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.

[CyberAnt]

Thank you so much for your comprehensive explanation for us laymen out here who are so interested or curious as to what happened to Columbina.

My question is this: From any of the video you have seen, did the insulation fall on the top edge of the left wing or did it strike the wing farther down (actually under the left wing).

The reason I'm asking that is that it was reported that David sent an email to his brother saying he had taken photos of the left wing which had some type of damage on it. I never did find out exactly what that meant.

I know that David could only see a small portion of the top part of the left wing - so if he saw some type of damage, is there any conclusion as to what could have caused that damage?

[CFF]

Regarding the email(s) that Dave Brown sent to his brother that reportedly discussed damage to the shuttle, these (reports) were FALSE and were recently addressed in a press release by the astronauts brother. Again, it seems like one of those mistakenly reported rumours that grows as it sweeps across the internet. There never was any discussion between Dave Brown and his brother about any damage to the orbiter.

CFF

[CyberAnt]

Thanks for clearning that up!

[XBob]

2480 - most excellent, full bubble on, you found what I have been looking for - IMO that is the 'block' of foam which was 'sucked' off. Apparently this is a standard access hole (unless this photo is of the same tank/mission which I posted with the 'beautiful' picture), which is filled later. This is approximatlely at the point point where the shock waves converge.

Exact specifications of this block on Colombia's 107 tank should be available.

It appears that someone didn't do their job on securing the 'patch'.

On your quesiton, all of us have a bit of different equipment and eyes, and see things a bit differently, however, weall agree that the 'block' comes off and breaks into two pieces.

Personally, with my equipment and eyes, I can see the 'block' making a circle, breaking into two pieces, one smaller (seems like a slice - thinner) piece 'disappears', and the other moves down to the underside wheel well door area and impacts, spattering like a snowball hitting a wall at an angle, and spreading. It may have made a 'bounce' first (my intuition only - I can't see it - but it just seems to hit a bit later than it should have)

Others see two blocks 'falling'. Some see nothing falling off.

[XBob]

2482 - "Regarding the email(s) that Dave Brown sent to his brother that reportedly discussed damage to the shuttle, these (reports) were FALSE"

Where do you get that information, newbee?

[halfbubbleofflevel]

Two pieces of information:

First.......................................
This would not be the first time that foam was lost at the intertank region. I quote: "According to NASA, during several previous Space Shuttle flights, including the shuttle launched Nov. 29, 1998, the shuttle external tank experienced a significant loss of foam from the intertank"
Here is the URL: http://www.arnold.af.mil/aedc/newsreleases/1999/99-041.htm


Secondly........................................
That spot on the intertank appears in previous missions too. Here is a high res photo for STS-107 that shows that spot:
http://science.ksc.nasa.gov/shuttle/missions/sts-107/images/high/KSC-02PD-1892.jpg

I believe there is an identical spot on the other side of the ET. I found this picture: http://www.space-frontier.org/Projects/ExternalTanks/ which shows the other side.

At first I thought it was a byproduct of the ET towing system. There is a photo on the last link showing how the tank is towed. Another good towing picture is http://www.space.com/news/spaceshuttles/interactive_sts_externaltank.html but since then I found other towing pictures that look like they disprove this idea.

What I am looking now for is information/photos showing how the ET is placed erect on the launch pad. I would assume a crane. From what I have learned, there is some "main thrust support beam" located in the ET in the intertank region and I think this would be the proper area to hook up something for a crane attachment point (if that's how it's done).

Don't have time to look anymore.. "I owe I owe, it's off to work I go..."

[Budge]

Just got this pic this morning, I think from xBOB.

[Budge]

I have uploaded some of your pic finds to my Fotki.

Help yourselves. Also, the one of the Columbia on the launch pad is huge when full sized. (Beautiful Picture, BTW.)

[Cold Heat]

It appears that someone didn't do their job on securing the 'patch'.

A most likely culprit, IMO.

In a earlier article on Michoud, a retired employee says he believed that he had inspected this tank and had found areas where the under coating was too thin and/or not properly covering the tank in the areas of the attachments.

