The Challenger Disaster

1
The Challenger Disaster

• Risk Management
• Jameson Smieja
• Andrew Tilstra
• Kurt Butz
• William Schaffer
• Fall 2004, University of Minnesota

2
Risk Management

• The art and science of identifying, analyzing,
  and responding to risk

3
The Challenger Mission 51L

• 10th mission for the Challenger Shuttle
• TISP Teachers In Space Program
• Christa McAuliffe
• Politically Charged Launch
• Christa was to appear via television link during
  Reagans State of the Union Address in 1986

4
Challenger Delays

• Liftoff Initially Scheduled for 1543 EST on Jan.
  22, 1986
• Delays in 61-C mission pushed liftoff to Jan. 23,
  then Jan. 24
• Reset to Jan. 25 due to weather
• Postponed another day due to launch processing
  problems
• Rescheduled for 937 EST Jan. 27 due to weather
• Delayed again due to equipment failure for 24
  hours
• Final 2 hour delay due to hardware interface
  module problems

Liftoff 1138 EST January 28, 1986
5
The Challenger Disaster
73 Seconds After Liftoff
6
What Went Wrong??

• Failure of an O-ring seal in the solid-fuel
  rocket on the Space Shuttle Challenger's right
  side
• Flames cut into main liquid fuel tank

7
Four Main Causes of O-Ring Failure

• Pre-flight Leak Tests
• O-Ring Erosions
• Joint Rotation
• Low Temperatures

8
Poor Risk Management

• Risks were managed using Critical Items Lists
• Criticality 1-Loss of Life or Ship
• Criticality 2-Mission Aborted
• CIL Flaws
• Unreliable
• In previous missions, criticality1 issues
  occurred but loss of life/ship did not
• Negotiable
• Identified risks could later be waived

9
Known Potential Problems

• O-rings were Criticality 1 feature
• O-ring seal failure on previous missions
• Launch Constraint placed on subsequent launches
• These constraints had been imposed and regularly
  waived by the SRB Project Manager

10
Known Potential Problems

• Very low ambient temperatures recognized as
  concern by Tiokol
• O-ring performance at this temperature not
  understood
• NASA officials pressured Tiokol to withdraw its
  concerns
• Upper officials at NASA were unaware of these
  discussions and ignorantly approved launch

11
References

• Space Shuttle Challenger 1986
  (http//www.jlhs.nhusd.k12.ca.us/Classes/Social_Sc
  ience/Challenger.html/Challenger.html), (1996)
• Space Shuttle Challenger Disaster-A NASA
  Tragedy (http//space.about.com/cs/challenger/a/c
  hallenger.htm)
• Expert Panel Recommends Improvements for Space
  Shuttle Safety Program, (http//www4.nationalaca
  demies.org/news.nsf/isbn/NI000494?OpenDocument),
  (March 3, 1988)
• An Accident Rooted In History
  (http//spacelink.nasa.gov/NASA.Projects/Human.Exp
  loration.and/Development.of.Space/Human.Space.Flig
  ht/Shuttle/Shuttle.Missions/Flight.025.STS-51-L/An
  .Accident.Rooted.in.History), (June 6, 1986)
• The Challenger Accident (http//www.me.utexas.ed
  u/uer/challenger/chall2.htmlmechflaw), (1997)