Memo from Roger Boisjoly on O-Ring Erosion

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Morton Thiokol, Inc

Wasatch Division

Interoffice Memo

31 July 1985

2870:FY86:073



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

completed.)



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



Concurred by:

J. R. Kapp, Manager

Applied Mechanics

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Return to "Roger Boisjoly on the Challenger Disaster."