The Challenger Accident Magnus Jansson, Electrical Engineering Fredrik Mannesson, Engineering and Industrial Management Per Martinell, Civil Engineering

The Challenger Accident Mechanical causes Administrative causes Mechanical redesign Changes in administrative procedures Summary Source: JSC Digital Image Collection - STS51L

The Challenger Accident Mechanical causes The tendency for holes to form in the putty which protected the seals from the high temperature exhaust gases The erosion of the O-rings due to contact with the hot gases which penetrated the putty An instantaneous increase in the size of the gap between mating sections of the booster caused by the high internal pressures of the solid rocket booster The inability of the seal to quickly respond to the changing gap size during low temperature operating conditions

The Challenger Accident

Administrative Causes Engineers and managers different views on O-ring erosion Engineers: Alarmed by O-ring erosion in 1984 Renewed concerns when secondary O-ring also eroded Delay Challenger launch until temperature reaches 12 °C

The Challenger Accident Administrative Causes, continued Managers: O-ring erosion acceptable No previous incident due to O-ring erosion No method of quantifying risk Result: Substantial difference in risk awareness

Administrative Causes, continued Strict chain of command: Engineers  Group Manager  Project Manager  … Difficult communicate concerns upward: Problems mitigated or silenced Adhere to chain of command Result: Only one path for information to travel The Challenger Accident

Administrative Causes, continued Challenger delayed several times Desire to keep flight rate

The Challenger Accident Mechanical Redesign Blowhole solution O-ring erosion solution Joint rotation solution Poor resilience solution

The Challenger Accident Changes in Administrative Procedures Shuttle management restructure Hazard analysis review Improved communication Flight rate revision

The Challenger Accident Summary Causes of solid rocket booster joints failure: Blow holes O-ring erosion Increased gap size Lack of O-ring resiliency  Redesign of field joint

The Challenger Accident Summary, continued Flawed communication and administrative policies  Restructure of shuttle management  Review of hazard analysis  Improving communication  Revision of flight rate