB components that we are finding.
Now that we have characterized this debris field, we are better able to marshal our assets to speed the recovery of these elements. This is an important step in that we now know the major areas that have to be investigated, and we can put all of our submersibles in that area, as well as our recovery ships.
This chart, the right SRB aft components - the next chart, please. This chart indicates the SRB aft - right SRB aft components as fragments, as laid out on a plane form. As you can see the aft segment broke into many pieces. They are scattered in a fairly large area of the floor: and it is going to take a fairly lengthy period of time to recover all of these individual pieces.
We will be using the STENA Workhorse in that recovery. I have not indicated on this chart, the upper part of this chart, any location of anything associated with the clevis or the joint that is suspected of being the failure point.
If there are no questions associated with any of that material, I would like to proceed with the discussion of contact or target 292. This has recently received a lot of press attention because it has been identified as an external tank attach segment.
The first chart is a sketch of this component as it was on the ocean floor. This component has now been recovered.
Okay, would you roll the video now, please.
COLONEL O'CONNOR: I have a short video segment here showing the STENA Workhorse. This is the vessel used to recover this component. The component is being taken from the ship at this time. This was yesterday afternoon at Cape Canaveral.
That is part of the clevis joint. As you can see, it is badly damaged.
On the screen is O-ring grooves.
DR. COVERT: Colonel O'Connor, that damage, has a metallurgist had a chance to decide whether it was impact damage or damage that existed prior to impact with the water?
COLONEL O'CONNOR: In the preliminary - and I need to stress, preliminary - review of that joint, there does not appear to be any erosion or melting associated with it. That is very preliminary. So it would be expected that that joint was probably damaged at the time of command destruct, as the case experienced some torsion, or at water impact.
DR. COVERT: Thank you very much.
MR. HOTZ: Colonel O'Connor, could you give us any additional information you might have on the external tank stub attachment points, the condition of them and how much of them is left?
COLONEL O'CONNOR: Yes, I can. I have two photos here I think that might help go through that process. Let me bring those up, and then I will address your question.
This is a still photograph of that same component. This is showing the inhibitor, one of the things that we use to characterize whether it be a left or right SRB.
On this photo you have a better view of the clevis joint, if you look at where the white tag is attached. That is part of the ET attach strut assembly. There is some deformation in that area. There is some insulation just above it that has been eroded and removed.
This is helping us to characterize where on the aft segment this would be located.
DR. COVERT: Do you want to make a guess as to where it is, please?
COLONEL O'CONNOR: I'm not prepared to guess at that right now, sir. We have got a lot of contacts out in the area. We think it may be in that vicinity, but this is a fairly small fragment of the case and the dynamics aren't very well understood now to say it would fall in this vicinity or be taken with a larger structure a further distance.
DR. COVERT: I meant, was this at 300 degrees or 180 degrees?
COLONEL O'CONNOR: Where it is on the case?
DR. COVERT: Yes, sir.
COLONEL O'CONNOR: I have a sketch on that, sir. Next chart, please.
This chart lists the status of this particular component, seeing it is of such high interest. The portion was recovered on the 17th of March. It was brought into port by STENA Workhorse yesterday. It was removed from the STENA Workhorse yesterday about noon.
We took it over to our ordnance area on Cape Canaveral. Our engineers were evaluating it yesterday afternoon and late into the night. The preliminary evaluation indicates there are no part numbers or other positive identifying features.
It is a confirmed aft segment component. It is a confirmed ET attach portion. The external surface is darkened and blistered. The ET attach stud hole spacing and deformation is consistent with this case segment being from a 90 to 180 degree quadrant on a segment.
It is most probably a right SRB component. Because of the lack of any identification number or anything that can definitely tie it to the right SRB, we have to qualify it being right at this time. We are continuing the evaluation at this time. We brought other engineers in.
We have been reviewing the other stacked SRB's at the Cape, looking for other identifying features.
CHAIRMAN ROGERS: Why would you say «most probably» if you don't know which it is?
COLONEL O'CONNOR: Looking at the propellant depth, the inhibitor shape, we have about 20, possibly 25, inferential characteristics would say it is the right SRB. We have nothing that would point it toward being the left SRB.
But we don't have that crisp nice part number stamped on the side that would let us really track it down and say for sure.
CHAIRMAN ROGERS: Thank you.
COLONEL O'CONNOR: This particular view looking down on the orbiter stack indicates a right SRB with the label pointing to where the black smoke was initially found at the time of launch. Looking at the different characteristics of this particular segment piece, we would suspect it would be, as indicated on that chart, approximately 180 degrees away from the black smoke.
That completes my briefing.
CHAIRMAN ROGERS: Thank you very much.
Any questions?
(No response.)
CHAIRMAN ROGERS: Thank you, Colonel.
Mr. Germany.
TESTIMONY OF: DAN GERMANY, CHAIRMAN, PHOTO AND TELEVISION SUPPORT TEAM, CAPE CANAVERAL, AND DEPUTY MANAGER, SPACE STATION PROJECT OFFICE, JOHNSON FLIGHT SPACE CENTER, HOUSTON, TEXAS; CHARLES STEVEN SON, GEORGE McDONOUGH, AND GEORGE ERICKSON
CHAIRMAN ROGERS: Mr. Germany, do you want to proceed?
