[bonesmccoy]

Based upon the volume, size, and color of the plume; one wonders if the plume in the last frame has significant amounts of tile silica and only minimal amounts of insulation or ice. This would give the relatively large amount of white plume for such a small object.

Another freeper noted that the orientation of the insulation/ice object changes the impact force based upon the surface area of the impact. The individual made the observation that if the object had impacted "edge" on, the damage would be greater than if the object impacted flatly on the leading edge.

The white plume seen in this frame may be partly composed of silica particles from pulverized tiles. Given the substantial size of the plume when compared to the relatively small size of the object, one wonders if the plume size is actually the density and size one would expect from an insulation approximately 2 feet in diameter.

Once it is established that ET insulation alone can not create the plume seen (via the colorimetric test), it should be possible to create a second test scenario. A mixture of ice and ET insulation can be created to mimic estimated launch conditions. That mixture should be fired at the test article and the plume colorimetrics studied.

The resulting data could be compared to the photographic evidence and permit the composition of the plume to be evaluated in a scientific manner.

It is my contention that if one compares the plume from a 2' piece of ET insulation to the plume in the photo: 1. The photo has a plume with greater white tones 2. The photo has a plume in greater size than expected. 3. The differences in size of plume and tone are accounted for by silica pulverized by the impact.

Knowing hindsight is always 20/20, I welcome discussion and criticism. This posting is meant to contribute to the scientific process and only suggests one scientific method to approach the accident investigation.

Thanks... God bless and rest the crew of STS-107 and 51-L.

[Starrgaizr]

"the object is tumbling"

the object is accelerating, relative to the Orbiter. The Orbiter is at maximum acceleration UP and the object is rapidly deccelerating as it is not aerodynamic and it is tumbling.

Also, how massive must a piece of ice be to withstand the relative wind as an intact piece of ice rather than be smashed to smithereens by the "slipstream" prior to impacting the wing?

The latter suggests at least some insulation, no? Would ice hold together? If so, it would have to be more than a thin, low-mass sheet.

[ironman]

"NASA yesterday also released its engineers' initial analyses of the damage that might have been done to the shuttle's protective tiles when a piece of foam apparently broke free from its external tank during launch on Jan. 16.

The analyses, which were worked out while the shuttle was in orbit, included one hypothetical worst-case scenario involving a piece of foam 20 by 16 by 6 inches and weighing 2.67 pounds hitting the underside of a shuttle wing. That analysis estimated there could be "tiles missing over an area of about 7 in. by 30 in." It also predicted that even though there might be "localized heating, with some effect on the basic structure in that area, you would not have damage sufficient to cause a catastrophic event" or even affect the vehicle's flight capabilities, Dittemore said. The engineers' conclusion was that the scenario posed "no safety of flight issue."
http://www.washingtonpost.com/wp-dyn/articles/A21208-2003Feb3.html

[dfwgator]

Aren't there satellites that could have taken pictures of the shuttle as it was re-entering Earth in order to get a better idea of really happened?

[Stefan Stackhouse]

I can imagine an alternative design for a smaller "space plane" designed to carry human payloads only. This smaller vehicle would be mated to a "service module" somewhat similar to that of the Apollo, containing engine, fuel tanks, and perhaps O2, H2O, and fuel cell tanks for in-flight supply, all of which would be jettisoned immediately after the re-entry burn. It would include enough fuel on each mission to assure that the spacecraft could make it to the ISS, and perhaps a rendezvous with the ISS should even be a routine feature of all missions, allowing the ISS crew to do a visual inspection of all tile surfaces.

This assembly in turn would sit atop one or a cluster of solid fuel boosters. Such a design would mean that there would be NO external fuel tank, and nothing adjacent to or above the orbiter as it was ascending -- thus nothing that could break off and damage the tiles. Such a design would vastly improve the safety of the tile system and drive down the risks of catastrophic failure to more acceptable levels.

Your thoughts?

[Atlas Sneezed]

"This plume has a white color. Unfortunately, ET insulation is orange/brown in color."

Good analysis, except that I am doubtful about the certainty of the above. Colored things can look white (and I see redness in the picture) when pulverized and illuminated brightly.

[holden]

I'm a flight instructor and have seen ice form on numerous occasions. It gets your attention any time you suspect it's there.

Ice is definitely a fickle thing. You may have come through a lot of visible moisture on a flight with nothing but a light dusting, then, as you come in from the outer marker, whammo--it builds up as if it's trying to convince you there's no tomorrow.

Comment was made herein that someone was surprised that a chuck of ice wouldn't break up in the slipstream, as it was not "aerodynamic." Though I'm surprised how far down the ET ice was forming (or perhaps traveling--channeled down grooves?), one has to note that roughly half the shape of ice would be as a result of a structure that was designed to be at least somewhat aerodynamic, such that, if it presents itself to the relative wind and behaves as something other than an irregular mass in low-velocity turbulence, it should surprise no one.

Fickle as ice seems to be, it forms in areas where moisture is generally visible. That is, when the air temp meets or falls below the dew point. If the visible moisture is ice, it usually will be resistant to sticking (melting sufficiently then refreezing), but not always. So-called supercooled droplets which have some, presumably environmental reason for not crystalizing (impurity, micro-turbulence, ?), may all-too-readily "decide" they have an affinity for some passing by structure (whose surface temperature also tends to be below freezing).

