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.
http://www-pao.ksc.nasa.gov/kscpao/images/medium/03pd0243-m.jpg
Your analysis matches NASA's. It appears they believe there is more than one object falling into the orbiter.
Question for NASA: What color is that plume?
Weather too cold? Could the "ice" hitting the tile under the wing Have plowed a channel up to and under the leading edge of the landing gear door? Dittemore said the temps rose in that area but he didn't say what normal would be at that time.
Are you aware of the live FR thread that was going on prior to and at the time of breakup? Dittemore backed up 1 second to 5:52 PST on problems on descend. That would put it at or near the Ca coast.
Something is on the tail service mast which was sitting in front of the LH wing (which is the same side seen being hit by the "object" in the photos above).
this photo is looking from the launch platform up towards the gantry tower. The yellow plume is the rocket exhaust as the shuttle is clearing the tower. The arrow is pointing to some debris on the top of the service mast after the vehicle has launched.
KSC-03PD-0251 (01/16/2003) --- KENNEDY SPACE CENTER, FLA. - At the launch of Space Shuttle Columbia on mission STS-107, long, flexible debris comes out of the liquid helium 2 Tail Service Mast after the door closes. Columbia and crew were lost in a tragic accident over Texas as they made their approach to landing at KSC.
This is a photo of the tail service mast while the orbiter was still on the launch pad.
Certainly Dettemore himself does not deserve your self-serving smart-Z$$ed remarks. Your capacity for empathy is severely crippled.
But the piece of foam wasn't at Mach 2 relative to the Columbia wing. If you think about, it the foam had about 100ft +/- to accelerate from 0 mph relative to the wing to whatever speed it impacted at. That speed was certainly well below the speed of the entire shuttle/tank/solid rocked combination at that point. If I had to hazard a guess I'd say relative impact speed was below 200mph - but it could be determined accurately by time-lapse analysis of the film.
Someone did just that, and estimated it at about 125mph, plus or minus about 30%.
When you calculate the total energy, it sounds like alot, but so is a slap in the face.
I am sure NASA has the data on that by now. They are working round the clock.
The three files run on windows media player, and when you blow it up to full screen, you can see a whole lot more.
mpeg 1 - clearly shows a piece coming off in the area of max turbulence, near the forward attach point, moving up for some feet, then turning in the turbulence, and moving down. (this is the video everybody has been looking at.
mpeg 2 - not so clearly, but enough to see when expanded to full screen, it shows the underside of the wing, and the thing hitting the underside of the wing just about where the front of the wheel well would be.
mpeg 3 - shows the same thing again, slightly differently.
These are great, you can see what is hidden on the first mpeg.
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