|Columbia Accident Investigation Board Press Briefing
Tuesday, April 1, 2003
Center for Advanced Space Studies
Lunar and Planetary Institute
3600 Bay Area Boulevard
Clear Lake, Texas
LT. COL. WOODYARD: Good afternoon and
welcome to the Columbia Accident Investigation Board
press briefing. We will begin today's briefing with
opening comments from the chairman of the board,
ADM. GEHMAN: Good afternoon, everybody.
We'll use our usual format here today. We have a
couple of introductory comments to make. We will let
each of the board members speak, representing their
group, and then we'll take your questions.
First of all, I would like to thank the
Center for Advanced Space Studies, particularly the
Lunar and Planetary Institute, whose facilities we're
using here again. I appreciate it very much. Thank
you very much.
This has been a good week for us, not
just because of the promise of data from the famous OEX
recorder, which we're going to get into in great
detail, but also because of progress on a number of
other fronts which we will mention here.
I think it's worth mentioning to kind of
remind us all: Today is two months to the day since
the loss of Columbia. Maybe it's useful for us to just
take a second and reconstruct what we're doing.
The board is essentially working on three fronts simultaneously. The first is to determine the
direct cause or the initiating event of this tragedy.
As we have mentioned on several occasions, to do that,
we are essentially pursuing six parallel avenues of
technical investigation, and I have mentioned these
before. That's the thermodynamic analysis, the
aerodynamic analysis, the reconstruction of the debris
and the testing of debris to learn what we can, the
building of a detailed time line based on the telemetry
and now the OEX recorder, analysis of the photos and
the videography that we have received, and analysis of
the maintenance and modification documentation. Those
are the six areas.
If we find the direct cause because of
physical evidence, that would be wonderful; but if we
have to infer or deduce the initiating event, what we
will do, of course, is to attempt to get these six
avenues of investigation to line up somehow. Somebody
has once described it to me as getting the holes in the
Swiss cheese to line up. Then that, we believe, will
point us with some degree of surety toward the
The second front that we're working on in
parallel with great rigor -- and will hear about it
today -- is the investigation into all the contributing and root causes. This has to do with all the issues of
budget and management and committees and boards and
processes and all of this that's about ageing
spacecraft and E-mails and all those kinds of things.
We are going to run all that stuff to ground in due
course; and it will be part of our report if it rises,
in our view, to the level of being a contributing
cause. You're going to hear about that today.
Then the third front that we're working
on is this context issue that I had mentioned before --
that is, we're going to put our report in context. By
"in context," I mean that this accident, in our view,
is not necessarily a random data point on a continuum
graph. It probably fits into some kind of an overall
context. That context could be the context of budget
patterns. It could be a context of changing
priorities. It could be the context of perhaps the
psychology of continued success. It could be the
context of work force patterns -- that is, it could be
that the work force has changed or the way they look at
the shuttle program from being an operational or a
research and development -- a whole number of contexts
that we will attempt to put this accident in, and it
will be part of our report. Several members of
Congress have indicated to me that their work just begins when our work ends, and so we've got to provide
them a document which will be a smooth bridge into the
things that they need to do.
That's really all I have. I want to get
to the meat of the press conference, which is listening
to my colleagues here on the left. We'll start off
with Steve Wallace, who is in the group we call
Group 2, which is basically called the operations.
MR. WALLACE: Thank you, sir. So
following Admiral Gehman's three fronts, I think we are
largely in the second front in Group 2 in terms of
contributing on root causes. The two gentlemen to my
left are a little more into the debris and hardware,
and we're more focused on decision-making and
Let me just first give a quick report on
where my colleagues are. There are three board members
assigned to Group 2. Major General Ken Hess is at the
Marshall Space Flight Center this week. He'll be doing
a series of interviews and inquiries relating to
external tank issues, particularly disposition of
falling foam events in earlier flights and their role
in the Flight Readiness Review and Certification of
Flight Readiness process.
Dr. Sally Ride is the third member of our group, who is just this week kind of off, closing up
some other personal commitments from her past life
before Admiral Gehman drafted her to join our board.
So she'll be back with us next week. I will say we
worked with her for a couple of weeks before and she is
a very effective and valued member of our team,
especially on issues of communications and
decision-making, obviously brings a terrific historical
context and a great deal of technical expertise, as
I'm going to talk about foam a little
now. Our part of the foam, again, is largely the
decision-making on the disposition of prior foam events
and we are doing what we're sort of calling foam audit
where we're looking at falling foam throughout the
history of the shuttle program, both when it was sort
of popcorn and falling and then different events and
particularly, of course, issues of bipod ramp foam and
a particular focus on STS 112 where there was a
substantial piece of bipod foam and the sort of
disposition of that and whether there was a tendency to
sort of normalize falling foam, it happens all the
time, or whether it needed to be a distinction between
the sort of popcorning small pieces of foam that was
addressed a long time ago and these later issues. I will say we've reached no conclusion on foam's exact
contribution. There's testing going on this week under
Mr. Tetrault's group, or in the near future will be
some testing to determine the possible foam impacts on
different parts of the TPS system.
The other issue that we're heavily
involved in is the request for DOD assets, the
much-discussed on-again-off-again requests for DOD
imaging. That's largely the subject of all the E-mails
that have gotten so much publicity. I'd like to say
about the E-mails that they are important but they are
one part of a very complicated story. Other parts
include interviews which we have done, over a hundred
by this board already. In a great number of those,
some of those same issues that are in E-mails are
discussed -- minutes of meetings, various logs, audio
recordings of meetings, comparing those to the minutes
to try to get a sense for the dynamic. Mr. Tetrault
will be talking later about all these various sensor
inputs, sensors that were downlinked and sensors from
the OEX recorder. I think I sort of view all these
E-mails and interviews as our sensor inputs. We have a
very complicated story that we are trying to fit
together and ours is not a sort of mechanical story but
it's very much of a human story in terms of interaction and decision-making and communications. And that part
of our story on the overall safety processes, those
that are written and procedurally defined, of which
there are many, I think this is a very process-intense
operation, a deeper question for us is how these work
in reality and how communications, the various dynamics
of the organization, which this part of our inquiry
then flows into Group 4, not here with us today but
recently constituted, headed by Dr. Logsdon, who is the
director of the Space Policy Institute at George
Washington University. And Admiral Gehman spoke
earlier about putting our findings into context, work
force patterns, budget. I think his group is entitled
Organization and Policy. That's where we sort of meld
into Dr. Logsdon, who will be having the lead on that
issue and who is pulling together an extremely
qualified group of experts who have a lot of historical
context in the NASA organization.
Just to touch briefly on a couple of
mundane aspects, relatively speaking, of our group's
work. Training and payload issues. We're bringing
those to closure. I can say we are close to completing
a very thorough review of the training of the ground
and flight personnel for STS 107. The records are not
flawless; but they are such that, while it's not officially off the table, we've found nothing that
would suggest any contribution to the accident. And
the same with payloads. There's actually a fault tree
on payloads that NASA will be closing out, and we're
doing it in an effort in conjunction and oversight of
that. Again, there were some minor irregularities with
payload but nothing that would suggest a contribution
to the accident.
