The Best Part #4 of CAIB Report

The 2nd Schomburg email I refer to in #3 is in response to a
discussion started by L. Ham who asked in an email if they could make
the following blanket statement:

"No safety of flight damage" for ANY ET foam loss due to foam density.

This idea, that any foam hit could not possibly be a safety of flight
risk, seems to be drawn from the process of performing a flight
readiness review after STS-112 (also had bi-pod foam fall off). This
explains partly why managers were so unconcerned with the foam strike
and so rock-solid sure that it was a turnaround issue without any good
analysis to prove so.

(see Chap. 6, pg. 154 of the CAIB final Report for the email:
-----Original Message---
From: HAM, LINDA J. (JSC-MA2) (NASA)
Sent: Wednesday, January 22, 2003 9:33 AM
To: AUSTIN, LAMBERT D. (JSC-MS) (NASA); ROE, RALPH R. (JSC-MV) (NASA)
Subject: ET Foam Loss
Can we say that for any ET foam lost, no ‘safety of flight' damage can
occur to the Orbiter because of the density?")

(see Chap. 6, pg. 126 of the CAIB final Report: "During the brief at
STS-113's Flight Readiness Review, the Associate Administrator for
Safety and Mission Assurance scrutinized the Integration Hazard Report
37 conclusion that debris-shedding was an accepted risk, as well as
the External Tank Project's rationale for flight. After conferring,
STS-113 Flight Readiness Review participants ultimately agreed that
foam shedding should be characterized as an "accepted risk" rather
than a "not a safety-of-flight" issue. Space Shuttle Program
management accepted this rationale, and STS-113's Certificate of
Flight Readiness was signed.")

(see Chap. 6, pg. 125 of the CAIB final Report: "Because the bipod
ramp shedding on STS-112 was significant, both in size and in the
damage it caused, and because it occurred only two flights before
STS-107, the Board investigated NASA's rationale to continue flying.
This decision made by the Program Requirements Control Board at the
STS-113 Flight Readiness Review is among those most directly linked to
the STS-107 accident. Had the foam loss during STS-112 been classified
as a more serious threat, managers might have responded differently
when they heard about the foam strike on STS-107. Alternately, in the
face of the increased risk, STS-107 might not have flown at all.
However, at STS-113's Flight Readiness Review, managers formally
accepted a flight rationale that stated it was safe to fly with foam
losses. This decision enabled, and perhaps even encouraged, Mission
Management Team members to use similar reasoning when evaluating
whether the foam strike on STS-107 posed a safety-of-flight issue.")

Ellen