The Challenger Accident

1
The Challenger Accident

• Magnus Jansson, Electrical Engineering
• Fredrik Mannesson, Engineering and Industrial
  Management
• Per Martinell, Civil Engineering

2
The Challenger Accident

• Mechanical causes
• Administrative causes
• Mechanical redesign
• Changes in administrative procedures
• Summary

Source JSC Digital Image Collection - STS51L
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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

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The Challenger Accident
5
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

6
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

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The Challenger Accident

• 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

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The Challenger Accident

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

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The Challenger Accident

• Mechanical Redesign
• Blowhole solution
• O-ring erosion solution
• Joint rotation solution
• Poor resilience solution

10
The Challenger Accident

• Changes in Administrative Procedures
• Shuttle management restructure
• Hazard analysis review
• Improved communication
• Flight rate revision

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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

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The Challenger Accident

• Summary, continued
• Flawed communication and administrative policies
• Restructure of shuttle management
• Review of hazard analysis
• Improving communication
• Revision of flight rate