Observation on TPS damage on Orbiter

NASA photos | 2-3-03 | BoneMccoy

[bonesmccoy]

In recent days the popular media has been focusing their attention on an impact event during the launch of STS-107. The impact of External Tank insulation and/or ice with the Orbiter during ascent was initially judged by NASA to be unlikely to cause loss of the vehicle. Obviously, loss of the integrity of the orbiter Thermal Protection System occured in some manner. When Freepers posted the reports of these impacts on the site, I initially discounted the hypothesis. Orbiters had sustained multiple impacts in the past. However, the size of the plume in the last photo gives me pause.

I'd like to offer to FR a few observations on the photos.

1. In this image an object approximately 2-3 feet appears to be between the orbiter and the ET.

2. In this image the object appears to have rotated relative to both the camera and the orbiter. The change in image luminosity could also be due to a change in reflected light from the object. Nevertheless, it suggests that the object is tumbling and nearing the orbiter's leading edge.

It occurs to me that one may be able to estimate the size of the object and make an educated guess regarding the possible mass of the object. Using the data in the video, one can calculate the relative velocity of the object to the orbiter wing. Creating a test scenario is then possible. One can manufacture a test article and fire ET insulation at the right velocity to evaluate impact damage on the test article.

OV-101's port wing could be used as a test stand with RCC and tile attached to mimic the OV-102 design.

The color of the object seems inconsistent with ET insulation. One can judge the ET color by looking at the ET in the still frame. The color of the object seems more consistent with ice or ice covered ET insulation. Even when accounting for variant color hue/saturation in the video, the object clearly has a different color characteristic from ET insulation. If it is ice laden insulation, the mass of the object would be significantly different from ET insulation alone. Since the velocity of the object is constant in a comparison equation, estimating the mass of the object becomes paramount to understanding the kinetic energy involved in the impact with the TPS.

3. In this image the debris impact creates a plume. My observation is that if the plume was composed primarily of ET insulation, the plume should have the color characteristics of ET insulation. This plume has a white color.

Unfortunately, ET insulation is orange/brown in color.

In addition, if the relative density of the ET insulation is known, one can quantify the colorimetric properties of the plume to disintegrating ET insulation upon impact.

Using the test article experiment model, engineers should fire at the same velocity an estimated mass of ET insulation (similar to the object seen in the still frame) at the test article. The plume should be measured colorimetrically. By comparing this experimental plume to the photographic evidence from the launch, one may be able to quantify the amount of ET insulation in the photograph above.

4. In this photo, the plume spreads from the aft of the orbiter's port wing. This plume does not appear to be the color of ET insulation. It appears to be white.

This white color could be the color of ice particles at high altitude.

On the other hand, the composition of TPS tiles under the orbiter wings is primarily a low-density silica.

In the photo above, you can see a cross section of orbiter TPS tile. The black color of the tile is merely a coating. The interior of the tile is a white, low-density, silica ceramic.

[XBob]

XBob, the e-mail address you sent me reported back as undeliverable . . .

that is strange - that's the correct address. Maybe it is busy or tied up or full or something. or perhaps security is too high.

[bonesmccoy]

XBob's diagram is pretty convincing. (ACK! Must I agree with a NASA man?)

Actually, I was thinking of looking up the wing spars. I don't agree that the entire glove is gone. it would be interesting to juxtapose the outline of the MLG door on the diagram by XBob (accounting for viewing angle). If the angle of the camera is nearly immediately below the vehicle's trajectory, then XBob is correct and the MLG well forms the forward most portion of the wing. The burning elements visualized by people in AZ/NM may have been aluminum skin and structure from the area.

[XBob]

http://www.nasa.gov/columbia/COL_landgear_email_030212.pdf

d.l.dwuoyer, 1/31/03 2:.00 I'M -0500, Fwd: FUI: Main Gear Breach

Concerns

1 g?; oarid, , I talked r ; ~ C u r l l d e a bit ago and he lot ma

OW you guys at MOLY were
Uet.ting i n t o .the loop on t h e .tile dwouge Issue. I'm

.writing this errnil. zrot
roully i n a.n official caDacity but since welvc worked togather 50

roarry
times 1 feel. Like 1 can say gre,tty much aaytkiirig t o you. And

before I
begin I would o f f e r t h a t 5 am aatnittedly errin0 way on the

side of absolute
worst-case sconariou arid I don't really believe thi:ngs are us bad

us Z ' m
wtting ready to make them o'ut.
ready lor a gut-wrenchina decision after seeing i n s . t r w n t a

t i o n in the
wheel well not be there aftelc ent-ry i s irresponsible,
theories is that you should seriously consider ,ttle possibility