Again, we are following and talked about
this a little bit in the last press conference, about
return-to-flight issues. There's the effort going on
in the program level, there's an effort now directed
from NASA headquarters with Astronaut Jim Halsell
melding these two together, and the board will also be,
in its recommendations, working on some
return-to-flight issues. I would emphasize that we're
all largely, I think, along the same lines; and there
isn't a contest here. We all want to get back to
flight. So that's the Group 2 update.
ADM. GEHMAN: Thank you very much.
GEN. BARRY: Sure. Good afternoon. I've
got a couple of updates. First of all, Admiral Steve
Turcotte, another member of our board, is at Langley
today. General Duane Deal is here at JSC with me for the week. We've got a couple of trips with our
subgroup members who are going to KSC and Marshall. So
we're going to spread out again.
Let me give you a couple of updates.
Maintenance, management and human factors, and then
materials and structures. Let me just briefly mention
on the maintenance side.
This Friday the board will receive a
briefing that will close out, provided we approve it,
the SSME as one of the fault trees, followed by,
shortly, the SRB and the RSRM next week. So we're
getting a full briefing, and we've been involved and
engaged all along. So we'll be taking that.
ADM. GEHMAN: John, maybe you better
spell out those abbreviations.
GEN. BARRY: The SSME is the space
shuttle main engine; of course, the RSRM is the
replaceable solid rocket motor; and then the solid
The other point I want to make is on
management human factors. We've been engaged with
numerous interviews, examining the Palmdale move and
the Huntington Beach engineer move. So there's been a
lot of work being done on that by our group.
The main thing I want to talk to you is to give you an update on foam, RCC ageing, and the
Day 2 debris that we've got some updates on.
If I could ask for the first slide.
General Deal has been leading the charge
on the foam for our efforts. We've got Lieutenant
Colonel Larry Butkus from the Air Force Academy who's
been helping also, as has Clare Paul. What I want to
do is concentrate and focus your eyes on our dissection
that we've got on the Y pod. We've also started
cutting into the left side. So this is the right side,
plus Y, minus Y, and I'll give you some information
Next slide. All right. Again, the big
picture. I want to focus here. This is where it's
located on the external tank, as indicated in red up
here. A lot of different kinds of foams on the
external tank, but we'll be focusing on this area.
Next slide. All right. I just wanted to
show some of the loads that happen. This is the exact
time that we've been able to record, 2.46 Mach is when
the bipod foam came off on the left-hand side,
allegedly. We're still trying to confirm that
100 percent. This is at the 81-second point. You can
see it's a pretty dynamic engagement zone right now
insofar as the aerodynamic loads.
Next slide. This will give you a color
depiction. Again, there's a lot of intersecting shocks
that are happening at this point for vortex pressures.
You can see there's a lot more pressure from inside out
here. There is no indication right now that the bipod
design has not been adequate enough to accept these
aerodynamic loads. However, I do want to point out
that we're still examining cryopumping. So it looks
like something else other than the aerodynamic loads is
one that contributed to some of the losses in the past
and the one we're looking at right now with STS 107.
Next slide. All right. Here is just a
rehash on the previous ones we've had. This is in
Challenger in '83. You can see the location of the
actual paragraph and then a little bit of a schematic
illustration of what they think actually happened.
This was '83.
Next slide. '90. Again, the picture and
then what piece we think came off.
Next. This is '92. And again, a larger
Finally the one prior to Columbia. Next
This was ten years later from the
previous one. Last one before this was '92, and this was the piece that came off.
All right. Next slide. We are examining
closely, as you know, the cryopumping issue; and what
we think is there's purging that goes on in the
internal part of the external tank. So inside here is
purging to kind of act as a safety gas between oxygen
and hydrogen. Well, some of that turns into liquid and
seeps out and gets into the ablative or gets into what
I'll show you here as the voids. So the cryopumping is
a flash evaporation when it goes from very cold
temperatures, liquid, to warmer temperatures and then
turns into gas and has to find some vent there.
Next slide. Now, here is the cuts that
we've been experimenting with down at Michoud. This is
where I'll show you some of the photographs. This is
Region 6A here, as indicated right back. We have
problems with voids and de-bonding.
Next slide. You can see here we've got
void and rollover. That's when the foam goes over the
top as it's applied, disbonding, and then primer. We
have some problems at the bonding levels.
Next slide. There are some closer
photographs now here of voids that we have found in the
right side pod of ET 120. That's the one we cut into.
We're trying to get better at our ability to do this cutting and looking into it so when we tap into
ET 94 -- that is the one that's exactly the same as
ET 93 -- and ET93, as you will recall, External Tank 93
was the one that was on the STS 107.
Next slide. We've got a bigger picture
here of the voids that were indicated. Again, these
can capture liquid, which eventually can turn to gas
when it gets warmer and then looking for a vent or a
Next slide. Here's another picture of
voids. Now, right now we've found about 14 voids in
the right side and we're up to 18 on the left side now
that we've cut into it in the last couple of days.
Next slide. All right. Now that I
talked about the foam, follow the foam, this is a
little bit about following the ageing. This is a
pinhole on the RCC. So we have the foam come off and
one of the scenarios, as you all know, is we're looking
at something that hit the RCC. This was first
discovered on 102-12 in 1992 and we've been examining
some of the potential contributory elements that may
have gone to them and we think one of the leaders is
the corrosion from zinc oxide.
Next slide. Scale on the pinhole. If it
is greater than .04 inches, it is out of tolerance. So this one right now is out of tolerance because of the
increase in the expansion on the corrosion.
Now, this pinhole was first discovered
in '92. It's on all the orbiters now, and at any given
time you can look at any panel and you can count 20 to
40. The root cause of the pinholes is the paint primer
that seeps down after the rain from the infrastructure
that's on the pad. So the pad topcoat hasn't been
refurbished and the primer gets exposed and then zinc
becomes zinc oxide which then falls on the leading edge
of the RCC and then we have pinholes.
Let me show you the next slide. You see
the orbiter on the pad. When we have the collapse of
the rest of the pad over it and expose some of the
areas of that infrastructure that haven't been painted,
we get the primer and get the zinc oxide. So that's
one of the things that we've been contributing.
Okay. Bring down the slides, please.
All right. Day 2 debris. That's the
final thing I want to bring to your attention. We do
have some more information on that. As you remember,
this was discovered on the sixth day after the mishap,
by DOD. It was one of the most laborious reviews of
radar data in history of Space Command. If you will
recall, we assessed this thing when the shuttle was going on a rear vector. It turned into a right wing
vector and then back to a rear. In the course of those
maneuvers, we noticed that something came off; and this
is what's been commonly called the debris of Day 2.
All right. Here's what we have so far on
the testing. With the 3100-plus observations of
Columbia by DOD, we've got a lot of radar cross-section
feedback. There have been 29 various materials
examined at Wright Patterson Air Force Base and we've
concluded right now that only the carrier panel remains
a viable candidate for the Day 2 object. Now, this
radar cross-section came from Pave PAWS radar at Cape
Cod, space surveillance radar at Eglin, Pave PAWS at
Beale and Navy fence radar. All those combined gave us
a pretty good data base on what to look for on this
Day 2 debris. Then, of course, we took it to Wright
Patterson Air Force research lab and put it in the
sound room that we have over there and then tested it.
