CAIB Briefing Transcript 11 March 2003 (Part 3)
QUESTION:
I have a question for Dr. Widnall that to some extent relates to the boundary
layer issue. I’d like to follow up on a comment made last week by Roger
Tetrault.
Last week
he said Columbia had flown, I quote, "a very hot reentry," and
my question is, compared with most other reentries does the data support
that Columbia was, indeed, flying a somewhat hot reentry as Tetrault said?
And if so,
does that indicate that Columbia had an early boundary layer transition?
WIDNALL:
Well, I have certainly heard that, but I’ve asked for data on anomalies
from some previous flights of Columbia, and I’m going to look at that
very carefully.
As I mentioned,
the magnitude of the asymmetric boundary layer, in terms of forces, is
not large enough to explain the observed aerodynamic imbalance.
But on the
other hand, it could cause heating problems, and obviously anything that
creates a heating problem can’t be ignored.
GEHMAN: We
have begun a line of investigation into that. General Barry has some facts
over here, which I don’t think we need to recite, but generally speaking,
as far as time of shuttles being in the period of max heat, other kinds
of facts like that, Columbia has not endured any more punishment than
any other–than anybody else.
I think what
Mr. Tetrault found was, though, that if you look at various temperature
instruments, that there are signs that even though Columbia hasn’t been
subjected to any more punishment than any other orbiter, he found some
places where some of the skin temperatures and things like that were higher
than other orbiters, and we haven’t made any conclusion about that.
BARRY: I
might also mention that (OFF-MIKE) information on the history of the transition
for Columbia. The transition time in seconds is how they measure it as
it makes its entry.
The average
for Columbia prior to the mishap was 1,204 seconds at point three, which
is about a third of the way down the orbiter, and 1,160, point six, so
two-thirds of the way down the orbiter.
The average
for the fleet–as I said, for Columbia it was 1,204, the average for the
fleet was 1,190; not much difference. For the, what they call XI.6 (ph),
was 1,160 for Columbia, and for the fleet average it was 1,173; again
not much difference.
These are
in seconds.
GEHMAN: These
are in seconds, in the transition zone, it’s how NASA measures it. Now,
that’s what I referred to as far as time is concerned, and we have to
find out whether or not even though they–Columbia spent the same amount
of time in transition, whether or not she endured any extra higher temperatures.
And that review is still going on.
QUESTION:
For whoever knows about it, can you address the mystery object that was
tracked in orbit with the shuttle? Has anybody done an area/mass calculation,
ballistic coefficients, anything like that? And what else can you provide
us in terms of information about it?
All we heard
was 24 hours after launch it was tracked by radars. Do you have a more
precise time or which radar tracked it first? And the time of day when
it reentered over the South Pacific?
(UNKNOWN):
Yes, this is what I alluded to earlier. We’ve got the radar signature
study being done at Wright-Patterson right now, in the Air Force Research
Laboratory, and we’ve got a number of pieces from the orbiter.
Of course,
they’re new pieces, so we’re going to have to do some examination of what
might be extrapolated off of damaged pieces.
But the intent
here is to try to compare those signatures off a number of radars, not
only from what we had for air traffic control, but also from the Air Force
radars that came and gave us some information on signatures.
So hopefully
with that comparison we’ll be able to maybe put some substance to that
second-day orbit piece of material that came by or off the orbiter.
QUESTION:
So, General, do you have any more data on the actual orbit of the object,
that NASA orbital information group just recently unembargoed the Keplerian
elements of–for Columbia. But nothing has been provided as far as the
orbit of this particular object.
(UNKNOWN):
No, we have nothing new that we didn’t release last time. The only thing
that’s new is this reflectivity and luminosity studies going on to see
if we can figure out what the part was by matching it up with known pieces.
QUESTION:
I have one quick question for General Barry on the problem report on the
foam damage. Where on the external tank was the damage reported?
BARRY: The
damage in the problem report was at the bipod. So just as we showed up
here and also on the screen. So it was on the bipod region of the left
side.
QUESTION:
You showed some RCC panels with some voids and some non-conformities in
the material. Are you examining whether that is a possible entry without
any kind of space or foam (inaudible)?
(UNKNOWN):
Well, yes and no. It’s possible that some of this damage might have led
to the loss of an RCC panel, but highly unlikely.
What we’re
really looking at is a complex failure of a complex system. It’s possible,
one of the scenarios we’re looking at is it’s possible that the foam striking
a healthy orbiter would not have done–not done enough damage to cause
the loss of this orbiter. But it’s possible that foam striking an unhealthy
orbiter that had problems in it, either due to stresses on launch–we
talked about the wind sheer–too much heating and recoveries of too much
heating and transition of the years before, aging of the orbiter like
the RCC faults we see, or a whole number of other complex issues, it’s
possible that you could do some damage to this orbiter that would have
been as a result of a normal event which she could have survived at age
10, maybe she couldn’t survive it at age 21.
