Just 73 seconds after launch on January 28th, 1986, the Challenger space shuttle broke apart over the coast of Florida and ended the lives of all seven crew members. A subsequent investigation determined that an O-ring failure on one of the shuttle's solid rocket boosters, coupled with extremely cold weather around the time of launch, caused the accident. 6 months prior to the launch, the following memo was sent by Roger Boisjoly — an engineer working at Morton Thiokol, the manufacturers of the solid rocket boosters — to the company's Vice President, in which he predicted the problem and warned of a potential "catastrophe of the highest order."
Boisjoly's warning went unheeded. He later attempted to halt the launch, unsuccessfully.
(Source: National Archives; Image: Roger Boisjoly, via.)
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 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
J. R. Kapp, Manager