We think with the horse collar and the
carrier panel it gives us one of the best candidates
we've had so far, after reviewing all the testing, to
be the leading candidate; but we still have some more
testing to do. The engineer is going to do follow-on
testing for four tiles versus three tiles on the
carrier panel, and we also have some other looks that we want to take a look at.
Thermal blankets from the bay were also
considered a possibility but because of the correct
area and mass ratio when it re-entered the atmosphere,
it doesn't look like that is a possible candidate. So
the bottom line is the carrier panel. It looks like
our best candidate so far. We do have some final
refinements, and we'll continue to work that as we go
ADM. GEHMAN: Thank you very much. In my
opinion, it's a good week's progress; and we haven't
even mentioned the OEX recorder yet.
So over to you, Roger Tetrault.
MR. TETRAULT: Right. I represent the
technical committee; and, of course, we actually are
the largest of the groups. We have five members; and
those members include Sheila Widnall, who was at
Langley yesterday, watching some of the wind tunnel
testing that they're doing and getting updated on that
wind tunnel testing. In addition to that, we have Jim
Hallock, who is at Kennedy today; and he is reviewing
the debris or looking at the debris. We also have
Scott Hubbard, who is working the Southwest Research
testing plan; and that plan is in a little bit of flux
as of today. Also we have Dr. Doug Osheroff and, amongst other things that he's taken on, one of them is
to try to come up with mechanism for chemical analysis
of some of our debris to sort out at what altitudes
various events happened, using Nobel gases. So that's
a very tricky kind of area that he is helping us with.
As most of you are probably aware, I am
the person who is responsible for both the leading edge
of the wing and also the management of the debris and
its analysis down at Kennedy. Today what I'd like to
do is update you with four different areas; and I'm
going to update you on flight data, including the OEX,
and also one small item on the old telemetry data line.
Then I would also like to give you a little bit of an
update on the photo analysis and what's going on in
that particular area, talk briefly about the orbiter
aero off-nominal results and the struggle that we're
having to try to come to some conclusions about the
meaning of those results, and then show you one piece
of the debris which is, in fact, at least answering one
of the questions that we have on these off-nominal aero
So if we put up the first slide, this one
you've seen before; but it is the OEX recorder which,
as you can see, is in pretty good shape. Let me give
you a kind of verbal description of what's on the recorder and what we can get out of it. It has two
types of data. Data called PCM, which is pulse code
modulation. This is low-frequency data and normally is
used to get information about pressures, temperatures,
and strain. It has FDM data, which is frequency
division multiplex data, basically wide band. That
data includes stress and strain sensors relative to the
structural area, the vertical fin, the speed brake, and
the heat shield, and also contains data relative to the
main engine vibration.
The tape contains both ascent data and
re-entry data, and I think most of you are probably
aware that they turn on the OEX recorder 15 minutes
prior to launch and it's kept on until main engine
cutoff plus six minutes. On reentry, it's turned on
ten minutes prior to entry interface; and the data that
we have goes to the end of the tape.
Last week Scott Hubbard talked about what
we could expect to find, and he told that you that
there were 721 sensors that were recorded on this
recorder. Of course, we're in very much a preliminary
sort of stage on the information that we're receiving
out of the recorder, but let me kind of put these 721
into buckets so that you have an idea of what kinds of
data we're seeing.
Over the weekend there were over
100 people working at NASA to try to extract this data.
They were able to extract good data from approximately
420 sensors, all on the PCM side. There were
approximately 50 sensors that we don't have good data
from and we don't expect to have good data from because
they were not necessarily hooked up or for a variety of
other reasons they were not essentially ready to take
data. There was, over the weekend, 150 sensors -- and
these were all strain gauge -- that were on PCM No. 3
that we were not able to read over the weekend,
primarily because of a synchronization problem. They
were able to read that data yesterday and we now have
150 extra pieces of sensory data, but it is all strain
That leaves you with approximately 100
sensors. Those sensors are in the FDM, and they have
not been read as of now. Most of this or a good
portion of it needs to be sent to Boeing and also to
California before it can be read. It can't be read
here. So that gives you a pool. That accounts for 720
out of the 721 I just gave you, kind of putting them in
Let me tell you kind of in a gross-order
fashion what we are finding from these sensors. We've taken a quick look at what they are telling us about
ascent. That quick look on the strain gauges says that
we are not seeing anything unique. Everything seems to
be within family. I think Scott mentioned last week
that he did not believe that we would see any foam
strike at L plus 82 or something like that. We don't
appear to be seeing anything that matches that
L plus 82.
Let me talk about the descent. The FDM
data went to Greenwich Mean Time 14, zero minutes, and
19.4 seconds. That's 15 seconds after any of the other
sensory data that we previously had received. By that
I mean the 32-second piece that we had that you may
recall had a 5 seconds, 25 seconds missing, and then
2 final seconds. So we've got 15 seconds more than
that now. In addition, we have sensors that now tell
us about the 25 seconds which previously was missing.
The PCM data did not quite go so long.
It went to Greenwich Mean Time 14, zero minutes,
13.4 seconds, or 9 seconds longer than the previous
one. What all this suggests, of course, is that the
OEX recorder, which is inside the fuselage, was
receiving power during that entire period of time; and,
of course, at that point the fuselage had probably not
Let me put another slide up, if I could.
This is a very preliminary slide. It's under revision,
but what I wanted to show you is I wanted to talk about
four sensors and give you some information about four
sensors. One is going to be on the OMS pod, which is
not shown here. This is the lower portion of the left
wing. The three that I want to talk about are all
going to be in this area. One sensor is not shown. It
is a strain sensor, and these are two temperature
This is 9910 and 9895. 9910 is in front
of the spar. 9895 is behind the spar. Now, let me
talk about these sensors and how they affect the
beginning of the time line for events that we've seen
The first one I want to talk about is not
shown on here. It is Sensor G9921, and it is right in
this area behind the spar, at approximately RCC Panel
No. 9. As I said, it is a strain gauge. It starts to
increase and goes off nominal at Greenwich Mean Time
13:48:39. That's EI plus 270 seconds; and I'm going to
try to give you, where I can, both the Greenwich Mean
Time and the entry interface plus seconds after entry
interface, because that's how these gauges are
As I said, it's located behind RCC Panel
No. 9; and it did go off nominal at 270 seconds.
That's 206 seconds earlier than the first event on our
previous time line. And the first event, you may
recall, on the previous time line was the start of the
delta yaw which was at EI plus 476 seconds.
The second one that I want to talk about
is Sensor 9910, which is the one in front of the spar.
It is actually attached to the clevis. I believe it is
the clevis which is the outboard attachment for the RCC
Panel No. 9 and where it mates with T Seal No. 10. So
it's on the outboard side of RCC No. 9, forward of the
spar. That one went off nominal at 13:48:59. That's
at EI plus 290 seconds. It went off signal low at
EI 492 seconds or approximately 52 minutes and 19
seconds. When it went off signal low, it had read only
about 50 degrees, which probably suggested that the
wire had been cut; and that is not particularly
surprising when you recognize that this sensor actually
has insulation which is packed around it, which are
referred to as earmuffs.
