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.

[vortigern]

Speaking of telescopes...why couldn't NASA have taken a closer look at the shuttle, while still in orbit, with an earth based telescope? If we can look into deep space with telescopes, is there no means to take a close look at an object in a predetermined orbit around the earth?

[small_l_libertarian]

Thanks for the explanation. I was getting nervous there for a minute. It would seem, though, that there would be a plasma trail coming off of the tail, too, so the outline would show.

I don't know anything about analyzing photos, though, so I'm probably wrong.

[freepersup]

Someone posted that our command of space flight should be routine to the point of up and back in the same day.

In 66 years we went from the first flight to landing a man on the moon. Over the past 34 years, we haven't made a comparable leap.

I agree that a revolution in space technology is in order. A paradigm shift at NASA HQ's. Anti gravity is the new propulsion frontier. I wouldn't discount the possibilities of nuclear energy either. Maybe use it as a bridge until anti gravity flight is solved. An interim source of propulsion.

The (rate of) return on the shuttle is diminishing.

[small_l_libertarian]

I really think the tail should be visible in this photo. If you look at the photo in #564, you can see the curve of the top of the fusilage. I think that's what I see in the AF photo, on the shuttle's right (left of photo). The fusilage sides are straight (see the diagrams above), but when the shuttle is slightly tilted (relative to the camera, like in #564), the top of the fusilage makes the side of the silhouette appear curved.

So, if you take the photo in #564 to be an exaggerated approximation of how the shuttle is positioned in the AF photo, the broad part of the tail should be partially exposed to the camera. It should be a fairly big trapezoidal shape. But I don't see it.

Like I said, I know absolutely nothing about analyzing photos, so I am perfectly willing to accept another explanation. So, why don't I see the tail?

[freepersup]

Isn't the photo infrared ? The underside has a heat signature. The tail would be much cooler therefore it wouldn't 'register' right ?

[small_l_libertarian]

Wouldn't the front part of the tail be glowing hot, though? It's slicing through as much atmosphere as anything else, isn't it? I would think that at least the outline should be visible.

And I don't think that it's only the underside that we see. I think that the curved edge on the shuttle's right is actually the outline of the top of the fusilage.

[XBob]

excellent freepersup - where did you get the first (complete) image?

[freepersup]

From a previous thread here at FR (today). I have to think a moment... I'll check my comments to see if I posted to it.

[Thud]

Columbia had to make a greater number of high attitude banks to shed energy on re-entry than any previous shuttle mission. The period of maximum heat loads appears to have been significantly higher for Columbia.

Given that and Xbob's comment about a near total burn-through of an elvon on a less hazardous re-entry, I wondered if the simplest loss explanation is the re-entry profile.

[Thud]

That's the best mechanical explanation for tile failure I've seen so far.

[XBob]

1. Question: would that same burn-through have brought down that orbiter if the orbiter had the re-entry profile of Columbia?

i don't know, but I do know that a few more seconds of high heat would have severed the shaft, killing the bird, through loss of control

2. I.e., is fatal elvon burn-through a more frequent potential occurance than discussed so far?

that is the only case I saw, however, it was so serious they changed the tile layout and types of tile in that position. and now ..... dah dah dah - I heard, they hadn't done it on the colombia, yet.

3. Are there simpler explanations for Columbia's loss than the foam strike?

that's the question we are all trying to figure out.

[freepersup]

Air Force imagery confirms Columbia wing damaged

http://www.freerepublic.com/focus/news/837858/posts?q=1&&page=251

post # 238

[freepersup]

Equalized histogram shows heat concentration on left wing?

http://www.freerepublic.com/focus/news/838455/posts?page=115#115

[freepersup]

that is the only case I saw, however, it was so serious they changed the tile layout and types of tile in that position. and now ..... dah dah dah - I heard, they hadn't done it on the colombia, yet.

Isn't that interesting, odd and damning ? (if true ?)

[freepersup]

This is where I found the histogram (?).

http://www.freerepublic.com/focus/news/838455/posts?page=115#115

[freepersup]

Here's that quote-

Space is the high ground. We need access on a ho-hum basis. Fly into space, return the same day. Fly into space again. When this happens, the United States will become the Federation. We will inhabit space. We will make sure that a representative Republic rules the high frontier. Commercially, privately, governmentally, militarily, this should be the only acceptable outcome to citizens of the United States.

[John Jamieson]

I didn't rule it out; only chose to ignore it for a while to look at other things. A lot of the engery went into pulverizing the foam, but can't tell what fraction.

[John Jamieson]

Carbon/Carbon is not very heavy. 9 pounds per cu ft.

[freepersup]

I just reviewed the sensor indicator time line. The first 3 sensors to reflect an anomaly are located in the wheel well. The are off nominal but functioning. The next 5 sensors to FAIL, are all in support of the left elevons (1 of the 5 is in the left inboard elevon).

Interesting... You may be on to something with your re-entry profile (excess heat) hypothesis.

I've read 4 turns were scheduled and I've read 2 turns were performed ?

[John Jamieson]

The wires for all of them connect infront of the wheel well. It was the wires, not the sensors.