MR. GERMANY: Yes, sir, Mr. Chairman.
CHAIRMAN ROGERS: I guess you haven't appeared before us. You might identify yourself and identify your colleagues.
MR. GERMANY: I would be glad to do that. My name is Dan Germany. My parent organization is the Johnson Space Center in Houston, Texas, My current assignment is chairman of the Photographic and TV Support Team, which is a part of the task force that is assisting the Commission in this investigation.
I have with me today three additional representatives of the team: Charlie Stevenson on my right, George McDonough on my left, and George Erickson on his left.
These are primary focal points in each of the center. We have a total integrated effort among the field centers in order to try to focus and understand all of the photographic and TV products that we have accumulated from this particular incident.
CHAIRMAN ROGERS: Thank you.
We know Mr. Stevenson very well. He testified before. Now he is here as an expert. Last time he said he speculated. Now we want to ask him what his opinion is as an expert witness.
[Laughter.]
MR. GERMANY: Could I have the first chart, please.
I think it is important to try to give you an overview before we get into the details, Mr. Chairman, of some of this photographic activity, to help the Commission fully understand the way we are organized and we are proceeding with the efforts amongst the various teams that we have as part of the task force.
The TV team, as well as the salvage support team that you just heard from, are in fact support groups. The four analysis teams are the four blocks that show right below Admiral Truly's block, as well as Mr. Thompson's block there. Those are the teams that are responsible for taking the results of the activities that they have themselves, as well as the activities from our two support teams, and integrating them together to come up with the engineering conclusions that will be drawn as a result of the final report for this entire incident.
The activities that we're going to have for you today are centered around looking at photographic products and describing to you what we were able to see from those photographic products. The accident analysis team, with Mr. Jones and his people, are the ones that are responsible for taking that information, combining it with the engineering data base, as well as the other overall telemetry data from the flight, and coming up with the engineering conclusions that we will be forthwith as a result of the final report.
Next chart, please.
I have three charts that are coming up, Mr. Chairman, that will give you, help give you an overview of the photography in general. I'm not going to brief the details of the charts. We have included them for reference sake as much as anything, so as the Commission goes through its deliberations and you hear us talking about various cameras this might help you to pinpoint.
The first chart right there we are looking at is one that gives an aerial view of the pad itself.
There are six positions around the radius of that pad where there are cameras that are located. The fifth position, which is the 270 degree point, you are looking across the gantry structure, so we don't really use cameras there.
But they are in those other positions, and from a total point of view we have somewhere over 100 cameras, which includes photographic cameras as well as video cameras, not only here but on the mobile launch platform, the tower itself, and the surrounding areas as you go external to the pad and the tracking cameras.
This is a chart that depicts the mobile launch platform itself. As you can see, you have a multitude of cameras that are located on what we call the MLP.
This is a chart that shows the tower itself and the locations of the cameras on there.
Now what we're going to do is move into the part of the presentation that deals with the integrated time line that has been put together. The photographic team uses the integrated time line as a road map, so to speak, to step through all of the events that occurred and try to understand the photography and the video that goes with that.
I'm starting off with this dynamic coordinate system chart for you because I know that it is easy to get confused in the many coordinate systems that we have for this particular vehicle. And so at the front of your integrated time line we have put this chart for clarification as much as anything else, to help you try to remember which axis is which.
And I will try to walk through this to help you try to visualize it. If you were sitting in the cockpit of the orbiter and can visualize yourself sitting there, the plus axis, plus X axis, is in this direction like so. The minus X axis is behind you.
If you think about the torso of your body, the plus Z axis is down through your feet and the minus Z axis is like up through your head. And if you can visualize your arms being out like this, this would be like the Y axis of the vehicle.
So everything that you will see on the time line is related back to this particular coordinate system, to try to help you keep that straight.
Since the last time that you've seen this, we have changed the graphics of the time line just a little bit, and let me describe the graphics for you so you will understand it as we go through it. We tried to separate out the camera events from the other instrumentation.
On the left-hand side of your chart there, you will see the camera events. You have to read this chart from the bottom of it to the top. The bottom, you start with T-zero, the ignition command. In the subsequent charts that follow it, we read from the bottom to the top.
On the right-hand side of the chart, you will see the other telemetry events that go with the trajectory itself. Now, what we will try to do today for you is, first we will walk through this time line like this, and I will use this model to help depict part of it.
And then what we are going to do is show you a video film that we have put together that is a combination of about 14 different cameras, which includes photographic cameras as well as TV cameras all the way through this time line.
And we also have it set aside-it goes back and corresponds to the events that we have on this time line. But because of the way the presentation facilities are here, we could only do one screen at a time.
So we are going to step through this way first, and then we will do the video second, and we will do the video in a stop-start manner, whichever way you want to go to help you understand the things that we are trying to depict for you.
