Re: NASA probes damage to fuel tank

This is from the news piece you posted, which directly states the caibs
theory, so yes my reply is rellevant. The point of my post is to
demonstrate a possiblity there is another cause for the loss of sts-107
crew and columbia simply because the caib did not validate it's own
theory.

Thursday, March 30, 2006; Posted: 10:19 a.m. EST (15:19 GMT)
CAPE CANAVERAL, Florida (Reuters)
"...A piece of foam insulation that fell off the tank and hit
Columbia's wing
during liftoff was responsible for heat shield damage that led to the
ship's destruction and the loss of seven crewmembers during atmospheric

re-entry on February 1, 2003."

The caib provides only a basic correlation of hole size from it's
vast testing to the actual flight data. But the caib does not provide
consistency with possible hole sizes (4", 6", 10", 17" ) amongst its
testing or, to the flight day 2 object of or a 140sqin, or to the
actual sts-107 flight data, and therefore does not validate it's own
theory.

Caib report vol 1, page 63 paragraph 2:
"After exhaustive radar cross-section analysis and testing, coupled
with bal-listic analysis of the objects orbital decay, only a fragment
of RCC panel would match the UHF radar cross-section and ballistic
coefficients observed by the Space Surveil-lance network. Such an RCC
panel fragment must be ap-proximately 140 square inches or greater in
area to meet the observed radar cross-section characteristics."

Caib report vol v part 13 page 92 par 6
"4.4.2 Damage Progression Theory and Supporting Aero
Based on the damage assessment and timeline period correlations covered
in Section 4.4.1, the
following is a postulated damage progression theory based on the
results of the aerodynamic
investigation. This damage progression, approached from an aerodynamic
perspective, is
consistent with the working scenario and attempts to maintain
consistency with other data from the
investigation. References are made to figures which include a
combination of aerodynamic
extraction results and the major timeline events noted.
An initial WLE breach (small hole or slot) in an RCC panel exists at
entry interface. By EI + 300 sec
thermal events are occurring internal to the WLE cavity, however no
identifiable aerodynamic
increments are observed."

Caib report vol v part 13 page 521 par 7
"A comparison of the times at which these critical events occur
during the entry is shown in Table 6-7. As expected, failure times are
accelerated for the 10 inch case compared with the 6 inch due to the
higher levels of internal heating. Thermal response of instrumentation
within the left wing of STS-107 have suggested the initial breach
through the spar occurred at 491 seconds after entry interface. With a
predicted spar breach time of 470 seconds, the 6 inch provides a better
comparison to flight data than the 10 inch case. As shown in Figure
6-82, better agreement for the 6 inch damage case can also be seen by
comparing the temperature response of V09T9895 (panel 9 spar rear
face*** thermocouple)"


Caib report vol v part 13 page 92 par 6
Holes Through Wing
Limited parametric studies of simulated damage in the form of a wing
breach from the windward surface to the leeward surface were attempted
in this facility and were primarily associated with aerodynamic testing
(see Section 4.3.1). Initially, circular holes dimensionally consistent
with the width of a carrier panel (approximately 4 inches full scale)
were placed at the interfaces for carrier panels 5, 9, 12, and 16. The
holes were found to force boundary layer transition on the windward
surface to the damage site. The model and IR setup for the aerodynamic
tests at this point in time precluded imaging the side fuselage. Since
the model also incorporated damage in the form of missing RCC panel 6,
it is believed that effects (if any) from the carrier panel holes would
have been dominated by the disturbance from the missing RCC panel. TPS
damage in the form of a much larger breach through the wing was
attempted, but the side fuselage heating measurements were considered
qualitative due to compromised phosphor coatings on the models that
were used. The holes were orientated normal to the wing chord and were
located near the left main landing gear door. One hole location was
approximately located at the center of the forward bulkhead
(X=1040-inches in Orbiter coordinates) and the second location was near
the center of the outboard bulkhead (Y=167-inches in Orbiter
coordinates). At each location, the wing hole diameter was
systematically changed from 0.0625 to 0.125 and 0.25-inch at wind
tunnel scale (8.3, 16.7, and 33.3-inchfull scale). While the
compromised phosphor coating considerably degraded the image quality,
it was evident that no change in side surface heating was apparent for
any tested combination of location or diameter."

Surface heating on reentry was indifferent to hole size, not plasma
flow internal to the wing. The caib did not resolve inconsistencies,
nor provide correlation and therefore their theory of foam impact
causing a breach has not be proven or validated.

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