QUESTION:
(OFF-MIKE)
(UNKNOWN):
Right now it is Lockheed Martin, and that is what we’re going up to see
on Tuesday of next week. We’re going to the vendor with a team of experts
from different variants, both in NASA and outside NASA and from academia.
And we’re going to go up there and look at…
QUESTION:
What are you looking for?
BARRY: Well,
we’re just going to look into when you do a O&N, better known as a
depot in the Air Force terms, they will look at the RCC panels, identify
any anomalies. And if there are, they will send it back to the vendor,
all right. And when they do a process flow between flights, same thing.
They will identify any problems like pinholes or any abrasions or some
kind of corrosion. If that’s the case, then they will remove the RCC and
send it back to the vendor.
We’re curious
as to see what kind of testing has been done by the vendor. And we’re
particularly interested in providing some information on possible recommendations
on what NDE profiles, non-destructive examinations, engineering could
be done in order to improve the process.
So I mentioned
tomography, which is CT scans. I also mentioned thermography, which is
the heat one. So we’re looking to see if we can provide some additional
insight for the board as well as a possible recommendation on where we
would want to go for follow-on return-to-flight considerations for the
RCC.
QUESTION:
General Barry, have you looked at the communication between Space Command
at the Johnson Space Center as far as this object that came off the orbiter
and flew by? Was there any–maybe I misunderstood early on, that that
information was not given to NASA early on? Or was–have you looked at
the communication between the two groups? How soon do they know?
BARRY: It
was well communicated and well transmitted. So this was something that
was very evident early on.
It is not
unusual, by the way, to have this happen. Ice has come off. We have had
reports from astronauts that screws and washers, even parts of blankets
when the orbiter doors are opened, for some things to fly out in there.
The question now is, with all the seriousness and obviously with the mishap,
was that something that was off the left wing that subsequently was damaged
on ascent. So it obviously has a heightened awareness. And it wasn’t cited
by any of the astronauts reported by in communications (ph). So we have
to go back to the detective story of trying to figure out what it is on
radar signatures that might help us find out what that is.
QUESTION:
Is there any thinking in your mind, after you’ve been looking at all of
this data, of recommendations that may lead to better sensor equipment
on the orbiter? If we have another tragedy like this, do you have any
feelings early on what’s missing in your…
GEHMAN: We’re
going to issue either preliminary recommendations or preliminary findings
as soon as we are content with them. And we–in addition to working hard
many, many hours a day, seven days a week of finding out what went wrong
with this thing, we’re also working hard on the cultural, management,
budget issues.
We’re also
working very hard on the return-to-flight issues. And so all these things
are going on simultaneously.
Yes, we have
already had a couple of sessions on what could we tell NASA and when.
Right now we’re not ready to announce anything.
QUESTION:
On the nature of the debris, whether it’s foam, ice combination, has NASA
told you that in their belief that debris contained no ice?
GEHMAN: Let’s
see; I don’t know that anybody’s been that firm about it yet. I think
that that’s still an open question as to whether or not there might be
ice in there or not.
(UNKNOWN):
This is a concurrent effort that’s going on, it’s not just a board effort.
They are also cooperating with Air Force Research Lab to figure out what
it is, and also with Kirtland to figure out what it is on the spectral
analysis.
So this is
an ongoing effort that we hope to get some results here in the next week
or so.
GEHMAN: I
mean, it wasn’t part of your question, but just to give you an example
of why this–we just keep working these questions, we never give up on
them. We worked for a long time on the issue of whether or not debris
passing through the hot exhausts of the shuttle engines would be like
putting a piece of metal in a Bunsen burner. And you would get a color
flash depending on what the debris was.
We worked
that issue for a long, long time and got a lot of smart people working
on it, and the answer is that if it were certain kinds of metal, maybe,
but everything else, no: You don’t get any kind of a flash.
So, we just
never give up on these issues, and so I don’t want to indicate that we’re
not getting anywhere on the ice issue, it’s just that we keep picking
at it.
QUESTION:
General Barry, I have the impression–is this correct?–that you’re saying
that the existing examinations done between flights on the RCC might not
capture flaws that could come back and bite you later in some weird combination
or unlucky combination with other factors.
BARRY: No,
I’m not exactly–I’m not saying that. What we do have is the evidence
of what we’ve asked for questions on what kind of damage has been done
to RCC.
There’s six
that we have, what they record as dings. One was in STS-39 in ’91, 45
in ’92, 65 in ’94, 89 in ’98, 103 in ’99 and 102 in ’01. All of them are
a little bit different, some affect T seals, some are due to micro-meteors,
some have to do with impact damage, some were scrape due to large damage
that they indicate.