0;; t h e gear
But I c ~ r t a i r i t y believs t h a t t o n o t %E.
Crie of r:y personal
David F-M Lecher
Space Shuttle Mechanical S y s t ~ a r
Machariical, Maintenawe, A m 6 Crew Systorm ( W C S )
' ~ n i t e d Space A l l i a n c e , Johnson Space Center
(281) 483-1685
_ _ _ _ _ O w i g i n u l Messago-- - --
S C r r t ; Thursday, January 3 0 , 2003 5:23 PM
Cc: ~.iT.SH'LT;qRTQlarc.nasa.g-ov; W . n . ~ E L ~ @ l a r c - ~ ~

~ ~ . ~ o v ; CAEjiPmm,
Subject: Main Gear Breach Concerns
From: Robert H. Przugher,ty [m:i%,ta :-t I ? .v@larc 1 1
TO: LECXNEK, DAY113 %. (SSC-DFSZ) ('USA)
CARLISLE C., JR (JSC-ES2) (NASA!




not deploying at all if there is a substantial breach of the wheel

well. The reason might be that as the temps increase, the wheel

(aluminum) will lose material properties as it heats up and the

tire pressure will increase. At some point the wheel could fail and

send debris everywhere. While it is true there are thermal fuses in

the wheel, if the rate of heating is high enough, since the tire is

such a good insulator, the wheel may degrade in strength enough to

let go far below the 1100 psi or so that the tire actually bursts

at. It seems to me that with that much carnage in the wheel well,

something could get screwed up enough to prevent deployment and

then you are in a world of hurt. The following are scenarios that

might be possible and since there are so many of them these are

offered just to make sure that some things don't slip thru the

cracks... I suspect many or all of these have been gone over and

over by you guys already:

1. People talk about landing with two flat tires... I did too until

this came up. If both tires blew up in the wheel well (not talking

thermal fuse and venting but explosive decomp due to tire andor

wheel failure) the over pressure in the wheel well will be in the

40+ psi range. The resulting loads on the gear door, ( a quarter

million lbs) would almost certainly blow the door off the hinges or

at least send it ou into the slip stream... catastrophic. Even if

you could survive the heating, would the gear now deploy? And/or

also, could you even reach the runway with this kind of drag?


2. The explosive bungies... what might be the possibility of these

firing due to excessive heating? If they fired, would they send the

gear door into the slipstream?

3. What might excessive heating do to all kinds of other hardware

in the wheel well... the hydraulic fluid, uplocks, etc. Are there

vulnerable hardware items that might prevent deployment?

4. If the gear didn't deploy (and you would have to consider this

before making the commitment to gear deploy on final) what would

happen control wise if the other gear deploy on final) what would

happen control-wise if the other gear is down and one is up? (I

think Howard Law and his community will tell you you're finished)

5. Do you belly land? Without any other planning you will have

already committed to KSC. And what will happen during derotation in

a gear up landing (trying to stay away from an asymmetric gear

situation for example) since you will be hitting the aft and body

flap and wings and pitching down extremely fast ala the old x-15

landings. My guess is you would have an extremely large vertical

decel situation up in the nose for the crew. While directional

control would be afforded in some part by the drag chute... do you

want to count on that to keep you out of the moat?


6. If a belly landing is unacceptable, ditching/bailout might be

next on the list. Not a good day.

7. Assuming you can get to the runway with the gear deployed but

with two flat tires, can the commander control the vehicle both in

pitch and laterial directions? One concern is excessive drag (0.2

g's) during TD throughout the entire saddle region, making the

derotation uncontrollable due to saturated elevons... resulting in

nose gear failure. The addition of crosswinds would make lateral

control a tough thing too. Simulating this, because it is so

ridiculously easy to do (sims going on this very minute at AMES

with load-persistance) seems like a real no brainer.


Admittedly, this is over the top in many ways but this a pretty bad

time to get surprised and have to make decisions IN THE LAST 20

minutes. You can count on us to provide any support that you think

you need.

Printed for "Mark J. Shuart" ~j.shuartOpop.lurc.nnsa.gov>

http://www.nasa.gov/columbia/COL_landgear_email_030212.pdf

[Cold Heat]

Looks good to me Bob. Let's see where it leads!

