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.

[Cold Heat]

Understood. They are not much help with the sn# destroyed anyway.

The remains of that big "chunk" as the kid called it, must be out there somewhere. New mexico's desert or N.west Texas. I hope someone stumbles onto it. It definitely did not completely burn because it's outline was visible on the vid on a magnified view.

[bonesmccoy]

By use of following website one can convert deg/min/sec to decimal.

http://www.geology.enr.state.nc.us/gis/latlon.html

The Cal Tech observatory is at
37.23389
-117.71778

Now looking for testimony of astronomer... I seem to recall it in this thread.... hmmm...

Saw your comment XBob... Will plot on MapPoint the datapoints you guys have over NM

[freepersup]

Check- their time is erroneous to use, parallel with the time lines. Use the length in time of the video shot, as they basically got the shuttle coming and going, from horizon to horizon. Plus- Waputki is about halfway along the flight path of the shuttle through Arizona. It won't be exact, but it will help to line up the flare event with a particular sensor reading along the time line.

The sensors may not be remmotely connected to the actions that place within the ship, then again they might. If the cargo door is coming off as they are filming the ship's passing overhead, the sensors might corroborate this event. Notice the reading in New Mexico after the flare event has occurred.

[XBob]

I hate RP too.

I couldn't get budge's link to work, exactly. What I get up is a bunch of error messages, then finally a normal web site, with the image of an embedded player, and nothing at all to play or make it play.

I do have real player, but every time I upgrade my windows 2000, Microsoft screws up something else, and I think they are out to destroy real player.

Could you possible download to your hard drive, the file that it is playing? If you can, then possible you could e-mail it to me, and I could play it. i was able to do that with the side view of the 'insulation' coming off, and I have that file now in mpeg which now plays on my windows player, without linking back to the site where I got it.

[freepersup]

The kids were at this Indian ruins, northeast of Flagstaff. They would have gone here to get away from the ambient light of the city. Plus it is closer to the flight path. FWIW Flagstaff has about 50,000 people.

[bonesmccoy]

Located another website of a ground observer in San Diego area who claims to have noted debris falling off orbiter at 5:54 AM PT.

Website is http://www.moonglow.net/ccd/pictures/other/

[bonesmccoy]

where is that ruin exactly?

Lat/Long in decimal?

Is it off of AZ 395?

[Budge]

I have uploaded those timelines to my photo place. Again, pick the pic, then get original, move mouse pointer off then back on pic, and click the enlarge icon on bottom right.

Text is difficult to read even in the enlarged mode, but may be of some use.

[Cold Heat]

WAPATKI Monument, near Flagstaff.

[freepersup]

This is the next reading in sequence after the flare event in Arizona.

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

LOS loss of signal

[bonesmccoy]

OK gotcha...
Just watched the WFAA video you linked.

When are we conjecturing that the "object" came off the orbiter?

At the 1st Roll Reversal initiation point?
That's datapoint 46 on NASA's pdf.

[Budge]

Sure.

[freepersup]

I'll have to hunt for the lat/long. On the PDF file from NASA (Time Line) on the Arizona page, below box # 44.5, are 2 towns. Cameron and Gray Mountain are on highway 89. Just south of Gray Mountain is Wupatki National Monument.

[bonesmccoy]

Yes I see the Wapatki National Monument, but am uncertain when we are actually conjecturing that the object departed the vehicle.

I'm thinking that the exposure of the object to the slipstream while still attached to the orbiter would have induced significant drag. Are we assuming that the object is the MLG door or part of the wing glove assembly or part of the left wing leading edge?

Perhaps it doesn't matter.

I'll pick a point and let's just do some calculations based on college physics.

[Budge]

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

I'm using (GAG!) the latest free version of Real Player (under XP Pro). Unlike MS viewer,I have no way to save it.

[Cold Heat]

It appears that it is not on my drive. Or, some of it is. It still links and streams through my modem.

I sent the link to win amp, and it does not recognise it. I tried to save the link as a short cut and it comes up "page cannot be displayed".

I am at a totall loss for words to describe this.

Suggestion: Load a new copy of RP and then go to the WFAA link. I think it will work but it takes a bit of time to download real and set it up.

[bonesmccoy]

Guys,
I'm going to assume that the object departed the vehicle at the first roll reversal. I'm guessing that the the roll reversal imparted additional forces on the object that causes sep to happen. Jamieson will bag on me for this, but heck... I'm just guessing anyway.

Datapoint is:
coordinate 36.37187, -110.03
Height= 219820 feet
Velocity = 21.13 Mach

Guys, I'm guessing that when NASA labels "Mach" that I'm supposed to be taking 761 mph x the Mach number to get mph.

I know that's a lousy way to estimate mach at 200000+ feet (due to atmospheric properties), but is that what the NASA document is saying?

[freepersup]

Perhaps just preceeding that event by a second or two. Two significant sensor indicators register data that may indicate the loss of said door (if in fact the large flare is the door burning up).

1- 1st Roll Reversal Initiation

and

2- Left Upper Wing Skin Temp- Start of Off- Nominal Trend Temp Reading Trending Down potential sensor/wire damage

[Cold Heat]

Bones, I think a NASA mach is 1000KM/hr.

[Smokin' Joe]

I may be off base here, others are more knowledgeable. If the damage caused a breach in the wing undersurface or the landing gear bay, how open is the space inside the wing?

Presumably the structural elements are not solid (to conserve weight) and the plume of superheated material would blow into the hollow wing space, with vortices I don't pretend to be able to predict or model. (I'm only a rock scientist--no ET)

This might account for the pattern of temperature increases, plume circulation changing with the geometry of the eroding breach. Eventually, with drag or structural failure causing loss of attitude control and the orbiter.