This is a small benign statement on the surface, but when combined with the excessive rain and other things, there may be a connection.

Water seeping under the patch and freezing would have been enough to raise a corner a few millimeters and cause it to catch the supersonic air flow.

[Cold Heat]

I agree with your 2477.

Also, NASA has been sanding down areas of problem foam. This might explain the light patches here and there. But, the squared corners of the block that separated, indicate to me at least, that a patch or subsequently filled area is involved.

Human error could well be involved.

[XBob]

Thanks much, Budge. I sent it to you.

I took the 'beautiful photo', with the shock waves, and did the best I could, just by eye, of attempting to highlight the major shockwaves as the bird is flying.

They seem to intersect, (give or take a bit) right 'above' and slightly down wind of the 'patch'.

It seems to me that this would be an area of maximum turbulence and perhaps vacuum. Why would they purposely put a patch in this area?

Note, Budge - please check your FRmail, in about 30 minutes.

[CFF]

re: Where do you get that information, newbee?

http://spacelink.nasa.gov/NASA.News/NASA.News.Releases/03-02-10.Brown.Releases.Email.Statement

DOUGLAS BROWN RELEASES STATEMENT ABOUT EMAILS

Glenn Mahone/Doc Mirelson
Headquarters, Washington Feb. 10, 2003
(Phone: 202/358-1600)

RELEASE: 03-062

DOUGLAS BROWN RELEASES STATEMENT ABOUT EMAILS

"I wanted to clarify a couple of facts reported recently regarding my
brother, Dave Brown, a member of the Columbia STS 107 mission.

Dave sent several personal emails during the mission, but at no time did
he write about any concerns with damage to the left wing of the orbiter or
any other safety issues. As they reached orbit, Dave took his planned
photos of the external tank separation, which is standard procedure. These
are the photos I discussed with Senator Allen. When I asked Dave at
Christmas what he would want me to say if he didn't make it back, he said
the program must go on. He said "I accepted this risk when I took the job,
just as I did when I became a Naval aviator."

Douglas Brown
Feb. 6, 2003

David M. Brown was a captain in the U.S. Navy and was serving as a Mission
Specialist on the space Shuttle Columbia. He was a naval aviator and a
flight surgeon. STS-107 was his first space flight.

For more information about NASA on the Internet:

www.nasa.gov
~~~~~~~~~~~~~
XBob *lol* .... Nice to meet you too.

CFF

[Budge]

Got it. Did you see this pic? Thanks to 'halfbubbleofflevel' I found it in his 2486.

Notice where the scorched area on the ET is.

I should have made it larger.

[Budge]

Let's see if this is better.

What would cause that scorching near the top of the ET?

[Cold Heat]

Looks like it is scorched. There is much heat created at that speed. The foam is to insulate the tank while full of fuel to prevent ice and keep the fuel liquid.

When nearly empty and going into orbital insertion, there must be some scorching

I don't know enough about what normal is to comment.

[meema]

You guys are slowing down. I read everything everyone has written on this thread. Of course, in order to study it, I've had to print it out and take it to our 'smokin' lounge'. It's the best thread ever on the Columbia.
I hope when they start letting some info out in a serious way, you guys will ping me. Thanks.

[Cold Heat]

We slowed down because we are pretty much finished. If something interesting breaks, we will be back to hash it out, but so far the news being released seems to track with what we came up with weeks ago.

Thanks for the kind words.

[Resolute]

Here's a couple of links were people are asking questions that have been beaten to death in this thread . . .

NASA engineer warned of possible shuttle breach, e-mails indicate

NASA Engineer Warned of Shuttle Breach

[Cold Heat]

Yup, LOL we decided the other one or possibly two pieces did not strike the wing. We wonder why.

Some speculate that it was a matter of turbulence and a few, think it may have been the size and mass.

As to the engineers worries, that came out the first day, and it is really a moot point. There is nothing else they could have done to make the re-entry safer at that point. Nothing.

[XBob]

I would assume that the main engines would cause the scorch as the ET falls away from the bird on separation. However, that is an assumption. I don't think they would stop running, then separate the tank.