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.

[freepersup]

You described the kid's film to a tee.

[freepersup]

You are kind to want to respond to as many comments as are directed to you. No need to- Eyes wide open on this end. I'll contribute what I can, while I can. Thanks-

[Budge]

Here is the link to the video by the kids. I'm listening/watching it as I type. It's still there.

[bonesmccoy]

gravitational acceleration = 9.80665 m/s^2

[XBob]

The kid watched and said....Look at that! Wow! Did you see that!

I think that's the one I have been looking for.

bones, how about looking for this one instead?

[Budge]

I found some drawings, albeit old ones of attach points and have them bookmarked. I'll look for them in the morning and try to post them then.

[Cold Heat]

Agreed, but if it is a tile, it may well have survived.

It would have floated with the air currents (because it is so light) and could be anywhere.

[Thud]

I think it was Xbob who first thought there might have been two pieces of foam, each having a different impact point. I don't know who it was who had earlier first picked up on two different impacts.

[XBob]

budge - that is a jsp file, which I can't get to work, and it comes up as a non-playing real video player with a bunch of errors. what is a jsp file?

what are you using to view it, or download it.

[freepersup]

The shuttle is crossing northern Arizona according to this time line and is under observation by the kids filming at Waputki NationalMonument.

east of Kaibito, Arizona
13:56:16 GMT
Hyd Sys 1 LMG
Uplk Actr Unlk Ln
Temp- Temp rise Rate Change from 0.7 F/min (nominal) to 3.9 F/min and increasing to LOS
H 220,778'
mach 21.28

east of Kaibito, Arizona
13:56:17
Sys 3 LMG Brake SW Vlv Ret
Line Temp (FWD)- Temp Rise Rate Change from 1.5 F/min to 8.8 F/min (not increasing) to LOS
H 220,711
mach 21.27

east of Kaibito, Arizona
13:56:22
LMG Brake Line Temp B Temp rise Rate Change from 2.1 F/min to 9.1 F/min increasing to LOS
H 220,374
mach 21.21

The above events are unfolding overhead as the kids continue filming from Waputki National Monument.

[Cold Heat]

Bob, could you get Budges link to work? I have the source files on my real player. It came from that TV site, however I cannot put it in a form that will work if sent or hyperlinked.

I did however enable the player to link to it and play it for my own enjoyment.

I hate RP and someday will post a rant to tell real network what I really think!!!!!!!!

[Budge]

1644 - Most definitely the coup de grace...if that happened.

[freepersup]

Bingo ! That's the kid's film- to match with the time line we are posting here tonight.

Scott and Chris Valentine (kids)

[Cold Heat]

Yes, I put the video into my time line and came up with the same thing. (the brake hyd temp sensors)

I also considered the fact that the time on their VCR is probably as much as 60sec off.

Nobody syncs to GMT very often.

[XBob]

Agreed, but if it is a tile, it may well have survived.

It would have floated with the air currents (because it is so light) and could be anywhere.

---

that's possible, but they burned, otherwise we wouldn't have seen them.

The tiles are strange composition. Let me try to explain. Think of an old box of baking soda, which has absorbed moisture, and becomes a coherent clump, yet breaks apart easily. Think ofthe particle sizes of this clump to be much more grainy than baking soda, and more like particles of laundry detergent. Then think about them being very light in weight. They are not very coherent, these particles, without the coating on them, to hold them together. If you could see our local news here in Texas, they displayed numbers of pictures of them, which fell in the road, and were run over by cars, and were just crushed to powder.

What were the small flares? we were hearing about 'contrails' which people never saw on previous passes. Perhaps they were pieces of the aluminum 'glove/web', as it gradually disintigrated.

Some tiles did survive over texas, intact, but I think they had slowed substantially first, as they came loose in the breakup.

It's a good idea to look for them, what ever they were. and Bones, you idea is a good one, to figure out where to look.

[John Jamieson]

All right Bones, I'll play, it would be interesting to know just far a lose tile would fly. Best we're going to be able to do is a swag, but let's give it a shot.

I suggest we start with a 6"X6"X3" tile tumbling. Density of most tiles is 9 lbs/cu/ft, 500 or so are 22 pounds per foot.

I'll create an excel spreadsheet to track 'em that allows us to change the initial conditions for altitude, velocity, size, and density. Let the tiles fall where they may. I would expect them all to reach the ground.

[freepersup]

Below are the two final sensor readings from NASA, as the shuttle crosses northern Arizona and into New Mexico air space.

south of Shonto, Arizona
13:56:24 GMT
Left Upper Wing Skin Temp- Start of Off- Nominal Trend Temp Reading Trending Down potential sensor/wire damage
H 220,235
mach 21.17

southeast of Shonto, Arizona
13:56:30
1st Roll Reversal Initiation
H 219,820
mach 21.13

The shuttle passes out of range of the kids video camera and crosses into New Mexico. 23 seconds elapse before the next sensor reading provides NASA any kind of useful data.

east of Tohatchi, New Mexico
13:56:53 GMT
SYS 3 Left Main Gear Strut Actuator Temp Temp Rise rate Change from 1.7 F/min to 12.9 F/min (not increasing) to LOS
H 218,839
mach 20.80

The shuttle took 1:04 to cross out of Utah, across Arizona, and into New Mexico.

At approx. 13:56:02 GMT the shuttle sent data out, as it entered Arizona airspace. The last bit of data sent from the shuttle while in Arizona came at 13:56:30. That's 28 seconds of data that can be married up (sync.) to the kid's film that was taken from Waputki National Monument.

[XBob]

I haven't done that type of math since high school/college. I will leave it to you younger guys and engineers.

If you want a cost analysis, I'm your man, but for this stuff, I leave it to the engineers.

[bonesmccoy]

Hey, you're the expert!

I'm just trying to do some college Physics 101 (got yer' old green and yellow Halliday & Resnik book?)

GAG! My prof would be laughing if he saw me looking up those darn projectile equations!

Doing an analysis on the observation of the astronomers from Cal Tech. We can guess their position from the Cal Tech website: http://www.ovro.caltech.edu/

The Owens Valley Radio Observatory (OVRO) is the largest university-operated radio observatory in the world. The observatory is located near Bishop, California, approximately 250 miles north of Los Angeles on the east side of the Sierra Nevada. For reference, its coordinates are 37°14'02" latitude, 118°16'56" longitude at 1222 meters above sea level.

[bonesmccoy]

have you been able to locate where the kids were...where's the link to the article that described where they were standing.