BTW, the reason I have been off line, is that my ISP local server has crapped. I am currently on long distance.

I will be mostly off line till they replace it.

Your work and illustration makes great sense to me.

[XBob]

I don't know the viewing angle of the photo, but the flight path carried it directly over the camera at Albequerque.

My drawing is flat on, no isometrics, however the photo is angled. My graphics program is just the one which comes with windows, so has few fancy capabilities. In fact, I was amazed I could even do what I did with it.

One other thing to remember - the landing gear wheel well area is one of the strongest parts of the whole orbiter, as it must absorb the whole impact weight of the shuttle landing on one wheel. (and by strong, I mean mechanical, structural strength, made from thicker metals, and less likely to disintegrate.)

[bonesmccoy]

XBob,

There is still a "delta" shape in the glove area. The orbiter forward fuselage should be straight, but the geometry along the vehicles fore/aft axis seems equal until the assymmetry.

Do you think the Wing Glove structure is in place with the RCC gone? I don't understand how the RCC forward of the hypothetical debris impact could have been compromised.

[Cold Heat]

My Isap also said there is a e-mail issue going on. Sounds like a worm problem and might be nationwide.

[Cold Heat]

debris impact could have been compromised.

Possible tire explosion?

Goota go time is money. On long distance line.

[LaBelleDameSansMerci]

Truly, one of the great threads in all of human history.

Thank God none of you have any work to do.....

[XBob]

1502 - AKKK!!! I was called a NASA man LOL :

"XBob's diagram is pretty convincing. (ACK! Must I agree with a NASA man?)"

I am an OIL man, who took a short 3 year sojourn into aerospace as a Lockheed man. My brother is the lifetime NASA engineer.

This is what I have been trying to convey since I first saw the USAF picture, 1000 posts ago or so, mr Rockwell man. LOL

[Budge]

Let's see if this works.

This is the second page, bones.

Nope. You can view them in jpg format here.

Click the pic, then "Get Origional" then take mouse pointer off and back on pic, a button will appear in bottom right. You may have to do that twice to read them.

[Budge]

NP Blackie. Thanks!

[XBob]

1506 - "There is still a "delta" shape in the glove area. The orbiter forward fuselage should be straight, but the geometry along the vehicles fore/aft axis seems equal until the assymmetry.

Do you think the Wing Glove structure is in place with the RCC gone? I don't understand how the RCC forward of the hypothetical debris impact could have been compromised."

---

well, if you look more closely at the frame structure, on the other drawings posted previously, (and if you opent the pdf 2-7 file, you can really see them far better), you will see the attchments better, and I theorize that they may have 'folded' back against the fuselage, with the fuselage attachments remaining intact at the time of the photo.

However, we don't know exactly what the photo is of, is it heat or bird? If it is heat, the heat would pile up in that area. Note how the rear of the wing bows backwards too - it is not straight. It could be the elevon literally bending, or it could be heat.

you said "I don't understand how the RCC forward of the hypothetical debris impact could have been compromised."

I theorize that the impact eroded the tiles and wing structure forward of the wheel well, and behind the RCC, removing the support for the RCC, which fell off and zippered along the wing's leading edge.

Remember my analogy of laying a log on the beach and watching how it moves higher up onto the beach shore as the waves hit it, continuously digging a hole behind.

[XBob]

interesting, about a worm - hope you get back up soon.

World net daily seems to have a pretty good deal, 12.95 per month.

[TomServo]

Outstanding, Bob...

[XBob]

1509 - "Truly, one of the great threads in all of human history.

Thank God none of you have any work to do....."

Well, thankyou madam, we should have a little reward after working hard for 40 years.

[XBob]

many thanks.

[XBob]

thankyou TS

[bonesmccoy]

I do have work. That's the reason Budge, XBob, and the others keep out posting me in the thread I started!

LOL

[bonesmccoy]

Hey, I never said I was a Rockwell guy.

When you first posited the hypothesis around post 1000, I chose to discount it because I thought the angularity in the USAF photo was due to bleed from adjacent pixels (glare of extremely hot MLG door).

I am attempting to alter the TPS diagram to account for only loss of RCC.

Perhaps you can do that better since you appear to have better graphics software than I.

We still have not attempted to reorient the orbiter with MLG door open. We need a 3-D model to achieve this geometry. Perhaps a Freeper has an appropriate Adobe product.