Ethical Problem case study of space shuttle Challenger disaster based on Charles B. Fleddermann

1. ETHICAL
PROBLEMS
Case study

2. Origin of Ethical Thought
• Personal ethics are rooted in religious beliefs, cultural norms ,
not true for everyone
• There is a distinction between what is legal and what is ethical
• Many things that are legal could be considered unethical

3. Space Shuttle Challenger
disaster

5. Background
• Space shuttle challenger was designed to be reusable launch vehicle
with an orbiter, two solid-propellent boosters and a single liquid-
propellant booster
Liquid-propellent booster
Solid-propellent booster
Orbiter

6. Early Problems with solid rocket boosters
Problems with field-joint design had been
recognized long before the launch
• Internal pressure causes the booster wall to expand outward,
putting pressure on the field joint illustrasted in Fig.
• It was designed that internal pressure pushed on the putty
displacing primary O-ring into this gap and seal it.
A schematic drawing of a tang and clevis joint like the one
on the Challenger solid rocket boosters
tang

7. During test
• Engineers aware that this joint rotation problem was more severe than
expected
• Design changes made to thicken O-ring
• O-rings were being eroded by hot gases during launch
• Erosion is not necessarily a bad thing as long as O-rings don’t burn
• Design is fine
• Joint Failure during very cold weather found due to loss in resiliency of O-
ring materials is lost at reduced temperature
• Redesigned field joint without O-rings, steel billets to withstand hot gases
but the new design was not ready in time

8. Political Climate
• NASA budget was determined by Congress which was unhappy with delays in
shuttle projects
• They promised frequent flights (several per year)
• They felt some urgency because European Space Agency was developing a
cheaper alternative
• Previous mission had been delayed numerous times by both weather and
mechanical failure
• They got pressure to get Challenger launched on time so that the next shuttle
launch was to carry a probe to examine Halley’s comet which was to launch
before Russian probe design

9. The days before launch
• Temperature was predicted to be low 20’s (˚F) by new launch time
• NASA checked contractors to foresaw any problems
• Alan McDonald, Thiokol Director, was concerned about the cold weather
• Teleconference was arranged
• Two Thiokol engineers gave an hour long presentation on how the cold weather would increase the
problems of joint rotation and sealing of joint by O-rings
• Temperature of previous launch was 53˚F, there was blow by of O-rings
• Launch time temperature was predicted to be 29˚F
• Previous severe O-ring erosion at 53 ˚F and no data, no experience below this temperature

10. Decision
• Bob Lund, V.P of engineering manager, reasoned NASA should delay the launch
at least 53 ˚F !
• Interestingly, original design specified the booster should operate at 31 ˚F
• Larry Mulloy, solid rocket booster project manager at Marshall flight center, and
a NASA employee pointed out that data were inconclusive
• They disagree with Thiokol engineers
• Mulloy asked Kilminster, an engineering manager, for his opinion
• Kilminster backed up the recommendation of his fellow engineers
• Others from Marshall flight center expressed their disagreement
• Boisjoly and other engineers reiterated that the original decision not to launch was the correct one
It could be concluded no trend in data indicating that a launch at the expected temperature would necessarily unsafe
Jerald Mason turned to Lund and said
“ Take off your engineering hat to put on your management hat”
That phrase has become famous in engineering ethics discussions,
• Lund reversed his previous decision
• McDonald attempted to convince NASA to delay the launch, but to no avail.

11. Organizations
NASA The National Aeronautics and Space Administration, responsible for space
exploration.
Marshall Space Flight Center A NASA facility that was in charge of the solid rocket booster development for
the shuttle
Morton Thiokol A private company that won the contract from NASA for building the solid
rocket boosters for the shuttle
People
NASA
Larry Mulloy Solid Rocket Booster Project manager at Marshall
Morton Thiokol
Roger Boisjoly, Arnie Johnson Engineers who worked on the Solid Rocket Booster Development Program
Joe Kilminster Engineering manager on the Solid Rocket Booster Development Program
Alan McDonald Director of the Solid Rocket Booster Project
Bob Lund Vice president for engineering
Jerald Mason General manager
Who’s Who

12. The launch
• there was a significant accumulation of ice on the launchpad from safety
showers and fire hoses
• aft field joint of the right-hand booster was at 28°F
• One of the camera recorded puffs of smoke coming from the aft field
joint immediately after the boosters were ignited
• due to the extremely cold temperature, the O-ring didn’t seat properly
• heat-resistant putty was also so cold that it didn’t protect the O-rings
• hot gases burned past both O-rings
• Very quickly, the field joint was temporarily sealed again by byproducts
of the solid rocket propellant combustion
• the field joint were shattered by the stresses caused by the wind shear
• The joint open again, and hot gases escaped from the solid booster
• Flames quickly burned through the external tank
• The liquid propellent was ignited, shuttle exploded.

13. Discussion

14. THANK YOU
Kaung Myat Hein