Posted on 02/04/2003 1:34:19 AM PST by 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.
Previously, the largest foam debris was only about three inches square and caused serious damage to the tiles as a result of hitting the underside of the wing.
NASA engineers screwed up when they calculated the expected damage. They did not take into account the orientation and spinning of the foam as it stuck. The resulting angle of attack and energy released was much higher than they figured.
Am I seeing correctly? Is that an additional small plume or perhaps something in the background?
Then in post 967 I asked, 7:54:22 Mid fuselage left body line temp at x1215 - off nominal rise 6 degrees/min - not connected to wheel well wiring - Have we all been ignoring this sensor?"
Later on - 1198 - xBob posted the following: could the big flash have been the engine protection cover in the rear center? As there is no fuel, and the main engines are off line, what would the sensors detect there at this point in the return?
the insulation fragments did leave the ship toward the mid-section, if I remember correctly.
In 1551 Thud posted, "A double foam hit would explain a fair amount. I've been concerned all along that we're looking at two different, overlapping, event chains."
In 1570 labowski posted, "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?
Labowski's question about 'those three or four LARGE round objects' was answered, but the part about the 'something from the cargo bay/engine parts' was never addressed - as was xBob's "could the big flash have been the engine protection cover in the rear center?"
I have since been trying to find out the exact location of "x1215" with no luck. As near as I can tell it is near the aft shuttle bay area just ahead of the main engine compartment.
My question(s) - How many, if any sensors are there in the cargo bay area?
The engine covering area?
Could the initial "big flash" have been something from the left side/aft cargo bay/engine covering area before the wing burn-through?
I'm not expressing myself very well here, I hope y'all see the track I'm attempting that hasn't really been discussed by us or NASA.
IOW, perhaps the "big flash" was a section of the port fusalage/engine covering that isn't well protected from the heat, yet at that point in time didn't have much (if any) effect on the "flight" characteristics of the shuttle.
I do not have a highspeed connection, so I cannot comment on the differences.
However, I can see no debris. Only contrail.
It is not out of the question that this film and the Utah film is the same event, from different angles.
The angle and distance on the nevada film is not showing much detail. The Utah film was very shaky and had focus issues.
The pic from the telescope in NM was fuzzy and full of overloaded pixels, and to make matters worse, the film of the foam strike was also out of focus.
It seems the gremlins are responsible.
On the Friday prior to reentry cBS radio news reported a concern over a overheating dehumidifier in the Lab. I heard this twice that day. Perhaps someone astute with Google could do a news search on that day.
Did you hear them say the foam strike was in the number 6 7 or 8 RCC. They have several teams and contractors enhancing all the photos.
That was 41 minutes of the most unmitigated BS I have heard in a long time.
...and I really wish NASA would hire a sound man for their press conferences. The constant feedback howls were a real embarassment, as usual.
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