So, we’re
trying to go back to each one of these and find out was and is the inspection
of the RCC adequate enough? We know that they do visual inspections, some
at three feet, some closer than three feet, some with magnifying apparatuses
to give them better indications.
But what
is underneath the sealant? Is there oxidation that has provided some kind
of a gap underneath it that we have to be sensitive to?
Now, is this
something that contributed to the mishap, as the admiral said? You know,
if something hit an orbiter that is not brand new, that’s got–and this
is an issue that we clearly have to work in–aging spacecraft, OK? We’re
entering an era we’ve never been there before. And our space exploration
has always been either we had our capabilities to use it for one time,
but now the orbiter is getting into 20 years-plus in a lot of cases, certainly
in the Columbia’s case, and we have to be more suitably attuned to the
aspect of aging spacecraft in an R&D environment.
So this is
just one of our issues that we will look on as maybe a contributing non-significant–non-factor
contributing to the mishap, but something that we want to make sure that
we can provide some serious recommendations.
QUESTION:
Oxidation as in rust? Can you make carbon rust?
BARRY: No,
but you can eat away at it. I guess when you have a pinhole, you can have
oxidation occurring inside the carbon-carbon that makes a gap.
We’ve seen
evidence, as the photos that I showed you clearly indicate, with Atlantis
and Discovery. Some were attributed to faulty repair, but also some were
attributed to–no fooling–after it came back it was inspected and found
to be that way.
GEHMAN: Think
of termites. No, I mean really, or any of you that are boaters, it’s blisters
in fiberglass. This RCC is built up in layers, the oxidation gets inside
and starts opening up gaps from the inside out.
And so the
problem is when you do a visual inspection from the outside you never
see it. Just like in a sailboat, or when you get a–or any kind of a power
boat, when you buy a boat you get a survey and the surveyor has a little
brass hammer, and he goes up and down the hull tapping it, this is one
of the things that they do here because you can hear a change.
QUESTION:
At some point you’re going to know as much as you’re going to know from
the finding of the debris and so on. Do you anticipate when we’re going
to quit searching for debris?
I mean, they’re
still finding things, like at some point when they quit finding things
and it’s been two weeks and they haven’t found anything else, when do
you think that’s going to happen?
I mean, this
seems to be–you’re still finding more and more questions rather than
zeroing in on any answers?
GEHMAN: As
you probably are aware, we’ve just come off a period of actually very
bad weather. And the weather has now actually improved in East Texas and
Central Texas.
Some of the
debris that we’re really interested in is under snow, and we are hoping
that when people get outdoors and farmers start plowing fields and the
snow melts that more interesting debris farther west will start to emerge.
So debris
is still very important to us. I cannot give you a time. This board is
going to work as hard as we can for as long as it takes to get–until
we have some figure of merit of certainty on this.
So, no, I…
QUESTION:
You don’t have a time frame? I mean, the space station is up there and
the clock is ticking on getting the shuttles back in flight.
GEHMAN: But
if we don’t know anything, we’re not going to–we can’t say anything.
So we’re just–I mean, we can’t possibly work any harder than we are;
we’re already working seven days a week. So we have–like I said before,
we have either 4,000 or 5,000 people every day of the week out searching
for debris; every one of them covers about three acres at a shot. There
are divers out there, there are pilots, there are helicopter pilots.
Now, the
energy level’s still very high, both among the debris pickers-uppers,
the debris analysts and this board, and I would not want to put any kind
of time frame on it.
QUESTION:
So you think it’ll be at least several more months?
GEHMAN: It’ll
be a lot of weeks.
QUESTION:
This is for General Barry regarding the problem report on the bipod foam
area. Do you know whether that concerned the jack-pad close-out or the
bipod ramp?
And what
was done? And was there a hand patch done? Or what was the response to
that problem report?
BARRY: No,
as soon as you demate, you generate a program report as I understand it.
So that had to be inspected after it was remated. So after it was remated,
it was viewed to be OK, and they signed off on it.
Now, the
question we’ve got, you know, as we move these things around, were there
issues of cracks or things that could have contributed to cryo-pumping?
And we’re trying to do some experiments.
By the way,
I might mention also, down in Michoud we’re going to be doing a lot of
experiments with the tanks that we have right now. ET-120 is being looked
at this week as a kind of a test case to be able to do some analysis.
And we’ll do some cryo-pumping analysis and we’ll do some foam analysis
to see what the cracks are by trying to figure out with some kind of a
dipenetrant (ph), water-based–I think it’s–they’re still working on
trying to decide that, to get some kind of feedback what is it that could
be happening to that particular area by the bipod.
(END OF AUDIO
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