Let me talk about the third sensor, and
I'm giving you these in order. These are the four
sensors in order as they went off on this OEX recorder.
The third sensor is Temperature Sensor 9220. It is located on the OMS pod TPS surface and on the leading
side of the OMS pod. It starts to go off temperature
and it goes low off temperature at 13:49:53 Greenwich
Mean Time, which is entry interface plus 344 seconds.
It goes off low until approximately 540 seconds, and
then it makes a rapid switch and goes high. And it
actually goes as high as 1200 degrees.
Normal for that portion of the flight
would expect to be around 600. So what can you gather
from that? First we think that there is a change in
the mass flow which moves the mass flow probably below
the OMS pod and then there is something else which
happens that raised the temperature rapidly up, which
may be burning or burning aluminum or a number of other
effects that we have to go look at.
The fourth sensor is 9895. This is the
one behind the spar at RCC Panel No. 9. This one right
here. And it's pretty much in the middle of the wing
surface in terms of where it's positioned. It goes off
nominal at 13:51:14, or EI plus 425 seconds. It goes
off scale low at EI plus 520. So the wire is cut at
approximately 520 seconds.
This particular one behind the spar goes
up to approximately 450 degrees where it peaks and then
goes off scale low. This is 63 seconds before the old time line Temperature D sensor, which was the first
sensor in the old time line that was a temperature
sensor. And if I go back and look at Event No. 2 which
I gave you, which was the one in front of it, that was
188 seconds before brake line Temperature Sensor D
first showed an off-nominal.
Now, what I would like to mention to you
is it's probably even more of a delta than that because
we are finding that brake line Temperature D, which
established the first sensor previously, is probably
not off nominal at the time that's on the time line.
It's probably later than that. That's an important
point strictly because Sensor D goes off first and it
is in the aft of the wheel well and it is high in the
wheel well, which tends to indicate that the heat is
coming from the aft part of the wheel well, moving
forward. But if you really look at it and say what's
going on and that moves, it is much more likely that
the heat is coming from the forward side of the wheel
well going aft and this study that they've done that
indicates Temperature Sensor D is probably nominal for
a much longer period of time than they specified helps
in making that case that this all begins to line up a
little bit better than it had previously. In that
study which NASA ran, they found that at least 13 flights had had bit flips before EI plus 500, and
11 of them had been before this flight showed the same
kind of change.
Okay. Let me kind of give a general
summary of the data that we're seeing. This is very
general and very early, just as giving you some
information about some of these individual sensors are,
without a lot of review. In general, there are about
15 sensors in the left wing; and they all seem to go
off scale low about Greenwich Mean Time 13:22:54, which
is west of California. NASA has also looked at
17 sensors, all on the left wing, and has indicated
that they believe they see a warming trend compared to
previous flights with similar inclinations, and that
warming trend -- not off-nominal trend, just a general
warming trend -- occurs at EI plus 80. Very early in
Let me have the next slide, please.
Scott showed you this slide last week, and what I
wanted to do is update you on some photo analysis which
has been done. NIMA, which is the National Imaging and
Mapping Agency, has taken all of the photos that we had
and digitized them at 50 megabytes per frame. Having
done that, we have been able to actually come to some
conclusions, and let me say what those conclusions are.
ADM. GEHMAN: Roger.
MR. TETRAULT: Yes, sir.
ADM. GEHMAN: We have to hurry up.
MR. TETRAULT: Okay.
ADM. GEHMAN: Fifteen minutes has already
MR. TETRAULT: I apologize.
REPORTERS: We're happy.
MR. TETRAULT: The important issue here
is the debris size, which has now been calculated to be
24, plus or minus 3; 15, plus or minus 3, and 5, plus
or minus 1 -- which equates to approximately a 2-pound
piece. The 24 and the 15 are measured; the 5 is a
calculated value based upon the trajectory that it flew
and the mass that it would have had to fly that
trajectory and wind up with a velocity of 640 feet per
second at the end, which is the average of the measured
values that they have that it hit the wing.
There is no evidence of more than one
strike. The impact point as you see it here is between
RCC Panels No. 5 and 7; and no debris is seen over the
top of the wing. And that photo that we previously
showed you with before and after debris strike, with
16 frames and 17 frames and showing no damage to the
acreage tile is now done at 30 frames and we still see no damage to the acreage tile. So this portion of the
likely area that hit is a little bit suspect.
Okay. Let me just go quickly here. Next
slide. This is the anomalous aero moment that we're
looking at and are struggling with. The one that I
like to call your attention to -- and this chart, by
the way, was put together by Sheila Widnall to try to
get the trajectory matching the aero that we've seen --
this represents loss of lift in the left wing and then
additional lift in the left wing, which we have not
been able to explain. So trying to explain what's
going on here has been difficult.
If you were at the public hearings, NASA
showed some wind tunnel tests that indicated, if the
door was open and the ear was down, that it could
happen. Other things that had been postulated are
aluminum burning, missing bottoms to the RCC, a jet
flow out of the wheel well, and some kind of flow on
Let me go to the next slide. I just want
to show you that, given the debris that we're looking
at, one of these, which is that the left main gear had
deployed early and is creating an aero moment, is not
likely to be a correct theory. This is a wheel, the
wheel strut that you can see in this picture; and if you look, you can see nice, shiny chromium plating that
goes on that wheel strut. If the plating was eroded in
actual ballistic flight after breakup, the erosion
would be the same on both sides, which it isn't. What
you can see is there's more chromium on this side,
which is the forward surface when it's deployed. If
that had been deployed, that chrome would not be there.
That's the bottom line.
So it says basically that the wheel well,
as other data has begun to indicate to us, the wheel
well was closed, the door was there, the wheels were
up, and that's not the cause of that moment that we're
seeing. We're still struggling with how to get there.
That's all I have.
ADM. GEHMAN: Thank you very much. I
hope you can see from the three briefers -- for
example, John Barry talked about the radar reflectivity
studies at Wright Patterson Air Force Base -- the only
piece of debris left on the table is a carrier panel.
Roger's little pork chop diagram there covers two
carrier panels. You can see how much work it takes and
how these things need to line up, and you can see how
much evidence it takes to convince us of anything. We
are very skeptical.
I apologize for interrupting Mr. Tetrault there, but he could go on all afternoon. So, with
that, over to you.
LT. COL. WOODYARD: We'll turn it over
for questions. We'll continue our same format and
we'll start here in Houston and then we'll go to our
Please identify your name and your
organization, as well.
A REPORTER: USA Today. So are you
convinced now that it was a carrier panel that came off
on Flight Day 2, because you said there was some more
testing to be done and I wasn't sure if that was only
to narrow down the number of tiles that came off the
panel or if you had other objects to rule out?
GEN. BARRY: We've exhausted all the
testing on the parts that were given. There were
22 external and internal shuttle components tested at
Wright Patterson, and all of them were eliminated
except for the carrier panel as the leading candidate.
