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.

[halfbubbleofflevel]

Slightly off topic but...

Recently I found some 3D data on a shuttle. I'm not sure how accurate the 3D model is but it does look decent (imo).

I had a little time last night (gah am I tired) ... whipped up this quick program that allows me to display and manipulate a shuttle image over top a jpg image (ie: USAF photo). I don't have any way to post this project on the web.

Controls are a bit "primative" but it works. I just got it working so it does not have "fancy" features but I am willing to do extra stuff if time permits.

Is it even useful anymore? Anyone wants it? Willing to post it? File size is 180K including data.

[bonesmccoy]

Do you have any info on the ET insulation layers?

You seem interested in the "zippering"...an effect that has never been documented or observed on any STS mission to my knowledge.

I'm more interested in the ET insulation composition and the likelihood of NO zippering. The insulation may have damaged one or two areas enough to permit plasma to leak into the wing structure (just as you described). The argument should not hinge on "zippering or not".

It is obvious that the wing overheated. The question is the failure mode so that a better design can be created.

Regardless, if the ET insulation is falling off, that is a greater issue than the TPS. After all, the TPS flew for 100+ missions without failure.

Why is the ET insulation failing now?

Clinton Administration?

[XBob]

sorry - forgot california coast

7:52:20 first heating comes well out over pacific

08:53:44 crossing the California coast
just to the north of the San Francisco area.

7:55:53 some things comes off over california/nevada and make flares (photo of one posted with time stamp)

7:56:20 shuttle banks left and the last sensors grouped together running from same point in the web/glove (see NASA slide #17 of 25 with dwg and sensors) at 4 corners 150 miles from albequerque - these are above and below wing skin temp sensors.

albequerque we have photo of chunk gone

08:58:39 last sensor goes off line

08:59:28 last voice transmission

08:59:32 a.m. (LOS-00:00)
Loss of signal.

[Budge]

1558 - Bones, I'm not saying I'm correct in my point about the multi-hits. I'm simply presenting what I think I see and presenting my conclusions to you all, perhaps to tear to shreds, or work along another (possible) cause to this disaster.

If you, xBob, John, Wirestripper, Thud and any others see any merit to what I post, I expect y'all to prove me right, wrong, or under the bleachers in left field.

Heck's fire, I'm just an over-the-hill Wal-Mart greeter with little to few credentials and wanting to help all I can. :)

[XBob]

1562 - "Regardless, if the ET insulation is falling off, that is a greater issue than the TPS."
How old was that tank? I think it was 5 years old. sitting around, getting hard, collecting humidity, and sun. The venturi effect between the shuttle and the tank literally sucks the insulation off the tank, particularly where this chunk appeared from

"After all, the TPS flew for 100+ missions without failure."

ROTFL
TPS = 100 missions without totally destroying the orbiter, some TPS failed on every mission.

Why is the ET insulation failing now? -

How old is the tank?

[XBob]

Sounds interesting

budge may be able to post it. and bonesmaccoy wants something like that.

[Budge]

I'm willing to give it a shot, if you want, Half. See 1473 for e-mail.

No guarantees I can do it, but willing to try.

[Budge]

Have to work late tonight. Bed time for me now.

[XBob]

In view of your observations, budge, I just viewed my Ice Debris Team magnified view video of ONE thing coming off the ET, forward of the nose, traveling down to the nose, then disappearing, the splatting at the 'crotch' of the wing, then spreading and leaving near the center rear of the orbiter.

The other video (no wing bottom, side view only) shows the BLOCK coming off, circling around, breaking into 2 blocks, 1 of which disappears, the other of which splats (cant see where) then debris sprays away from ship toward flames of the solid booster.

Two pieces, or perhaps two bounces of one block?

[labowski]

Does anyone have any idea what those three or four LARGE round
objects they've been showing of the recovered materials are?

Something from the cargo bay? Engine parts?

[XBob]

if you are talking about the big 'beach balls', those are tanks, fuel, fluid, etc.

