Morton Thiokol, Inc
31 July 1985
TO: R. K. Lund
Vice President, Engineering
CC: B. C. Brinton, A. J. McDonald,
L. H. Sayer, J. R. Kapp
FROM: R. M. Boisjoly
Applied Mechanics - Ext. 3525
SUBJECT: SRM O-Ring Erosion/Potential Failure Criticality
This letter is written to insure that management is fully
aware of the seriousness of the current O-ring erosion
problem in the SRM joints from an engineering standpoint.
The mistakenly accepted position on the joint problem
was to fly without fear of failure and to run a series of
design evaluations which would ultimately lead to a solution
or at least a significant reduction of the erosion problem.
This position is now drastically changed as a result of the
SRM 16A nozzle joint erosion which eroded a secondary O-ring
with the primary O-ring never sealing.
If the same scenario should occur in a field joint (and it
could), then it is a jump ball as to the success or failure
of the joint because the secondary O-ring cannot respond to
the clevis opening rate and may not be capable of
pressurization. The result would be a catastrophe of the
highest order - loss of human life.
An unofficial team (a memo defining the team and its
purpose was never published) with leader was formed on
19 July 1985 and was tasked with solving the problem for
both the short and long term. This unofficial team is
essentially nonexistent at this time. In my opinion,
the team must be officially given the responsibility and
the authority to execute the work that needs to be done
on a non-interference basis (full time assignment until
It is my honest and very real fear that if we do not take
immediate action to dedicate a team to solve the problem
with the field joint having the number one priority, then
we stand in jeopardy of losing a flight along with all the
launch pad facilities.
R. M. Boisjoly
J. R. Kapp, Manager