As I mentioned earlier, there might have been some of
that with the blanket, but when you compare the results
of the area, the mass area ratio and the burn as it
re-entered, it didn't make any sense. So right now the
carrier panel is the leading indicator of all of the
29 candidate shuttle components that we provided at Wright Patterson and the Air Force research lab.
ADM. GEHMAN: But that does not equate to
we're being convinced that it is the carrier panel. As
a matter of fact, we were meeting earlier today; and we
came up with a couple of other things we would like to
MR. TETRAULT: In addition, the testing
that's going to go on at Southwest Research should help
us really narrow down what items are weak in this
entire system and where a breach may have occurred and
help either deny or confirm this piece of data.
A REPORTER: Houston Chronicle. For
General Barry. Can you just go over again the major
components in this area that were tested? I think
Admiral Gehman just mentioned there's a couple of more
things you would like to test. Can you tell us what
those are, please?
GEN. BARRY: The bottom line is that we
tested, including the different kinds of tiles, the
fibrous materials, the beta cloth, the insulation
blankets, the carrier panel that we talked about with
the horse collar, the RCC edge and earmuff seal,
different variants of those, all totaling to about
22 components. We had 29 to select from, but those
were the ones that we looked at for that part of the test. The eliminated majority of the components is
either unknown objects either due to low or too-low RCS
signatures, radar cross-section signatures. The
possible candidates still stood out, and we want to
look at the carrier panel now with not only three tiles
but also four tiles.
If you take the carrier panel and you
include the horse collar, it's a very strong candidate,
matches up with the radar cross-section. If you take
the carrier panel without the horse collar but increase
it to four tiles, that also gives you a pretty good
indication, we surmise. We've got that one added test
to go through. In any case, the others have been
pretty much eliminated for the reasons that I have
A REPORTER: New York Times. Is the foam
that's being shot at tile being tested with and without
ice, or are we just looking at foam?
MR. TETRAULT: The testing right now is
probably going to be delayed about a week. As I said,
it was in flux; and the reason for that is this new
photo information which tends to indicate a piece
that's larger than what we previously had been looking
at. So now the debate is what size do we actually
shoot. As I mentioned to you, the thickness dimension was 5 inches. That was calculated on the mass that it
would take to fly the trajectory that it would take.
So if there was ice in there -- this was calculated on
based on this being strictly foam. If there was ice in
there which would have added to the mass, then you
would have to subtract from it the 5-inch dimension to
be equivalent. So to the extent that there is weight,
it takes that into account already by having that
A REPORTER: Associated Press. For
General Barry. I wanted to talk a little bit about the
zinc oxide contamination. Was NASA aware of this?
Were they taking any steps to work around this? And
just how damaging, in your opinion, is an RCC tile that
got 20 to 40 pinholes?
GEN. BARRY: As you know, we've been
examining the issue of ageing and looking at candidates
for pinholes to explain them. Zinc oxide, that can
come from primer as the infrastructure ages and doesn't
get painted again, with the added rain, particularly
when the orbiter is on the pad and ready for launch.
This seems to be the leading candidate right now.
There are other explanations, something to do with
oxidation and so forth. We wanted to just kind of
focus on this one. This does seem to be, from the experts' standpoint, the leading candidate. So we've
taken that. We are doing some more study. We want to
examine all of the issues in the pinholes as close as
we possibly can to try to get to the bottom of the
question -- the question being, if something hit the
RCC and it was an aged RCC with pinholes or oxidation
underneath that, would that be a contributing aspect to
this mishap. If it hit a brand-new RCC, could it
withstand it? That's why this testing they're going to
do with the foam will be instructive, because we're not
only going to send it against tile but we're going to
send it against RCC. Roger, can talk a little more
A REPORTER: I was just wondering. Were
you aware of NASA having concern about this ageing?
GEN. BARRY: Yes. They had looked at
this as a possible contender, and this is one of those
things they have been working on for the pinhole
explanations. Remember, pinholes that are less than
.04 inches were greeted as okay. And they just went
about either refurbishment and it was out of tolerance
or they went on a repair, as Steve Turcotte mentioned
last week -- as he's our leading guy on the RCC, he and
his team. So they've gone through and listed all of
the different RCCs that have been either refurbished or repaired, and I can give you that data again if you
A REPORTER: ABC News. Mr. Wallace, you
mentioned that you think we're not really quite keeping
the E-mails in perspective. Would you care to put them
in perspective for us, sir?
MR. WALLACE: I think I would just say
again that they are part of a very complicated story
and you haven't seen the rest of the story. A lot of
it is developed in the context of interviews where they
are strictly privileged; and this being a safety
investigation where our sole objective is to determine
the probable cause and look for ways to raise the level
of safety, we grant these witnesses privilege, which
means that their identity and what they say is
protected, yet we use that information to form a part
of the entire story.
Of course, we have done extensive review
of material, much of which will be available to you as
well, things like records of meetings from NASA and
actually listening to tape recordings of meetings and
comparing them with the written records and trying to
sense the whole dynamic. So sort of a brush stroke by
brush stroke, it gives you a picture which we have not
completed; but I would just say that you don't get a balanced picture or a complete picture by any means by
seeing the E-mails.
A REPORTER: Orlando Sentinel for
Mr. Tetrault. Can you give us a sense of where the
analysis of the OEX recorder data will go from here on,
what kinds of questions and what kinds of data will be
MR. TETRAULT: Well, the kinds of data is
just going to be temperatures, pressures, strains, some
vibration, those sorts of things. What it is obviously
showing, though, is events that are occurring much
earlier in the time line, although my general sense is
that it's not showing us anything that we didn't
suspect that it was going to show us. It will show us,
I think the one thing that I see, is that when we start
looking at where the lines were cut, the electrical
lines were cut, part of them were cut around
540 seconds after EI, that it will begin to help
localize where in the front edge the problem is. Up
until now, if I took collectively all the data that we
had, I could in my mind locate this event somewhere
between RCC Panel No. 5 and No. 12. I think this will
help shrink that down to some much narrower one. Then
when you begin to put that where the photos are showing
where the foam hit, then I think you can start making some assessments of what are the probabilities of that
being an initiating event, if you will. I wouldn't say
necessarily the cause, but there may be an initiating
event that leads to a whole series of other things that
lines up with the accident.
ADM. GEHMAN: Roger, if I don't have this
exactly right, I believe that, in answering this
question, that this data is being looked at by
literally hundreds of engineers from different
disciplines and I believe that what will happen is that
we will put out revisions, more revisions to the time
line. We're up to Revision 15 already. I think that
periodically as this data is analyzed to a degree with
the engineers confident what they're looking at, we
will continue to put out Revision 16, then Revision 17
and Revision 18. As you may be aware, when we put
those revisions out, we annotate what's new on it.
That's my understanding.
MR. TETRAULT: That's exactly correct.
In fact, there is a preliminary time line that has some
of these sensors already on it, but that's what they're
working on and some of this data they only received
yesterday and some of it they still don't have. But in
looking at it, there's a lot of information on strain
and stress that isn't going to show you a lot.
ADM. GEHMAN: Keep in mind that Revision
No. 15 is dated like six weeks after the accident. A
lot of work.
