The Best Part #2 of CAIB Report

Crater actually written by Apollo engineers! Once again, the guys with
the horn-rimmed glasses and pocket protectors of the '60s shine while
our generation fizzles. Originally written to predict outcomes of
micrometeoroid strikes, then rewritten for small (1") ice, foam or
orbital debris hits. (see Chap. 6, pg. 24 of the CAIB final Report,
shaded box) When our foam strike numbers were fed in and Crater
PREDICTED A BURN THRU our 21st Century engineers made a "qualitative
extrapolation" that the lighter foam wouldn't cause a burn thru. IMO
they just sat around the office and made this up, rather than deal
with the scary ramifications of the software predicting a burn thru.
In the '60s, the engineers would have immediately notified Flight and
reached for their duct tape and slide rules to fashion a patch for the
hole (at least this is how I imagine it).

(see Chap. 6, pg. 145 of the CAIB final Report): "To determine
potential RCC damage, analysts used a Crater-like algorithm that was
calibrated in 1984 by impact data from ice projectiles. At the time
the algorithm was empirically tested, ice was considered the only
realistic threat to RCC integrity. (See Appendix E.4, RCC Impact
Analysis.) The Debris Assessment Team analysis indicated that impact
angles greater than 15 degrees would result in RCC penetration. A
separate "transport" analysis, which attempts to determine the path
the debris took, identified 15 strike regions and angles of impact.
Twelve transport scenarios predicted an impact in regions of Shuttle
tile. Only one scenario predicted an impact on the RCC leading edge,
at a 21-degree angle. Because the foam that struck Columbia was less
dense than ice, Debris Assessment Team analysts used a qualitative
extrapolation of the test data and engineering judgment to conclude
that a foam impact angle up to 21 degrees would not penetrate the RCC.
Although some engineers were uncomfortable with this extrapolation, no
other analyses were performed to assess RCC damage."

Ellen