In my limited(thankfully) first-hand experience with such phenomena, those structures which pose the greatest divergent angle to the relative wind are most prone to build-up, apparently because water molecules "linger longer" and can contribute to uncohesive airflow (turbulence). This is to say that ice seems to form most readily on those wetted areas which directly impact the relative wind. Ice formation farther removed from airflow diversion is unusual in my understanding.

Supposing it's ice I saw in the clips under discussion, it seemd to me the ice departed the ET fairly near to the shuttle's nose. That's unexpected! I wonder if the surface air pressure on the ET in such a vicinity is reduced by the aeodynamics of the shuttle itself. Could the shuttle's aerodynamics "help lift" ice from the ET body, through what must be a really high-speed, largely cohesive relative wind. The camera angles I've seen (and what little I could discern) tempt me to conjecture that the "ice" came toward the shuttle at its steepest angle immediately after leaving the ET (though my eyes could have been fooled), then the angle thereof decreased as it neared the shuttle body, only to impact near the port leading edge. To maintain such a divergent angle across a Mach One relative wind bespeaks one astoundingly large mass "launched" in that direction. Did it slide off some structure as if it were a ski jumper? If those suppositions are at least partly true, it could be that the configuration of the two main bodies and aerodynamics in those areas actually increase the possibility of being struck by ice, should ice be present. (note to self: check correlation of increased problems with winter weather.)

WRT channeling of ice along the surface of the ET, I'm led to wonder whether differential surface temps on the ET contribute to an uneven ice buildup or detachment likelihood.

Because of the latitude and proximity to moisture-bearing weather, potentially ice-laden Florida clouds are taller in the atmosphere than they would be elsewhere, as the troposphere goes to its greatest heights nearer the equator. Thus, a shuttle's lingering through such potentially ice-laden environment is greater than elsewhere, and such circumstances may be outside the ken of those trained in higher-latitude environments.

Translation: don't launch that the shuttle in the winter when clouds of any significance lie in its flight path.

HF

[Ichneumon]

The color of the object seems inconsistent with ET insulation.

Is the ET insulation orangish all the way through, or like the shuttle tiles, is it white inside with only a colored outer coating?

[ConservativeLawyer]

Bump for later read.

[demlosers]

BTTT Bump....read

[Political Junkie Too]

Since the space between the fuel tank and the shuttle is constricted, wouldn't this cause the air to rush through it at an accelerated rate? Would that cause any object that fell into that channel to propel at an increased rate than otherwise?

-PJ

[Justa]

Dude, go for broke. Check out the last frame of the sequence. There's a 'flare' of white as the debris approaches the exhaust. That ain't insulation, it's steam!

[freepersup]

I have been asking the question to no one in particular, why NASA keeps mentioning insulation ? Do they have proof it was insulation ?

Many threads and posts ago, I went with ice as the likely object, mainly- because after reviewing the video the spray coming off of the wing appeared to me to be just that, spray.

Not a cloud of dust per se. Not dust, in the sense that the foam disintegrated into dust. This didn't make sense. I had a hard time picturing the foam (flexible) turning into a pulverized state upon impact.

The supposition by the author, does make sense if in fact the spray (my description) is not in fact ice particles but is tile particles (dust). Or more likely, the spray is a combination of pulverized ice particles and the resultant dislodged tile material in the form of dust.

My lay theory: it's ice (unfortunaely 100% relative humidity at launch) striking the fragile tile, pulverizing the ice and tile into an ice spray-dust cloud combination, that we see cascading into the left booster rocket thrust flume.

[_Jim]

I'm taking it to be ice - that hit the leading edge of the wing in the LESS (Leading Edge Structural Subsystem) area and perhaps a tile or so as well ... damage to the LESS can also result in catastrophic failure of the shuttle on reentry due to plasma (hot gases) making their way in to attack the wing spars (constructed of aluminum) ...

[finnman69]

Good call. I started thinking myself that the plume we are seeing might not be the debris of the falling object only, but it could also include pulverized ceramic tile dust. We might be seeing the actual pulverized tiles flying off the orbiter in this video.

[finnman69]

Another super close up of the area where the insulation/ice must have come from.

http://science.ksc.nasa.gov/shuttle/missions/sts-107/images/high/KSC-03PD-0074.jpg

[wcbtinman]

I have another question. If your scenario is true, and I have no reason to doubt that it is, a strike of this magnitude should have caused some differential in telemetry readings re drag, heat, and pressure. The shuttle still had to further accelerate from the speed at which the chunk of material departed the craft, and I would think that at some point prior to orbit there should have been some odd telemetry readings from that side of the spacecraft.

IIRC, the shuttle has to achieve about 17,000 MPH in order to orbit, and that speed through the atmopsphere should have generated at least some abnormal data, such as yaw correction or localized heating after the shuttle was damaged.

[finnman69]

Look at this photo:

http://science.ksc.nasa.gov/shuttle/missions/sts-107/images/high/KSC-03PD-0113.jpg

and look at what appears to be a white object near the top of the external tank on the right side, along the external pipe(?). Could this be ice? You can also see it here:

http://science.ksc.nasa.gov/shuttle/missions/sts-107/images/high/KSC-03PD-0112.jpg

http://science.ksc.nasa.gov/shuttle/missions/sts-107/images/high/KSC-03PD-0131.jpg

http://science.ksc.nasa.gov/shuttle/missions/sts-107/images/high/KSC-03PD-0130.jpg

[M Kehoe]

Bttt.

You never know where a thread will go.

5.56mm

[lepton]

I recall the weight of the insulation of the size suggested was said to be about 2.5 pounds.

[CCWoody]

bonesmccoy seems to have neglected a few things in his analysis.