A REPORTER: NBC. For the chairman. I
would like to ask about the air search issue. Those of
us who are covering the story were shocked and
horrified by the crash. Our condolences to the team
and the people involved in the crash. I'm interested
in the other air search that was work going on with the
Army compass sensor that has apparently now been
withdrawn. Can you describe to me how helpful that
sensor was to your location and whether you intend to
try and get it back to do any searches out west?
ADM. GEHMAN: We are receiving a brief
tomorrow from the chief of the debris collection team.
So I will have to defer any answer specifically to
platform by platform just because I just don't happen
to currently know it. I will say, however, that the
debris search continues with the same vigor as it has
been. We've got between 4500 and 5500 people every
single day still picking up debris, and it continues to
be enormously important. Obviously this OEX recorder
is a piece of debris. I mean, that's how it was found;
and it was found by somebody walking along, 6 feet away
from the person beside them, and it was found in an area which had previously been gone over. So it just
emphasizes how important this is.
So we are going to receive a brief
tomorrow on the status, and the purpose of the brief is
the beginning of the process of trying to determine how
to terminate the debris search. We still have several
weeks to go before we do that, but we are starting to
talk about it. Air searches have been very important,
particularly for the larger pieces in the wide-open
area. Also, as we complete the debris searches in the
areas where most of the debris is, which is essentially
in East Texas, we now have to ask ourselves what do we
want to do in the areas where there is less probability
of finding debris but the debris that you're going to
find is more important. Obviously walking side by
side, 5 feet apart through West Texas is a different
story when there's not much debris out there. So we
don't know the answer.
A REPORTER: News 24 Houston. Admiral,
at the media bridge yesterday on the information you're
giving on the OEX recorder, a question was asked of you
whether or not the debris that you collected represents
any part of RCC Panel No. 9. Did you find that out?
ADM. GEHMAN: Roger.
MR. TETRAULT: The question was does any part --
ADM. GEHMAN: In other words, do we have
any debris from RCC No. 9 or the attachment points?
MR. TETRAULT: RCC No. 9. Let me take
just a second.
ADM. GEHMAN: I took that down and we
passed it on to our folks and we're digging. I also by
the way --
MR. TETRAULT: There is nothing on RCC
ADM. GEHMAN: We have nothing on RCC
MR. TETRAULT: Let me just give you one
other piece of information if you would have asked
this -- which if I were sitting out there, I would.
What carrier panels do we have and what carrier panels
are missing from the lower edge? We have pieces from
carrier panels on Area 5, 6 -- I'm sorry, this is the
missing ones -- from 5, 6, 8, 9, and 12.
ADM. GEHMAN: Missing.
MR. TETRAULT: Missing.
We have pieces from 1, 2, 3, 4, 7, 10,
11, and 13 and 14.
A REPORTER: NBC News. General Barry,
could you provide just a little bit more detail on the process through which the pinholes were created on the
RCC? It's a chemical reaction created by this
interface with the paint?
GEN. BARRY: It is; and let me just give
you a couple of other data points, if I may. The root
cause of the pinholes in the RCC, of course, is not
generally agreed upon; but the leading candidate we've
got right now, as I said, is zinc oxide. The other
possible contenders were salt spray from the ocean and
a TEOS application providing oxygen sourcing.
TEOS is an application that's applied to
the RCC in its development. What you do is you have
this oxidation element that goes on that makes these
pinholes and then, of course, if they get too large,
they get refurbished. I do want to give you this
detail, if I may; and it was highlighted last week a
little bit. There have been 11 panels and 12 seals on
the left side that have been refurbished, and then
there have been repairs on 7 panels and 6 seals on the
left side. Let me just give you an idea of what
happens when we do the refurbishment, and then I'll
talk about the repair real quickly.
If you're going to do a refurbishment on
the RCC, first of all, you inspect the part, you
disassemble it, you put a Type A sealant on it, you clean it, you repair the pinholes, you heat-treat the
part to 1800 degrees, you apply the TEOS, and then you
apply a second Type A sealant. That's refurbishment.
And by the way, refurbishment has to be sent back to
the vendor in Dallas. If you repair it, as I have
listed the numbers here, what you do is you clean down
the damaged area, you only apply a Type A sealant, you
heat-cure it, and then you verify the contour is flush
and send it on its way. So what we've been able to do
is track the numbers of them; and as I said, per RCC,
there were anywhere from 20 to 40 in them as they have
aged over the years. And then we either refurbish it
or repair it, depending on how large the pinhole is.
LT. COL. WOODYARD: Any other questions
from here? If not, we'll move to the phone bridge.
A REPORTER: NBC. We'd like to go back
to the carrier panel. It is now a likely suspect for
the mystery piece you discovered the day after the
Columbia reached its place in space. When it was going
up and the impact took place, was the Columbia locked
in its cradle right after that wind shear? Did that
cause something there possibly to spring loose that
carrier panel, or could it have come from the Palmdale
modifications in '99 or even from wear of age? What's
your best guess?
GEN. BARRY: Well, there's a series of
incidents here that we're looking into. Let me start
with the Palmdale OMM. They did do the normal depo
level work on the orbiter in 1999. As you recall, it
flew one more time at STS 113 and then, of course,
STS 107. After the OMM, they, of course, removed all
the RCC panels, put them back on, and then they found
with a step-and-gap test, you know, to see if they were
all flush and the right distances between them, that it
was not lining up. They had to take them all off
again. Then they got some of the old heads that had
done this before and reinstituted and put it back in
the right order. So there was some concern on our part
about whether that was done right. All indications are
that it has been done right.
The second thing is when the RCC
follow-on flow to see what was done with any kind of
changes. We know it was up near the leading edge of
the No. 1 RCC that some work was done in the flow
between STS 113 and 107. So what we're seeing is a
series of things. We're trying to examine if any of
them had factors. It's a long story, and it's still
going to take a lot of investigation to be able to go
through each and every one of them, from the paper
review to the quality assurance review as well as the interviews that we've been able to do with some of the
ADM. GEHMAN: The second part of the
question was whether or not Q-loading or wind shear or
anything like that on ascent could have contributed and
what was the timing of it.
GEN. BARRY: As you remember, I brought
up an issue where we had some what they call I-load
preparation at 62 seconds. There was an
out-of-experience movement of the solid rocket motor
that put the orbiter in position where it was supposed
to be countering a wind shear. We've looked into that
pretty thoroughly right now. I'm not fully convinced
yet. We've got another briefing this Friday coming in
from NASA integration here at JSC, but all indications
are that this was well within tolerance, certainly for
the solid rocket motor to move, but also this being at
62 seconds, 61 seconds, that's about max dynamic
pressure, pretty close to it. So we've still got some
concerns about it, but we do have a briefing coming in
Friday and we should be able to nail that one shut as
either a contributor or maybe one more piece of the
A REPORTER: Newsday. There was a
mention of 11 flights previously where there were bit flips prior to entry interface, and I'm just wondering
what conclusions you draw from that.
MR. TETRAULT: When I mentioned that, I
was referring to left main landing gear brake
Temperature D, which is the first one that went off or
went off nominal in the prior time line. The
conclusion that NASA had was that that temperature
sensor may not be off nominal and that the time line
may need to be corrected as a result of that.