On this particular chart, if you start at the bottom there, at the T-zero command-and let me reference myself here. This first chart shows the areas of activity that occur at about the first 3.375 seconds, and it all hinges from an imagery anomaly point of view around the business that we talk about, the puffs of smoke or the black smoke.
Up to this point, there have been different numbers associated with different events, as we have talked to you. This particular time line today is a current status of those events, trying to tie everything back and be consistent from this point on.
The confirmed smoke occurs at .678 seconds, as you see on the left-hand side of the chart. We've got two entries there. One says "confirmed smoke above the field splice," and it moves initially in the plus X direction, and then "confirmed black smoke." All that's trying to say is that there's been a lot of discussion about the colors of the smoke. We feel, after a thorough analysis of the film that we have available to us, that that smoke is really shades of gray. And it starts off, it is kind of like a light shade and it becomes darker as it goes, before we lose sight of it after a few seconds.
So those particular events there, I have just listed them twice to try to help you understand the fact that it is not a given constant shade.
Then we have what we have been describing as multiple puffs of smoke that occur in a time frame of about .854 seconds up through 2.259 seconds. And in the video film today we will show that to you so you can graphically see what we are talking about.
CHAIRMAN ROGERS: Now, that is new information from the presentation made two weeks ago?
MR. GERMANY: Yes, sir, I believe it is, in terms of the video that you will be seeing.
GENERAL KUTYNA: Can I ask, what was the frequency of those puffs of smoke? How many puffs per second?
MR. GERMANY: Well, we are off trying to analyze that right now, General. And it appears to have a beat frequency to it. We are not prepared at this point to say exactly what it is. We do have some enhancement work going on that will help us figure that out better.
GENERAL KUTYNA: Can you give me a ballpark? Two or three puffs per second, 20 puffs per second?
MR. GERMANY: Well, the numbers that I'm hearing at this particular point are approximately about three hertz.
GENERAL KUTYNA: Three puffs per second?
MR. GERMANY: Yes. But we're in the process of understanding that and it will be finalized a little bit later on. I want to emphasize that point for you.
The last positive evidence of smoke above the right aft SRB, ET aft ring occurs at 2.733 seconds. The last positive visual indication is 3.375 seconds. And in there you will see a little parentheses that says "E-217." That is a camera that perhaps is indicating potential smoke even further than the 3.375.
1 believe, based on the analysis we have done since the last time we have talked to you and what we will be doing over the next week, probably we will be able to delete that particular part. I'm not ready to take it off the chart now, but based on the stuff that we have done this week we are having difficulty validating for sure that smoke is occurring all the way up to that point.
We do feel very positive about the 2.733, and then the 3.375. So we will be updating this as we go.
DR. COVERT: Mr. Germany, on this 2.733, is the inference to draw that smoke is continually coming up until-in that interval, or is the inference that after the puffs the smoke hangs around at that interval with no material addition?
MR. GERMANY: Well, Dr. Covert, as you will see on the film, the smoke appears to not replenish itself after a point. As it is replenishing itself, it tends to be above that ring. As the vehicle moves on through that, it tends to go down.
So we're trying to figure out exactly, does that mean it stops or not, and we are just not prepared to say for sure yet.
DR. COVERT: Well, it must stop sometime.
MR. GERMANY: It must stop sometime, yes, and we are off to try to understand that.
DR. COVERT: You will report later to us what you have decided?
MR. GERMANY: Yes, sir, we sure will.
DR. WHEELON: Mr. Germany, having reviewed the similar photography of prior shuttle launches, can you state that no such smoke occurred on prior launches?
MR. GERMANY: We have been off trying to do that, and we have reviewed all of the film that we have from, I believe there is about six different launches for which people have talked about having erosion of the O-rings. On those flights, we have not been able to find any smoke that is duplicative of the smoke that we have seen on 51-L.
There are some other films we are looking at, too, but at this point we have not been able to find any visual evidence of smoke that is duplicative of what we have seen here on 51-L.
DR. WHEELON: Thank you very much.
DR. COVERT: When you say that it is duplicative, does that mean there may be other smoke of other kinds about, or are you just trying to be careful and be precise?
MR. GERMANY: I'm trying to be as precise as we can with the sometimes imprecise analysis that we do.
MR. RUMMEL: Can you account for the puffs versus continuing smoke? Does it relate to, oh, say the natural frequency of the structure or vibratory phenomena or some other situation? Do you know?
MR. GERMANY: Well, the importance of seeing puffs could be related back to what is happening with the joint, and that is why we're putting it on this time line now and trying to understand that. It could be that the aerodynamics of the situation at that point could be accounting for the puffs, and I'm just not ready to say that we know which it is right now.
But we are indicating it and we are doing enhancement work, and as that becomes clear then we will report what we find.
MR. RUMMEL: Thank you.
MR. GERMANY: Could I have the next chart, please.
DR. WHEELON: But just to be clear, you have said three hertz. Do you mean three puffs per second?
MR. GERMANY: Yes, sir.
DR. WHEELON: Thank you.
MR. GERMANY: Can you zoom in on that just a little bit, that chart, please. Bring it up a little bit closer. There you go.