[freepersup]

Hi Budge- Thanks for the reply. I haven't read each and every thread from where I left off, so I will spend some time catching up before I dare opine (further) than on this image / issue.

I groaned when I saw this graphic of the tile. It is of great detail and shows a vulnerability previously unseen in the glove area. I am addressing the HRSI (heat resistant shielding insulation ?) area, where an arrow (on the left) is pointing.

I can't tell if I am looking 'through' the wing and am seeing the left wing or that I am looking at the underside of the right wing ? For the point I want to make it doesn't matter.

Most views have been looking on at the glove area from a perspective about level with the wing and from a few, to several feet away. One could not see or appreciate the tile pattern (TPS) on the wing's underside. The RCC's- # 1-8, were the prominent wing design feature appearing in the images.

There are several of these graph's depicting the TPS where the entire ship is displayed. Having just joined back up in the conversation, I more than likely have missed the conversation regarding these tiles (HRSI at left arrow), and that is why the image is appearing for obvious reasons, where it does in this thread.

Now to the chase. By not having a design where the RCC's wrap under the leading edge of the wing, such as what we see around RCC # 9-22, a vulnerability exists, where an errant object debris strike would impact the TPS 'sooner'.

Perhaps 'sooner' isn't the operative word or point. The RCC's that wrap the underside of the wing offer more protection from a debris strike, as there is more material to absorb an impact, head on, or wing leading edge on.

In addition, the structure or frame lacks intersecting bracing behind the RCC's # 1-8, so an onrushing strike in the RCC # 9 area, as proposed previously, may cause to collapse sooner, the RCC's # 1-8, as they have substantially less material regarding the 'wrap' under the wing. An additional point, (made earlier) was the domino effect of RCC's # 1-8, due to lack of forward / aft bracing.

Whether the strike was here first or at the RCC # 9 point, it is by design weaker than at other points on the leading edge of the wing, such as RCC's # 10-22. RCC # 9 is weak as well, lacking the forward / aft bracing. RCC # 8, has some forward / aft bracing about half the distance from the wing edge to the fuselage framing.

In summation, the HRSI would, if struck, be more prone to peeling, zippering, etc. because of the exposure to the aero forces (by their location and design)

[freepersup]

It is of great detail and shows a vulnerability previously unseen in the glove area.

It's not previously unseen, as we have had several similar images displayed to aid the discussions. Credit goes to Budge or to whoever prompted Budge into displaying this view. The larger TPS images of the full ship's underside do show the area I comment on. The enlargement enhances the ability to see the lack of wrap, to the underside, by the RCC's. Several of you posting may have already alluded to this fact, hence Budge's display.

I did not mean to give an impression that I was bringing this point up for the first time. I mean to speak in agreement to the fact that it is a weak or vulnerable design, regarding a debris strike, because of the lack of RCC material, cupping or wrapping under the leading edge of the wing. I might add that this is solely hindsight 20-20.

[freepersup]

[freepersup]

[Thud]

I am no longer saying that tile unzippering caused the loss, though it might have. I am saying that tile unzippering was happening along with lots of other things.

[freepersup]

High Resolution Image (-Underside View-) of Above Shuttle Photo

[freepersup]

[Cold Heat]

I do not see any zipper effect in my model.

What I do see is a important tile that was dislodged by the foam impact. It likely remained in place, held in place by the packing, and fell off later in the flight.

I believe subsequent tile loss was more a result of the heating/destruction of the hull, or door as a direct result of the initial tile loss.

I realize it is a stretch to say that one single tile loss could bring the shuttle down, but the diagrams, and video, along with the timeline, seem to support this undeniably rare and statistically unlikely occurrence.

[Cold Heat]

FOX reporting that a gear down sensor was in fact recorded by NASA prior to breakup. I do not know the precise time.

It fits with the timeline I have believed and I also believe it was a result of the door loss and or/ pyro detonation.