ADM. GEHMAN: And that we had seen this
MR. TETRAULT: I say may. They have not
made the decision that that's correct, but they had
found that 11 flights prior to that flight had had that
same kind of impacts prior to the same time that this
A REPORTER: Aviation Week. For Admiral
Gehman. You mentioned that underneath the context
factors. I wonder if you could talk a little bit more
about the methodology you're going to use as you get at
those and how you're going to try to drive out such
activity and things like the psychology of continued
ADM. GEHMAN: We're going to approach it
from two angles. Group 4 has put together a panel of people who have written on, commented on, and studied
manned space flight for ever since the beginning of it.
They are going to put down some macro-level thoughts --
that is, thoughts of previous studies. NASA's always
being studied by somebody, and manned space flight is
always under review. So there's a rich treasure trove
of studies and data and views. They are going to
collect those, as well as their own. They're going to
take source material like not only budgets -- I'll just
give you a little example here.
Take budgets, for example. There are
budgets and then there budgets. There is the budget
which is appropriated by Congress that NASA uses to
spend on the space shuttle, but you can go to another
level of degree on budgets. You can compare what the
space shuttle program asked for with what NASA
submitted with what the administration submitted after
OMB marked it up with what the appropriation committees
finally gave them.
And there's actually a trend in there or
there may be a trend in there. For example, you can
find trends where the space shuttle program office
asked for a lot of money and was not supported by
somebody, any one of those categories. You can find
trends where the administration asked for money and Congress didn't give to it them or you can find trends
where Congress felt that NASA was underfunding the
space program and Congress gave them more money than
they asked for. There's all kinds of trends in there.
So Group 4 is going to take a kind of
top-down look to see what history teaches us, to see
what the previous studies teach us, to see what NASA
and the administration have been told or were warned
about. Meanwhile, my colleagues here are approaching
the same question from the bottom up. As they do their
inquiries, they are coming across habits and traits and
events that they have looked at in the STS 107
investigation; and then we will intersect the two.
Either their work will suggest to Group No. 4 an area
that they ought to look at -- like I think the
normalization of deviation was one of them that we
mentioned -- or else, as the Group 4 reports out to the
board as a whole on what they've found, we will find
specific evidences that either confirm or deny their
For example, if they say that there's
been a migration of some work force trend -- this is
popularly written on about changes in the NASA work
force -- and they therefore find that the work force
has done this, that, and the other thing, the work that people, my colleagues on the left will do, will either
confirm or deny that. Then we weave that into our
report. I hope that answers your question.
A REPORTER: I would like you to clarify
a couple of things for me. You said that on the RCC
panels there's a tolerance level of 40 thousands of an
inch for a pinhole. Does that mean below
40 thousandths of an inch, it will not be repaired or
refurbished and, above, it will? Second, you said that
there were 20 to 40 pinholes per panel. Is that over
time or is that at any given moment you could pull an
RCC panel and see that many holes and would those all
be repaired or would those be passed on if they're
below a certain threshold? And I was wondering,
finally, do you have to resolve the issue of whether
the breach occurred in a carrier panel or an RCC panel.
Is that a major development or conclusion that's still
facing the investigation? Thank you.
GEN. BARRY: First answer to the
question. If it's less than .04, that's correct. It's
a visual test and kind of a press on the area to see if
there's any voids underneath it, the way NASA's been
operating to date. We do and are encouraging them to
take some hard looks at NDE on RCC panels so you can
get a better look at what exactly that pinhole has underneath it; but right now if it's less than .04,
yes, it does past the test.
The 20 to 40 is over time. This is not
per panel per sortie or per launch. So over the period
of time, as I said, the flight the first time it was
noticed it was in '92.
ADM. GEHMAN: But it does mean that on
average over a long period of time there have been
20 to 40 pinholes either refurbished or repaired to
each RCC panel, which tends to accumulate. Obviously
what we're studying is whether or not -- we're studying
the effects of ageing is what we're studying. We're
not suggesting that RCC panel disintegrated and fell
off the orbiter.
GEN. BARRY: But we are concerned about
oxidation. As the Admiral explained a couple of press
conferences ago, it's like termites, you know,
underneath, digging holes. If we want to know what's
underneath those pinholes, then the only way you're
probably going to do is that certainly getting a little
better discipline on the RCC non-destructive
evaluations or examinations.
The final comment you had was the breach
in the carrier panel. Yes, it is definitely one of the
scenarios that is being looked at. We have about ten that we're looking at for the main landing gear and as
Roger kind of commented on a little bit in his
analysis, but also from the RCC or the carrier panel
but certainly that is one of the theories that we're
trying to go down and track down and nail shut.
MR. TETRAULT: Let me comment on the last
one, if I could. We seem to have narrowed this down
pretty well to the leading edge of the wing. In that
leading edge, there are a number of items that could
fail that could cause the accident. My list of those
items includes the RCC panel, the T seal, the stainless
steel structure which supports the RCC panels, the
bolts that support all of those, and the carrier panel.
So we have to sort our way through all of those and
make a determination of which one is the real failure
mode. If we fail to do that properly and we get the
wrong one, then we could have a future accident. So
we've got to bring it at least that far.
ADM. GEHMAN: Or else our recommendations
would be so broad and general and not specific enough
that they won't help the return-to-flight decision.
And we would not be happy with that.
A REPORTER: CBS News. Just to follow up
on that, for either Admiral Gehman or Roger Tetrault.
Do your failure scenarios, if you have a missing carrier panel either with or without the horse collar,
is the missing carrier panel by itself enough to
generate the heat that you see in that sensor on the
front of the wing spar behind RCC 9? Do you need any
associated damage to the RCC to make that happen, I
guess is what I'm wondering. Finally just as an
interpretive question, if you guys are seeing something
that looks pretty good right now that's an RCC panel,
perhaps it came off on Day 2, why shouldn't I consider
that the point where this breach occurred? I mean,
that seems pretty straightforward to me, assuming that
your continued testing pins that down.
MR. TETRAULT: The last item, I'd say
your logic could lead to someone's death; but, you
know, you can't rule out all these without specifically
knowing and make this leap of faith that something that
you know happened between Panels 5 and 12 actually
happened in this particular area. You just can't make
that leap of faith.
With regard to the size of the hole,
without running a thermal analysis, I can't answer it
specifically, but I would say I would tend to think
that it would be more than plausible that that size of
the RCC panel could cause all of these issues. We do
know that the thermal analysis when it was done down at Panel No. 6, which started with a 6-inch hole, tended
to indicate that the heat could get back into the wheel
well and so on and actually support an accident. I did
a quick check on the square area of an RCC panel at
Position No. 6 before I came here, and it was about
92 inches. So given the heat, the thermal stuff that I
saw based on 6 inches, I would say it's pretty well
assured that 92 square inches could give us the kinds
of conditions that we're seeing here. I'm saying that
with some degree of confidence, not having run a
ADM. GEHMAN: That's right. We have to
caveat that by reminding everybody of my introduction
in which the thermal story has to line up with the
aerodynamic story which has to line up with the time
line reconstruction story. So if you assume that you
have a breach of some sort in the vicinity of RCC
No. 6, either a carrier panel or a broken piece of RCC
or something like that and then your closest
temperature sensor is in the vicinity of RCC Panel
No. 9, you have to calculate whether or not the heat
can get over there and how does the heat get over there
and how would the sensor react. Then you have to find
out what the aerodynamic forces are. So you're way
ahead of us. We would in no way conclude that we found the initiating event here.
A REPORTER: Earth News. For General
Barry. With what you showed with your hand motion of
the maneuver of the shuttle on Flight Day 2, was that
at 23 hours after launch, the inertial measurement
maneuver, or was it some other time and, if so, do you
have that time? All I've heard for re-entry was four
days later over the Pacific Ocean. The Pacific Ocean's
fairly large. Can you narrow that down a bit or at
least give me a time for when it re-entered and
whatever the mystery object is? Any idea of what the
orientation was, especially if it was a carrier panel?
Was it edge on, slip stream, or sideways or what?
GEN. BARRY: We'll have to get back to
you on the exact time. It was on the second day. I
just don't know the exact location. My understanding
was the velocity vector was going backwards. You know,
they did about 250 maneuvers on these 16 days as part
of their experiments. So the orbiter was changing
many, many times. On this particular case, it was
going on a rearward velocity vector. It did turn into
a right wing going downstream and then came back to
having a rearward velocity vector. In the course of
that time -- and I don't know exactly where it was
located -- we can get that for you -- that is when we saw this piece come off, and we're relatively confident
now that it did come off the orbiter. It wasn't
something that showed up somewhere as a meteorite or
something like that. The velocity vector that it had
coming off there did lead us to believe that it did
come off the orbiter.
Things have come off in the past, as you
know. We've seen blankets when the doors have opened,
and astronauts have told us that screws and different
things that have been debris in the inside of the
payload bay have come out. So this is not unusual.
But the size of this -- and certainly to be tracked.
Now, remember this was not picked up by any DOD sensors
until six days -- really we started looking right after
the mishap, but it was a combination of all of the
looks from all those radars that I mentioned to you and
by the sixth day we concluded that we did see something
there and then we tracked it through to when it burned
up in the atmosphere.
ADM. GEHMAN: Let me follow on John's
answer there. John said we saw it come off the
orbiter. We did not see it come off the orbiter. The
first radar observation of something on orbit,
accompanying the orbiter, as I recollect, was an hour
after the last of these yaw maneuvers. So the orbiter was back flying stern first and the DOD system just
happened to look at the orbiter about an hour after
that and there it was. So it would be wrong to
characterize that we saw it come off the orbiter.
The second -- part of the question was
the object is tumbling. Is that correct? The object
is turning in space? It doesn't have an edge attitude
or anything like that?
GEN. BARRY: Initially it doesn't show a
lot of tumbling. Of course, as it re-enters the
atmosphere, it starts going into more tumbling. Sheila
Widnall has been looking into that as something else
that we can combine with Lewis Labs and be able to get
some more information. So there's still some more work
ADM. GEHMAN: We can calculate the mass
and shape of it.
A REPORTER: New York Times. Could you
tell me, please, do you have a candidate mechanism in
mind for how on earth you get a debris strike near
max Q on liftoff, you damage the carrier panel either
on the upper side of the wing or the lower side of
it -- I don't know if you can say which -- and it
survives all the way into orbit and is gently shaken
loose by the motion of the shuttle yawing?
ADM. GEHMAN: Well, the answer is, no, we
don't. But part of our testing at Southwest Research
will be to characterize debris strikes different than
the body of knowledge about debris strikes in the past,
to see whether or not these debris strikes can create
the kind of debris that the panel here has been talking
about, including a carrier panel.
As far as the second part of your
question, all of us have spoken to astronauts who on
their mission have looked out in space and seen some
part of the shuttle, which has been attached by nuts
and bolts and screws, go drifting by. So, you know,
these thermal blankets in the payload bay, they're all
held on with clips and they've got wires. They're not
supposed to come off either. One of the astronauts
told me he looked out the window on Day 2 and saw a
washer go by.
So, no, I don't think we're going to be
able to prove that something came off, but I know we'll
be able to get plenty of testimony of instances in
which things which were firmly attached to the orbiter
at one time came unattached later on. So that's the
best I can do for answering that question.
GEN. BARRY: The only thing I might add
is, you know, we did have a negative angle on attack on launch for a brief period of time. Then it goes to
positive; but the higher you go, the less dynamic
pressure you have. Of course, the less dynamic
pressure you have, you know, maybe there is some issues
there where there can be less chance for things to come
off. We haven't quite figured that out, but certainly
with the testimony we've gotten, as the Admiral has
said, and the indications that we've had from certainly
the radar cross-section, you can't rule out the aspect
of something coming off the orbiter. We've still got
some more work to do.
ADM. GEHMAN: One of the more common
events are blocks of ice coming off the orbiter.
Occasionally big blocks of ice which are attached to
dump nozzles or exhaust nozzles -- and they're really
attached pretty hard, I guess -- will just detach
themselves and float away.
You might mention ice as a radar
GEN. BARRY: We did. We looked at it,
and it didn't meet the test.
ADM. GEHMAN: Ice is out.
A REPORTER: Discovery Channel. I'd like
to know if you could please go back through three
different points in time, to the time of the Boeing analysis during the shuttle flight to the data from
last week and from the new analysis now and give us the
dimensions of the debris, of the foam, and the probable
strike zone on the orbiter and how that has changed as
time has progressed.
MR. TETRAULT: I can give you what it is
now. I'm not sure what was used in the analysis, so I
can't make the comparison for you. Maybe one of my
other friends up here knows that data off the top of
their head. What we're looking at now, based on the
photo analysis, is 25 by 15. These are 25, plus or
minus 3, by 15, plus or minus 3, by 5. And I think
that is probably larger than what they were using in
the crater analysis, although I must say that what
we're looking at is a strike which is not in the area
where they used crater analysis to analyze.
GEN. BARRY: I'd just mention a couple of
things on the crater. It is 20 years old plus, and
it's a simpler algorithm than certainly we have today
with hydro codes that are available. So I know NASA is
looking into that as another thing that can be added to
improve things. The model doesn't really account for
lift because, you know, it just takes the impact
velocities, the angles, and the density. Stiffness is
not really in the crater program to speak of. The crater can do 3-D orientation, ballistic
characteristics, and the crater analysis did not really
look at the worst case with carrier panel impact or RCC
as a case in point.
The one that is interesting also is the
debris assessment team judged that the densified layer
will remain attached to the crater even though it
predicted damage exceeding tile thickness. So we're
trying to not only look into the analysis that was
presented for crater but also what follow-on
improvements could be made based on the current
technologies of today.
MR. WALLACE: I would just add two quick
points, having gone through a lot of communication on
crater analysis but not into the analysis in technical
detail itself, is that there were several sets of
dimensions. So I think there were different
assumptions made. If it comes back to one specific
number, we'll get that and get back to you.
LT. COL. WOODYARD: This concludes the press briefing today. Again, we thank you for coming out.
(Conference concluded at 2:23 p.m.)
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